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. approved For.. Release 1999109/10 : CIA-RDP83-00423 R001200450002--7 MOTO C 30042 .and GENERATOR Approved For Release 1999/09/10 : CIA-RDP83-00423R001200450002-7 ALUSCNALMEF MOTOR and GENERATOR 0 Approved For Release 1999/09/10 : CIA-RDP83-00423R001200450002-7 Approved For Release 1999/09/10 : CIAO-RDP83-00423R001200450002-7 ' TBook his Allis-Ch lmers Motor and Generator Reference is r printed from the complete Electrical Reference Bool published by the Electrical Moderni- zation Bureau nd edited by Mr. iE. S. Lincoln. Allis- ,Chalmers sponsored this section of the book and furnished all o the text and illustrations for the part on integral hor iepower motors and generators. This is not int nded to be a text book on the broad field of motors and generators. lEt is rather a brief outline of information that we believe will assist in the selection o motive power to handle most indus- trial applications. For specific information on any of the equipment described in th se pages we suggest that you get in touch with th Allis-Chalmers sales office nearest you. A comple a list is given at the end of the book. The complete Electrical Referencebook of over 1700 pages cover the entire field of industrial electric operations from service entrance equipment to power distribution and tilization. It can be obtained for $18.75 each from The Electrical Modernization Bureau, Inc., 124 Mama- roneck Ave., White Plains, N. Y. Approved For Release 1999/09/10 : CIAO-RDP83-00423R001200450002-7 Approved, For Release 1999/09/10 : CIA-RDP83-00423R00120045Qn nn.'R--77 H-1 'N[ S AND MOTORS AND GENERATORS INTRODUCTION One of the most important functions of electricity is the production of mechanical power for industrial plants through the medium of electric motors. The millions of horsepower provided by electric motors have done much to make our modern standard of living possible. Motors, like all electrical equipment, have been developed to the point where they provide outstand- ing reliability and flexibility if they are properly applied. Basically, a motor is simply a means of producing mechanical power from electricity through change in the direction of a magnetic field. In ac motors, this change is produced by the current itself, while in do motors, the change is produced by a commutator, which acts as a switch to maintain the proper rela- tionship between the magnetism of the armature and field. In other words, both ac and dc motors operate on the principle of magnetic induction, attraction and repulsion, and differ only in the method by which magnetic action is applied. This same principle and distinction also applies to generators. Electricity can be generated commercially only from motion produced by a prime mover. STANDARDIZATION The National Electrical Manufacturers Association, in cooperation with other organizations, such as the AIEE and ASA, has done much toward developing standards for motors and generators. The standards define products, processes and procedures with ref- erence to nomenclature, composition, construction, dimensions, tolerances, safety, performance, quality, rating, testing, and service. GENERATORS CPYRGHT While conformance to the standards is not com- pulsory, most manufacturers generally adhere to them. Hence the difference between products of various manufacturers is in the means by which the applicable standards are met. This is one of the main reasons why manufacturers' descriptive literature emphasizes particular features of construction as the best means of simplifying comparison of different makes. Standardization benefits both the manufacturer and the purchaser. The standards are designed to eliminate misunderstanding between the manufacturer and purchaser and to assist the purchaser in selecting and obtaining the product for his particular need. Selection would be extremely difficult if every manu- facturer proceeded on his own entirely independent way. In addition, the standards help promote pro- duction economies, which benefit both manufacturer and purchaser. MOTORS-GENERAL INFORMATION Today, industry is more dependent than ever on uninterrupted operation of electric motors in successive production steps. At the same time, the motors are subjected to increasingly severe operating conditions. In many modern plants, processing has become an integral part of the production line, and the electrical equipment may have to operate successfully in the presence of corrosive and explosive fumes, conducting and abrasive dusts, steam, vapor, or dripping or splashing liquids. The insulation used on standard motors is suitable for most applications-even where moderate amounts of moisture, weak acids or alkalies, non-conducting abrasive dusts, oil, and so forth are present. But for unusually severe conditions, special insulation or enclosing features, or both, may be needed to give the motor a normal operating life. Fig. H-1. Squirrel-cage induction motor rated 250-hp, Fig. H-2. Centrifugal compressor for brine-cooling 1 17 arefre6b rPw ld1@88a ?9 p0 : CIAr!'KfYPtp3-C3 "Y3' L17~'~J' ~ r~tor motor. H-2 CPYRGHT MOTOApproved For Release 1999/09/10 : Cl -RDP83-00 M b0450002-7 GENERAL HORSEPOWER RA INGS Motor mane ac ure s, under the auspic is of NEMA, have agreed on certain rating standards based on definite operating conditions, such as voltage, fre- quency, speed, ambi nt temperature, etc. Standard horsepower ratings ar4 given under the various motor divisions which follow. Open-type general-~urpose motors are guaranteed to develop their ratedhorsepower continuously with- out a temperature inc ease of more than 40 C above a normal ambient of room temperature of 40 C. Where enclosures are fused, motors generally operate at higher temperatures because of ventilating re- strictions. Such motors have temperature ratings of 50, 55, 70, or 75 C, depending upon the type of en- closure and insulation. Open-type general-purpose motors, when operated at rated voltage (anc frequency in the case of ac motors), will carry Continuously 1.15 times their rated load without injurious temperature rise. This is known as their service factor. (Alternating-current motors smaller than three hp have slightly larger service factors.) There may bq slight differences in efficiency and power factor from those at rated load. For maximum efficiency, a motor that will operate as near full load as possible should be selected. In most cases, the manufacturer of the machine to be driven by the motor cap give the power requirements. If definite informatio is not available, the best method of obtaining he power requirements of a given application is b actual test, using a spare or rented motor. fficiency varies with the load placed on the motor Is usually highest when the motor is fully bade ected by variations of voltage and frequency. Large motors are more efficient than small motors r the same horsepower ratings, high-speed motor e more efficient than low-speed motors becaus gh-speed motors have louver losses since less materia required in their construction. Except for the large es, high-voltage motors (2300 volts and over) ar efficient than low-voltage motors of the sam rigs, due to the greater space .required. for insulatin windings. EED CHARACTERISTICS Except for synchronous motors, speeds of motors ry somewhat with their loads. This variation in ed is termed speed regulation arid is expressed in cent of full-load speed. 'For a normal speed of 1750 a variation of 10 percent below normal would an a loss of 175 rpm, resulting in a running speed 1575 rpm. sect-current motor speeds depend upon the tage of the circuit on which they operate and may increased or decreased by varying the supply tage. Alternating-current motor speeds, however, end upon the frequency of the circuit and cannot increased except by increasing the frequency of circuit. ynchronous speeds for different ac frequencies are en in Table 1. These speeds apply directly to syn- EFFICIENCY The efficiency of a rrtotor is the ratio of its output (or its input minus all; losses that take place in the motor) divided by its input expressed in the same terms. onous motors. Induction motors operate at slightly er speeds due to the slip which is inherent in their de gn. peed limitations recommended by NEMA for me ors using belt, gear and chain drives are given by Table 2. rig. H-3. This centrifugal blower is driven by a Fig. H-4. These 3000 and 2500-hp direct-current 750-hp sA~$ 88gdn A` F~'t 1b.1Mhig99 6i9 0 : Q' DP86e?042()4 }04.5O0Q2irb mill. H-3 Approved For Release 1999/09/10 : CIA-RDP83-00~F3YF~9 00450002a-5TORS GENERAL TABLE I-SYNCHRONOUS SPEEDS-AC GENERATORS AND MOTORS Poles X Rpm Frequency = 120 Number of Poles Revolutions per Minute When Frequency Is (Generator or Motor) 25 Cycles 50 Cycles 60 Cycles 6 0 2 1500 3000 0 3 4 750 1500 1800 6 500 1000 1200 8 375 750 900 10 300 600 720 12 250 500 600 14 214 429 514 16 188 375 450 18 167 333 400 20 150 300 360 22 136 273 327 24 125 250 300 26 115 231 277 28 107 214 257 30 100 200 240 32 94 188 36 83 167 200 40 75 150 180 44 - 136 164 48 - 125 150 52 - 115 138 56 - 107 129 60 - 100 120 66 - 91 109 72 - 83 100 76 - 79 95 80 - 90 84 86 80 90 The pull-up torque of an ac motor is the minimum external torque developed by the motor during the period of acceleration from rest to the speed at which breakdown torque occurs. For motors which do not have a definite breakdown torque, the pull- up torque is the minimum torque developed up to rated speed. The breakdown torque of an ac motor is the maxi- mum torque which it will develop with rated voltage applied at rated frequency, without an abrupt drop to the horsepower times 5250 divided by the full- load speed. The locked-rotor (static) torque of a motor is the minimum torque which it will develop at rest for all angular positions of the rotor, with rated voltage applied at rated frequency. The full-load torque of a motor is the torque necessary to produce its rated horsepower at full- load speed. In pounds at one foot radius it is equal MOTOR TORQUES One of the principal factors in the selection of the proper motor is the torque required by the driven machine from starting to shutdown. Following are the NEMA definitions of the torques that must be considered: TABLE 2-SPEED LIMITATIONS-BELT, AND CHAIN DRIVES This table, based on NEMA definitions, represents good practice (under normal operating conditions) for the use of these drives on motors and generators which are not provided with outboard bearings. Full-Load Rpm of Motor or Generator Maximum Maximum IIp Rating Kw Rating Above Including of Motor of Generator Flat-Belt Drive (1) 15 2400 3600 20 1800 2400 30 20 1200 1800 40 30 900 1200 75 50 750 900 125 75 720 750 150 100 560 720 200 50 1 V-Belt Drive (2) 15 2400 3600 0 20 40 30 1800 240 75 50 1200 1800 75 900 1200 125 750 900 200 100 720 750 250 150 560 720 300 Gear Drive (3) (4) 1500 1800 71/2 l5 1200 1500 15 25 15 900 1200 50 30 750 900 5 50 560 750 7 Chain Drive (5) 2400 3600 20 15 1800 2400 40 30 1200 1800 75 40 900 1200 125 200 125 750 900 50 250 150 720 7 200 560 720 300 See NEMA MG1-3.13 for dimensions of standard pulleys and for limiting dimensions of pulleys. (2) Limiting dimensions of V-belt sheaves for general-purpose motors in frames 505 and smaller are given In NEMA r nsions for v-,,, s eaves d i i (3) (4) ime ng t MGI-3.15. Lim motors in frames larger than 505 have not been standardized; they are specified by the motor manufacturer. These values are based on the use of steel pinions. In general, for quiet operation and freedom from severe vibration, the peripheral speed of cut-steel gearing at the pitch diameter should not exceed 1400 feet per minute. For further information, see American Standard Gear Tolerances and Inspection, Publication No. B6.6-1946, or latest revision thereof. (5) Limiting dimensions of chain-drive sprockets for general- purpose motors in frames 505 and smaller are given in NEMA MG1-3.14. Limiting dimensions of chain-drive sprockets for motors in frames larger than 505 have no been standardized; they are specified by the motor manu- facturer. NOTES: The above limitations are based on the use of pulleys etc., as standardized by NEMA. The limitations will be less tha those given when motors are belted to low-speed drives, sue as countershafts. The above values are not intended to establish a definit dividing line below which the use of outboard bearings is no the motor user what establish the manufacturers considert indicate to but be good practice in general service. The use of outboard bearings is approved and recommende for belted motors in frame sizes of 250 hp, 575 to 600 rpm an larger. t th h in speed. The pull-out torque of a synchronous motor is the motor will -P R dev r th q n i he moor. (IN 6 1200450002-7 a Where an outboard bearing is specified, it is assumed t late and slide rails, if r H-4 CPYRGHT MoTOApproved For Release 1999/09/10 : CI -RDP83-00423 R001200450002-7 .- rated voltage applied at rated frequency and with normal excitation. The pull-in torqu}? of a synchronous motor is the maximum constant! torque under which the motor will pull its connect ;d inertia load into synchronism, at rated voltage and frequency, when its field excitation is appliegl. The speed to which a synchronous motor will bring its load depends on the power required to drive it, and whethjer the motor can pull the load into step from this peed depends on the inertia of the revolving part, so that the pull-in torque cannot be determind without having the Wk2 as well as the torque of the load. The locked-rotor toque of a motor must be well above the torque requir red to start the driven machine from rest. This may be anywhere from 10 to 250 percent of full-load torque, depending upon the type of driven machine. Low voltage and the type of starter employed affect the locked-rotor torque of the motor. The torque delivered by the motor (after breakaway) for acceleration to fu4 speed must also be well in excess of the torque required by the driven machine. The greater this margin, the shorter will be the time equired to accelerate the inertia (Wka) of the rotating arts of the driven m' chine (and the rr..otor rotor) to full speed. In otherjwords, the time required for cceleration is a function of the torque available for his purpose and the ' Vk2. (Note also the effect of oad inertia on pull-in torque of synchronous motors 5 discussed under thIe NEMA definition above.) To prevent the inotoi from stalling, the breakdown r pull-out torque (see NEMA definitions above) ust be greater than the maximum torque required INSULATION AND 1EMPERATURE LIMITS Operating temperatures have a very pronounced cffect on the operating! life of motors because the t mperature, to a largq extent, determincas the life the insulation. The !type of insulation, in turn, determines the maximum temperature allowable for reasonable motor life. NEMA has defined several classes of insulation for c nsideration in connection with temperature limits. he two most commonly Ised on motors and generators are: Class A: (1) Cotten, silk, paper and similar organic materials when either impregnated or immersed in a liquid ! dielectric; (2) molded and laminated materials with cellulose filler, phenolic Class B: Mica, asbestos, fiber glass and similar inorganic materials in. built-up form with organic binding substances. A small portion of Class A material may be used for structural purposes only. The highest observable temperatures permissible r open machines, based on AIEE standards. a.ra easured by- Class A Insulation Class B Insulation sistance............ 100 C +y~ A_,__, ,_. 120C 1. - The limiting observable temperature for totally- .closed machines is 5 C higher than for open machines. It should be noted that while a standard motor can operated at the above temperatures without sacri- ing the life expectancy of the insulation, the rating d other operating characteristics may be based on ne other temperature. For example, open general- rpose ratings, which have Class A insulation, are ed 40 C rise based on a 40 C ambient temperature- it is, a total temperature of 80 C (by thermometer); this case, the additional permissible 10 C permits ervice factor, as discussed earlier under the heading rsepower Ratings. (rdinarily, Class A insulation is standard. Class B ulation, which is more expensive, is used principally permit higher operating temperatures but also >rds some other advantages in high-voltage ma- zes. Some machines lend themselves to a combina- i of the two classes of insulation. In some cases, additional cost of Class B insulation may be nterbalanced by the fact that it may permit the of a smaller frame size for a given rating. Inter- tent operation or adverse ambient conditions may ire specially treated insulation. 1)L ra in a; ins to affc chi: tr I the cou use mit regi ME ME folly are and exec vent whit tota: cools such spec( (or I with as th esins and other resins of similar properties; (3) Ope lms and sheets of dellulose acetate and other A cellulose derivatives ofd similar properties; and (4) whit arnishes (enamel) as lie t pgc Amroved 'fir Re?I6 &X9/09/10: . CHANICAL PROTECTION AND rHOD OF COOLING he mechanical protection. features covered by the wing definitions (NEMA unless otherwise noted) n general available in and applicable to most ac do motors and generators. There are of course ptions. For example, the totally-enclosed non- Hated type is limited to a few horsepower, after h the fan-cooled type takes over. Likewise, a ly-enclosed machine may be enclosed with air ors and use a recirculating ventilating system, but construction is generally confined to large high- 1 machines having a specific rating over 1 hp va) per rpm. The internal construction of motors various degrees of enclosure is basically the same at of open machines. Machines open machine is one having ventilating openings permit the passage of external cooling air over "R8 30?4 3ROO112204 02.7 CPYRGHT Approved For Release 1999/09/10 : CIA-RDP83-00423 R001200450002-7 H-5 MOTORS Fig. H-5. Sectional view of typical drip-proof, general-purpose, squirrel-cage induction motor. Fig. H-6. Typical construction for drip-proof, general-purpose, squirrel-cage induction motors. Fig. H-7. Drip-proof construction of large motors is illustrated by this 300-hp, 695-rpm machine. Fig. H-8. Sectional view of splash-proof 'squirrel- cage motor in general-purpose rating range. Fig. H-9. Splash-proof construction typical of that used in the general-purpose rating range. Fig. H-10. Two-pole cage motors, such as this 2000-hp unit, frequently must be splash-proof. A drip-proof machine is an open machine in which A splash-proof machine is an open machine in which the ventilating openings are so constructed that drops the ventilating openings are so constructed that drops of liquid or solid particles falling on the machine at of liquid or solid particles falling on the machine or any angle not greater than 15 degrees from the vertical coming towards it in a straight line at any angle not cannot enter the machine either directly or by striking greater than 100 degrees from the vertical cannot and running along a horizontal or inwardly inclined enter the machine either directly or by striking and surface. WfrplbOea&Fx r Release 1999/09/10 : Ct R83g0 2&R0(V32GQ45O02. d 12.) H-6 Approved For Release 1999/09/10 : Cl MOTORS GENERAL Fig. H-11. Large, 'splash-proof motor of the pedestal-bearing type. Fig. H-12. Splash-proof construction is also available in vertical motors. RDP83-00423M4$0002-7 Fig H-14. This dc motor Is semi-protected since it ha expanded-metal covers over top half openings. Fi!. H-15. Expanded-metal covers on both top and bo torn openings make this a protected dc motor. Fil. H-16. Drip-proof protected dc motors have solid and expanded-metal covers, as shown above. semi-protected machine is an open machine in w ich part of the ventilating openings in the machine, us ally in the top half, are protected as in the case of a "protected machine" but the others are left open. Fig. H-13. Large otherrsquirrel-cage A protected machine is an open machine in which A rAiW(~o~Qn6tlea ee1999/09/10 : C1 RtDM"~1aRo9f }bP45OO6r2a7d shape. -7 MOTORS GENERAL - ----?--?-- --? - ----- -CRAIGN.T-------- H-7 Such openings shall not exceed 1/2 square inch (323 square millimeters) in area and are of such shape as not to permit the passage of a rod larger than 1/2 inch (12.7 millimeters) in diameter except where the dis- tance of exposed live parts from the guard is more than 4 inches (101.7 millimeters), the openings may be 3/4 square inch (484 square millimeters) in area and must be of such shape as not to permit the passage of a rod larger than 3/4 inch (19 millimeters) in diameter. (Fig. 15.) A drip-proof fully protected machine is a drip-proof machine whose ventilating openings are protected in accordance with the preceding paragraph. (Fig. 16.) Fig. H-18. Tube-type, totally-enclosed, fan-cooled, wound-rotor motors installed outdoors. Note 2: Chicago covers consist of hinged perforated covers for all openings on the collector end of wound- rotor motors or the commutator end of de machines. Fig. H-17. Installation view of open, externally ventilated dc motor with frame-mounted blower. An open externally-ventilated machine is one which is ventilated by means of a separate motor-driven blower mounted on the machine enclosure. Mechanical protection may be as defined in the preceding para- graphs. (Fig. 17.) An open pipe-ventilated machine is an open machine except that openings for the admission of the venti- lating air are so arranged that inlet ducts or pipes can be connected to them. This air may be circulated by means integral with the machine or by means external to and not a part of the machine. In the latter case, this machine is sometimes known as a separately or forced-ventilated machine. Enclosures may be as defined in preceding paragraphs. A weather-protected motor is an open motor (protected in accordance with that definition above) whose ventilating passages are so designed as to minimize the entrance of rain, snow and air-borne particles to the electrical parts. Note 1: ASA C-42 definition is: An open machine is a self-ventilated machine having no restriction to ventilation other than that necessitated by me- chanical construction. Thus, in the sense of this definition an open machine, when the term is used without qualification, is understood not to include Totally-Enclosed Machines A totally-enclosed machine is one so enclosed as to prevent exchange of air between the inside and the outside of the case but not sufficiently enclosed to be termed air-tight. A totally-enclosed non-ventilated machine is a totally- enclosed machine which is not equipped for cooling by means external to the enclosing parts. (Fig. 20.) A totally-enclosed fan-cooled machine is a totally- enclosed machine equipped for exterior cooling by means of a fan or fans integral with the machine but Fig. H-19. Outdoor installation of vertical, tube- the lisA}Dp>> deForaReIease 1999/09/10: CIA-RDPOmID&49MO(I T l$SoW2p'Ptors. H-8 Approved or Release 1999/09/10 : Cl MOTORS GENERAL external to the enclosing parts. (Figs. 18, 19 and 30 show fan-cooled motor's in service. See also Figs. 21, 22 and 2s.) An explosion-proof; machine is a totally-enclosed machine whose enclo 'ure is designed and constructed to withstand an explosion of a specified gas or vapor which may occur within it and to prevent the ignition of the specified gas orb vapor surrounding the machine by sparks, flashes or explosions of the specified gas or vapor which may occur within the machine casing. (Figs. 24, 25 and 31 show typical explosion-proof motors.) Note: See page 10 for classification of hazards. Fig. H-20. Totally-enclosed non-ventilated design is limited to small motors-usually 2-hp or less. Fig. H-21. Totally-enclosed fan-cooled construction used for general-purpose ratings is shown above. RDP83-00423 R001200450002-7 Fig. H-23. Sectional view through typical general- purpose, totally-enclosed, fan-cooled cage motor. Fij. H-24. Explosion-proof construction is modifica- tion of totally-enclosed fan-cooled design. Fi~. H-25. Tube-type cooling makes large totally- enclosed explosion-piroof motors practical. dust-explosion-proof machine is a totally-enclosed machine whose enclosure is designed and constructed so as not to cause the ignition or explosion of an am- bient atmosphere of the specific dust, and also not to case the ignition of the dust on or around the machine. Vote 1: Successful operation of this type of machine equires avoidance of overheating from such causes excessive overloads stalling or accumulation of , , Fig. H-22. Large TEFC motors need special cooling xcessive quantities of dust on the machine. designs, such as the tube-type air-to-air heat exchanger Ap veidn "dR l as&4999/09110 : CI DP83*Q422&OdiA2Q,45OMJrds. CPYRGHT Approved For Release 1999/09/10 : CIA-RDP83-00423 R001200450002-7 u r, A water-proof machine is a totally-enclosed machine so constructed that it will exclude water applied in the form of a stream from a hose, except that leakage may occur around the shaft, provided it is prevented from entering the oil reservoir and provision is made for automatically draining the machine. The means for automatic draining may be a check valve or a tapped hole at the lowest part of the frame which will serve for application of a drain pipe. Note: A common form of test for a water-proof machine is to play on the machine a stream of water from a hose with a one-inch nozzle delivering at least 65 gpm from a distance of about 10 feet, from any direction, and for a period of not less than 5 minutes. A totally-enclosed pipe-ventilated machine is a totally- enclosed machine except for openings so arranged that inlet and outlet ducts or pipes may be connected to them for admission and discharge of the ventilating air. This air may be circulated by means integral with the machine or by means external to and not a part of the machine. In the latter case, these machines shall be known as separately or forced-ventilated machines. (Fig. 26.) Note: ASA definition of an enclosed, separately ventilated machine is a machine having openings for the admission and discharge of the ventilating air, which is circulated by means external to and not part of the machine, the machine being other- wise totally enclosed. These openings are so ar- ranged that inlet and outlet duct pipes may be connected to them. SERVICE CONDITIONS General-purpose 40 C motors are designed to give successful operation at rated load under the following MOTORS GENERAL Fig.'. H-27. Base ventilated motor with air intakes and discharge at the bottom of the stator yoke. Fig. H-28. Completely assembled cage motor using recirculating ventilating system with air cooler. service conditions defined by NEMA as usual: 1. An ambient temperature not exceeding 40 C. 2. A variation in voltage of not more than 10 percent above or below the nameplate rating. 3. A variation in frequency of not more than 5 percent above or below the nameplate rating. 4. A combined variation of voltage and frequency of not more than 10 er t b c p en a ove or below Fig. H-26. Pipe-ventilated motor with top air the nameplate ratin rii f e r uency intakeAp I &de R LdbgEOq98?/09/10: CIA-lad ' 4$e 3F~y e i~'do. LL C-PYRGHT H-10 Approved For Release 1999/09/10 : CI -RDP83-00423R001200450002-7 MOTORS ii6MERA L Fig. H-29. Splash-proof 75-hp cage motors were selected for chemicpl processing plant drive. 5. An altitude notj exceeding 3300 feet (1000 vent agents harmful to the insulation or to meters). Location or atmospheric conditions as to dust, current-collecting parts, the use of enclosed moisture or furies which will not seriously or separately ventilated motors may be necessary. interfere with the ventilation of the motor. Exposure to conducting or abrasive dusts, such Solid mounting and all belt and chain drives as coal, coke, carbon, graphite, iron, etc. Even and gearing in accordance with adopted in small amounts these may be extremely standards. harmful to insulation, and the use of enclosed In general, since the service conditions to which such motors is preferable.: Open motors with special motors are subjected are uncontrolled and not subject insulation may suffice for lower voltages. A combination of conductive or abrasive dusts to exact determination) I i the basis of rating chosen, in standards, provides a factor accordance with NEM plus sulphur fumes and moisture is often en- mperature rise at 100 percent of safety of 10 C in t countered in power plant boiler rooms around d coal-pulverising equipment. loading. Specific service con itions defined by NEMA as ash-handling and Exposure to hazardous atmospheres containing service conditions more favorable than usual are: flammable or explosive gases or combustible or 1. Operation at rated voltage and frequency. explosive dusts requires totally-enclosed explo- 2. Individual application to a machine where the sion-proof motors. loads and duty cycle are accurately known and The National Electrical Code designates haz- cannot be exceeded. ardous gas locations as Class I and hazardous dust-and-air locations as Class II. Class I is Unusual Service Conditions divided into Groups A, B, C, and D, Group A Where apparatus into be subject to any one or a being the most hazardous and Group D being combination of the following conditions, the manu- the least hazardous. Similarly, Class II is facturer should be consulted to make sure that the divided into Groups E, F, and G, Group E being proper motor is selected : the most hazardous and Group G being the 1. Exposure to st4am or excessive moisture from least hazardous. Motors for Class I Groups A other causes, such as vapor or excessive splashing and B are generallx not available. and dripping, as may be encountered in parts 6. Exposure to lint, such as encountered by tex- tile mill motors, may quickly clog ventilating of dye houseq . , bleacheries, packing plants, paper mills, metal mines, etc. These conditions of open motors and make totally- may require special insulation, low-voltage passages enclosed motors desirable for looms, and special designs, and/or enclosed motors. self-cleaning motors for spinning frames, etc. 2. Exposure to tl e corrosive action of salt-laden Exposure to abnormal shock or vibration may necessary. air usually requires special consideration of 7. 1 insulation and the use of non-corroding nuts, make special structural materials Exposure to ambient temperatures above 40 C bolts and currnt-collecting parts. S (104 F). Where the windings will be subjected fi v es or 1` o nts TAW, r9 1 CI -RD -Q04 04x11 * tempera- H-30. Dust in lime plant dictated selection of this 71/2-hp, totally-enclosed fan-cooled motor. ical, fertilizer and similar plants. Where the ambient atmosphere contains corrosive or sol- fwb~ Approved For Release 1999/09/10 : CIA-RDP83-00422386 d(T450002-MOTOWlt RS GENERAL Fig. H-31. Explosion-proof, totally-enclosed fan- cooled motors were needed for oil pipe-line station. ture plus operating temperature. rise) above 90 C for open motors, or 95 C for enclosed motors, Class B insulation is required. Maximums for Class B are 110 and 115 C respectively. Outdoor operation requires a degree of enclosure dependent on the climate involved. Usually totally-enclosed types are preferable. Splash- proof construction should be limited to the milder climates and lower voltages. Low ambient temperatures require special consideration of the bearing lubrication. In general, outdoor in- stallations are not recommended under condi- tions of extreme cold and heavy snows. Operation in poorly ventilated rooms or pits is undesirable. If such locations are unavoidable, means should be provided for separate forced ventilation to insure an ample volume of cooling air. TABLE 3-COMPARISON OF DC AND AC MOTORS Speed adjustment Direct Current Alternating Current Limited to 230 Any standard volt- volts on ordinary age available with circuits. use of transformers. Good. Unsatisfactory and heavy current- except wound- rotor motors. Efficiency High. Intermittent Good. starting service Starting Generally low. High for cage type. currents Maintenance Higher because of Low. commutator. Constant speed Semi-constant speed Speed adjustable but remaining constant Shunt motor with In combination with field control. magnetic coup- lings. Fig. H-32. Special textile motors are available for applications like these cotton spinning frames. SELECTING A MOTOR There are many factors to be considered in selecting the right type of electric motor for a specific drive. First, the requirements of the machine to be driven must be considered. This involves not only establishing the motor size (which may be a problem in itself) but also consideration of other characteristics of the load which have a direct bearing on the type of motor to be selected. What is the required operating speed? Should it be constant, adjustable or variable? What are the torque requirements? These and many other factors must be considered if an intelligent selection is to be made. Second, there are questions of power supply. What current is available-direct or alternating? Should plant power factor be improved? Are there power company current limitations? Third, ambient conditions must be considered. Will the motor need special protective enclosures? Special insulation? Separate ventilating equipment? Fourth, the available forms of motors must be weighed in relation to the characteristics desired, and the economics of initial and future costs must be investigated. Take a compressor for example. If initial cost is the main consideration and plant power factor can be ignored, a squirrel-cage induction motor is the obvious choice for small and medium sized compressors. For heavy-duty compressors requiring large motors, the smooth acceleration and low starting current of wound- rotor motors justifies their use. But if there are already numerous induction motors in the plant, the best choice may be a synchronous motor to provide cor- rective kva for plant power factor improvement. Tables 3 and 4 are provided as a general guide for use in selecting motors. Whenever there is any question about an application, the motor manufacturer should be furnished with as complete information as possible. Failure to do so might result in misapplication. Table 5 Speed varying Series motor. Wound-rotor motor formation with Approved For Re lease 19991*09 91: C lP 8 !O At2 ? O 4V66b? -' H-12 CPYRGHT MOTORSApproved For Release 1999/09/10 : CIAO-RDP83-00423R001200450002-7 . GENERAL Fig. H-33. Sectional view through ring-ailed sleeve bearing used on large end-shield bearing motor. APPLICATION Agitator Baler (power) Ball mill Blower (positive pressure): Boring mill Buffer Cement kiln Compressor Conveyor Crane Crusher Dough mixer Drilling machine Drying tumbler Elevator Fan (centrifugal Finishing stand Grinder and propeller) Hammer (power) Hammer mill Hoist Jordan Keyseater Lathe Laundry extractor Laundry washer Line shaft Metal grinder Metal saw Milling machine Mill table Mine hoist Molder Ore grinder TABLE 4-MOTOR MOTOR ;SYMBOL Alternating Direct Current Current lA-1B-2B 6A 1D 6B-7 1C-2B-3A 611 lA-1B-2B-3A-4 6A 2A-3A 6A-8 IA-1B-2A 6A 3A 8 IA-1B-1C-3A-.4 6B-8 IA-IC-2B-3A 6B-8 1D-2A-3B 7 1A-1C-1D 6A-6B IA-1B-1C-2B 6A-6B IA-1B-2A 6A-8 IA-lB-1.D 6A 1D-1E-2B-3B 611-8 lA-1B-2C-3A.4 6A-8 3B 8 IA-1B-2A 6A 1D 6B 1C 6A 1D-2A-3B 7 IA-1B-4 6A IA-1B 6A IA-1B-2A 6A-8 1C-1D 6B IA-1B-1D 6A lA-lB 6A IA-1B 6A IA-1B 6A IA-1B-2A 6A-8 3A 8 3B 8 IA-1B 6A Pipe threader IA-1B Planer IA-1B 6A Polisher 1A-1B-2A 6A Printing press (job) IA-1B-3A 6B-8 Printing press (rotary and offset) 3A 611-8 Pulverizer 1C 611 Pump (centrifugal) 1A-1B-211-3A-4 6B Pump ppred For 6 as 19"/09/10 Fii. H-34. Partially dismantled capsule-type sleeve earing of same type as that shown in Fig. H-33. MOTOR SYMBOL Roo PPLICATION k crusher Alternating Current 3A Direct Current 6B-7 Sat der IA-1B 6B Sat d mixer (centrifugal) 1C 6A Sa (circular) 1A-1B 6A Saw (band) IA-1B-.1C-3A 6A-6B Ser w machine IA-1B 6A She per IA-1B 6A Spi m nning and weaving achinery IA-1B 6A Sto er IA-1B-1C-2B 6A-8 Tu bling barrel 1C 6A Wit ch 1D-3A 6B-8 EXPLANATION OF SYMBOLS 1. uirrel-Cage, Constant-Speed Normal torque, normal starting current I. Normal torque, low starting current . High torque, low starting current D. High torque, high slip Elevator 2. S uirrel-Cage, Multi-Speed . Constant horsepower Constant torque Variable torque Note: Classes "A," "B" and "C" listed under "1" are a so applicable to multi-speed motors. The listing ("A," " "or "C") for the constant-speed motor indicates the firm of motor to use under "2." For example: If the Ii ting shows 1C-2B, then the multi-speed, constant torque motor should also be high torque, low starting current. 3. 'Wound-Rotor A General-purpose B Crane and hoist 4. Synchronous 6. D rect-Current, Constant-Speed A-Shunt-wound - B Compound-wound 7. D rect-Current, Variable-Speed, Series-Wound N te: Series motors must be connected directly to the to d (not belted). X0660*1?0450002-7 H.13 Approved For Release 1999/09/10 : CIA-RDP8t-ng01200450002-WOTORS Fig. H-35. Various types of ball bearings are used on motors. Above unit is a double-shielded type. required for various types of motors. To this the purchaser should, of course, add any other desired characteristics and features and indications of any unusual operating conditions. MOTOR BEARINGS Bearing design, including provision for lubrication and protection, forms one of the most vital features of motor construction. Bearings are one of the few wearing parts in electric motors; in cage motors they are, in fact, the only element that can be considered as a wearing part. NEW, In properly designed sleeve bearings, the shaft rotates on a film of oil, which prevents actual contact between the shaft and the bearing during operation. With clean oil, free from abrasive materials, sleeve bearings should provide long years of service, and they are very quiet in operation. They do, however, normally require more attention than the anti-friction type. Figs. 33 and 34 show typical sleeve bearing mountings. The use of anti-friction bearings is usually confined to ratings in the general-purpose classification (200 hp and less). The type most commonly used is the ball bA roved For Release 1999/09/10 : Cl fl 3nGO423R0O12O0450002-7'.""'"' grease-lubricated ball bearing, Figs. 35 and 36, which requires little attention except for checking grease about once a year. Most ball-bearing troubles in the smaller machines are, in fact, due to overgreasing. Experience indicates that for ratings of 250 hp and larger, particularly for speeds above 1000 rpm, anti- friction bearings are not as reliable as oil-lubricated sleeve bearings. For lower speeds, anti-friction bearings are usually satisfactory in ratings up to 1 hp per rpm. The balls, or rollers, undergo cyclical compression and release with every revolution, so that high speeds and high loading cause fatigue and ultimate failure. Exceptional cases may permit the use of oil-lubricated Fig. H-36. Cutaway view showing shielded ball bearing installed in a general-purpose cage motor. TABLE 5-INFORMATION REQUIRED FOR SELECTING MOTORS GENERAL Type of motor (cage, wound-rotor, synchronous, or de) ........ Quantity ........ lip ........ Rpm ........ Phase ........ Cycles ........ Voltage ........ Time rating (continuous, short-time, intermittent) ............ Overload (if any)...... % for ........ Service factor........ % Ambient temperature........ C Temperature rise.......... C Class of insulation: Armature.. Field.. Rotor of w-r motor... Horizontal or vertical .......... Plugging duty............ Full- or reduced-voltage or part-winding starting (ac) ........ If reduced voltage-by autotransformer or reactor......... . Locked-rotor starting current limitations ................... Special characteristics ..................................... INDUCTION MOTORS Locked-rotor torque.......... % Breakdown torque........ % or for general-purpose cage motor: NEMA Design (A, B, C, D) .................................... SYNCHRONOUS MOTORS Power factor.... Torques: Locked-rotor.... % Pull-in.... % Pull-out.... % Excitation...... volts dc. Typo of exciter..... . If m-g exciter set, what are motor characteristics?.......... Motor field rheostat........ Motor field discharge resistor.... . DIRECT-CURRENT MOTORS Shunt, stabilized shunt, compound, or series wound.......... Speed range ........ Non-reversing or reversing .............. Continuous or tapered-rated ............................... MECHANICAL FEATURES Protection or enclosure............ Stator shift............ Number of bearings .......... Type of bearings............ Shaft extension: Flanged ...... Standard or special length ..... Press on half-coupling ........ Terminal box ................ NEMA C or D flange... ' * . . Round-frame or with feet . ..... . Vertical: External thrust load.... lbs. Type of thrust bearing... . Base ring type ............ Sole plates .................. Accessories .............................................. Load Data Type of load .............................................. If compressor drive, give NEMA application number .......... Direct-connected, geared, chain, V-belt, or flat-belt drive ....... Wk2 (inertia) for high inertia drives Starting with full load, or unloaded ........................ If unloaded, by what means? ............................ For variable-speed or multi-speed drives, is load variable torque, H-14 INDUCT roved For Release 1999/09/10 : CI -RDP83-00423R0012004506YGHT AAMnic INDUCTION MOTORS Applicable to a broad range of applications, induction motors are the most; widely used because of their simple construction. As is true of practically every type of polyphase motor, the operation of an induction motor depends on the production of a revolving mag- netic field in the stator: the rotor of the machine being pulled around by the ;revolving magnetic field. This revolving field is produced by increasing and decreasing currents in the stator winding. In a two- phase motor, the magnetic field, at a given instant, is produced entirely by the first phase winding. As the instantaneous current decreases in the first phase and increases in the second; a slight shift of the magnetic field takes place. This shift continues to the point where the second phase is producing the entire mag- netic field. In a three-phase motor, the third-phase winding has a maximum field which is still further shifted around the stator. The windings are so distributed as to allow uniform continuous shifting or rotation of the magnetic field around the stator; Beyond this, induction motors operate on the prin- ciple of magnetic indiction; that is, the magnetic field in the rotor is induced by the current flow in the stator. The rotor maybe (1) the squirrel-cage type, or (2) the wound-roto? type with the ends of the winding brought out through collector rings to an external circuit. SQUIRREL-CAGE POLYPHASE INDUCTION MOTORS Squirrel-cage motors, Figs. 5 to 10, the most common- ly used type of polyphase induction motor, derive their name from the similarity of their rotor windings to squirrel cages. Since thee motors operate by induction, the stator is sometimes' called the primary because it receives power from th~ line, and the rotor, the sec- ondary because its curr~nts result from the action of the primary currents. Fig. H-37. Wound stator for small general-purpose, defi A'fE~IifUfp@~'It? 1999/09/10 :, . H-38. Stator yoke and core for large cage motor readyiFor winding. he operation of a cage motor can best be explained by starting with the motor at rest. When current is supplied to the stator (primary) winding, a revolving magnetic field is set up as described above. This re olving field cuts the rotor conductors (cage bars) an thereby induces voltages in the bars. s a result of the induced voltages, current flows in th cage winding. The current loops through the bars an short-circuiting end rings are distributed in such a manner as to create a magnetic field similar to that of he stator. Interaction of these two magnetic fields res Its in a force that tends to pull the rotor along wi 1 the revolving field of the stator. The motor the efore starts and gains speed. he rotor cannot, however, rotate as rapidly as the rev lving field of the stator. If it did, the cage bars, instead of being cut by the revolving field, would bee me magnetically stationary with respect to the revolving field. In that case, no voltage would be induced in the rotor, and there would be no attraction between the rotor and the rotating field in the stator. 1: 1 other words, the rotor constantly slips back and an induction motor cannot operate at synchronous speed. Obviously increasing the load will increase the slip, an the motor will run slower. However, at full load, the slip is small, and motors of this type are usually considered to be of constant speed. Cage Motor Construction Features e basic simplicity of cage motors is favorable to ope ational reliability, but, careful engineering and quality construction are nevertheless essential to reliability and minimum maintenance. Te stator construction (Figs. 37, 38, 39) is the same for age, wound-rotor and synchronous motors. It com- pris s a supporting yoke, a slotted laminated sheet- Stec core, and insulated coils connected to provide ite polar areas providing the revolving magnetic -RDP83-00423R001200450002-7 CPYRGHT H-15 Approved For Release 1999/09/10 : CIA-RDP83-00423 R0012004500gAb~CT1ON MOTORS 6011, Fig. H-39. Wound stator for large, end-shield bearing, squirrel-cage induction motor. A cage motor rotor (Figs. 40, 41, 42) consists of a shaft, core, and cage winding. The core is built up of slotted laminated-steel punchings mounted directly on the shaft or supported by a spider mounted on the shaft (Fig. 43). The winding consists of bars short-circuited by end rings. In smaller motors, the winding is fre- quently cast in one operation, and aluminum is often used for this purpose. In larger motors, heavy copper bars or rods are used, and these are brazed or otherwise fastened to the end rings. Due to the very low voltage in the bars, insulation is not necessary between the bars and the rotor core. End-shield or bracket bearing construction is used for most cage motors. Pedestal bearing construction is, however, commonly used for ratings above one hp per rpm. Ball bearings are generally confined to general-purpose sizes; sleeve bearings are available for both general-purpose and large motors. Fig. H-40. Squirrel-cage rotor construction typical of ratings beyond general-purpose sizes. Shaft rigidity and bearing quality are especially important in these motors because, to obtain good efficiency and power factor, the air gap between rotor and stator must be small. It should be noted, however, that too small an air gap can be detrimental to con- struction, to sound level, and, by producing parasitic torques, to efficiency. Cage Motor Characteristics Polyphase squirrel-cage induction motors are the most reliable and, with the exception of large syn- chronous motors, the most efficient motors available. This presupposes that the motor selected for any definite load is of such size that it can be operated at nearly full load because the power factor and efficiency Fig. H-43. Rotor spider and core assemblies for Fig. /If3~rO~e R l' R~N~+HS ih99941?9~PO : C IA-RDP T)VOTI9O1MV4*3JN!2!T H-16 AVroved For Release 1999/09/10: Cl -RDP83-00423gpQ1gp450002-7 INDUCTI MOTORS also important to remember that high-speed motors have higher power factors than lower speed machines. Under normal load And voltage conditions, squirrel- cage motor speeds are practically constant and, like those of synchronous-motors, are dependent on the number of poles and the frequency of the power supply. But, as previously notod, the cage motor slows down sufficiently to produce 'the necessary torque when load is applied. This slip is 4xpressed as a percentage of the synchronous speed. For example, if a motor with a synchronous speed of ;1200 rpm is loaded until the speed drops to 1164 rpm, the slip is: 1200 - 1164 36 = 3% 1200 1: 1200 A definite relationship exists between the slip and the efficiency of the motor; that is, the higher the slip, the lower the efficiency, for slip is a measure of the losses in the rotor winding. In the above example, about 3 percent of the total power input would be lost in the rotor winding. However, relatively high slip motors may be necessary if high starting (locked- rotor) torque is required by the application. To provide the best gtarting torque consistent with high power factor and efficiency, cage motors must be of well-balanced design}. Within limits, the amount of starting torque developed will depend on the re- sistance of the rotor winding. Increasing the rotor resistance will increase; the starting torque-with a corresponding increase in slip and decrease in efficiency. NEMA Design Classifications To simplify the selection of motors by providing some uniformity of design, NEMA has divided poly- phase squirrel-cage motors into classes based on electrical characteristics!. While these classifications TABLE 7-BREAKDOWN TORQUE T e break-down torque of Design B and C cage motors, wit rated voltage and frequency applied, shall be in accordance wit th following values which are: expressed in percent of full-loa to que and which represent the upper limit of the range o ap lication for these motors. Synchronous Speed in Rpm Hp (60 and 50 Cycles) 1/2 900-750 ]Design B 250 Design C ... Lower than 750 200 ... 3/4 1200-1000 275 ... 900-750 250 ... Lower than'750 200 ... 1 1800-1500 300 ,.. 1200-1000 275 ... 900-750 250 ... Lower than: 750 200 ... 1-1/2 3600-3000 275 ... 1800-1500 300 1200-1000 275 ... 900-750 250 ... Lower than 750 200 ... 2 3600-3000 250 ... 1800-1500 275 ... 1200-1000 250 ... 900-750 225 ... Lower than 750 200 ... 3 3600-3000 250 1800-1500 275 1200-1000 250 225 900-750 225 200 Lower than 750 200 ... 3600-3000 225 1800-1500 225 200 1200-1000 225 200 900-750 225 200 Lower than 750 200 ... 1-1/2 3600-3000 215 1800-1500 215 190 1200-1000 215 190 900-750 ::15 190 Lower than 7:50 200 0 3600-3000 200 1800-1500 200 190 1200-1000 200 190 900-750 200 190 Lower than 750 200 5-25 All Speeds 200 190 30 a d Larger All Speeds 200 190 D sign A values are in excess Of those for Design B. D sign D motors have no sharply defined breakdown torque TABLE 6-LOCKED-ROTOR TORQUE The locked-rotor torque of Design A, B and C motors, with rated voltage and frequency applied, shall be in accordance with?the following values, which are expressed in percentage of full-load torque and represent the upper limit of the range of application. - 60 Cy 3600 1800 1200 -DE900 N A and B Hp 50 Cy 3000 1500 1000 750 600 Poles 2 ! 4 6 8 10 1/2 ... ... 150 150 3/4 175 150 150 1 275 175 150 150 1-1/2 175 265 175 150 150 2 175; 250 175 150 145 3 175; 250 175 150 135 5 150; 185 160 130 130 7-1/2 150 175 150 125 120 10 150: 175 150 125 120 15 150; 165 140 125 120 20 150; 150 135 125 120 25 150; 150 135 125 120 30 150; 150 135 125 120 40 1351 150 135 125 120 50 125 150 135 125 120 60 125; 150 135 125 120 75 1101 150 135 125 120 100 1101 125 :125 125 120 125 100' 110 :125 125 120 150 100' 110 125 125 120 200 100 100 ]125 2 20 The locke -DESIGN C 600 514 450 1800 1200 900 500 428 375 1500 1000 750 12 14 16 4 6 8 115 110 105 ... ... ... 115 110 105 ... ... .. 115 110 105 ... ... .. 115 110 105 ... ... ... 115 110 105 ... ... ... 115 110 105 250 225 115 110 105 250 250 225 115 110 105 250 225 200 115 110 105 250 225 200 115 110 105 225 200 200 115 110 105 200 200 200 115 110 105 200 200 200 115 110 105 200 200 200 115 110 105 200 200 200 115 110 105 200 200 200 115 110 105 200 200 200 115 110 105 200 200 200 115 110 105 200 200 200 115 110 105 200 200 200 115 110 105. 200 200 200 1 0 00 knP8 Approved For Release 1999/09/10 : CIA-RDP83-00423F&110002-7 H-17 INDUCTION MOTORS TABLE 8-LOCKED-ROTOR CURRENT Locked-rotor current measured with rated voltage and fre- quency, shall not excee 1 the following values for 220-volt Design B (and C and D 60 cycle) cage motors. Hp 60 Cy 50 Cy 1/2 12 14 3/4 18 21 1 24 28 1-1/2 35 40 2 45 50 3 60 70 5 90 105 7-1/2 120 140 10 150 175 15 220 255 20 290 335 25 365 420 30 435 500 40 580 670 50 725 835 60 870 1000 75 1085 1250 100 1450 1670 125 1815 2090 150 2170 2495 200 2900 3335 Locked-rotor current at other voltages is inversely propor- tional to the voltage. TABLE 9A-STANDARD HORSEPOWER RATINGS -INDUCTION MOTORS GENERAL-PURPOSE MOTORS: 1/2, 3/4, 1, 1-1/2, 2, 3, 5, 7-1/2, 10, 15, 20, 25, 30, 40, 50, 60, 75, 100, 125, 150, 200. LARGE MOTORS: 250, 300, 350, 400, 450, 500, 600, 700, 800, 900, 1000, 1250, 1500, 1750, 2000, 2250, 2500, 3000, 3500, 4000, 4500, 5000, 5500, 6000, 7000, 8000, 9000, 10,000, 11,000, 12,000, 13,000, 14,000, 15,000, 16,000, 17,000, 18,000, 19,000, 20,000, 22,500, 25,000, 30,000. TABLE 9B-STANDARD VOLTAGES-INDUCTION MOTORS Voltage Approximate Hp Range 110 1/2 - 20 208, 220 1/2 - 200 440, 550 1/2 - 1000 2 300 40 4000 100 -1 ro e~ 4600 250 01.9 q 6600 250 13200 1000 TABLE 9C-STANDARD SPEEDS-INDUCTION MOTORS Speed in Rpm (60 Cycles) Number of Poles Approximate Hp Range 3600 2 1-1/2 - 5000 1800 4 1 - 5000 1200 6 3/4 - 5000 900 8 1/2 - 10000 720 10 1/2 - 10000 600 12 1/2 - 10000 514 14 3 - 22500 450 16 3 - 400 18 50 - 360 20 50 - 327 22 50 - 300 24 50 - v" 277 26 75 - 257 28 100 - a.q 240 30 125 - 225 32 150 - 200 36 200 - specify locked-rotor (starting) torque, breakdown torque, locked-rotor (starting) current, and slip, variations in practically all types can be obtained by changes in the design of the rotor slots and resistance of the rotor windings. Except for coil design, stator construction remains the same for all types. It is, however, advantageous to specify motors meeting the NEMA standards, which are as follows: A Design A motor is a squirrel-cage motor de- signed to withstand full-voltage starting and de- veloping locked-rotor torque as shown in Table 6, breakdown torque as shown in Table 7, with locked- rotor current higher than the values shown in Table 8 and having a slip at rated load of less than 5 percent*. (See Fig. 44.) Standard horsepower ratings, voltages and speeds of induction motors are given in Tables 9A, B and C. A Design B motor is a squirrel-cage motor de- signed to withstand full-voltage starting, developing locked-rotor and breakdown torques adequate for general application as specified in Tables 6 and 7, drawing locked-rotor current not to exceed the values shown in Table 8 and having a slip at rated load of less than 5 percent*. (See Fig. 45.) A Design C motor is a squirrel-cage motor de- signed to withstand full-voltage starting, developing locked-rotor torque for special high-torque applica- tion up to the values shown in Table 6, breakdown torque up to the values shown in Table 7, with locked-rotor current not to exceed the values shown To obtain normal torque with higher than normal starting current, rotor bars are placed close to surface of rotor. Rotor reactance is relatively low, resulting in high power factor and efficiency. Fig. H-44. DESlaN- a To obtain normal torque with normal starting current, rotor bars are deep and narrow, producing relatively high reactance when frequency of magnetic flux is high. Fig. H-45. NOTE: Some of the smaller ratings listed are not normally gd-rot ,, are availabotl lepp IBb O(sRa some s : ClP RDP8 0423800120045have 00102-7 tly greater H-18 A , proved For Release 1999/09/10 : CIA-RDP83-00423R0012004 O HT MOTORS TABLE 10-PERFORMANCE DATA SQUIRREL-CAGE, CONSTANT-SPE OPEN AND ENCLOS D, DESIGN B MOTORS: Di TYPES 3 PIIASI3, 60 CYCLES, 208-2 EFFICIENCIES AND POWER FACTORS 0-440-550 VOLTS RICH MIGHT BE EXPECTED2 HP Rpm Efficiency Power Factor Full-Load Currents Amps per Phase (Synchronous) 4/4 3/4 1/2 4/4 3/4 1/2 220 Volts, 3 Phase 1/2 9100 66 60 53 54 45 37 2.74 3/4 1000 70 68 64 66 55 43 3 18 3/4 9;00 68 63 55 57 49 38 . 3.8 1 1800 76 74 68 71.5 62 48 3 6 1 12,00 71 70 64 67 57 45 . 4 1 1 9;00 70 66 57 60 51 39 . 4.66 1-1/2 36',00 79 76 69 84 78 67 4.48 1-1/2 1800 79 76.5 72 72.5 66 54 5.14 1-1/2 12.00 76.5 76 71 70 61 49 5.5 1-1/2 900 74 73 67 63 52 40 6.3 2 3600 81.5 78 73 84.5 78.5 68 5.7 2 1800 80 78 73 76 68 54.5 6.44 2 1200 77 76 73 71 62 50 7.16 2 9,00 75 74 69 65 55 43 8.04 3 3660 82.5 82 80 85 79 69 8 4 3 1800 81 81.5 77.5 79 73 61 . 9 2 3 1200 80 79 75 75 66 51 . 9 8 3 960 78 76 70.5 65 56 44 . 11.6 5 36)0 83.5 83.5 81 85 79 69 13.8 5 1800 85 85 83 81 75 64 14.2 5 1200 82 81.5 80 77 73 60 15.5 5 9 81 80.5 79 71 63 50 17.0 7-1/2 36 0 85 85 82 87 82 75 19.9 7-1/2 18 0 84 83.5 81 85.5 80 71 20.4 7-1/2 12 0 83.5 83 80 80 74 62 22.0 7-1/2 900 82.5 82 79 71 63 50 25.0 10 3600 86 86 84 88 84 77 26 10 1800 85 85 84 87 83 76 26.5 10 1290 84 84 83 81.5 77 68 28.6 10 900 83.5 83.5 81 80 75 63 29.4 15 3680 86 86 84 90 87 81 38 15 1800 86 86 85 87 84 76 39 4 15 12' 0 87 87 86 82 77 67 . 41 2 15 9 0 84 84 82 81 75 64 . 43.2 20 36 0 86 86 85 91 89 .84 50 20 18 0 87.5 87.5 86.5 87 84.5 79 51 6 20 12 0 87 87 86 82 77 67 . 55 0 20 9 0 86 86 85 81 75 64 . 56.4 25 36 0 87 86 85 90 87.5 33.5 62.6 25 18 0 88.5 88.5 873 87 84.5 79 63.6 25 12 0 88 88.5 87 86 83.5 72 64.8 25 9 0 87 87 86 82 76 66 68.8 30 360 0 89 88 86 90 87.5 133.5 734 30 180 0 89 89 88 88 85 80 75.0 30 120 0 88.5 89 88 87.5 85.0 73.5 76 30 90 0 88 88 87 82 78 70 81.4 40 3600 89 88 86.5 90 87.5 83.5 98 40 1800 89 89 88 88.5 86 81 99 6 40 1200 89 _ 89 88 88 84.5 78 . 100 0 40 900 . 108.0 50 3600 89 88 85.5 89 87 113.5 124.0 50 1890 89.5 89.5 88 89 87 .112 123.0 50 120;0 89.5 89.5 88 88 84.5 78 124.4 50 900 88.5 88.5 87 83 79.5 71 134.0 60 3600 90 89 87 90 89 85 145 60 18010 90 90 89.5 89 87 112 147 60 12001 , 89.5 89.5 88.5 87.5 84.5 76 150 60 go 88.5 88.5 87 83 79.5 71 160 75 1 3601 90.5 90 88 89.5 883 84.5 181 75 1800 90 90 89 89 87 82 184 75 1209 90 90 89 87.5 84.5 76 187 75 900 89 89 88 86 84.5 74 192 1 For 2-pole, totally-enclosed fan-cooled motors, efficiency should be reduced 1% at 4/4 load, 2% at 3/4 load, and 3% at 1/2 load. 2 Not to be used for guarantees; consult motor manufacturer? 3 Full-loadArp ybin! fov` fts IaS M VOM ee( 4 DP813d80A RcOW.200450002-7 P83-60423R0012004500 H-19 Approved For Release 1999/09/10: CIA-REWCTioN MOTORS LOW R#S/STQ4'CE W/ND/NG To obtain high starting torque with low starting current, two sets of rotor bars are used. The operation of this type is described under the heading "Double-Cage Motors." Fig. H-46. "ED/UM LEHKRGE FLUX HIGN RES/STANCE WIND/MG 0ES/GN- D To obtain high starting torque with normal starting current, thin high-resistance bars are used, producing relatively high reactance. Fig. H-47. inTable 8 and having a slip at rated load of less than 5 percent. (See Fig. 46.) A Design D motor is a squirrel-cage motor de- signed to withstand full-voltage starting, developing high locked-rotor torque as shown in Table 6, with locked-rotor current not greater than shown in Table 8 and having a slip at rated load of 5 percent or more. (See Fig. 47.) NOTE: Standard speeds for most 25-cycle motors are 1500, 750 and 500 rpm for which no torque values have been established. Typical Applications Design A motors obtain higher breakdown torque than Design B motors, but they do this at the expense of higher locked-rotor current. Design B motors are the standard, forming the basis for comparative motor performance of all other types. Their torque, starting current and slip char- acteristics make them suitable for most applications. Efficiency is relatively high-even under fractional loads. Power factor is also good at full load, although it does decrease quite rapidly with decrease in load. Both efficiency and power factor decrease as the number of poles increases. (See Table 10.) Design A and B motors are used for such constant- speed applications as light conveyors, line shafts, blowers, fans, woodworking machines, rotary com- esign but lower breakdown torque than Design B motors, while locked-rotor current and slip are the same for the two designs. Design C is for applications requiring high initial torque to start, such as vibrating screens, conveyors, milling machines, pulverizers, reciprocating pumps, crushers, and compressors without unloading devices. It should be noted that while these motors develop high starting torque, they are not intended for applications requiring frequent starting and stopping. Design D motors have high torque and high slip. They are generally used on applications involving high inertia and frequent load changes, such as fly- wheel-equipped punch presses. The high slip enables, the motor to pick up the load when the excess energy stored in the flywheel has been released during the working stroke of the cycle. The high torque enables the motor to repeatedly accelerate the load to full speed, without overheating, to restore energy to the flywheel. This alternate supplying and releasing of, power irons out the load peaks, that is, the maximum power demand. Other applications include elevators,' metal drawing, shears, hoists, and bailers. Double-Cage Motors A double-cage motor is a polyphase induction motor having a rotor with two separate squirrel-cage wind- ings, one within the other, as shown in Figs. 48 and 49. The stator is of standard construction. Double-cage construction is used only when it is necessary to obtain high starting torques with relatively low starting current. It provides higher starting torques than ordinary single-winding motors, but not as high torques as single high-resistance winding motors. In a double-cage motor, the outer cage has high resistance and the inner cage has low resistance. The former provides high torque in starting, while the latter carries most of the current at full load. ,9-LOW RESISTANCE SOU/RR#L CRGE C-STRTOR W/NDINO' B-NIGH RESISTRNCE SQUIRREL GRGE This diagram shows two things: (a) Typical rotor and stator slot shapes used in small double-cage rotors. (b) Relative current flow at time motor is ready to start; most of current is carried by high-resistance outer cage bars, giving high starting torque with low starting current. INDUC roved For Release 1999/09/10 : Cl iivDUc MOTORS srRTOR CORE R-LOW RES/STANCE C-STHTOR WINO/NF B-H/Gh RES/STRNCE S4U/RREL CRGE SQC'/RREL CI9aE (a) Typical rotor and s tator slot shapes used in large double-cage motors. (b) *elativc current flow when motor has reached normal sped, most of current is carried by low-resistance inner cage, giving high efficiency during operation. Fig. H-49. Figs. 48 and 49 shovlr that the inner cage bars are more completely enclosed by stator core iron than are the outer cage bars. Thus the magnetic path around the inner cage bars is more satisfactory than that around the outer bars. This, however, means that the path around the inner bars has greater in- ductance. Now, at the instant of starting, the revolving field produced by the stator current induces currents in both sets of rotor conductors-at full line frequency. But at full line frequency, the high inductance of the inner winding impedes he current in the inner con- ductors. However, even at fulfil line frequency, considerable current is set up in the outer conductors since they have relatively low inductance. But this is a high resistance winding, and this plus the choking action of self-induction at line frequency limits the current in starting. In Fig. 48, the depth of shading indicates the com- parative density of the currents in the two sets of conductorswhen the motor is ready to start. As the rotor gains speed, the frequency of the cur- rents induced in the rotor decreases, and the relation- ship between the currerts in the two squirrel cages automatically changes. This is due to the fact that the frequency of the induced currents is proportional to the slip, and at normal speed this frequency be- comes only a few cycles er second. At this low frequency, the higher inductance of the inner cage windings produces only a small choking effect. Therefore the resistances of the two cages are the essential factors influencing the distrijution of and limiting the flow of the rotor currents. Thus, at normal speed the greater part of the total rotor current is carried by the low-resistsance inner cage, as indicated CPYRGHT RDP83-00423R001200450002-7 . and-rotor motor are quite similar to those of the he general principles of operation of the polyphase g. 50 shows a standard wound-rotor motor.) rt-circuited or closed' through suitable circuits. lyphase winding or coils whose terminals are either tor in which the secondary circuit consists of a lap-rang motor, is defined, by NEMA as an induction A wound-rotor induction motor, sometimes called OUND-ROTOR MOTORS yphase squirrel-cage type. he essential structural difference between the and-rotor motor and the squirrel-cage motor is in rotor. The wound-rotor motor has a distributed se-wound rotor winding arranged for the same ber of poles as the stator winding. The terminals the rotor winding are connected to three collector (slip rings) mounted on the shaft (Fig. 51). From shes riding on the collector rings, leads are brought for connection to a secondary control-which vides resistance for starting or speed regulating poses. o increase the speed, the resistance is gradually cut of the circuit until, for operation at full speed, the r winding is short-circuited through the control. he torque of a polyphase induction motor is a tion of its impedance,: and the function of the nd-rotor motor secondary control is to change impedance to an optimum value. By properly ortioning the external resistance, it is possible btain a locked-rotor torque that is nearly equal Fio. H-50. Open, drip-proof wound-rotor motor. by the sha$r;g ,- d or Release 1999/09/10 : CIA-PtDFli6 -00rAPZRG1Qd QM, Q.QDZ;7 Approved- For Release 1999/09/10 : CIA-RDP83-0RM6MI0045000~H 21 UCTION MOTORS to the breakdown torque, and this can be done with much lower locked-rotor (starting) current than with squirrel-cage motors. Wound-Rotor Motor Advantages The wound-rotor motor thus has some very distinct advantages over the squirrel-cage motor: a) It can develop high starting torque with rela- tively low starting current. This characteristic makes it suitable for high load-torque drives where starting current must be limited. As noted above, it is possible to obtain starting torques nearly equal to the breakdown torques. This depends on the external resistance in the rotor circuit and its method of distribution. The breakdown torque, with collector rings short-circuited, is not less than .200 percent for general-purpose ratings, and larger values can be obtained for special load requirements. b) The major portion of the heat developed during starting can be dissipated in the external resistors (provided that they are suitably proportioned) instead of being concentrated in the rotor winding, as is the case in squirrel-cage motors. This makes the wound- rotor motor suitable for drives having such high load inertia as to be beyond the thermal capacity of the starting windings of squirrel-cage or synchronous motors. c) The wound-rotor motor can be used for ad- justable-varying speed regulating duty for such ap- plications as fans, cranes, hoists, etc. It should be noted that this does not, however, provide good speed regulation on non-steady loads as the speed changes with changes in load, due to the slip inherent in in- duction motors. The percentage of speed reduction obtainable depends on the character of the load; a 50 percent reduction is usually permissible on variable torque loads without producing unstable operation. The temperature of the motor will usually be higher at reduced speeds, due to the reduction in normal ventilation. Other Characteristics When a wound-rotor motor is operating at full speed with the secondary short-circuited through the control, its operating characteristics are very similar to those of a normal-torque, normal starting-current cage motor. The main differences are usually slightly lower slip (2 percent for larger sizes to 5 percent for smaller ones) and somewhat lower power factors (due to certain magnetic "leakage" factors inherent in the design). Wound-rotor motors are limited to two xe spee because of complications in rotor construction. How- ever, each "fixed" speed is capable of further speed adjustment in the same manner as outlined above for single-speed motors of this type. For example, the speed can be adjusted from the higher one through the range to the lower fixed speed. Multi-speed squirrel-cage construction constitutes the simplest form of adjustable-speed motor, since there are no brushes, commutators or collector rings involved. Its principal drawback lies in the fact that it provides only the two, three or four speeds for which it is designed-there are no intermediate speeds. Construction Principles The stator may have either one or two windings, each of which will produce either one or two of the desired rotor speeds-depending upon the ratios of the various speeds required. Two-speed motors (for operation on 3-phase circuits) having a speed ratio of 2 to 1 (1800 and 900 rpm, or 1200 and 600 rpm, for example) are usually furnished with a single stator winding. The two speeds are ob- tained by means of a selector switch which renders either all or half of the poles effective. With all of the poles effective, the motor operates at the low speed; with half of the poles effective, it operates at the high speed. This is called a consequent-pole winding, and the low speed is always one-half of the high speed. If the two speeds required are not in a 2 to 1 ratio, two separate stator windings are required. This applies to such speed ratios as 1200/900 rpm or 1800/1200 rpm. When three or four speeds are required, the motor is built with two separate windings, with one or both of the windings being of the consequent-pole type. This permits speed ratings such as 1200/900/600 rpm or 1800/1200/900/600 rpm. Diagrams of windings and coil connections of consequent pole motors are shown on pages 124 and 125, Section F. Torque Characteristics Multi-speed motors are available with any the following three torque characteristics: Constant-horsepower motors produce the same horse- power output at all speeds. They are used for lathes, boring mills and other machine tools where the torque demand decreases as the speed increases. Constant-torque motors produce the same torque at all speeds and the horsepower is in direct proportion to the speed. These motors are used for conveyors, stokers, etc. MULTI-SPEED INDUCTION MOTORS Multi-speed squirrel-cage motors can be designed t ate at two three or four speeds-having con- e Variable-torque motors produce a torque that de- creases with the speed, resulting in a horsepower output which decreases with the square of the speed. Atl"e dtFiMcRelea 9/09/10 : C IA 'D UU64223 '1 ( 0 fo er require- stant CPYRGH-T. H"ZTAooroved For Release 1999/09/10 : CI -RDP83-00423 R001200450002-7 INDUCTJdt4 MOTORS TABLE 1-SUMMARY OF PROTECTION AN Standard Type of Approximate Temperature Rise Enclosure I Range of Sizes Class A Insulation l1/2 hp and larger Semi-protected 1/2 hp and larger 50 C Protected 1/2 hp and larger 50 C Frame 224 and larger Enclosed, forced- Frame 364 and larger ventilated Enclosed, self- Frame 364 and larger ventilated Totally-enclosed, Fkames 204 to 254 non-ventilated Totally-enclosed, Frame 254 and larger fan-cooled TABLE 12-REPRESENTATIVE CAGE MOT Open D4-Proof ENCLOSURES-INDUCTION MOTORS Approximate Application Cost Increase Information 0 to 10% Protection against dripping liquids or falling: particles. 5% Same as protected. 10% Protections against metal chips in machine shops, cite. 10 to 15% Protections against dripping and splash- ing liquids; used in breweries, food plants, dairies, etc. 4 to 20% Same as fis-cooled.. 40 to 115% Used where abrasive dust, dirt, grit, or corrosive fumes are too severe for open moltors-in ruetal-working plants, ;foundries? machine shops, etc. 10 to 20% For oil refineries, varnish plants, lac- higher than quer plants, or others where flam- fan-cooled mable, Ivolatile liquids are manu- factured, used or handled. R DIMENSIONS (IN INCHES) Splash-Proof Frame A$ Bj i C D t Et Ft L M N 0 P Ut W AL AM AN ACOt A12f Keyt 203 204 99( 6% J3% 5 4 2% 53 5% 2% 9% 9?/a .750 3a 14 11 6% 5 49( %x%al 224 9% 7% 14% 1 5 4 33 634 634 2% 9% 95% .750 38 14 12 6% 5 53( %z%a1 225 109( 8% 6% 534 434 3% 69( 69( 3% 10% 10 98 1.000 38 1534 ; 123,( 7% 534 5% 3(z3ja2 254 109/ 9 17% 534 43 3% 738 7% 3% 10% 10% 1.000 3 1534 13' 7% 534 594 3483x2 119( 10 40 6% 5 43a 834 8X 33 12 V, 11% 1.125 3a 17% 1533 8% 63 41 6% 348/x298 284 324 129( 1134 22 % 7 534 49( 9% 9% 3% 13% 2 % 1.250 38 199( 16 T/,i 9 7 7A (x 3(x2% 326 14% 8 12% 25% 2 8 634 53 1D% 10% 5% 15% 4% 1.625 % 223/4 1939; 1034 8 8% / s8%s3% 364 % 14 1738 1434 14 7% 2 8 634 6 11% 113( 536 15% 4% 1.625 % 229( 20% 1038 8 934 8 %x %x3( 8 % 9 7 598 1134 1134 5% 179 7 % 1.875 34 2538 2035 1134 9 9 y 34z34s4 34 364-S 365 1734 14 2 6 9 7 5 % 1134 1134 334 17% 7% 1.625 34 365-S 17A 173 15 15 29% 27 9 7 638 119( 119( 5% 17% 7% 1.875 3j 253 2134 1138 9 9% 3aa34s43( 9 7 638 11% 1184 33; 179( 7% 1.625 34 .... .. .. .. 988%zlY8 9% 2.125 34 2838 22 13 10 9% 34z34a5 404-S 405 1938 19 153 1 29 10 8 638 1:134 12,14 4 19,% 9% 1.875 % .... .... .... .... 3/8x3482 405-S 34 19 6% 3$ YS 0 10 8 6% 1'; Y4 13% 6% 199% 9% 2.125 34 2834 233 13 10 109 34834x5 444 34 21 16% 3 38 5 10 8 6% 1:43( 1334 4 19.% 9% 1.875 34 .... .... .... 34z35z2 444-S 34 2134 1734 17 3 38 $ 11 9 7% 154 14 7% 21% 134 2.375 % 31 24 4 14 11 11 988 %x534 34 3 11 9 7% 144 14 5 21% 134 2.125 3( .... .... .... .... ... 34z34z2% 445 445-S 2134 21 19% 1 3;% 11 9 8Y, 15 15 7% 21% 134 2.375 3% 31 2634 14 : 11 12 %z /x534 34 9% 3 11 9 834 15 15 5 21% 1A 2 125 % 504-U 2434 19 4 v 12 1 8 . .... ...I .... 35z34z2U 505 a Appioved4 orme4ease '~ 9I 24, I 4 J ~a/a734 mppruvt;ca rur mwiucrsu i ziuvivvi i v : .w-muroo-vv,+zomL( `Jp plgvvL INDUCTION MOTORS STANDARD OPEN DRIP-PROOF AND SPLASH-PROOF STANDARD TOTALLY-ENCLOSED MOTORS MOTORS (60 CYCLES) (60 CYCLES) HP 3600 1800 1200 900 720 600 Motors above line are non-ventilated. 1/2 .... .... .... 204 224 225 Motors below line are fan-cooled. 3/4 . 203 224 225 254 1 ... .... .... 203 204 225 254 254 Hp 3600 1800 1200 900 720 600 1-1/2 203 204 224 254 254 284 1/2 .... .... .... 204 224 225 2 204 224 225 254 284 324 3/4 .... .... 203 224 254 254 3 224 225 254 284 324 326 1 .... 203 204 225 254 254 5 225 254 284 324 326 364 1-1/2 204 204 224 254 254 284 7-1/2 254 284 324 326 364 365 2 204 224 225 254 284 324 3 224 225 254 284 324 326 10 284 324 326 364 365 404 5 225 254 284 324 326 365 15 324 326 364 365 404 405 7-1/2 254 284 324 326 365 404 20 326 364 365 404 405 444 10 284 324 326 364 404 405 25 364S 364 404 405 444 445 15 324 326 364 365 405 444 30 364S 365 405 444 445 504U 20 326 364 365 404 444 445 40 365S 404 444 445 504U 505 25 365S 365 404 405 445 504U 50 404S 405S 445 504U 505 .... 30 4045 404 405 444 504U 505 60 405S 444S 504U 505 .... .... 40 405S 405 444 445 505 75 444S 445S 505 .... .... .... 50 444S 444S 445 504U 100 445S 504S .... .... .... .... 60 4458 445S 504U 505 125 504S 5055 .... 75 504S 504S 505 150 5055 .... .... .... .... .... 100 505S 505S- TABLE 12-REPRESENTATIVE CAGE MOTOR DIMENSIONS (IN INCHES)-Continued Frame At Bt C Df Et Ft L M N 0 P Ut W AL AM AN AOt ARt Keyt 203* 9% 6% 13 34 5 4 2% 5% 5 6% 2% 9% 9% .750 34 14 11 6% 5 4% Xx X135 204* 9% 7% 14% 5 4 334 634 6% 2A 9% 93% .750 34 14 12 6% 5 534 %z%az1% 224* 10% 8% 16% 5% 4% 3% 6% 6% 334 10% 10% . 1.000 34 15% 12% 734 534 5% 34x%x2 225* 10% 9 17% 534 4%4 3% 73s 7 3% 10% 10% 1.000 34 1534 13 7% 534 534 3(z %z2 254 11% 10 22%j 6% 5 438 10% 838 3% 12 1134 1.125 34 17% 1538 834 634 6% %%34x238 284 12% 11% 24% 7 5% 434 11% 934 3% 1334 12% 1.250 34 19% 16% 9 7 734 1%z%z2% 324 14% 12% 2834 8 634 534 12% 10 % 538 15% 1534 1.625 34 22% 1934 1034 8 8% %x%z334 326 14% 14% 29% 8 634 6 13% 11 5%8 15% 1534 1.625 34 20% 22% 1034 8 934 %a%a3% 364 17% 14 31 % 9 7 5 % 14 1134 5% 18% 19 1.875 34 25% 20% 11% 9 938 34x3484% 364-S 1734 14 28% 9 7 5% 14 1134 334 1834 19 1.625 34 .. .... .. ... * .. %.%x1% 365 1734 15 323s 9 7 6% 14% 11% 5% 1834 19 1.875 34 25% 21% 1134 9 9 % %z34z434 365-S 1734 15 29% 9 7 638 1434 11% 334 1834 19 1.625 34 .... ... %z38z1 % 404 1934 1534 3434 10 8 638 15% 1234 6% 2068 20 % 2.125 . 34 2834 22 13 10 9 % 34z34z5 404-S 1934 1534 31% 10 8 636 1534 1234 4 2038 20 % 1.875 34 .... .... .... .... .... 34xMx2 405 1934 16% 35% 10 8 6% 16 1334 634 2034 20% 2.125 34 28% 2334 13 10 10% 3az3az5 405-S 19% 16% 3334 10 8 6 % 16 1334 4 20% 20 % 1.875 34 .... .... .... .... .... %z%z2 444 21% 1734 3934 11 9 734 17% 1434 7% 22% 23% 2.375 34 31 24% 14 11 11 %x%853 445 2134 19M 41% 11 9 8% 18% 1534 7% 22% 2334 2.375 34 31 2634 14 11 12 %z %x5% 445-S 21%4 1934 38% 11 9 834 18% 1534 4% 22% 2334 2.125 34 .... .... .... .... .... 3483482% 504-U 2434 21 4436 1234 10 8 19 16 % 834 24% 2434 2.875 34 3434 27 34 16 1234 1234 348%8734 505 2434 23 46 % 1234 10 9 20 1734 8% 2434 24% 2.875 34 34% 2934 16 12A 13% 348348734 *Dimensions shown for these frames are for totally-enclosed non-ventilated construction. tThese are NEMA standard dimensions. Other dimensions may vary, depending upon the manufacturer. :These PllVrCY'dtPP rnRClLy'tbSLP".7.7/V.7/'IVMACIA-RDP83-004238001200450002-7 H-24 Approved For Release 1999/09/10 : Cl -RDP83-00423R001200450DQrHT INDUCTION MOTORS ments of a fan decreas' approximately as the cube of the speed. Squirrel-cage multi-speed motors are built to the same NEMA design standards for torques and starting currents as single-speed pnotors. ! MOTOR PROTECTIO14 Classification of maclines by types of mechanical protection and methods of cooling will be found in the definitions of pages 4 to 9. Accompanying illustra- tions, Figs. 5 to 28, inclusive, show the construction employed for the various types, and Table 11 gives a brief summary of such, features. This table shows (a) the approximate range of sizes or ratings in which each type is built, (b) tlie maximum temperature rise for Class A insulated machines, (c) the approximate increase in cost over tllie standard open type, and (d) application suggestions. STANDARD DIMENSIONS Table 12 gives representative dimensions for foot- mounted motors, while Table 13 shows representative frame sizes for various horsepower and speed ratings in open drip-proof and totally-enclosed motors. tota ly-enclosed types are also available, as well as vert cal types. Performance and cost are b.sually consistently better tha for direct-connected motors of the same output spec is. For smaller ratings, !gearmotor construction is the only practical answer for low output speeds. Figs. 52 and 53 show two types of gearmotors. Ratings and Classifications U its of this type are available in ratings up to 50 hp or all applications and up to 75 hp for some ap- plications. Table 14 gives output speeds listed in the NE 1A Recommended Standards, but it should be not that some of these speeds, namely 1430, 1170, 950, 6, 5, and 4 rpm, are seldom used and are not always avai able. Aft Gearmotors meet the demand for a highly efficient, economical and dependable source of power for low- speed drives. Basically, a gearmotor consists of a 1750-rpm motor and a double-, triple- or quadruple- reduction gear unit. The standard motor is the squirrel- cage type, but wound-rotor and direct-current motors are occasionally used. Construction The gear units use precision-cut gears, some manu- facturers using the helicaljtype and others the planetary type. The gear efficiency usually is not less than 97 percent. High efficiency and, in jthe case of induction motors, good power factor result: from the use of high-speed motors. Motors usually are of the standard open drip-proof type, but in most cases splash-proof or ravrer_iaT... TAB .E 14-OUTPUT SPEEDS FOR INTEGRAL-HORSE- PO ER GEARMOTORS OF PARALLEL CONSTRUCTION ominal Nominal Gear Output Gear Output Ratios Speeds Ratios Speeds 1.225 1430 25.628 68 1.500 1170 31.388 56 1.837 950 38.442 45 2.250 780 47.082 37 2.756 640 57.633 30 3.375 520 70.623 25 4.134 420 86.495 20 5.062 350 105.934 16.5 6.200 280 129.742 13.5 7.594 230 158.900 11.0 9.300 190 194.612 9.0 11.390 155 238.350 7.5 13.950 125 291.917 6.0 17.086 100 357.525 5.0 20.926 84 437.875 4.0 These output speeds are based on an assumed operating spec of 1750 rpm and certain nominal gear ratios and will be modified: 1.. By the variation in individual motor speeds from the basic operating speed of 17,150 rpm. (The same list of outputispeeds may be applied to 25- or 50-cycle gearmotors when employing motors of 1500 rpmsynchronous speed if ;an assumed motor operating speed of 1430 rpm is used.); (This list of output speeds may be applied to 60-cycle gearmotors when employing motors of 1200 rpm syn- chronous speed if an assumed motor operating speed of 1165 rpm is used.) 2. By a variation in the exact. gear ratio from the nominal, which variation will not chaiige the output speed by more than plus or minus 3 per cent. foot-mounted motors-recommended when Fig. H-53. Integral-type gearrmotor uses round-frame Approved w lease 1999/09/10: n Or*0@42 RO@tl"4800W-lbngth. Approved For Release 1999/09/10 : CIA-RDP83-00423R0M0002-7 H-25 INDUCTION OAGI4RS AGMA recommended practice calls for three classi- fications of gearmotors as follows: Class I-For steady loads not exceeding normal rating of motor and 8 hours a day service. Moder- ate shock loads where service is intermittent. Class II-For steady loads not exceeding normal rating of motor and 24 hours a day. Moderate shock loads for 8 hours a day. Class III-Moderate shock loads for 24 hours a day. Heavy shock loads for 8 hours a day. As shown by Table 15, gearmotors in these various classifications are available for most applications. To assure proper selection of units, it is essential that the manufacturer be given complete application data. TABLE 15-COMMONLY AVAILABLE GEARMOTOR RATINGS Output Rpm Hp (1750 Rpm Motors) Class I Class II Class III 520, 420, 350 1 to 50 1 to 50 1 to 40 280, 230,190, 155 1 to 50 1 to 50 1 to 50 125 1 to 50 1 to 50 1 to 40 100 1 to 50 1 to 50 1 to 30 84 1 to 50 1 to 30 1 to 25 68 1 to 40 1 to 30 1 to 20 56 1 to 40 1 to 25 1 to 30 45 1 to 30 1to20 1to15 37 1 to 25 1 to 20 1 to 10 30 1 to 20 1to15 1to10 25,20 l to 15 Ito10 1to7.5 16.5, 13.5 1 to 10 1 to 7.5 1 to 5.0 11.0, 9.0 1 to 7.5 1 to 5.0 1 to 3.0 7.5 1 to 5.0 1 to 3.0 1 to 3.0 TABLE 16-OPERATION;ION OFF-STANDARD VOLTAGES AND FREQUENCIES VALUES SHOWN ARE FOR GENERAL-PURPOSE DESIGN B CAGE MOTORS AND WILL VARY SOMEWHAT FOR DIFFERENT RATINGS AND DESIGNS. *Torque Locked-rotor and breakdown (Speed Synchronous Full load .................... Percent slip ................ Efficiency Full load .................... 3/4 load ..................... 1/2 load ..................... Power factor Full load .................... 3/4 load ..................... 1/2 load ..................... Current Locked-rotor ................ Full load .................... Temperature rise Maximum overload capacity... Voltage (in percent of rated) 110% 90% No change Increase 1% Decrease 17% Increase 0.5 to 1 Little change Decrease 1 to 2 Decrease 3% Decrease 4% Decrease 5 to 6% No change Increase 5% Decrease 1.5% Increase 5% Increase 23% Little change Decrease 2 Slight increase Little change Slight increase Increase 1 to 2 Slight increase Increase 1% Slight increase Increase 2 to 3% Slight increase Increase 4 to 5% Slight increase Increase 10 to 12% Decrease 10 to 12% Decrease 5 to 6% Decrease 7% Increase 11% Slight decrease Decrease 3 to 4 C Increase 6 to 7 C Slight decrease Increase 21% Decrease 19% Slight decrease Magnetic noise ................ Slight increase Slight decrease Slight decrease *The locked-rotor and breakdown torque of ac induction motors will vary as the square of the voltage. tThe speed of ac induction motors will vary directly with the frequency. OPERATION ON OFF-STANDARD VOLTAGES AND FREQUENCIES Guarantees of motor characteristics (torque, power factor, efficiency, etc.) are based on operation of the motor at rated (nameplate) voltage and frequency. As explained earlier, under the heading Service Condi- tions, motors will operate successfully despite some deviation from rated values, but not necessarily in accordance with the standards established for operation under rated conditions. Table 16 shows the approxi- mate effects of variations in voltage and frequency on motor performance. The values will vary somewhat with the rating of the motor. SYNCHRONOUS MOTORS A synchronous motor is defined by NEMA as a Decrease 5% Decrease 5% Little change Slight decrease Slight decrease Slight decrease Slight decrease Slight decrease Slight decrease Increase 5 to 6% Slight increase Slight increase Slight increase Slight increase from an alternating-current system into mechanical power. Synchronous motors usually have direct- current field excitation. A synchronous motor consists essentially of a stationary armature (stator) and a revolving field with windings arranged for excitation from a source of direct current. Fields of motors with four or more poles are of the salient pole type. Two-pole motors, which are seldom used except in very large sizes, are usually of the non-salient pole type and are similar to steam-turbine-driven synchronous generators. The speed of a synchronous motor is a function of the number of poles. It remains in synchronism with the supply frequency and is unaffected by the load. (See Table 1.) Efficiencies are generally higher than for induction synchrgoW,8,V6( '`&*6li6%rW& *oby,V! ClA DP834E} B4 4d( ' cularly so H-26 Approved For Release 1999/09/10: Cl -RDP83-00423ROO12004500o '7{RGHT SYNCHRONOUS MOTORS Fig. H-54. Engine-type, 6b0-hp, 150-rpm synchronous motor driving 450-ton-pe!-day ammonia compressor. in the case of unity powei factor motors and/or lower speeds. Application of synchronous motors requires careful consideration of all factor involved, especially: Power factor. Locked-rotor (static) toque. Pull-up (accelerating) torque. Pull-in torque, Pull-out torque. Effect of load inertia o'n pull-in torque and thermal capacity of the am rtisseur winding. Effect of voltage variation on torques. POWER FACTOR Normally, one does not think of induction .motors as requiring excitation, but actually they do. The fact is, the exciting current is supplied from the 'line. And because the magnetizing !component lags 90 degrees, the result is that the line current lags at all loads to an extent depending on the r agnitude of the magnetizing current. In synchronous motors the excitation is supplied to the field from a separate dc source. Thus, by varying the field strength, the phase relationship (power factor) of the armature current. and voltages may be changed. With a given field strength the power factor is unity; that is, the armature current is a minimum and in phase with the voltage. Decreasing the field strength causes the increasing current to lag, increasing the field strength causes the increasing current to lead] the voltage. In other words, lagging or leading powe . factor results. Synchronous motors can therefore be made suitable for power-factor correction purposes. The above should not be interpreted to mean that Wk2 any such motor is necessarily suitable for operation at in t other thanAliPPfM 0raReIeA$0499 YA9/10 : Cl ING rtisseur Winding armature (stator) winding is wound for operation a polyphase (2 or 3-phase) source. When voltage lied at the terminals, a revolving; magnetic field duced in the stator; its speed is proportional to equency and number of 'poles. rotor assembly contains, an amortisseur winding pole faces. This winding is similar to the cage ng of an induction motor. It is shown in Fig. 55. revolving field of the armature acting on the isseur winding produces (a) the static torque auses the motor to break from rest and (b) the p torque for acceleration. Depending upon the of load and the resistance of the amortisseur ng, the motor will accelerate to a speed of from percent below synchronous speed.. us, the synchronous motor is actually started and ht up to near synchronotis speed as a squirrel-cage r. Then the field excitation is applied. If the motor : application, the field of perly designed for the otor will "pull in" and. lock in step with the ng magnetic field of the stator. t of Load Wk2 rtain types of drives are characterized by high inertia (load Wk2), as indicated by Table 18. The inertia which a synchronous motor can accelerate finitely limited by the thermal capacity of its tisseur winding. aller motors can accelerate relatively higher load than larger motors, until a point may be reached e very large sizes where the motor may be capable 82342d0O2. oft Approved For Release 1999/09/10: CIA-RDPO0049WO01200450002- 1-27 Fig. H-56. Besides driving 3000-gpm pumps, these 500-hp synchronous motors improve plant power factor. As indicated by the NEMA definition of pull-in torque on page 4, the matter of load Wk2 has a most important effect on the pull-in capabilities of syn- chronous motors. Effect of Voltage on, Torques It must be remembered that all torque values listed are based on full voltage at the motor terminals. Hence, if the voltage at the terminals is below rated voltage, the starting and pull-in torques should be based on values adjusted to compensate for the re- duction in voltage so that the required torques will be obtained with the actual voltage at the terminals. This condition exists when reduced-voltage starting is used and/or when the line voltage drops below rated voltage during the starting period. Starting and pull-in torques vary approximately as the square of the voltage. For example, suppose you have an application that requires 100 percent starting torque (static torque) and 100 percent pull-in torque. Suppose also that reduced voltage starting on 85 percent tap and pull-in on full voltage is to be used but that line voltage will drop to 95 percent during the starting and pull-in period. You would then require a motor with rated starting and pull-in torques as follows: Starting torque = 100 = 153% 0.852 X 0.952 _ Pull-in torque = U 952 = 111% torque. The increased torque requirement is produced by a backward shift or lag in the position of the field poles with respect to the revolving magnetic field. The motor, however, still maintains its synchronous speed. The motor develops its maximum torque when the field poles have shifted backward approximately one- half the distance between adjacent poles. Any further increase in load will cause the motor to pull out of step and stop. The maximum torque that a motor will develop without pulling out of step is called its pull-out torque. Typical pull-out torque requirements for various SYNCHRONOUS MOTORS TABLE 17A-STANDARD HORSEPOWER RATINGS GENERAL-PURPOSE MOTORS: 30, 40, 50, 60, 75, 100, 125, 150, 200*. LARGE IIIGII-SPEED: 200**, 250, 300, 350, 400, 450, 500, 600, 700, 800, 900, 1000, 1250, 1500, 1750, 2000, 2250, 2500, 3000, 3500, 4000, 4500, 5000, 5500, 6000, 7000, 8000, 9000, 10,000, 11,000, 12,000, 13,000, 14,000, 15,000, 16,000, 17,000, 18,000, 19,000, 20,000, 22,500, 25,000, 27,500, 30,000. LOW-SPEED: 20, 25, 30, 40, 50, 60, 75, 100, .125, 150, 175, 200, 225, and larger ratings as listed above for large highspeed motors. *At 1.0 pf. **At 0.8 pf. TABLE 17B-STANDARD VOLTAGES Voltage Approximate Hp Range---1.0 Pf 208, 220 20 - 200 440, 550 20 - 1000 2300 20 - 10000 4000 75 - 17000 4600 75 - 20000 6600 400 - 30000 13200 1000 - Any Speed in Rpm Number (60 Cycles) Poles 3600 1800 1200 900 720 600 514 450 400 360 327 300 277 257 240 225 200 180 164 150 138 128 120 109 100 95 90 86 80 of Approximate Hp Range--1.0 Pf 1000 & Larger 30 - 5000 30 - 10000 30 - 30000 40 - 30000 50 - 30000 100 - 30000 20 - 10000 20 - 10000 20 - 10000 20 - 10000 20 - 10000 20 - 10000 20 - 10000 20 - 10000 20 - 10000 20 - 10000 20 - 10000 20 - 10000 50 - 10000 60 - 10000 75 - 10000 100 - 10000 100 - 10000 100 - 10000 150 - 10000 150 - 10000 150 - 10000 150 - 10000 re pose ion w p of the armature. A load applied to the motor develops Standard speeds for other frequencies will be proportionate to the fre uenc using the pole groupings listed above for 60 a torq A d cFsaR@fsi3swr"99/G9/1QQ1: CIA- DP 3-60423 R001200450002-7 PULL-OUT TORQUE When a synchronous motor is operating at no-load, the individual field poles of the motor have a fixed s ect to the revolving magnetic field t' ith "28Approved For Release 1999/09/10 : CIA-RDP83-00423R00120a0MWT The following, taken in the main from NEMA MG1-8.9, represent ypical locked-rotor, pull-in and pull-out torque requiremen of various synchronous motor applications. In individual cases, lowjr values may be satisfactory or higher value may be necessary, depending upon the characteristics of th particular machine and the effect of locked-rotor kva on the line voltage. TYPICAL TORQUE REQUIREMENTS In P cent of Full-Load Torque Max. APPLICA7iION "Load 1-CENTRIFUGAL MAcIIINERY-Blowers, Compressors, Fans and Pumps 12 Blowers .............i................. ..... ..... ..... ..... ..... 10-15 is Compressors. ........i ................. ..... ..... ..... ..... 15-25 1 Fans-(except sintering) ............... ..... ..... ..... ..... ..... 20-50 4 Inlet or discharge .valve closed...... 40% ..... 60% ..... 150% ..... 5 Inlet or discharge valve open........ ..... 40% ..... 100% 150% ..... Sintering-Inlet gates either open or closed ..... ................. 40% ..... 100% 150% 25-60 Propeller-type Discharge open.. ..... 40% ..... 100% 150% 25 Pumps-Centrifugal (Horizontal) ...... ..... ..... ..... ..... 1 4 With discharge valve closed High-and medium-speed......... 40% ..... 50-60% ..... 150i?1, Low-speed .. . . . . . . . ........ ....... 40%. ..... 70-100% ..... 150% ..... With discharge valve open.......... ..... 40% 100% 150% -Centrifugal (Vertical) 4 With discharge vale closed High-and mediurkr-speed......... 50% ..... 60-70% ..... 150'70 Low-speed ......................... 50% ..... 75-100% ..... 150'7/, ..... With discharge valve open.......... ..... 50% ..... 100% 150% ..... 4 Adjustable-blade--Vertical......... 50% ..... 40% ..... 150% 1 Screw-type....... ..... ..... ..... 1 Started dry...... i ................ 40% ..... 30% ..... 150% Primed, dischargl open........... ..... 40% ..... 100% 150% Axial-flow type.... I ................ ..... ..... ..... I With discharge open .............. ..... 40% ..... 100% 150% ..... With discharge closed ............. ..... 40% ..... 200-300% Sante 2-CEMENT, ROCK PRODUCTS AND MINING MACHINERY Grinding Mills 1 Attrition............ ............... 100% ..... 60% ..... 175% 12 Ball and Compeb Rock and coal ....................... ..... 150% ..... 110% 150010 2 ....... Ore...... . . . .~ ................ ..... 175% ..... 110% 175c,,-, 2 Rod and tube mills-O4e ............... ..... 175% ..... 110% 175% 3 Crushers B. and W............................... 200% ..... 100% ..... 25050 3 Bradley-Hercules ...................... 100% ..... 80-100% ..... 250% 3 Cone .................................. 100% ..... 100% ..... 250% 6 Gyratory ..............!................ 100% ..... 70-100% ..... 2505, 4 Jaw ................................... 100% ..... 70-100% ..... 25050 2 Roll ................................... 100% ..... 70-100% ..... 25050 3 Hammer mills .......................... 120% ..... 100% ..... 250% 15-40 Flotation machines.....: ................ 150-175% ..... 110% 17550 1 Fuller mills............ ................ ..... 125-150% ..... 110% 175% -METAL ROLLING MILLS Structural and rail-Roughing......... 40% ..... 30% -Fiiishing......... 40% ..... 30% Plate .................. i ............... 40% ..... 30% ..... Merchant trains ...................... 60% ..... 40% ..... Billet, skelp and sheet 1)ar- (Continuous with layll~ shaft drive) .... 60% ..... 40% Hot-stria. continuous. iinrlivirlnal dri?a -6- ---e --- ..... I ............... "70 ..... 4u% 250-300% Tube-piercing and. expatding.......... 60% ..... 40% ..... 300-350% Tube-rolling (plug) ................ 60% ..... 40% ..... 250% Tube-reeling. ............... 60% ..... 40% ..... 250% Sheet and tin (cold-rollijng)............ ..... 200% ..... 150% 250% REQUIREMENTS OF SYNCHRONOUS MOTOR APPLICATIONS Locked-Rotor (Static) Pull-In Pull-Out Wk2" Unloaded Loaded Unloaded Loaded Ratio / A .......... % Brass and copper --Roughing........... 50% ..... 40% 250 ApprovfT . Release 1999/09/145PC1 -RDP83-00428800120 002-7 ZO"us Approved, For Release 1999/09/10 : CIA-RDP83-00423R0012T0045gpQ& No 9 MOTORS TABLE 18-TYPICAL TORQUE REQUIREMENTS OF SYNCHRONOUS MOTOR APPLICATIONS-Continued TYPICAL TORQUE REQUIREMENTS In Percent of Full-Load Torque Max. "L d APPLICATION Unloaded Loaded Unloaded Loaded P-11-Out oa Wk2" Ratio 4-PULP AND PAPER MACHINERY (Approx.) Beaters-Standard ..................... ..... 125% ..... 100% 150% 5 5 -Breaker ...................... . ..... 125% 100% 200% 250% 30-100 1 Chippers (empty) ...................... 60% ..... 50% ..... 150 Hydraupulpers ........................ ..... 125% 125% % 50 ..... 1 Jordan (plug out) ..................... 50% ..... 50% ..... 1 % 150% 5 Pulp grinders-Magazine type......... . 50% 50% ..... 4 -3 or 4 Pochet type ....... 40% ..... 30% ..... 150% 1 Screens-Centrifugal .................. 50% ..... 100% 150% 200 4 Vacuum pumps-(Hytor) .............. ..... 60% ..... 100% % 5 30 1 Wood Hogs ............................ 5-RECIPROCATING MACHINERY 60% ..... 60% 100% 22 % Blowing Engines ....................... Compressors 40% ..... 50% ..... 150% ..... 10 Air and gas ............................ 40% ..... 30% ..... 150% Ammonia (discharge pressures 100 to 30% 150% 7 250 psi) .............................. 1 Ammonia boosters? 40% ..... 4 Freon ............................... Carbon dioxide (with piston rod di- ameter of 30% to 60% of piston diameter) : 40% ..... 50% ..... 150% 5 10 1 Single-cylinder, double acting.... 40-120% ..... 40% ..... 150% - 4 7 Two-cylinder, double acting ...... 40-90% ..... 40% ..... 150% - I Pumps-Positive displacement........... ..... ..... . ? ? ? ? ? ? 150 Started dry ............................ 40% ..... 30% 40% ..... % 150% ..... .? By-passed ............................. 40% ..... ..... 100% 150% Not by-passed (3-cylinder) ............. .... 150% ..... ... 10 1 Vacuum pumps ....................... 6-RUBBER MILLS 40% ..... 60% ..... 150% Banbury mixers ....................... 125% 100% 250% 1 .......................... Line shafts 125% 110% 225% 1 .. .......................... Plasticators 125% 100% 250% 1 . Individual drive ....................... 7-SAWMILLS 125% 100% 250% 1 Saws-Band mills ...................... 80% ..... 40% ..... 250% 50 100 5 -Edger ........................... 40% ..... 30% ..... 2 % 10 -Gang' .......................... 60% ..... 30% ..... 200% 1 -Trimmer .. 40% ..... 30% 200% 30 1 Wood hogs ............................ 8-MISCELLANEOUS 60% ..... 60% 100% 225% ' Blowers-Positive displacement, 40% 150% 8 rotating, cycloidal type .............. 6 Bowl mills-(coal pulverizer) 40% , ,, ,, (with common motor for pulverizer 125% 150% ? ? ? ? . and exhaust fan) .................... Compressors-Positive displacement, rotating, sliding-vane type: ..... 150% 50 By-pass open.. 60% ..... 30% ..... 1 % 150 ..... Inlet open, by-pass closed.......... ..... 60% ... 100% % ?... 15 5 1 Flour mill line shafts .................. ..... 175% 110% 150% 150 - 25 1 Gas cleaners-(Thiessen) .............. 40% ..... 60% % 1 Vacuum pumps-(Ilytor) 150% 4 In other than paper mill service...... 40% ..... 60% 1 These applications have high inertia, and the Wk2 of the load may require a motor design which cannot be determined from the for ue requirements alone. For these applications the motor manufacturer should always be provided with the actual value of the Wk2 of the load. 2 a 4 The torque requirements may vary for the individual machine. The manufacturer should be consulted 5 May require higher torques under certain conditions; such as starting with cold air when rating is based upon normally warm air. 6 On some mills the exhaust fan may be separately driven and different torque values will apply; in either case the mill manufacturer should a consulted. s s At sng method. "Te:??~ '"17 ?~"~ ,? ?;~ ..ailhnua~aihYwvaith alilieren~pR~9PS1litA>A'iSIP- YNCH b10p~0S p0ro ved For Release 1999/09/10 : Cl -RDP83-00423RO01200450002-7 CPYRGHT MOTORS Fig. H-57. This pedestal-bearing, 1000-hip, 720-rpm synchronous motor has direct-connected exciter. synchronous motor applications are given in Table 18. Standard horsepower ratings, voltages and speeds of synchronous motors are given in Tables 17A, B and C. CONSTRUCTION OF SYNCHRONOUS MOTORS Synchronous motors nay be divided into two general classifications: (a) Hig -speed motors, operating at speeds of 500 rpm or more, and (b) low-speed motors, having speeds below 500 rpm. High-Speed Motors For high-speed synchronous-motors, the temperature rise, based on an ambient temperature of 40 C, normal conditions of ventilation' and an altitude o:' 3300 feet (1000 ,meters) or less, will not exceed: Unity power factor motors : Armature.............40 C by thermometer Field .............. ... 50 C by resistance Leading power factor ;motors and all motors having greater than normal torques: Armature..............40 C by thermometer Field ..............1...60 C by resistance End-shield bearing construction is generally con- sidered standard up to and including the following ratings; these limitations' may be exceeded for certain steady-load applications such as centrifugal com- pressors, at speeds from 600 to 900 rpm: Hp per Rpm Rpm 1.0 Pf 0.8 Pf 500 to 900......... . 1.0 1.0 1200 ............. . 1.0 0.8 1800 .............. 1 .0.7 0.;i Larger motors are generally furnished with a base and two pedestal-type bearings. Provision :l'or stator shift (to facilitate inspection and repair of windings) is not standard but can be obtained at slight extra cost Fig. H-58. Rotor for 900-hp, 0.B-pf, 900-rpm synchronous motor shows collector ring details. Lo i-Speed Motors he temperature rise for standard :low-speed moto is 5 C, that is, 10 C higher than for high-speed motor However, the use of motors. with this temperature ri is u wally confined to such applications as reciprocatin co pressors and other non-overloading drives. Motoi wit] i the same temperature rise as high-speed units ar ava lable and essential for many types of application sue] L end as metal rolling mills, ball mills, etc. )w-speed motors are available in engine-type shield bearing, and pedestal-bearing construction (Fi s. 54 to 62.) Engine-type units, which are furnishe without shaft, base or bearings, are widely used fa app ications such as reciprocating compressors. End shied bearing construction is limited to some smalle ratings. Pedestal-bearing construction, with base ar ranted for stator shift optional, is available in al larg r sizes. - Ve ical Motors V rtical construction is generally available for mos rati gs and is widely used for pump drives. in most ratings, except that it is usuall ALLIS-CHALMERS MFG. CO. P y impractical Fi -59. Verticals o u o gently in four anc~op veO'Fet- Release 1999/09/10 : fRD i Qo1I i Z rpm. CPYRGHT Approved For Release 1999/09/10 : CIA-RDP83-00423R001200450002-7 H-31 ZTiml-FIKUNOUS MOTORS Fig. H-60. Enclosed synchronous motor rated 4500 hp driving roughing stand in eastern steel mill. Excitation Field excitation should be provided from a source that is not subject to circuit interruption. Direct- connected exciters are preferable for high-speed motors. For low-speed units, belted exciters or separate motor-generator sets are recommended. MOTOR PROTECTION Classification of machines by types of mechanical protection and methods of cooling will be found in the definitions on pages 4 to 9. Accompanying illustrations show some of the types applicable to synchronous motors, and Table 19 gives a brief summary of such features. Because synchronous motors are not built in ratings as small as induction motors, some types (such as totally-enclosed non-ventilated construction) are not practical. DATA ON COMPARISON As a further aid to motor selection, the various characteristics of synchronous and induction motors have been summarized in Table 20. Fig. H-61. Five 3500-hp, 11,200-volt, 257-rpm syn- chronous motors driving paper mill pulp grinders. Fig. H-62. Built for cement grinding mill use, this synchronous motor is rated 1500 hp, 180 rpm. TABLE 19-SUMMARY OF PROTECTION AND ENCLOSURES-SYNCHRONOUS MOTORS Standard Type of Approximate Temperature Rise Approximate Enclosure Range of Sizes Class A Insulation Cost Increase Application Information Drip-proof All ratings Same as open motor 4 to 10% Protection against dripping liquids or falling particles. 15% Protection against dripping and splashing liquids. Enclosed collector All ratings Same as open motor 4 to 30% Used in both explosive and rings non-explosive at- mospheres. Totally-enclosed, High-speed 55 C 135% Used where abrasive dust, fan-cooled only dirt, grit, or corrosive Approved For Release 1999/09/10 : CIA-RDP83-00423R00''4=V2T7 ere for Enclosed, forced- All ratings ventilated Enclosed-self- High-speed ventilated only H-32 Approved For Release 1999/09/10 : Cl RDP83-00423R001,200450002-7 - SYNCHRONOUS CPYRGHT CONDENSERS TABLE 20-COMPARISON OF GENE AL CHARACTERISTICS OF SYNCHRONOUS AND IND UCTION MOTORS Synchronous Motors Induction Motors Power Fact r Operates at unity (1.0) power factor with current in phase with Po wer factor is always lagging due to magnetizing current re- eed and large motors than hi h-s h hi It i voltage, or at leading power factor with current leading voltage. q Hence, eminently suitable for power factor correction or im- in g p er in g s rements. low-speed and smaller motors. It is highest at full load and provement. de reases with decreasing load: Speed The speed is an inverse function of the number of poles and B ( the power supply frequency, with which the motor is synchro- sy l h d h cause of slip, standard motor speed is a few percent below ichronous speed but remains constant under constant load ue motors have higher slip. Motors ecial hi h-tor S diti e co ess t ange un nized. The speed is constant and cannot be c frequency is changed (except in the case of two-speed motors, ca d q g p ons. i be designed as high-slip machines, with slip of 5 to 12 percent i di e which are available in the larger sizes only). ze. ng on s pen Wound-rotor motors with external adjustable resistance in ro or circuit can provide a wide range of ispeed. Constructio n Salient poles, an amortisseur winding, and a field winding with T lace the simpler cage rotor of the induc- a re a collector assembl e polyphase squirrel-cage motor is the simplest in construction for that reason it is the most reliable of all motors. y p tion motor. The wound-rotor type has a phase-wound rotor winding, Motor is started with the field circuit closed through a re- co sistor to prevent injury from high voltages due to transformer de action. When excitation is removed, on shutting down the motor, re lector rings and brush rigging, but these do not affect its pendability. However, wound-rotor motors for plugging duty uire special attention in design because of the double normal the field is closed through a resistor to protect windings from vo high discharge voltages. With present control, failure from these ltage when plugging on full voltage. sources seldom occurs. Auxiliary App ratus Requires a separate exciter with shunt field rheostat, or a motor N auxiliary apparatus is required for squirrel-cage motors. field rheostat if excited froln a source common to several motors. ound-rotor motors require secondary control. Requires additional metering and field switches on the auxiliary control. Torques and Start ng Kva Starting, pull-up, pull-in, and pull-out torques ample for nearly all types of constant-speed applications are obtainable. High- to otor design classification determines variation of cage motor rques from starting to breakdown. Locked-rotor (starting) speed motor torques have been standardized by NEMA for cu rrent for general-purpose ratings is in accordance with NEMA common applications, but other values can also be obtained. st ndards, and ranges from 400 to 650 percent for large ratings. Locked-rotor (starting)! current is proportional to torque requirements. It ranges from 250 percent for low-speed, low- re Starting currents for wound-rotor motors depend on secondary sistance and nature of the load. Starting current may be as torque compressor motors .to 600 percent or more for high-speed, 1 as 25 percent for first step and usually will not exceed 250 high-torque motors. t 300 percent for full-load torque. Average accelerating current fo r average conditions is 125 percent. Starting Met hods May be designed for starting (1) on full voltage, (2) on reduced squirrel-cage motor may be started on reduced or full voltage. voltage by means of an a@itotransformer or a reactor, or (3) by li t the latter case a push-button-operated magnetic line con- the part-winding method,] in which full voltage is applied suc- t a ctor may be all that is needed. cessively to each of several sections of the stator winding. Manual or fully automatic magnetic controls are available With present-day controls providing at least some automatic fo r both the primary of cage and wound-rotor motors and the functions, such as automatic field application, starting has a condary of wound-rotor motors. become nearly as simple as for cage motors. Some precautions must, of course, be observd in selecting the control; for example, a motor designed to start a machine wholly or partially unloaded should not have a control 'arranged for automatic resynchroniza- tion unless the driven maphine also has an automatic unloading device. Controls are usually semi- or fully-automatic and provide protection for various causes of failure. Sizes and - Efl'i encies Not extensively used in ratings below 40 or 50 hp. In ratings smaller than this, it is always a good idea to consider induction P able 10 shows the efficiencies of standard induction motors. olyphase induction motors can be built in any practical size motors for high speeds and gearmotors for low ?.peeda. a d speed. The only limit to size is the capacity of the au orting and effect of lagging current limitations startin r s stem For high speeds, weights and dimensions are comparable to p those of squirrel-cage motors except as added to by the exciters. p , g y , we wer factor on the system. For lower speeds, the synchronous type gradually becomes smaller, than the induction type; this is particularly true at unity fo For very large sizes at low speeds, such as large pump motors r irrigation projects, the synchronous motor usually warrants power factor. p reference. ties for unity ower-factor motors are somewhat proxima s u CPYRGHT Approved For Release 1999/09/10 : CIA-RDP83-00423R001200450002-7H-33 SYNCHRONOUS c^nNn~r~ccne rig. H-63. Air-cooled synchronous condenser with wound-rotor induction starting motor. SYNCHRONOUS CONDENSERS A synchronous condenser is essentially a synchronous motor running without load while connected to an lectrical system. From an economic standpoint their se is confined to the larger systems where correction values are 1000 kva and over. These condensers can lso be described as synchronous phase modifiers nning without mechanical load, whose field excitation an be varied so as to modify the power factor of the ystem, or through such modification to serve as oltage regulators. Fig. 63 shows a 12,500/6250-kva, 160-volt, 900-rpm air-cooled synchronous condenser 'th its wound-rotor starting motor. Small condensers are mainly used for their corrective fleet on system power factor, by supplying reactive va to the system. The condenser may be controlled Fig. H-64. Air-cooled synchronous condenser rated 25,000/12,500 kva is used in a southern steel plant. to maintain a given system power factor, or it may be operated at full leading kvar to supply all or part of the system reactive kva. If the condenser is over- excited it supplies leading kva, and if under-excited it supplies lagging kva. In either case, system losses are reduced, and capacity is released for useful work. Synchronous condensers are also much used for system voltage regulation. This function is especially important on long high-voltage transmission systems with high line charging capacity and loading. The inertia of a synchronous condenser improves the speed regulation and overall stability of the system. The flywheel effect (Wk2) enables the condenser to act momentarily as a generator to reduce system dis- turbances caused by sudden load increases. System improvement depends upon the inertia ratio ABLE 21A-NEMA STANDARD KVA, SPEED AND VOLTAGES, AIR-COOLED SYNCHRONOUS CONDENSERS Leading Lagging Speed Voltage Ratings Kva Kva 60 Cycles 240 480 600 2400 4160 6900 *11,500 13,800 100 50 1200 x x x x x 200 100 1200 x x x x x 250 125 1200 x x x x x 300 150 1200 x x x x x 400 200 1200 x x x x x 500 250 1200 x x x x x 750 375 1200 x x x x 1000 500 1200 x x x x x 1500 750 1200 x x x x x 2000 1000 900 x x x x x x 2500 1250 900 x x x x x x 3000 1500 900 x x x x x 4000 2000 900 x x x x x 5000 2500 900 x x x x x 7500 3750 900 x x x x x 10000 5000 900 x x x x x 15000 7500 900 x x x 20000 10000 720 x x x 25000 12500 720 x x 30000 15000 720 x x 40000 20000 Inn 75000 37500 514 X *This ratilfei-i4 v6d F eFW dl9 /1ot elA D,P88 OO 23 R001200450002-7 H-34Approved For Release 1999/09/10 : CIA-RDP83-00423R001200d4gT- CONDENSERS Fig. H-65. Outdoor installation of 40,000/16,800- kva, hydrogen-coaled synchronous condenser. of the system and the condenser, which is influenced by the size of the condenser. For example, the inertia constant II ranges from 1.0 for a 5000-k,za condenser to 2.0 for a 75,000-kv'a condenser, in the case of air- cooled condensers rated at 13,800 volts. Synchronous condensers are available in two forms, air cooled, including indoor and outdoor types, and hydrogen cooled. The! construction of the indoor air- cooled condensers is wi~ry similar to that of an ordinary synchronous motor. hey depend for cooling on the free circulation of air i through and back of the core and windings of the .'stator. Outdoor ai::?-cooled con- densers may be either! self-ventilated, or they may be totally enclosed, using a recirculating ventilating sys- tem with coolers in the foundation. Ratings 3,000 kva and larger are availably in the completely enclosed type. Table 21A gives the NEMA ratings for air-cooled synchronous condense. Maj or operating dvantages of hydrogen-cooled condensers can be summarized as follows. First, the windage loss drops about 90 percent for average operating conditions, with a consequent drop in leading kva load losses. Second, the higher heat transfer coefficient of hydrogetr makes for better output from a given rating, and pe I rmits operating under overloads. TABLE 21B-NEMA STANDARD KVA, SPEED AND ,VOLTAGES HYDROGEN-COOLED ! SYNCHRONOUS CONDENSERS Finally, maintenance is reduced because damage to t insulation from corona-produced ozone is prac- tically eliminated, and so is overhea-ting caused by the accumulation of dirt in the ventilating passages. Fig. 65 shows a hydrogen-cooled condenser installed in a substation, and Table 21B gives the NEMA r ings of such condensers. Excitation Exciters are usually of the direct connected type. I cases where condensers are serving as voltage regulators, the condensers, must be able to deliver both lagging and leading kvar, possible variations ranging from 40 percent lagging to 100 percent of the le ding capacity. An excitation system that acts accurately and rapidly is necessary to obtain a smooth variation of k ar over the entire operating ranges. The system recommended for both large air-cooled condensers and hydrogen-cooled condensers consists of the following equipment: 1. Direct connected stabilized main exciter. 2. Standard motor-operated main exciter field rheo- stat (for manual control in emergencies). 3. Motor driven Regulea, exciter set. 4. Static impedance type automatic voltage regu- lating control, using :a saturated transformer and a discriminating circuit. Starting There are several way$ available for starting syn- onous condensers, but, reduced voltage starting f om autotransformers is the one most commonly u ed. Taps are provided for from approximately 20 to 3 percent of rated voltage, depending on the require- ents of the system. As the larger condensers are p ovided with high pressure lubrication, which reduces tie breakaway torque, most machines can be started ith no more than full lead line current when auto- tfansformers are used. If minimum starting kva is desirable for any reason, direct connected wound-rotor induction motor can used. The motor is designed with two poles less than t fie condenser in order to accelerate the latter to nchronous speed, and the condenser is synchronized s y ith the power supply in the same manner as a syn- +ronous generator. The motor and control are usually ased on a starting time of about 2-1/2 minutes for Leading Lagging Speed Voltage Ratings Kva Kva 60 Cycles 4,160 6,900 *11,500 13,800 # 15,000 6,300 900 X X X X 20,000 8,400 900 X X X 25,000 10,500 720 X X 30,000 12,600 720 X X 40,000 16,800 720 X X 50 000 21 000 6 0 X X , 60,000 , 25,200 6D0 x 75,000 31,500 514 X *This i~ is not pf !k'M1'&t' W Rel?I'e%te Ngwb `Th'b't: CIA 5000-kva condenser, and up to 5 minutes for the rger sizes. :ondensers as Power. Factor Correctors The application and effect of a synchronous con- enser for power factor correction can probably be est shown by taking a concrete example. This case is xRDPa3 Oe423RQ OO45oOO-7j improve Approved' For Release 1999/09/10: CIA-RDPO-d63W001200450002-7H-35 the power factor of a 300-kw system operating at 0.75 pf. The first step is to express the components of the system as shown in Fig. 66. 300 Kw B Fig. H-66. Vector presentation of a system delivering 300 kw at 0.75 power factor. A 300 KW=ENERGY COMPONENT B Fig. H-67. Determination of condenser output needed to raise power factor from 0.75 to 0.9. H U. W SYNCHRONOUS kw Using the equation pf = kva and solving for kva 300 we have 0.75 or 400 kva. In Fig. 66 line AB equals 300 kw. Since kvar is always at right angles to kw, the perpendicular BH is erected at B on AB. With A as a center, and a radius equal to 400 kva an are is described that cuts BII at C. The triangle ABC shows graphically the total kva (AC) of the generator, its energy component (AB) and the wattless component (BC), which is 264.5 kvar. The triangle also shows the phase relation between AB and AC : angle A. This angle need not be determined be- cause its cosine (AB) equals the power factor, 0.75. As the next step, using the same equation pf = k a and assuming that a power factor of 0.9 is desired, solving for kva shows that the system must be altered (kva \ so that it delivers only 333.3 kva = 300 0 9 J Then using the triangle already developed, with A as a center, and 333.3 kva as a radius an are is described that cuts BC at E (Fig. 67). By scale, or otherwise, BE = 145.2 kvar, and EC = 119.3 kvar. Therefore, a synchronous condenser with an output of 119.3 kva at zero pf leading would correct the system power factor to 0.9. To take another phase of the problem, assume that it is desired to find out what the effect would be of adding a 150-kva condenser; 150 kvar is laid off on line CB. The value of AK can be found by scale measurement, or by solving the triangle; ABK, to be 321.1 kvar. (Fig. 68.) The resultant power factor is 3200 = 0.93.4. DIRECT-CURRENT MOTORS Direct-current motors are used for applications that require continuous operation under fairly constant load (such as fans, blowers, line shafting) in plants having direct-current rather than alternating-current power service. In addition, they are used for applica- tions such as machine tools when fine speed adjustment and other characteristics of dc motors are so necessary that the cost of conversion equipment is warranted when the source of electrical power supplies alternating current. Direct-current motors are divided into three classes: series, shunt and compound wound. These terms refer to the relationship of the connections between the armature and fields. Each type is explained briefly below, while Table 22 on page 36 provides a ready ti li ti d h f h ca ons an opera ng c ar- e app t H-68. Effect of adding a 150-kva synchronous comparison o Apprm nF*rbftJG0l0.1999/09/10 : CIAE b 83-00423 R001200450002-7 H-36Approved For Release 1999/09/10 : CIAO-RDP83-00423 R001200450d92-- GHT DC MOTORS ' TABLE 22-COMPARISON OF GENERAL CHARACTERISTICS OF DC MOTORS Series Motors Shunt Moto s Applieatio s Where speed can be regulated and where Wt-ere starting conditions are not severe Required where high starting torque high starting torque is necessary. Car and where constant or adjustable speed combined with fairly constant speed is retarding, traction, car dampers, hoists, is :necessary. Metal wor mg machines, necessary. Conveyors, plunger pumps, gates, etc. elegy ators, centrifugal pu s, line shafts, bending rolls, punch presses, elevators High. Varies as square of voltage. Limited by commutation and heating. High. Limited by comin.utation and heating. Zero to maximum, according to load and control. Speed varies inversely with the load. Races on light loads and full voltage. Good. Constant field, va: voltage applied to armat High. Limited by heating. es directly as .re. Speed Cent Any range desired, actor mol;or and system. TABLE 23A-STANDARD HORSEPOWER RATINGS -DC MOTORS GENERAL-PURPOSE MOTORS: 1/2; 3/4, 1, 1-1/2, 2, 3, 5, 7-1/2,10,15, 20, 25, 30, 40, 50, 60, 75, 100, 125, 150, 200. LARGE MOTORS: 250, i 300, 350, 400, 500, f'00, 700, 800, 900, 1000, 1250, 1500, 71750, 2000, 2250, 2500, 3000, 3500, 4000, 4500, 5000, 5500, 4000, 7000, 8000. TABLE 23B-STANDARD VOLTAGES-DC: MOTORS Voltage Approximate Hp Range 115 1/2 - 30 230 1/2 - 200 250 250 - 1D00 600 250 - 8D00 TABLE 23C-STANDARD Speed in Rpm SPEEDS--DC MOTORS Approximate Hp Range 3500 1-1/2 - 40 1750 1 - :100 1150 3/4, - 800 850 1/2 - 1't50 690 1/2 - 2250 575 3/4 - 2500 500 3/4 - 3000 450 1 - 3500 400 1 - 4000 350 1 - 4500 300 10 - 5000 250 20 - 5000 225* 250 - 5000 200 75 - 5000 175* 250 - 6000 150 75 - 7000 140** 7000 - 8000 130** 7000 - 8000 125* 250 - 6000 120** 7000 - 8000 110* 250 - 8000 100 75 - 8000 90 500 - 8000 80 600 - 8000 70 700 - 8000 65 800 - 8000 60 800 8000 55 900 - 8000 50 1000 - 8000 Higher than for shunt motors, according to amount of compounding. High. Limited by commutation and heating. Any range desired, according to type of motor and control. Drops 7 to 25 percent from no load to full load, according to type of motor and control. he armature and fields of the series motor are co netted in series (Fig. 69), and the speed of the motor varies inversely with the load; that is, the speed increases as the load decreases. This is due to the change in field strength with changes of current in the fie caused by the load on the motor. or this reason, a series motor should never be applied to a drive which can become unloaded. In ge eral, a series motor should be direct-coupled to its loa 1, for with full voltage 'applied and without load, its speed increases to the destruction point. odifications of the series motor include a small shunt winding of sufficient strength to prevent the mo or reaching dangerous speed but not materially ch nging its series characteristic. he armature and fields of the shunt motor are co' spe to d ng to type of ected in "shunt" or parallel (F'ig. 70), and the d of the motor is practically constant. This is clue he constant strength of the field. odifications of the shunt motor include a small seri~s winding of sufficient strength to assure a drooping shu con d characteristic over a field weakening range. his type of motor is commonly called a stabilized t motor. Connections are the same as shown for pound-wound motors. COMPOUND MOTORS The compound-wound motor has both series and shunt windings (Fig. 71), resulting in the characteristics of both series and shunt motors. That is, it provides *These s cods standard f r motors larger than 200 h on1 ., hig starting torque and constant speed. The exact **These roved Fou Release 1n989A9/~10 : ({. aR &3 -004a23d 0> 12~4~5Q0Q2* r will Speed Regula ion Varies with size and spec range from 2 to 75 percent. Close regula ion obtainable with special control. CPYRGHT Approved For Release 1999/09/10 : CIA-RDP83-00423R0012004500Q 7MOroRs Fig. H-72. Armature for small dc motor. Fig. H-69. Field and armature relationship in a series-wound dc motor. Fig. H-70. Field and armature relationship in'Ja shunt-wound dc motor. Fig. H-73. Field yoke ready for insertion of special compensating winding in pole faces. Application Information Protection against dripping liquids or falling particles. Protection against metal chips in machine shops, etc. Combines above features. Protection against dripping and splashing liquids. Same as totally-enclosed. Same as totally-enclosed. Used where abrasive dust, dirt, grit, or corrosive fumes are too severe for open motors. Metal- working plants, foundries, ma- Fig. H-71. Field and armature relationship in a compound-wound dc motor. depend upon the relationship of the series and shunt fields. Standard horsepower ratings, voltages and speeds of direct-current motors are given in Table 23. MOTOR PROTECTION Classification of machines by types of mechanical protection and methods of cooling will be found in the definitions on page 4. Illustrations on pages 5 to 9 show the construction employed for various types, and Table 24 gives a brief summary of such features. This table shows (a) the approximate range of ratings in which each type is built, (b) the maximum temperature rise for Class A insulated machines, (c) the approximate increase in cost over the standard open type, and (d) application suggestions. Type of Approximate Temperature Approximate Enclosure Range of Sizes Rise Cost Increase Drip-proof All sizes 50 C 2% 40 C 10 to 17% All sizes 50 C 5% 40 C 12 to 20% Drip-proof, All sizes 55 C 5% fully protected 40 C 12 to 20% Splash-proof All sizes 50 C 8 to 15% 40 C 16 to 27% Separately ventilated All sizes 40 C 9 to 15% Self-ventilated All sizes 40 C 15 to 30% Totally-enclosed: Non-ventilated 1/2 to 15 hp 55 C 35 to 110% Fan-cooled 1 to 100 hp 55 C 35 to 90% Approved For Release 1999/09/10 : CIA-RDP83-00423RObl OF45DD02-7 H-38 CPYRGHT: A Dproved For Release 1999/09/10 : Cl DC MOTO -RDP83-004238001200450002-7 EFFECTS OF VOLTAGE VARIATION Direct-current systems, like alternating-current sys- tems, are subject to variations in voltage above or below the rated value.: Standard-voltage motors will operate successfully, but not necessarily in accordance with standard guarantees, at voltages 10 percent above or below the nameplate stamping. Table 25 shows the general effects of operating shunt and compound-wound motors at voltages above and below normal. ADJUSTABLE-SPEED CONTROL In many plant operations adjustable-speed control is essential to production efficiency and product quality. In metal-working shops rubber mills, paper mills, and textile finishing plants,; for example, the advantages of having operating speeds that can be exactly ad- justed to suit the dimensions, materials and. conditions that affect quantity and quality of production can hardly be overemphasized. Where do power is available, obtaining adjustable speed presents few difpiQulties, for do motors have the characteristics most desirable for adjustable-speed service. And a wide ariety of control equipment makes it possible to select a suitable drive for prac- tically any application. Where only the more (widely used 3-phase ac power is available adjustable-speed operation is not as readily obtainable, but neither xs it impossible of attainment. In either case, it is inrportant not to overlook the fact that selection of a satisfactory method of speed control, when required, can quickly pay for itself with even a slight increase it daily output. Following is a summary of the principal methods available for plants having direct current and for those limited to alter- nating current : Fig[ H-74. Test assembly: of shunt-field controlled wi -drawing machinery with 30/40-hp dc motors. Direct-Current Plants Shunt-field control. Armature control. Combined shunt-field: and armature control. Variable-voltage control. Al ernating-Current Plants 1. Wound-rotor induction motors. . Multi-speed induction motors. . Use of conversion equipment to provide de power. Page 11-48. Variable-pitch V-belt drives. Magnetic or hydraulic couplings. SHUNT-FIELD CONTROL ariation in the speed of a shunt-wound or stabilized shut-wound motor is obtained by inserting an ad- justable resistor in the shunt-field circuit of the motor. This provides adjustable-speed control because the sped of the motor varies inversely with the strength TABLE 25-EFFECTS OF VOLTAGE VAtIATION ON DC MOTORS STANDARD SHUNT OTORS Voltage Variation from Normal Full Load 75% Load 50% Load 10% low Slightly lower No change Slightly higher 10% high Slightly higher No change Slightly lower 20% high Slightly higher No change Slightly lower Percent Starting Full Maximum Load Full Load Running Speed Current Torque -5% +11-1/2% -16% Maximum Overload Temperature Rise, Capacity Full Load -16% Main field higher. Commutator, field and armature higher. +15% Main field higher. Commutator, field and armature lower. +30% Main field higher. STANDARD COMPOUND-WOUND MOTORS 10% low Slightly lower; No change Slightly higher -6% I+11-1/2% -16% -16% Commutator, field and armature lower. Main field lower. Commutator, field and armature higher. 10% high Slightly higher No change Slightly lower +6% -8-1/2% +15% +15% Main field higher. Commutator, field and armature lower. 20% high Slightly higher No change Slightly lower +12% -17% +30% +30% Main field higher. Approved For Release 1999/09/10: CI -RDP83-00423R00120&UWifwA sower. CPYRGHT H-39 Approved, For Release 1999/09/10 : CIA-RDP83-00423ROO12O 9 Q LL SPEED Fig. H-75. Variable-voltage and shunt-field control are used for 600-hp, flywheel-type tube-mill motor. of the fields. That is, the stronger the fields the lower the speed; as the fields are weakened the speed in- creases. As the strength of the field is decreased, the torque delivered by the motor also decreases; but since the speed increases proportionately, the horsepower output of the motor would be expected to remain constant. However, due to increased ventilation at the higher speeds, the horsepower capacity will actually be slightly more than at the low speeds. This increase in capacity can be used to advantage in providing an economical drive. The efficiency is relatively high at all speeds, and the speed regulation from no-load to full-load can be held within close limits. Motors with speed ranges of 4 to 1 are regularly supplied, and ranges of 6 to 1 are sometimes practicable. The limitation to the speed increase is the ability of the motor to carry the load at the high speeds without sparking. Compound-wound motors are sometimes used for this method of speed adjustment, but the results are not as satisfactory as with shunt or stabilized shunt- wound motors. When the compound-wound motor has its shunt fields weakened to too great an extent, it more nearly approaches the characteristics of the series motor-with the inherently poor speed regulation of the series type. ARMATURE CONTROL Speed control using this method is obtained by inserting a variable resistor in the armature circuit. A shunt-wound motor is generally used. Speeds obtained are below the normal motor speed, and the horsepower output decreases directly with the speed. Armature control is not usually employed for speed reductions greater than 50 percent below normal: The efficiency of the motor is reduced at the low speeds, and the speed regulation, while satisfactory at the high speeds, becomes poor as the speed decreases. Nevertheless, the armature control method can be Fig. H-76. Planer drive with 30-hp motor also has combined variable-voltage and shunt-field control. is so small that the low efficiency is not important, and where a constant-horsepower output with close speed regulation is not required. This system is frequently used for fans and blowers, especially where the unit operates at the low speeds for only a few hours a day. By using a compound-wound motor it is possible to obtain better starting characteristics for heavy loads than with the shunt-wound motor; but because ` 'of poor speed regulation, adjustment should be limited to about 30 percent below normal. Series-wound motors are occasionally used with armature control for adjustable-speed service. Of course, with this type of motor, increased load will result in decreased speed, and decreased load will result in increased speed. Their principal use is for hoisting machinery in which some load is always present. While the load is being lifted, the speed can be adjusted fairly closely by regulating the amount of resistance introduced into the circuit. Series motors are useful where heavy starting loads are involved, since the torque developed is, up to the stalling point of the motor, determined by the load imposed. COMBINED SHUNT-FIELD AND ARMATURE CONTROL Combined shunt-field and armature control provides a wider speed range than can be obtained by either system alone. The speed is reduced below normal by armature control and increased above normal by field control. Such a combination is used on printing presses, fans, blowers, and similar applications. That is, it is used where low speeds without close regulation are required at times but with most of the operation above normal, since the efficiency by field control is much better than by armature control. VARIABLE-VOLTAGE CONTROL As the name implies, this method makes use of the fact that the speed of the motor will vary in direct proportion to the voltage of the current supplied to the used f(AlDJb1 60d*W Fit o44)W Pt CIA PYP$T b 42T O M64'dt}0-l' where a IIII-e ADuSUffay For Release 1999/09/10 : CIAO-RDP83-00423R001200450&e2YI GHT smooth, gradual increase in speed is needed-over a wider range than cart usually be obtained by other methods. In its simplest fora this system consists of (a) an adjustable-speed dc motor, (b) a motor-generator set to supply the power-,t variable voltage---to drive the motor, and (c) a constant-potential sou:?ce of direct current for exciting the fields of both the adjustable- speed motor and the motor-generator set generator. The armature of the generator is connected elec- trically to the armature of the adjustable-speed motor. Since the motor has its fields separately excited at a permanent flux value, its speed will be in direct propor- tion to the voltage stiipplied by the generator. The torque imparted to the motor armature will remain practically constant atall times. Thus the horsepower output of the motor ill vary with the r.'iotor speed, being greatest at the highest speed. Speed control is just as simple as for shunt-field control. It is accomplis#ied with a field rheostat in the shunt field of the generator. Speeds of :10 to 1 are frequently used, while 4 15 to 1 or even 20 to 1 range may be obtained under favorable circumstances. Speed regulation is at its best at the higher speeds; at the lowest speeds it is close enough to be satisfactory for most applications. The efficiency at high speed is not as high as with other forms of control; a.t low speed the efficiency is higher than with armature control but lower than with shunt-field control. It is more economi- cal in the use of power than either of the other two methods. TABLE 26. SUMMARY OF PRINCIPAL M M th d Range of Speed Speed e o Hp Ratings Range Regulation Shunt-field t l 1/2hp 4 to 1, Can be held con ro and larger sometimes within close 6 to 1 limits. Ar comature 1/21hp 2 to 1 Satisfactory al and I#rger high speeds, not so good at low speed Motor field weakening; above base speed may be employed along with variable-voltage control to pro- vide a very wide speed range of do motor operation. The variable-voltage system can, be used in both a and dc plants. When used on alternating current, the generator is usually driven by a squirrel-cage induction motor; larger sets may be driven by syn- chronous motors, and flywheel sets for reversing hoist o metal rolling mill motors are driven by wound- ro or motors. Excitation is usually provided by an exciter direct-connected to the motor-generator set. For the smaller horsepower drives, the last few years have seen increasing use of electronic tubes to rectify alternating current to direct current to power d motors. See Section Q.. A wide motor speed range may be obtained by varying the output voltage of the power tubes. Excitation for the field of the motor is a ho obtained from electronic tubes. In addition, by su tably controlling the power tube output, motor IR drop compensation may be obtained, providing very god motor speed regulation even at very low speeds. T le 26 gives a summary of the principal methods of sp ed control. METHODS DISCUSSED ELSEWHERE he use of wound-rotor and multi-speed squirrel-cage motors is discussed in the section on induction motors (se pages 20 and 21, respectively). Equipment for converting alternating current to direct current is discussed in various sections of this book, including the preceding section on variable-voltage control and a subsequent section on motor-generator sets. THODS OF SPEED CONTROL Torque Characteristics Remarks Reduction of Most frequently used of all torque as speed for dc adjustable-speed increases. motors. Horsepower de- Used principally for smaller creases directly motors and where oper- with speed. ation at low speeds is for only a few hours a day. Series motors used for hoist drives. ombined shunt-field 1/2 and 1 rger 6 to 1 See above See above andarmature listings. listings. control Variable l 1 lip 10 to 1, Good at high To i vo tage and larger sometimes; speeds, satis rque rema ns constant. 15 or 20 factory at to I low speeds. Wound-rotor 3/4 hp 2 to 1 Poor at reduce Ho d motor and larger speeds. rsepower e- creases with i speed. 1/2 lip d l 2to 1, Same as single. Constant horse- an ager 3 to 1, speed motor. power, constant or Approved For Rele`aae 1999/09/10 : Cl -RDP torque s4'vbt?O -7 Used where most operation will be above normal speed. Requires separate motor- ! generator set. Iligh starting torques; low efficiencies. Gives 2, 3, or 4 fixed speeds, except when wound-rotor Approved For Release 1999/09/10 :CIA-RDP0 0012004500c9 - H-41 RATORS GENERAL Fig. H-77. Geared turbine-driven, 250-kw, 312-kva, 1200-rpm synchronous generators. GENERATORS The rapid growth of power-generating central sta- tions and power-transmission systems has provided industry with an abundant supply of electric power. Development of water power, which accounts for about 25 percent of the total, and refinements in the design of steam-generating equipment have resulted in the production of power at remarkably low cost. Since utilities generate power with large and con- sequently more efficient units, purchased power is economically satisfactory for most industrial purposes. However, there are cases where industry finds it desirable to generate its own power: Where steam is essential in manufacturing processes, it may be ad- vantageous to install a non-condensing turbine-genera- tor unit. In some locations, the advantages of large-scale generation may be unobtainable; on shipboard it is obviously impossible. If continuous operation is impera- tive, it may be essential to provide standby power. The advantages and disadvantages must be carefully weighed, both from the standpoint of cost and manu- facturing efficiency. If the decision favors power generation, the selection must be made between alternating current and direct current. There are fields where only direct current will meet the requirements, such as extra-wide speed range or severe accelerating or reversing duty. For most ap- plications, alternating current is satisfactory, since suitable performance can usually be obtained with ac motors and control, and there are many fields in which alternating current is the only suitable choice. ALTERNATING-CURRENT (SYNCHRONOUS) GENERATORS Synchronous generators are generally divided into three groups, as follows: Fig. H-78. Horizontal hydraulic-turbine driven, 3000-kva, 720-rpm synchronous generator. 2. High-speed generators, operating at 500 to 1800 rpm. 3. Low-speed generators, operating at less than 500 rpm. As the problems involved in the selection and operation of two-pole turbine-generators are so closely related to those of the steam turbine, it has been considered advisable not to attempt to describe this class of equipment here. The following information applies to Groups 2 and 3 only. AC Generator Ratings Alternating-current generators are rated at the load they are capable of carrying continuously without exceeding their temperature guarantees. Each rating is expressed in kilovolt-amperes available at the terminals at 0.8 power factor. Standard ratings for 0.8 pf lagging generators are shown in Table 27A, B and C. 1. Two-pole, 3600-rpm (60-cycle) generators direct- Fig. H-79. Diesel-driven engine-type, 1875-kw, drpe bV6&"PR,6Iease 1999/09/10 : CIA-R f$l9'- d` $PUbSP'2d bo7- ator. H-42 Approved For Release 1999/09/10 : Cl AC GENERATORS TABLE 27A-STANDARD KILOWATT RATINGS- SYNCHRONOUS GENERATOR; The following are NEM4. listings for 60, 50 and 25-cycle, 0.8 power factor lagging, polyphase synchronous generators ex- clusive of turbine-driven, water-wheel and inductor synchronous generators. Kva Kw *a Kw Kva Kw 1.25 1 50 200 4375 3500 2.5 2 12 250 5000 4000 3.75 3 75 300 5625 4500 6.25 5 38 350 6250 5000 9.4 7.5 $00 400 7500 6000 12.5 10 625 500 8750 7000 18.7 15 750 600 10000 8000 25 20 $75 700 12500 10000 31.3 25 1 00 800 15625 12500 37.5 30 11;25 900 18750 15000 50 40 1450 1000 25000 20000 62.5 50 1163 1250 31250 25000 75* 60* 1875 1500 37500 30000 93.8 75 2188 1750 43750 35000 125 100 2100 2000 50000 40000 156 125 2 12 2250 62500 50000 187 150 3 25 2500 75000 60000 219 175 . 3150 3000 *The standard speeds for inclusive. For standard generators, the temperature rise, based on an ambient temperature of 40 C, normal conditions of ventilation, and an altlitude of 3300 feet (1000 meters) or less, will not exceed : Armature (stator).'. .... 50 C by thermometer, or 60 C by temperature detector Field (rotor) ............50 C by thermometer, or 60 C by resistance AC Generator Construct'on High-speed generato1s are usually available with shaft and bearings for coupled duty. End-shield con- struction is, in general, standard for the smaller sizes, while pedestal-bearing construction is available for the larger ratings. Engine-type.and belt-driven generators are also available in the high-speed range. For speeds below 50 rpm, engine-type generators are commonly furnished (Fig. 80); that is, the shaft, bearings and base are supplied by the engine builder. Sole plates for the staor are, however, included as standard equipment ith engine-type generators. When required, two-baring coupled-type or three- bearing belted-type generators can be furnished in the low-speed ratings. Generator field rheostats are normally furnished with ac generators, but may be omitted under tic following circumstances : 1. When the generator is excited from its own individual exciter and the exciter is used for no other purpose. (Fot operation without a generator field rheostat, the qxciter must be of the stabilized type, stable down; to the voltage corresponding CPYRGHT RDP83-00423 R001200450002-7 TABLE 27B-STANDARD VOLTAGES- SYNCHRONOUS; GENERATORS Voltage Approximate Kva Range---0.8 Pf 120 Up to 93.8 240 Up to 875 480, 600 6.3 - 1875 2400, 2500 25 and larger 4160 62.5 and larger TOTE: Higher voltages (4330, 6900, 11,500, and 13,800 , ts) are available, at additional cost, for large generators. 4BLE 27C-STANDARD; SPEEDS--SYNCHRONOUS GENERATORS Speed in Rpm (60 Cycles) Number of Poles Approximate Kva Range -- 0.8 Pf 1800 4 Up to 625 1200 6 12.5 - 3125 900 8 31.3--5000 720 10 31.3- 600 12 31.3- 514 14 31.3 - 450 16 125 400 18 125 360 20 125 327 22 125 300 24 125 277 26 125 257 28 125 240 30 125 225 32 187 200 36 187 180 40 187 164 44 187 150 48 250 138 52 312 129 56 438 120 60 438 109 66 438 100 72 438 When the exciter will never be paralleled with other exciters. When certain forms of automatic voltage regula- tors (which have rheostats or their equivalent contained in the mechanism) are used. to the field voltage required by the generator Fig H-80. Stator and rotor assemblies for a large at_nAo#rbved For Release 1999/09/10: CI-RD 0Q4%R8Cha0 0042-7 CPYRGHT Approved For Release 1999/09/10 : CIA-RDP83-00423R001200450002-7H-43 AC GENERATORS Fig. H-81. V-belt drive is used for exciter economy on this low-speed ac generator. The recommended practice is to include a generator field rheostat, as the same refinement of voltage control cannot be expected when the rheostat is omitted. Exciters Direct-connected exciters (Fig. 82) are preferable for high-speed generators. Standard construction provides for overhanging the exciter armature on the generator shaft, with the field frame supported from the generator end-shield or by an extension of the generator base. Occasionally, two-bearing coupled-type exciters are used. Belted exciters, either V-belt or flat-belt driven, are commonly used for the low-speed generators. Parallel Operation Successful parallel operation of ac generators driven by steam or internal-combustion engines is dependent upon the following: 1. Laminated-pole generators must be equipped with damper windings when one of the prime movers is an internal-combustion engine. 2. The speed characteristics of the prime movers must be similar so that there will be a proper division of load. 3. The governors of the prime movers must be designed and adjusted to prevent hunting, with interchange of power between the generators. 4. The value of the flywheel effect of the units in parallel must be such that: (a) The varying turning effort of the engine does not produce more than 0.5 to 0.6 percent variation in speed when the unit is operating alone. (b) The natural frequencies of oscillation of the units are far enough from the impulse frequencies so that objectionable oscillations are not set up; usually 20 percent difference between impulse and natArpJJrbVMigsse 1999/09/10 Fig. H-82. Small, high-speed synchronous generator has direct-connected overhung exciter. Impulse frequencies are: four-cycle engines- one-half the speed of the engine and any multiple thereof; two-cycle engines-the speed of the engine and any multiple thereof. For any given unit the natural frequency, at which the generator rotor tends to oscillate, can be changed by changing the flywheel effect. Successful parallel operation calls for cooperation between the engine and generator builders. The genera- tor manufacturer can be of assistance by furnishing technical information and by providing the requisite flywheel effect in the generator. Voltage Regulation When an ac generator is furnishing power to a steady load, both its speed and voltage remain constant. Any sudden increase in load, such as might be caused by starting a large motor, will affect both voltage and speed. The effect on the voltage is an instantaneous drop, the extent of which depends on the magnitude of the load change and the inherent characteristics of the generator. After this instantaneous drop, a further and more gradual decrease takes place before the automatic voltage regulator can act to bring back normal voltage by strengthening the generator field. The subsequent rise in voltage is more gradual than the drop, due to the reactance of the field windings (magnetic inertia) of the exciter and main generator rather than the time required for the voltage regulator to act. Should there be a sudden reduction instead of an increase in load, there will be a sudden rise in voltage followed by a gradual decrease to normal. Such voltage fluctuations due to change of load are C NAARb 3 OO423R?dV200 a7 present H-44 Approved or Release 1999/09/10 : CIA-RDP83-00423 R001200450002PYRGHT AC GENERATORS II that can prevent them-The degree of voltage uc ua- 25 percent were Better regu tion will depend on: other reasons. 1. Kva capacity and, pf rating of the generator. 2. Inherent regulation of the generator. 5e ection of AC Generators 3. Kva and pf of the load change. he intelligent selection of ac generating equipment 4. Kva and pf of the load the generator is carrying to meet the needs of a particular installation fully and economically requires mature engineering judgment when the load change occurs. based on experience and on complete information about If the above data is available, it is possible to calcu- the amount and character of the loads to be carried. late the amount of ti4 resulting voltage change and ncluded in this information should be: amount of thereby determine the, effect on the quality of the lig ting load; amount of power load and its average service. power factor; number and size of motors, with details In general, voltage disturbances are caused by two of control showing whether across-the-line or reduced- classes of applications: vo tage starting is used and. the frequency of starting; 1. Starting and stopping of motors or other power de ree of voltage fluctuation that can be tolerated; loads, particularly: told curve showing the variation of total load through- a) Alternating-current elevator motors-for both ou the day and night. passenger and freight service. 3ecause of the limited capacity of smaller systems b) Pump and cgmpressor motors started and co pared to large central-station systems, the question stopped frequently by automatic starters con- of voltage fluctuation is of great importance. If con- trolled by pressure or liquid levels. sic oration of the class of service indicates that the c) Crane and hoist motors. pr bable voltage fluctuations would be objectionable, d) Drives requiring frequent reversal of motors. co sideration must be given. to: e) Motors using; full-voltage starting-particu- Reduction of motor starting currents through the larly high-speed motors. use of reduced-voltage starting of squirrel-cage f) Induction or electric-arc furnaces. motors, or even further by the use of wound- rotor motors. g) Spot welders. . Use of flywheel m-g sets for part of the load-for 2. Variation in motor loads, such as: cushioning the frequent starting of elevator a) Air or refrigeration compressors with auto- motors, for example. matic loading 4nd unloading devices. Use of separate generators for lighting and for b) Punch pressed and similar machines with power. intermittent loads. L. Use of generators with better than standard c) Compressors with insufficient flywheel effect. regulation. Voltage fluctuations must be given part:.cular atten- tion in the case of hotels, apartments, clubs, schools, of the number and size of units which will provide libraries, office buildings, hospitals, and other places efficient operation at times of light load, to provide where reading or close work calls for steady lighting. sufficient standby capacity for emergencies, and to allow Even a 2-volt drop will cause an observable flicker in periodic inspection and cleaning. a 120-volt lamp, and the degree of flicker will increase When full data is not already available, it can fre- with greater voltage drop. Of course, how objectionable q ntly be obtained from'a study of monthly power the flicker is depends to some extent on its frequency. bi In considering the degree to which voltags fluctuation Is. Demand charges will give the peaks to supplement may be tolerated, there are several classes of equipment a rage load data, and in many cases power factor data will also be available. 'T'hese figures will, however, other than lamps which require unusually good voltage us ally have to be supplemented by readings from regulation: re ording or indicating wattmeters and ammeters. X-ray equipment. If such readings cannot be obtained, the various Motion-picture sound projectors. motor loads may be tabulated, and the lighting load Teletype machines, may be estimated from the number and wattage of Continuous-tube seam welders. lamps and their usual hours of use. Magnetic brakes on' some elevator motors may set In plants not already electrified, the required data if the voltage drops more than 10 or 15 percent. In ca be obtained to some extent from engine indicator general, motor control requires a voltage drop of ca ds, by comparison with similar plants which have 40 to 60 percent to shut down motors under their ben electrified, and from figures obtainable from the n s Approved For Release 1999/09/10: CIA-RDP83-00 11-200450002-7 H-45 AC GENERATORS TABLE 28-INFORMATION REQUIRED FOR SELECTING AC GENERATORS GENERAL Type of generator (engine, coupled, belted) ................ Quantity.......... To be driven by ...................... Kva.... Pf.... IRpm.... Phase.... Cycles.... Voltage.... Ambient temperature......... C Temperature rise .......... C Class of insulation: Armature (stator) ...... Field (rotor) ...... Is special insulation treatment required? .................. Are damper windings required? ............................ Excitation...... volts de. Type of exciter ........... ...... Special characteristics (special efficiencies, etc.) .............. MECHANICAL FEATURES Protection or enclosure (drip-proof, splash-proof, etc.) ........ Number of bearings........ Type of bearings .............. Coupling (half, whole, none) ........ Sole plates............ Engine type: Is shaft to be pressed into rotor? ............... Is split stator required? ...... Split rotor? ...... Split hub? .... LOAD DATA Division of load (motors, lighting, etc.) ..................... Voltage regulation required ................................ Make and type of voltage regulator, is used ................. Will generator run in parallel with other generators?......... . If so, give make and kind ................................ Motive power of other generators ........................ Are there any formal specifications? ........................ Additional information .................................... While the foregoing material does not provide a means for solving specific problems, it does indicate the importance of providing complete information to the builders of the power generating equipment. Where consulting engineers draw up specifications, these will usually give all of the required information. A brief outline of the information required will be found in Table 28. TABLE 29B-APPROXIMATE KW RANGES AT-STANDARD SPEEDS AND VOLTAGES-DC GENERATORS 125 Volts 250 Volts 600 Volts General-Purpose General-Purpose Standard Speed in Generators Large Generators Large Large Rpm and Exciters Generators and Exciters Generators Generators High-Speed 1800-1750* 3/4 to 150 1200-1150* 3/4 to 150 900-850* 3/4 to 150 720-700 1 to 150 600-575* 1 to 150 514-500 1 to 150 - 3/4 to 150 200 to 250 3/4 to 150 200 to 300 3/4 to 150 200 to 500 1 to 150 200 to 600 1 to 150 200 to 1000 1 to 150 200 to 250 200 to 750 200 to 500 200 to 750 200 to 1250 200 to 1250 200 to 1250 200 to 1250 200 to 1250 200 to 2500 150 to 2000 200 to 2500 125 to 2000 200 to 2500 125 to 2500 200 to 3500 100 to 2500 200 to 4000 100 to 3000 200 to 4500 100 to 3000 200 to 4500 100 to 3500 200 to 5000 75 to 3500 200 to 5000 75 to 3500 200 to 5000 75 to 3500 200 to 5000 60 to 3500 200 to 5000 50 to 3500 200 to 5000 50 to 3500 200 to 5000 50 to 3500 200 to 5000 40 to 3500 200 to 5000 DIRECT-CURRENT GENERATORS The standard kilowatt ratings of standard direct- current generators and the approximate kw ranges available at the various standard speeds are indicated in Table 29. These speeds are approximately the same as for 60-cycle synchronous generators so that the do machines can be used with the same prime movers. Speeds of generators direct-connected to internal- combustion engines may range from 164 rpm for a 5000-kw unit to 1200 rpm or more for a 25 or 50-kw unit. The lower speeds listed were originally set up for the once popular Corliss-type steam engine. Vertical multi-cylinder steam engines may have speeds up to 500 or 600 rpm in moderate capacities. Since steam turbines perform most economically at high speeds, they are usually geared to dc generators with the maximum permissible speeds for the kw and voltage ratings required. TABLE 29A-STANDARD KILOWATT RATINGS -DC GENERATORS GENERAL-PURPOSE GENERATORS AND EXCITERS: 1, 1-1/2, 2, 3, 5, 7-1/2, 10, 15, 20, 25, 30, 40, 50, 60, 75, 100, 125, 150. LARGE GENERATORS: 175*, 200, 250, 300, 350*, 400, 500, 600, 700*, 750, 800*, 900*, 1000, 1250, 1500, 1750, 2000, 2250*, 2500, 3000, 3500, 4000, 4500, 5000. Low-Speed 450 2 to 125 150 to 1000 2 to 125 400 2 to 100 125 to 1000 2 to 100 360 2 to 100 125 to 1000 2 to 100 327 2 to 75 100 to 1000 2 to 75 300 2 to 75 100 to 1000 2 to 75 277 3 to 75 100 to 1000 3 to 75 257 3 to 75 100 to 1000 3 to 75 240 5 to 60 75 to 1000 5 to 60 225 5 to 60 75 to 1000 5 to 60 200 5 to 60 75 to 1000 5 to 60 180 71/2 to 50 60 to 1000 71/2 to 50 164 10 to 40 50 to 1000 10 to 40 150 10 to 40 50 to 1000 10 to 40 138 10 to 40 50 to 1000 10 to 40 128 10 to 30 40 to 1000 10 to 30 *AppliesAftlfC7VL&ibgiDbf-Rww&w,tsssi,;0, : CIA-RDP83-00423 R001200450002-7 H-46 Approved For Release 1999/09/10 : CIA-RDP83-004231 1 10002-7 Fig. H-83. Diesel-driven 1700-kw, 327-rpm, engine-type diect-current generator. Standard voltages are 125, 250 and 600 volts for 2-wire units-125/250 volts for 3-wire units. Special voltage generators area procurable, but the cost is usually higher becauso of the added development expense. Standard open-type gneral-purpose generators are rated 40 C rise for full-lead continuous dutir. However, when operated at rated voltage and speed they will carry continuously 1.15 times the rated load without injurious temperature ~ rise, provided the ambient temperature does not exceed 40 C. Standard open-type low-speed generators and large high-speed machines will carry 1.25 times their rated load for two hours and hneet the following temperature guarantees: Core and windings..... . Commutator....... .. . Bare copper winding .. . DC Generator Construction Full-Load Continuous Duty 40 C 55 C 50 C 2&% Overload for Two Hours 55 C 65 C 65 C High-speed generators in the general-purpose class, that is, up through 150 kw, are usually furnished for coupled service, with one or two end-shield type bearings. Small sizes can be furnished for close-coupled service. These generators have the same external appearance as general purpose do motors (see pages H-6, H-7, 11-38 and H 39) and are available with the same types of protecti'e features. For some speeds, Juch as 1200 rpm, end-shield construction usually c,n be furnished for ratings up to 300 kw at 250 or; 600 volts. Larger high-speed generators generally are furnished with one or two pedestal bearings for mounting on an extension of the Figi H-84. End-shield bearing design is used for the smaller dc generator ratings. ow-speed generators (below 500 rpm) are usually furnished in the engine type, that is, without shaft, bearings or base. The armature is mounted on the engine shaft, and the beari::rigs, and base if required, are supplied by the engine builder. However, coupled- ty e parts, including shaft, bearings, and sole plates or ase, can be furnished if required. Pa allel Operation f two or more de generators are to be operated in pa allel, it is essential that they have the same char- ac ristics. That is, the terminal voltage drop from no load to full load (with constant rheostat setting) must be the same for all generators to be paralleled, an the generator voltage regulation curves must have similar shapes. hunt-wound generators in. parallel form a stable co dition under all ordinary circumstances. To obtain exact division of the load, the percentage terminal vo tage drop for a given percentage load change should be the same for all machines. Ordinarily, division of the load is controlled by adjustment of the respective fie d rheostats. en compound-wound generators are operated in pa allel, equalizer connections must be used except in ca es, such as street railway systems, where the genera- tors are located quite a distance apart. In such cases, the distances involved would make equalizer connec- ti is ineffective, but at the same time the unavoidably high resistances of the transmission lines make such connections unnecessary; generator characteristics in st, of course, be suited to this type of operation. he purpose of the equalizer is to maintain the proper current in the series windings of the machines so that ea -,h armature will carry its proportionate share of th load. Compound-wound generators can usually be adjusted at the factory for parallel operation with prime ~wed For Release 1999/09/10 : CI DPWtM4 3 112b 0O }7provided 'Approved For Release 1999/09/10 : CIA-RDP83-00 fi Wtk 0450002-7 H-47 DC GENERATORS the station wiring is such that the voltage drop from the equalizer through the series field to the bus bars at normal load is the same for all generators. Paralleling of generators with and without interpoles may be satisfactory under certain conditions but is generally not recommended. Generators without inter- poles have more rapidly drooping characteristics than those with interpoles. At best, the interpole generators will probably require external resistances in the series circuits. To parallel with standby storage battery systems, generators should have a rapidly drooping voltage characteristic from no load to full load. The generators should be either shunt or differentially compound- wound. If the batteries are to take the peak load, the differential winding should be used so that the generator voltage will drop faster with load than the battery voltage. From the foregoing it is obvious that the manu- facturer must be supplied with complete information if a generator is to be built to parallel with existing generators. The information furnished should include the nameplate data together with compounding and regulation data and the voltage drop in the series winding. With this information, the machines can usually be fully adjusted at the factory for parallel operation. If the information is not available, or if the existing generators have very unusual electrical characteristics, it will be necessary to make final adjustments in the field. Three-Wire Distribution In three-wire dc systems, the lower voltage between the neutral and outside wires is used for lighting TABLE 30-INFORMATION REQUIRED FOR SELECTING DC GENERATORS GENERAL Type of generator (engine, coupled, belted) .................. Quantity............ To be driven by .................... Kw.... Rpm.... Voltage: Rated.... No load.... Full load.. . Overload rating (if special) ................................ Ambient temperature ...... C Temperature rise ............. Class of Insulation: Armature... Field... Special treatment.. . Two-wire or 3-wire...... Percent unbalance (if 3-wire) ....... service, and the higher voltage between the outside wires is used for power. This provides an economical dc distribution system. Its use is usually limited to 120/240 or 125/250 volts. There are two methods commonly used to meet the demands for three-wire service. One method uses the so-called three-wire generator, with the voltage obtained by means of external auto- transformers connected through collector rings to the armature windings. Basically, the construction of three-wire generators differs from that of standard two-wire generators only in the addition of two collector rings and suitable brush rigging. The rings, which are usually mounted on the shaft near the commutator, are connected to suitable points of the armature winding. The lead from each ring is connected to one leg of a balance coil, which is usually separately mounted. To make the compounding of the generator inde- pendent of the unbalance of the load, the series fields of three-wire generators are split into two circuits. One circuit, consisting of the north poles, is connected to one side of the armature, and the other, consisting of the south poles, is connected to the other side of the armature. Standard construction provides for an unbalanced load of 10 percent. Generators can, however, be built for 25 or 50 percent unbalance. The other three-wire system commonly used is the rotary-balancer system, which consists of a two-wire single-voltage generator operating with a rotary- balancing set. The rotary-balancer system has several advantages that should be carefully considered. Regulation is better than in other systems because the balancers can be compounded to give full voltage at any desired load. Any amount of unbalance can be handled, as this depends solely on the size of the balancer. And the full capacity of the generator is always available whatever the condition of unbalance. Table 30 gives an idea of the data required before an intelligent selection of a do generator can be made. MECHANICAL FEATURES Protection or enclosure (drip-proof, splash-proof, etc.) ........ Number of bearings ........ Type of bearings .............. Coupling (half, whole, none) ...... Sole plates .............. Engine type: Is shaft to be pressed into armature?........... . LOAD DATA Nature of load ........................................... Working voltage of plant.................................. Make and type of voltage regulator, if used ................ Will generator run in parallel with other generators? .......... If so, give data ......................................... Are there any formal specifications? ........................ Fig. H-85. Geared 250-kw turbine-generator for AdditionApp ed. For. Release 1999/09/10: CIA-RDF686004461 09"0"0 6rI- H-48 Approved For Release 1999/09/10 : CIA-RDP83-00423R00120045(Wo~--HT M-G SETS II Fig. H-86. Four Regulldx exciter sets, an 844-kw auxiliary synchronous m-g set, and :3500-kw flywheel m-g set supporting 4000-hp, 0-50/120-rpm dc reversing blooming mill motor in.background. MOTOR-GENERATOR SETS Motor-generator sets,; consisting of a motor and one or more generators, are used to transform electrical energy from one form to another as follows: 1. From alternating 'current to direct current. 2. From direct current to alternating current. 3. From direct current to direct current at different voltages. 4. From alternating current to alternating current at different frequepcies. Wherever practicable,; motor-generator sets are built up of units of standard designs; but where this is not feasible, special combinations are designed to suit the requirements. nder some conditions, the induction motor is preferable to the synchronous motor for driving ge erators of larger capacities. This is true, for example, wh re the load on the generator is of a widely fluctuating na ure. While the induction motor has the advantage of not requiring excitation, its effect on the power fac or of the system may be undesirable, especially wh n the circuit supplies other apparatus taking a lag ing current. flywheel may be used to advantage with an induc- tion set required to supply high peak loads of short duration. Since the motor slows doom when the load is applied, the stored energy in the flywheel then drives the generator. This greatly reduces the temporary excess load on the m-g set motor and on the main ge crating system. Alternating Current to Direct Current Most electrical systems supply alternating current because it can be more. economically transmitted and distributed than direct current. Where direct current is-desirable or essential, it can be obtained from an ac system by means of an }n-g set consisting of an induc- tion or synchronous niotor driving a do generator. The choice of motor depends upon the conditions to be met. Induction Motor-Generator Sets Alternating-current/direct-current motor-generator sets rated less than 50i kw are almost invariably of the induction motor-driven type, and most of these have squirrel-cage induction motors. (Fig, 87.) They are used to supply excitation, lighting, and general power. Approved For Release 1999/09/10 : ound-rotor motors are also used on flywheel m-g set k. The control can be arranged to produce a greater speed drop in the wound=rotor motor and 'thereby fur her limit peak loads on the line supplying the m- set motor. Syr}chronous Motor-Generator Sets he chief advantage of using synchronous motors to dri e the dc generators of ra-g sets lies in the power- fac or corrective effect that can be obtained by over- ex Sting the field of the motor. In other words, synchronous m-g sets can advantageously be used even in fairly small ratings to correct poor power factor res Elting from induction motors, transformers, are lig ts, and other inductive apparatus on the circuit. ynchronous motors do, however, require direct DR e8Q423800fI2G046WO2'- -g sets, Approved For Release 1999/09/10: CIA-RDP83-0042311&T50002-7H49 M-G SETS this is not a particularly significant disadvantage though, since the set can readily be supplied with a direct-connected exciter. In fact, the m-g set generator can, if its voltage is not much above 250 volts, supply the required excitation. Fig. 88 shows a large syn- chronous motor driven motor-generator set. Direct Current to Alternating Current Although m-g sets for conversion of direct current to alternating current are not in great demand, they can readily be supplied if required. Such a combination includes a do driving motor coupled to an ac generator. Direct Current to Direct Current Motor-generator sets consisting of dc motors driving de generators are used to furnish a circuit with a voltage different from that of the main power circuit or with a voltage that can be varied independently. Where a set supplies a special voltage circuit, the set also serves to insulate the main and special circuits from each other if their requirements differ. Boosters sets are used when the load on some feeders in a do distribution system requires a voltage regula- tion for which the main generator cannot be adjusted without disturbing the potential at other parts of the system. The booster, connected in series with one wire of the feeder, keeps the voltage constant or varying to suit local conditions. This method frequently has been used by central stations to compensate for line loss in long runs. It is also used to raise the voltage for battery charging. Booster generators are usually driven at constant speed by shunt-wound motors receiving power from the line. A three-unit balancer is sometimes employed in connection with a standard single-voltage do generator to produce a multi-voltage supply from which dc motors may be operated at various speeds. For example, a three unit balancer generating 40, 80 and 120 volts used in connection with a 240-volt generator would supply six voltages to the motors so that they could be run at six different speeds. In addition, field and armature control can be used to TABLE 31 NEMA KILOWATT AND SYNCHRONOUS SPEED RAT- INGS FOR 60 CYCLE 2 AND 3-PIIASE SQUIRREL-CAGE INDUCTION MOTOR-DRIVEN SETS Generators: 125 or 250 V Shunt or Compound-Wound Motors: 110, 220, 440, 550 and 2300 V Generator Motor Motor Voltage Rating Rating 110 208-220-440-550 2300, Three-Phase Kw Hp Synchronous Speed-Rpm 1 2 1800 1800 11/2 3 1800 1800 2 3 1800 1800 3 5 1800 1800 5 71/2 .... 1800 71/2 15 .... 1800 10 15 .... 1800 15 25 .... 1800 20 30 .... 1800 .... .... .... 25 40 .... 1800 .... .... 1200 30 50 .... 1800 .... 1800 1200 40 60 .... 1800 1200 1800 1200 50 75 .... 1800 1200 1800 1200 60 100 .... 1800 1200 1800 1200 75 125 .... 1800 1200 1800 1200 100 150 .... 1800 1200 1800 1200 125 200 .... 1800 1200 1800 1200 150 250 .... 1800 1200 1800* 1200 *250-volt generators only. TABLE 32 NEMA KILOWATT AND SYNCHRONOUS SPEED RATINGS FOR 60 CYCLE SINGLE-PHASE MOTOR-DRIVEN SETS Generators: 125 or 250 V Shunt or Compound-Wound Motors: 110 or 220 V Generator Rating Kw Motor Rating IIp Synchronous Speed Rpm 1 2 1800 11/2 3 1800 2 3 1800 3 5 1800 *5 *230-volt motor only. 71/2 1800 Fig. H-87. Two 15-kw induction m-g sets used for Fig. H-88. Synchronous m-g set rated 500 kw, 900 excit~q'gppb T-BlpFRpIW*-"o?99' IOW10 : CIA-RDFbegJ90 Fk06q,20V451d6-02ryrive. H-50 Approved For Release 1999/09/10 : CIAO-RDP83-00423 R0012004OC7HT M-G SETS increase or decrease the speed of the motors from the six fundamental speeds, thus providing a wide range of easy control. As has already been noted in the discission of do generators, a two--unit balancer can be used to change a single-voltage, two-wire do system into a three-wire system. Alternating Current to Alternating Current Frequency-changer sq,ts normally consist of a syn- chronous motor driving a synchronous generator, but occasionally an induction motor is used to drive the synchronous generator.; Since there is a fixed) relationship between speed and frequency, the numbe~~ of poles for the motor and generator must be, chosen so that the two frequencies desired will be obtained! at the same speed. For example, in changing from 60 toy 25 cycles a 300-rpm set can he used; in this case the motor would have :34 poles and the generator 10 poles. Frequency changers are used (a) to interchange power between two systems of different frequencies, or (b) to supply power at either a higher or lower frequency than that of. the available supply. Another means of changing frequencies is the induction frequency congerter set, consisting of a wound- rotor induction machine driven by a suitable motor. The primary circuits of the wound-roi,or machine are connected to a fixed-frequency sours; of electric power. The secondary circuits deliver ,power at a frequency proportional, to the relative speeds of the primary magnetic field and the secondary (rotating) member. If a frequency higher than that of the power lines is desired, the rotor of the frequency converter is driven in the direction opposite to that in which it would run as a motor. By using a multi-speed or varying-speed driving motor, the converter caii deliver a secondary frequency that varies to suit the requirements. It should be noted that the secondary voltage of the wound-rotor machine varies directly as the secondary frequency. Tables 31, 32, 33 and 34 give the standard NEMA ratings for motor-generator sets. TABLE 33 NEMA KILOWATT AND SYNCHRONOUS SPEED RATINGS FOR 60 CYCLE 2 AND 3-PHASE SYN- CIIRONOUS MOTOR-DRIVEN SETS, O.>, POWER FACTOR LEADING AT FULL LOAD Generators: 125 or 250'V Shunt or Compound-Wound Motors: 220, 440, 550 or 2300 V Generator Rating Kw Motor Rating Hp Synchronous Speed Rpm 50 75 1200 60 100 1200 75 125 1200 100 150 1200 Approved FoVRelease 1999/09/10: Cl TABLE 34 MA STANDARD KILOWATT AND SPEED RATINGS R SYNCHRONOUS MOTOR-GENERATOR SETS 200 KW AND LARGER Rating 125 Volts--60 Cycles Speed Type Kw Rpm of Set 200 1200 Two-Unit 250 1200 Two-Unit 300 1200 Three-Unit 300 900 Two-Unit 400 1200 Three-Unit 400 720 Two-Unit 500 1200 Three-Unit 500 720 Two-Unit 600 900 Three-Unit 800 720 Three-Unit 1000 720 Three-Unit 200 250 Volts--60 Cycles 1200 Two-Unit 250 1200 Two-Unit 300 1200 Two-Unit 400 1200 Two-Unit 500 1200 Two-Unit 600 900 Two-Unit 750 900 Two-Unit 1000 720 Two-Unit 1250 720 Two-Unit 1500 514 Two-Unit 2000 360 Two-Unit 2000 720 Three-Unit 2500 720 Three-Unit 3000 514 Three-Unit 4000 360 Three-Unit 300 600 Volts--60 Cycles 1200 Two-Unit 500 1200 Two-Unit 600 1900 Two-Unit 750 .900 Two-Unit 1000 720 Two-Unit 1250 720 Two-Unit 1500 514 Two-Unit 1750 514 Two-Unit 2000 514 Two-Unit 2000 720 Three-Unit 2500 :514 Three-Unit 2500 720 Three-Unit 3000 360 Three-Unit 3000 514 Three-Unit 3500 .514 Three-Unit 4000 .514 Three-Unit 5000 514 Three-Unit 6000 360 Three-Unit tandard rating for two-unit motor-generator sets above tandard rating for three-unit motor-generator sets above 4000 514 rpm, will be in steps of 1000 kw. . H-89. Two 2500-kva, 600-rpm, 40/60-cycle quency-changer sets. Generator in background has -Rf P@&A1Y4i1& AN?' 45Q0$eTce. CPYRGHT ALLIS-CHALMERS PRODUCTS POWER GENERATION STEAM TURBINES ... for all power plant applica- tions ... ship propulsion. GAS TURBINES ... for use with axial blowers in process work ... power generation ... locomotives. HYDRAULIC TURBINES ... Francis, propeller and impulse types ... all sizes. GENERATORS . synchronous, induction, direct current ... vertical and horizontal ... all sizes. GENERATOR VOLTAGE REGULATORS ...for providing constant output voltage on generators of all sizes. SYNCHRO-OPERATORS . . . for full automatic synchronizing of ac generators. CONDENSERS . surface and jet types complete with condensate and circulating pumps and drives .. air ejectors. BOILER FEED PUMPS ... drives. WATER CONDITIONING equipment, chemicals and service. POWER TRANSMISSION AND DISTRIBUTION POWER TRANSFORMERS ... all sizes, including load-ratio control, regulating, phase-shifting, rectifier, furnace, and welding types. DISTRIBUTION TRANSFORMERS ... urban and rural types, net-work, subway, vault, non-inflammable, and dry types. INSTRUMENT, METERING TRANSFORMERS ... complete line. FEEDER VOLTAGE REGULATORS ... for station, distribution and branch service. SWITCHBOARDS to suit application. SWITCHGEAR ... vertical lift metal-clad. CIRCUIT BREAKERS . oil, magnetic and air blast types ... outdoor and indoor ... manual and automatic. MOTOR CONTROL standard and special for motors of all sizes above 1/2 hp. UNIT SUBSTATIONS . . . single circuit, multi- circuit and load center types. POWER CONVERSION RECTIFIERS . mercury arc power, with metal tanks, single and multiple anode ... also permanently evacuated type. MOTOR-GENERATOR SETS . all sizes, with synchronous or induction motor drive ... frequency changers . . . converters. SYNCHRONOUS CONDENSERS .. . for power factor correction and improvement of system stability. GENERAL INDUSTRIAL PRODUCTS ELECTRIC MOTORS ... all types, synchronous, in- duction, direct current, 1 hp up to largest ... motor control. TEXROPE DRIVES, multiple v-belt ... cast iron and pressed steel sheaves . . . variable speed . . . speed changers. CENTRIFUGAL PUMPS ... single and multi-stage ... 10 to 300,000 gpm. COMPRESSORS ... rotary sliding-vane. BLOWERS ... single and multi-stage centrifugal ... axial. DIELECTRIC HEATERS ... for heating, dehydrating, bonding, non-conducting materials. INDUCTION HEATERS . . . for heating, brazing, melting, metals. METAL DETECTORS ... electronic device that safe- guards quality ... prevents damage to machinery. OTHER ALLIS-CHALMERS PRODUCTS ROCK AND ORE CRUSHERS, VIBRATING SCREENS, GRINDING MILLS, WASHING EQUIP- MENT ... KILNS, COOLERS, DRYERS ... COPPER AND NICKEL CONVERTERS ... FOUNDRY SHAKEOUTS AND ELECTRONIC CORE DRYERS ... HYDRAULIC LOG BARKERS ... GRAIN AND CHEMICAL MILLING MACHINERY ... SOLVENT EXTRACTION PLANTS ... BETA- TRONS ... WHEEL AND TRACK-TYPE TRACTORS . . . TRACTOR DRAWN FARM IMPLE- MENTS ... ROAD AND CONSTRUCTION EQUIPMENT ... GASOLINE POWER UNITS. Approved For Release 1999/09/10 : CIA-RDP83-00423R001200450002-7 An Prl Fnr Please 1999109110, : CiA- ALLIS-CHALMERS S General Offires...Allis-Chalmers Manufacturing Telephone NE P83-00423P001.200450002-T, CPYRGHT LES OFFICES Company, Milwaukee 'l, Wisconsin Telephone MEXICO Birmingham 3, 2000 First Ave., North... ...... 4-5494 Alb ARIZONA i Phoenix, 30 West M#dison St......... ..ALpine 3-2159 CALIFORNIA Los Angeles 13, 4171S. Hill Sr......... Mt.dison 6-2231 San Diego 1, 747 ],'Ninth Ave. ......... Main 8-4684 San Francisco 7, 650 Harrison St....... Douglas 2-8384 COLORADO Denver 2, 1920 Market St- .............Cherry 6556 CONNECTICUT Hartford, 750 Main Sr ............... Hartford 46-5675 New Haven 10, 157 Church St. ......... ... State 7-1176 DISTRICT OF COLUMBIA Washington 5, 14th & H Sts., N. W.... Ex:cutive 3-2800 FLORIDA Jacksonville 7, 2031 .Hendricks Ave ............. 98-1651 Miami 32, 25 S. E. 2nd Ave............. Miami 2-7744 Tampa 2, 405 S. Mprgan St.... ...............2-8371 GEORGIA Atlanta 3, 57 Forsythe St., N. W........... Walnut 7116 ILLINOIS Chicago 3, 135 Soy LaSalle St......... Franklin 2-6480 Peoria 2, 301 S. Adams St.. ........... ...... 4-9279 Rockford, 303 North Main St .......... ...... 5-5721 INDIANA Evansville 9, 129 Locust St.. ................ 4-8219 Indianapolis 4, 11 S. Meridian St.......... MArket 7415 IOWA Davenport, 326 W.I Third St ................... 3-9793 KANSAS Wichita 2, 111 So Main St.. ................... 3-97 KENTUCKY Louisville 2, 241 S4 i Fifth St ............ .... Clay 7656 LOUISIANA New Orleans 12, 210 Baronne St......... Raymond 8623 Shreveport 23, 624 Travis St. .... ............ 2-3274 MAINE Augusta, 269% later St ................. Augusta 463 MARYLAND Baltimore IS, 11 L5 East 30th St....... HOpkins 7-4480 MASSACHUSE'T'TS Boston 16, 31 Sr. James Ave........... Hubbard 2-3700 MICHIGAN I Detroit 2, W. Grand Blvd. & 2nd Blvd. Trinity 1-2300 Grand Rapids 2, 5-7 Lyons St., N. W........... 9-8249 Jackson, 297 W. !Michigan Ave ....... ......... 2-2419 MINNESOTA 1 Duluth 2, 10 E. Superior St. ..................7-5061 Minneapolis 2, 8~1 Marquette Ave....... ATlantic 6455 MISSOURI Kansas City 6, 6 East 11th St ............. Victor 0132 St. Louis 3, 1205 Olive Sr ...............Central 4313 NEBRASKA Omaha 2, 14th& Farnam Sts......... Atlantic 1780 NEW JERSEY Newark 2, 1060 road St. ............. Market 3-7170 YORK lo 3, 535 Washington St......... Washington 1741 York 7, 50 Church St .............. Beekman 3-9100 ester 4, 241 East Ave., ....Ave.................. Baker 7510 use 2, 472 S. Salena St......... Syracuse 3-0147 Ch lotte 2, 212 S. Tryon St ......... .......... 2-3188 0 '1 0 Ak n 8, First National Tower............ Portage 7648 Cin innati 2, 617 Vine St ............... Main 7300 Cle eland 14, 815 Superior Ave., N. E..... Main 1-5182 Tol do 4, 245 Summit St ................. Adams 5269 Yo ngstown 3, 25 E. Boardman St..... Riverside 3-5175 O LAHOMA Ok ahoma City 1, 401 N. Harvey St...... Regent 9-1631 Tu sa 3, 320 E. Archer St ...................4-9163 O EGON Po tland 4, 520 S. W. 6th Av........... Capitol 9835 P SYLVANIA Ph ladeiphia 3, 1617 Pa. Blvd....... Rittenhouse 6-8412 Pi sburgh 19, 421 Seventh Ave........ Atlantic 1-4154 W lkes-Barre, Market & Franklin Sts., (Bell) W.B. 3-2413 Y rk, 42 East King St ................... York 5415 R ODE ISLAND Pr vidence 3, 111 Westminster Sr....... Jackson 1-8820 T NNESSEE C attanooga 2, 737 Market St....... .......... 6-5101 K oxville 2, 531 S. Gay St ......... .......... 2-2165 =phis 3, 46 N. Third St .................. 5-0583 TEXarilloAS A , 301 Polk St .......................31766 B aumont, 490 Bowie St .....................5-2535 El Paso, Corner Oregon & Mills Sts. - ........... 3-7439 Fbrt Worth 1, 408 West 7th Sr........... FAnin 5083 IRGINIA ichmond 19, 627 East Main St ........ ....... 3-6646 ASHINGTON EST VIRGINIA ISCONSIN lwaukee 2, 715 N. Van Buren St.,-BRoadway 1-4729 ontreal, Quebec, 1520 Mountain Sr......... Ma. 2411 Distributors in all principal cities throughout the United States Offices and distributors locat d throughout the world Approved For Release 1999/09/10 : C~A-RDP83-00423R001200450002-7 Approved For Release 1999/09/10: CIA-RDP83-00423RO01 00'2-7 INDEX Subject Page Condensers, synchronous __-___ 33-35 Direct Current Motors ---_--_ ---___--__ 35-40 Control ------------- -_ 38-40 Enclosures -------------------------------------------------- Types ------------------------------------------------------------ Generators -------------------------- ----------------- 41-47 Alternating current ------------------------------------ 41-45 Construction ---.----------------------------------------- 42 Parallel operation ---------------------------------- 43 Regulation ------------ ------------------------ 43 Selection -------------------- ----------------------------- 45 Direct current ------------------ ___-------- 45-47 Induction Motors -------------------------------------------- 14-25 Applications ------------------ -------- ---- 19 Characteristics ------------------------------------------ 15 Comparisons with synchronous ---------------- 32 Construction features -------___ _-------- 14 Design classification, NEMA _--------- ---------- 16 Double cage ------------- __-__ 19 Frame sizes ------------------------------------------------ 23 Multi-speed -------------------------------------------------- 21 Operation on off-standard circuits ------------ 25 Torques -------------------------------------- ------ 16, 21 Wound-rotor ----------------------------------------------- 21 Introduction ---------------------------------------------------- 1 Motors, general ---------------------------------------------- 1 Bearings ---- --------------------------------------- 13 Comparisons --- -------------------------------- 11 Cooling -------------------------------------------------------- 4 Subject Page Direct current-see dc . ---------------------__------ 35-40 Induction, see induction 14-25 Insulation limits _-____ -------------- 4 Protection mechanical ------------------------------ 4-11, 22 Ratings ----------------- ---------------------------- 2 Selecting ---__ ___ 11,13 Speed characteristics --------------------------------- 2 Synchronous-see synchronous ____ 25-32 Temperature limits ------------------------------------ 4 Torque ----- ---------------------------------------- Motor-Generator sets _-_------------------------------ 48-50 AC to DC ------------------- ------- 48 DC to AC -------- ------------ 49 DC to DC -_-_-_- __-__ AC to AC --------------------------- --------- 50 Power Factor Correction ._. --------------------------- 26, 35 Standardization ---------------------------------------------- 1 Synchronous Condensers _ ------------------- 33-35 Synchronous Motors -------------------------------------- 25-32 Standard ------------------------------------------------------ 25-32 Construction of ------------------------ _____ 30 Excitation ---------- -------------------------- 31 Power factor of -------------------------------------- 26 Protection of ------------------------------------------- 31 Speeds, standard -- --------------------------------- 27,30 Starting --------- ----------------- 26 Torque requirements -------------- 26-29 Vertical ---------------------------------------------------- 30 Voltages, standard -------------------------------- 27 Approved For Release 1999/09/10 : CIA-RDP83-00423ROO1200450002-7 V - I I ATIG" F-1-f ,I I Here's a pump specially designed or quick, easy applica- tion to hundreds of everyday pumping jobs. It offers you top value for your pumping dollar because it has all the quality features that you need to keep your pumping costs low, yet its price is exceptionally low. Quality Features. You get high grade construction, such as ball bearings, mechanical shaft seal, and generous metal sections. Built to the same top quality precision standards as all Allis-Chalmers pumps. Easy Installation. The Allis-Chalmers frame type pump is built or e ve. IL Lan be IIIUU11L(:Zt i positions and connected to any type of prime mover with- out difficult alignment problems. Wide a pumping jobs requiring capacities up to 500 gpm and heads as high as 135 feet. Head and capacity can be changed by simply changing sheave size on the V-belt drive. One pump can serve you many places with only this simple change. Low Maintenance. Rigid base holds alignment, keeps bearing wear down. Mechanical seal requires no attention in normal service. Wearing rings on larger pumps mean efficiency can be maintained easily through years of service. if yen iinve ~e@" io8kitqg, fog; 10 petitive price, you'll find it among these Allis-Chalmers frame type pumps. _ CPYRGHT d f scast iron frame pre- viE ibratian, maintains) ment , Mounting bolt, 0aroeasily accessible, I' a Single' row ball bear - iggswell supported in a rigid cast On frame carry tte shaft.. Bearings are grease lubricated through a s ngle point in the frame. Two single row ball bear. Ings well supported in a rigid cast iron frame carr the shaft, Bearings are grease lubricated through a single point in the frame. CAP -RDP83-0 A sG er and seal assembly 'keep liquid out of bear- ings, prevents rust and corro ion. \ , good for hundred; of hours of operation without atten- tion. Mechanical seal makes packing unnecessary, is good for hundreds of hours of operation without atten. tion. \ A linger and seal assembly k ps liquid out of bear- in s, prevents rust and co rosion. Rigid cast iron frame pre vents vibration, maintain: alignment. Mounting bol holes are easily accessible Te ra r'wbal ar- ~i ported rn a ii c irp frarpe carry A - 4. ,. a rugs are gr a dbrica ed through a sore paint i the frame. MBChanical seal makes packing unnecessary, is good for hundreds of hours of operation without atten- L tion. A slip er and seal assembly steep liquid out of bear- ings, prevents rust and carro bit: I an-- a d cast iro erne pre, ains, kg tk ble 'se recip n Cast bronze im? sac ng unnecessary is r ller is of enclosed type Cast and machined bronz impeller is of open type.' I IN Smooth surfaces inside and out speed water flaw, keep efficiency high. Cast bronze impeller is of enclosed type. Smooth sur- faces inside and out speed water flow, keep efficiency high. Wearing rings front and rear on larger sizes, front only on smaller sizes. CPYRGHT Approved For Release 1999/09/10 CIA-RDP83-00423 8401200450002-7 -~ r 7 Size.... I x 3/4 11/4 x 1 A 13'/2 141/,6 B 11/a 1216 C 21a 1/a D': 2/s 33/6 E 2a/a 2 F 33 215/16 Size.. 11/2 x1'/2 2x2 2'/2 x2'/2 3x3 A 145/s 14% 14/a 15 C 21/2 2/a 2% 2/a D 45/8 43/4 4 /a 5 E 2% 31/4 3/a 4'/2 F 31/8 3'/4 3 j6 3% G 11% 11 11/4 11%2 Size.... 1 x 1 21/2 x 21 A 10, 141/a B 7 A 113/a C 2%s 2'/a D 11/a 2/a F 25A6 41/a G 7/4 10 H 6/8 31/z J 4% 6 K 1/2 11/4 L 1'/z 11/4-- M M 21/2 3 _ N '/a 0 1'/2 2 VAR.- cumEA-6512 s*E1 X ImP P-10 TYPE SS-RHB '!5 MAx Du 5 . MAX. sPNER6 y . '32 3 L- R ~. )19 . I P L E S I _ O 0 3 7 8 10 15 N. 1 .H. E . lij%j" ISO "EI.~XIJ. 00FSS-BHB'~' .,, "P .P-1071 M . IA.3}fr.. VAR R M-CVRVF A -640T slzE I X I 'T 'Po 5S C R 5 IMV: P 1017 A IA 4 ' MAx ERF~. Mw. DIa ~, _rV - VAR. RPM CURVE A-6511 sizol.14X I OrooSS-RrlE MP. P-1070 MA% UTA 6' . MAD. SPHF!iE ` N. DIA. 3 - JEI LI RS - U b a. --- 30-40, ES?~LrR~~ i[ 3dA k a.-,nu.