ELECTRICAL DESIGN PROJECT AT INSTITUTE NO. 88, GORODOMLYA ISLAND

• Document Type: CREST
• Collection: General CIA Records
• Document Number (FOIA) /ESDN (CREST): CIA-RDP80-00810A001100320004-0
• Release Decision: RIPPUB
• Original Classification: S
• Document Page Count: 4
• Document Creation Date: December 22, 2016
• Document Release Date: May 28, 2010
• Sequence Number: 4
• Publication Date: May 21, 1953
• Content Type: REPORT

Sanitized Copy Approved for Release 2010/05/28: CIA-RDP80-0081 OA001100320004-0
CENTRAL INTELLIGENCE AGENCY
INFORMATION REPORT
SECRET
SECURITY INFORMATION
COUNTRY USSR (Kalinin Oblast)
DATE OF INFO.
REFERENCES
THE SOURCE EVALUATIONS IN THIS REPORT ARE DEFINITIVE.
THE APPRAISAL OF CONTENT IS TENTATIVE.
(FOR KEY SEE REVERSE)
Moment Transmitter
STATE }C. ARMY
This Document contains information affecting the Na-
tional Defense of the United States, within the mean-
ing of Title 18, Sections 793 and 794, of the V.S. Code, as
amended. Its transmission or revelation of its contents
to or receipt by an unauthorized person Is prohibited
by law. The reproduction of this form is prohibited.
Electrical Design Project at DATE DISTR.
Institute No. 88, Gorodomlya Island
NO. OF PAGES
x NAVY '.X AIR
(Net, Washington Distribution Indhated '8y "X"; Field DWrIbution By ",*"I
21 May 1953
4
design an actuator or drive system for the Rahn-
mode , which had been developed by the Germans on the island of
Gorodomlya. The actuator consisted of a pair of moment transmitters
(Momentgeber) designed to.-conform to the following specifications:
a. Torque or torsional moment of at least four kg cm for a pair of
transmitters.
b. Diameter of the movable part of the actuator was not to exceed
400 mm,
c. Diameter of the complete unit was not to exceed 550 mm.,
d. Rotary moment was to be constant across the entire travel
'(plus-minus 20 degrees) of the movable coil.
25X1
25X1
0
Sanitized Copy Approved for Release 2010/05/28: CIA-RDP80-0081 OA001100320004-0
 "A j
Sanitized Copy Approved for Release 2010/05/28: CIA-RDP80-0081 OA001100320004-0
SECRET
- I
e.
No sliding parts were to be incorporated into the unit.
f.
The movable coil was to be designed for a maximum current
of Is 50 ma and V. = 250 volts.
g.
An auxiliary direct voltage of V. 120 volts was to be
used for the exciter coils.
2. The Unipolar work principle was chosen for the moment trans-
mitter since this system, by virtue of its specific construction,
offered the greatest prospects for a constant rotary moment.
It was predetermined that the rotation angle would not be
excessive. In the Unipolar system, the coxe, curved in the
shape of an arc sector, formed one pole, and an identically
formed pole arc formed the second pole of the magnetic system.
A free swinging coil encircled the core. The core therefore
move: in a field between the core and the pi Le.,.,are. If a our-
rent I passed through the coil, th;e coil moved in"the current
direct!on to either one side or the other with .a force which
directly proportional to the coil current I... The moment
which effected the rotary system of the Bahniodell Vas computed
according to the Biot-Savart Law:
M D - 1.02 x B L x W x lw x Is x a x 10- 7 Kg om.
Where:
BL equals the induction in ?air cavity (or slaoe)
W equals the number of windings
equals the median winding length (length of average
winding) in om
Is equals the coil current in amperes
equals the length of lever arm in cm
As shown in the drawing, Za-ee ketch on p.'. the swinging coil
moves in a space between the rectuAgular pole core and the U-
formed pole arc. The exciters are arranged between the pole
arc and the magnetic return (yoke arc). The swinging core is
divided into two halves which are inclined at a 15 angle in
order to conform to the curved formed air gap. Each half of the
coil contains two windings, each winding having 2,500 turns
(wire diameter 0.1 mm). The coil bobbin was built as light
as possible in order to decrease the added inertia moment.
In or der to eliminate possible eddy currents, no metal parts
were used for the portion of the coil which moved in the air
gap. The following prerequisites govern this particular feature
of the unit:
a. Equal air gap induction along'the entire pole arc; that is,
equal air gap distances between the core and pole arc at
every point.
b. Inductions must lie below the break of the magnetization
curve in the core and in the pole arc.
B - 5,000 gauss (measure of magnetization) was established for
tke induction air gap. The core, pole arc, and yoke are were
dimensioned in such a manner that the induction in these parts
lay below 8,000 gauss.
SECRET
Sanitized Copy Approved for Release 2010/05/28: CIA-RDP80-0081 OA001100320004-0
 Sanitized Copy Approved for Release 2010/05/28: CIA-RDP80-0081 OA001100320004-0
SECRET.
3-.
The torsion moment of a pair of transmitters which were built
into the Bahnmodell was approximately 7.2 kg. cm. as opposed to
1.1 kg. cm. obtained by former design. The torsion moment
which was developed from the transmitter.was accurate to a
plus-minus 1.~~ constant in an angle range of approximately
plus-minus 23 After satisfactory tests were run on the moment
transmitter, it was installed in the Bahnmodell.
L:___
25X1
Sanitized Copy Approved for Release 2010/05/28: CIA-RDP80-0081 OA001100320004-0
 Sanitized Copy Approved for Release 2010/05/28: CIA-RDP80-0081 OA001100320004-0
Sanitized Copy Approved for Release 2010/05/28: CIA-RDP80-0081 OA001100320004-0
af~a-a : AnQv+St
toleciive parP's of Aie
Alagneiic Assembly. Mild Steel
MOMENT TRANSM/TTJR
fa* bAMNMDDELL
6abrnxx~eQ