CORES FOR RADIO POWER TRANSFORMERS

• Document Type: CREST
• Collection: General CIA Records
• Document Number (FOIA) /ESDN (CREST): CIA-RDP80-00809A000700150149-9
• Release Decision: RIPPUB
• Original Classification: R
• Document Page Count: 2
• Document Creation Date: December 22, 2016
• Document Release Date: September 13, 2011
• Sequence Number: 149
• Publication Date: November 24, 1953
• Content Type: REPORT

Sanitized Copy Approved for Release 2011/09/13: CIA-RDP80-00809A000700150149-9
! CLASSIFICATION RESTRICTED
SECURITY INFORMATION
CENTRAL INTELLIGENCE AGENCY REPORT
INFORMATION FROM
FOREIGN DOCUMENTS OR RADIO BROADCASTS CD N0.
COUNTRY USSR DATE OF
INFORMATION 1953
SUBJECT iific - Electronics, magnetic materials
HOW DATE DIST. ,'r,~Nov 1953
PUBLISHED Monthly periodical
WHERE
PUBLISHED Moscow N0. OF PAGES 2
DATE
PUBLISHED Aug 1953
LANGUAGE Russian
. '.~.. o .. .. .~ ,ono. ~.~ ,.., .~ ~o, .. .
SUPPLEMENT TO
REPORT N0.
~omment: The following information xas taken from an article
by V. Dvinskikh, Saratov, describing power transformer cores Por the
benefit o#' radio-amateur designers. Sections on selection of core
construction and mechanical features of core assembly were omitted.
Although the article is written primarily for radio amateurs building
their own seta, the care materials mentioned may also be employed in
commercial receiver production
Ordinarily, type E4A and E4AA transformer steels are employed in the cores
of power transformers used in radio receivers. The first type is characterized
by low eddy current losses but is quite brittle because of its 4~, silicon con-
tent. The brittleness of type E4A steel distinguishes it from other types of
transformer steel which have a lower silicon content. The magnetic properties
of type E4AA and E4A are the same, except that type E4AA has lower hysteresis
losses than type E4A.
Laminations for cores of power transformers can also be made from dynamo
steels type E1 and E2, although these have poorer magnetic properties and
higher losses than type E4A steel. Light sheet iron is similar in mngnetic
properties to type E1 steel.
Recently, special types of electrical steel, far example, KhVP and KhT-7.8,
have come into use as core materials. These are characterized by high permis-
sible values of induction. The use of KhVP and KhT-18 steels in radio-amateur
practice is also very desirable. One must keep in mind, however, that the
magnetic properties o; these steels may differ by 10-15~ from one factory ship-
ment to the next.
Core lamiuations cf all the above materials with the exception of IShVP
and KhT-18 steels are produced in thicknesses of 0.35 or 0.5 mm. Although the
production of thinner laminations would reduce eddy current losses in the core,
STAT
STAT
NSNB
FBI
DISTRIBUTION
Sanitized Copy Approved for Release 2011/09/13: CIA-RDP80-00809A000700150149-9
 Sanitized Copy Approved for Release 2011/09/13: CIA-RDP80-00809A000700150149-9
it is not recommended for the following reasons. These losses account for
15-20j6 of the total core losses. If, for. example, the lamination is made half
as thick, the losses will be reduced by 10-15~. But a reduction in the thick-
ness of the lamination will cause an increase in core losses of 8-10~ because
of the irregularity of the laminations and the presence of an oxide layer,
leading to rec;uced active core cross section and increased induction.
STAT
??~ _ ~~
Sanitized Copy Approved for Release 2011/09/13: CIA-RDP80-00809A000700150149-9