US1707023A

US1707023A - Transformer

Info

Publication number: US1707023A
Application number: US93843A
Authority: US
Inventors: Einar N Rauland
Original assignee: ALL AMERICAN RADIO CORP
Current assignee: ALL AMERICAN RADIO CORP; ALL-AMERICAN RADIO Corp
Priority date: 1926-03-11
Filing date: 1926-03-11
Publication date: 1929-03-26
Anticipated expiration: 1946-03-26

Description

March 26, 1929.

' E. N. RAULAND TRANSFORMER Filed March 11, 1926 Patented Mar. '26, 1929;

UNITED STATES PATENT OFFICE.

EINAR N. RAULAND, OF RIVER FQREST, ILLINOIS, ASSIGNOR 'IO ALL-AMERICAN RADIO CORPORATION, OF CHICAGO, ILLINDIS, A CORPORATION OF ILLINOIS.

TRANSFORMER.

Application filed March 11, 1926.

This invention relates to transformers and particularly to an improved casing and construction for audio frequency transformers.

It is the object of the present invention to shield the transformer windings so as to eliminate intern ction between adjacent transformers, but without reducing the efliciency of the transformer.

The invention will be best understood by reference to the drawings in which Fig. 1 is a. side elevation; Fi 2 a front elevation; Fig. 3 a vertical cro section along lines 3*?) of Fig. 1; and Fig. 4L a vertical crosssection along lines 4-dof Fig. 2.

The transformer coil consisting of primary 1 and secondary 1 windings is pro vided on an iron core 2 composed of sub stantially rectangular laminae 3. Each lamination is provided with two perforations l within which the coil is held, and is slit at 5 so that the coil may be slipped in place. The primary 1 is wound over the secondary winding 1 in order to reduce the mean turn length of the latter. The distributed capacity is thus reduced to a minimum. The laminations are sheared so that the magnetic leakage and core reluctance maybe as small as possible. A heavy gauge of high silicon steel is used whereby maximum iron space is obtained.

The core stands on a platform 6 of sheet metal having a bent-down flange 7. On two sides the coil is surrounded by two steel shells 88 which have suitably bulging portions. The shells 8 are placed on the platform 3 and may be provided with lugs 9 which. project through the platform and are bent up to hold the shells in place. A plate 10 is provided against the lower surface of platform 6 within the substantially rectangulz'zr space surrounecd by flange 7. This plate 10 is so fastened that access to the transformer is prevented. The upper ends and two sides of shells 8 are flattened against the core 2, strips of insulation 11 being provided between the core and the shells. A. substantially U-shaped yoke 19. surrounds the iron core 2 on three sides and completes Serial No. 93,843.

the transformer casing. The yoke 12 may be provided with lugs like 9 to hold it against the platform 6 or such lugs may be provided only on the yoke since by means of it shells 8 will be clamped in place. The edges of the yoke are bent down to form flanges 13 clan'iping the edges of shells 8. Strips of insulation i i are placed between flange 13 and the of shells 8. The terminals of the coil 1 are brought to the outside through perforated binding screws 15 which are mounted on the sides of shells 8 and are insulated therefrom by means of discs 16.

By insulating the halves of the steel shell 8. no magnetic circuit will be formed around the coil in plane perpendicular to its axis. Otherwise, the shell would act as a low resistance turn and decrease the impedance of the primary. Owing; to the shape of the shell 8 and the location of the binding posts 15, the lead wires from the coil windings to the posts may be short.

l hat I claim is:

In an audio frequency transformer, a core composed of substantially rectangular, heavy gauge silicon steel laminae, a coil surround ing part of said core and surrounded by said core. said coil being composed of a secondary winding surrounded by a prin'iary winding,

twosteel shells substantially conforming; in

shape to the core and coil assembly each sh ll having an outwardly bulging portion enclosing said coil and flat portions enclosing; said core, binding); posts mounted. on said bulging portion, insulation between contiguous portions of said shells and core, a substantially ttshaped steel yoke surrounding said core on three sides and clamping to- ;z'chcr said shells, insulation between said yoke and shells, and a base on which the ends of contiguous portions of said core and shells rest. fastened to said yoke.

In testimony whereof, I have signed my name to this specification this 8th day of March, 1926.

EINAR N. RAULAND.