US2531697A

US2531697A - Transformer

Info

Publication number: US2531697A
Application number: US767402A
Authority: US
Inventors: Meycrhans August
Original assignee: BBC Brown Boveri France SA
Current assignee: BBC Brown Boveri AG Germany; BBC Brown Boveri France SA
Priority date: 1939-11-23
Filing date: 1947-08-08
Publication date: 1950-11-28
Anticipated expiration: 1967-11-28

Description

INVENTOR ATTORNEYj A- MEYERHANS TRANSFORMER Filed 1947 Nov. 28, 1 950 Patented Nov. 28, 1950 UNITED TRANSFORMER August Meyerhans, Nussbaumen, near Baden,

Switzerland,

assignor to Alstiengeseilsehaft Brown, Boveri 623a, Baden, Switzerland Application Angus. 8, 194?, Serial No. 767,462 in November 1939 Section 1, Public Law 699, August 8, 1946 Patent expires November 2?), 1535.)

3 Claims.

When building transformers it has been usual up to the present to make the iron core composed of columns for the windings and yolre parts for the magnetic return flow out of sheet metal stampings of diiferent length and width, which are superposed in parallel planes and may be interleaved. If in this arrangement the column form is adapted as closely as possible in crosssection to the circular form of the windings, the number of different sized stamping operations is increased and the work entailed in stamping and the waste of sheet metal also becomes greater. The building up of the columns and the putting together of the iron core entails much labor and is costly. The cost Of building up the core is reduced by employing columns composed of metal sheets which are layered substantially radially and which are connected at their end surfaces by welding seams. This method of building up columns is not only simple and cheap as regards manufacture, it is also favorable from the magnetic and electric point of view. However, the usual way of building up the return flow is still unfavorable, as it entails a considerable amount of stamping work and a substantial waste of sheet metal and makes it necessary to employ arrangements for supporting the windings.

The object of the present invention is to provide a transformer having a column built up of radial metal sheets, in which the described disadvantages are eliminated through the magnetic return flow path being formed according to the invention of stampings which are built up in substantially U-shaped packets and are pressed with their flanges against the column.

In the accompanying drawing there is shown diagrammatically as a construction example of the above invention a single phase transformer. Figure l is a view in longitudinal section taken on line I| of Fig. 2 and Figure 2 is a view in transverse cross-section taken on line 2-2 Of Fig. 1. Figures 3 and 4 show constructional details.

In the figures a represents the column of the iron core with radially-stacked stampings and the concentric high and low voltage windings b, c. The magnetic return flow iron is formed of U-shaped yokes or packets of stampings 01, all to (is, which are arranged radiall around the periphery of the column and are pressed with their flanges die. to (18s against the column, so that they surround the windings. The end faces dlb to dab of the flanges of the U-shaped packets of stampings which confront the exterior surface of the column a have a concave curvature complementary to the convex curvature of the column, in order to facilitate the direct passage of the flux between the column and the return flow iron. The stampings of t e U-shaped packets of the return fiow iron can simply be stacked over a former corresponding to the circular periphery of the column. The stampings of the U-shaped yokes are held together by welding seams which are provided in places, preferably on the outwardly disposed surfaces of the webs and/or flanges. In the example shown, connecting strips e1, e2 are used for the welding connection. The strips e2 which are welded to the flanges of the U-shaped packets are used with the aid of strips 63 welded to the end surfaces of the column and of bolts f for producing the pressure between the column and the U-shaped packets of the return flow iron. The active part of the transformer is inserted in a circular tank h. At least one sector of the radially ouilt up column is replaced by a sector of insulating material for instance wood. This increases the space for the leads. It represents a bushing insulator.

The packets of the magnetic return flow iron may be formed either of metal sheets stamped out in U-shape (Fig. 3) or of rectangular stamped sheets built together and interleaved in U-form (Fig. 4), whereupon they are welded in the manner described above. It is recommended to hold the stampings together at certain points by means of bandages 91 (Figs. 1 and 3), which consist at least in part of insulating material. The bandages will suitably consist of cord windings which are placed over angle pieces 92 of layered insulating material, and cover the corners of the packets of stampings.

Through the iron core being built up in accordance with the invention the magnetic return flow part will also have a shape in which the stamping work is reduced to a minimum. Metal sheets stamped out in rectangular form and put together in U-form are held together very simply; no insulated screw connections are required for the packets of stampings. The welding seams hold the metal sheets together rigidly. When the packets are composed of U-shaped stampings, it becomes possible to use the rectangular waste as column stampings for a smaller transformer. The special form of welded connections in the case of the column and the return flow part enables the two parts to be united under pressure in a very simple manner. The building up of the transformer is thus greatly facilitated. By means of wedge-shaped distance pieces n1, m (Fig. 1) pressure may be applied to the wind- D core diameter H=0.195D.

As the normal transformer has a yoke height of about D, for the transformer according to the .invention the overall height will be reduced by 2D0.39D=1.61D.

The manner in whichthe iron core is built up in accordance with the invention provides a furtheradvantage as regards cooling. 1 Cooling tubes m may be disposed in'the spaces between the ray-like or radiallyarranged stamping packets -of the return'flow part. The cooling tubes m may also be corrugated in the direction of the longitudinal axes of the transformer.

T The "space occupied by --the transformer is in this way considerably reduced; its Weight is also reduced, to which the round form of the casing also contributes, whereby reinforcement becomes-unnecessary.

"For building up athree-phase transformer the possibility is provided of mounting three singlephase transformers of the construction above'described axially one behind the other in one vessel.

The construction according to theinvention is particularly suitable for enabling-transformers ofconsiderable output to be housed in a recumbent position on avehicle frame,'so asto enable the railway loading gauge to be utilized to the -best ossib1e advantage. The bushinginsulators can be arrangedso as-t be distributed over-the two ends of the transformer tank.

' I claim: 1; In atransformer, a magnetic structure comprising aradially laminated cylir'idrica'lv core, a

plurality of U-shaped laminated yokes surrounding said core with the yoke laminations arranged in planes parallel with the core axis, the two end flange portions of each said yoke confronting said core and being provided with iconcave end faces the curvature of which is the complement of the convex outer surface of said core so as to lie directly against the core with the core and yokelaminations arranged in substantially radial alignment, spaced and confronting rigid strips welded respectively to and extending axially outward from the opposite ends of said core and the opposite ends of said yokes, and means extendingybetween'and drawing said confronting core and yoke strips towards one another thereby to .draw the end faces of the flange portions of said yokes into pressure contact with the outer surface.of..said core.

' 2. A transformer magnetic structure as defined in claim 1 wherein thelaminations of each said yoke are constituted-by U shaped'stampings.

'3. A transformer magnetic structureas defined in claim 1 wherein the yoke la-minationsare-constituted'by rectangular stampings interleaved to form the U-shaped contour of the yoke.

, AUGUST MEYERHANS.

.' REFERENCES CITED The following references are of record-in the file of this patent:

UNITED STATES PATENTS Number Name .Date

850,863 Wooldridge Apr. -16, .1907 854,278 Darlington ;;May 21, 19.07 1,140,843 Nichols ".'May :25, 1915 1,623,345 Hopkins Apr; 5, .1927 2,107,973 Bajon Feb. 23,1938 2,252,461 Franz Aug. .121, 1941 2,279,239 Meyerans Apr. 7:,131 l2 FOREIGN PATENTS Number Country .Date

' 421,512 Great Britain Dec. 21, 19-34. 482,771 -Great Britain 'July ,8; 1937