US2116404A

US2116404A - Electrical induction apparatus

Info

Publication number: US2116404A
Application number: US132528A
Authority: US
Inventors: Vincent M Montsinger
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1937-03-23
Filing date: 1937-03-23
Publication date: 1938-05-03
Anticipated expiration: 1955-05-03
Also published as: GB512957A; FR835628A

Description

May 3, 1933- v. M. MONTSINGE 2,116,404

ELECTR I CAL INDUCTION AP PARTUS File-d March 23, 193'? bg M L His Abborneg.

Patented May' 3, 1938 PATENT oFFicE 2,116,404 ELEc'rnlcAL nvnUo'rloN APPARATUS Vincent M. Montainger, Pittsfield, Mass., assigner to General Electric Company, a corporation of New York Application March 2 3, 1937, serial No. 132,528 s claims. (c1. 11s-362) I'he invention relates to electrical induction apparatus, such as a transformer or reactor, wherein a winding leg of a magnetic core is surrounded by a winding or windings. The invention is furthermore particularly concerned with apparatus having high voltage windings of the disk coil type. Such a high voltage winding must be effectively insulated from the winding leg of the core and from any low voltage winding which it may surround, and suitable provision must be made for dissipating heat from the winding to prevent ex- 'y cessive temperatures. The necessary insulation is usually provided by one or more insulating cylinders between the high voltage windings and the winding leg of the magnetic core. The disk-coils i forming the high voltage winding are usually spaced from each other and from the insulating cylinder which they surround to provide passageways for an insulating and cooling liquid in whichv theapparatus is immersed. It has been found that if the voltage of the winding in such an arrangement is increased to the point of breakdown,

corona will rst appear and breakdown will first take place along the inner edges of thedisk coils D where they are spaced a short distance from the insulating cylinder.

The general object of the invention is to provide an improved arrangement of high voltage winding with its insulating cylinder wherein a '30 much higher voltage is necessary before corona and breakdown will occur.

The invention will be better `understood from the following description taken in connection with the accompanying drawing in which Fig. 1 is a simple partially diagrammatic view of a core type transformer having windings which may be arranged in accordance with the invention; Fig. 2 is an enlarged view of a portion of the transformer, the windings in this view being shown 40 partly in section; Fig. 3 is a sectional view on the line 2 3 of F18. 2: Fig. 4 shows a detail'on the.

line 4-4- of Fig. 2. and Fig. 5 shows a modified form of the invention. Y

,Like'reference characters indicate similar parts 45 of thediiferent figures of the drawing.

' The transformer shown in the drawing includes a magnetic core il having two winding legs il y surroundedby high voltage windings I2 and low voltage windings-i2, each low voltage winding I2 so being next to its winding leg Il and surrounded by its high voltagewinding I2. Each high-voltage winding i2 is insulated from its low voltage winding il by two concentric insulating cylinders Il and Il which are spaced from each other to prou lvide a duct or passageway It for a cooling liquid.

'Ihe' insulating cylinders Il ,and i5 are imperiorate and are formed with end flanges il and il respectively which provide insulation between the ends of the winding and the adjacent yokes` I9" of the magnetic core. Suitable spacing strips are provided between the insulating cylinders i4 and I5 and between their flanges i'l and il.

In accordance with the inventionv the high voltage winding I2 includes. a plurality of spaced disk coils 2| with their inner Iedges in contact with the outer surface of the insulating cylinder i4 which they surround. There is thus no space for cooling liquid between thesedisk coils 2| and their insulating cylinder il so that if any corona 'starts at all it must startin the solid insulating material of the insulating cylinder Il instead of in an insulating liquid and it is well known that corona will start much more easily in' liquid insulation than in solid insulation. It is, however, not necessary that'the disk coils 2| fit so tightly against the insulating cylinder Il -as to exclude all liquid because the dielectric strength of a thin illm of insulating liquid is much higher in`proportion to its thickness than is that of a thicker layer of such liquid.

The disk coils 2i are maintained in spaced relation by U-shaped spacers 22 and simple spacing strips 23. The winding I2 must of 'course be heldin placeunder considerable pressure and it is therefore necessary that the

spacers

22 and 23 be held in alinement to avoid distortion of the individual coils 2|. To assure such alinement of the

spacers

22 and 23, the insulating cylinder I4 is formed with longitudinal grooves 24 in its outer surface and the inner ends of the spacers extend and fit into these grooves. The spacers 22 extend along opposite faces of the coils 2| and around the inner edges where they iit into the grooves 2l. The spacing strips 23 are disposed between the U-shaped spacers 22 and their inner ends also extend into the grooves 24. The spacing strips 22 may of course be of any desired thickness depending upon the desired spacing of the coils 2i or they may be omitted if not needed.

The insulating liquid in which the transformer may be immersed will have free access to the upper and lower faces and to the outer edges'ofeach of the coils 2l so as to absorb heat from these coils to improve the circulation of the liquid. To improve the circulation of the liquid so that it may carry away the heat more rapidly, alternate coils are formed in two concentric spaced portions so that ducts 2l extend between the upper and lower surfaces of these alternate coils. The cooling liquid may thus flow surfaces of those coils which are provided with the ducts 25 but also along the surfaces of the other coils not so provided with ducts and which are therefore solid, and thus the heat is dissipated effectively from all of the coils even though the cooling liquid is substantially ex-I, eluded from the inner edges of the coils next to the i:ieriiisula'ting cylinder upon which they are suppor In the modified form of the invention shown in Fig. 5, alternate solid coils are wound. tightly over the insulating cylinder il and with -their inner edges in contact therewith -The ducts 2l associated with the other coils, however, are provided by. spacing the inner edges of the other coils from the cylinder il instead of forming these ducts through these coils near their inner edges. 'I'he spacing of the inner edges of alternate coils from the cylinder Il to provide the ducts ZI is permissible because of the i'act'that the adjacent coils are in contact with the insulating cylinder and definitely establish the potential distribution along the cylinder` at .frequent intervals so that the voltage across the ducts 25 will not be sufilcient to produce corona.

'I'he invention has been explained by describing and illustrating a particular transformer constructed in accordance therewith, but it will be apparent that changes may be made without departing from the spirit of the invention and the scope of the appended claims.

' insulating vcylinder with longitudinal grooves in its outer surface, and spaced disk coils surrounding said cylinder with their inner edges in contact with the cylinder, alternate coils having y ducts near their inner edges, and the other coils being solid.

3. Electrical induction apparatus including an insulating cylinder with longitudinal grooves in its outer surface, spaced disk coils surrounding said cylinder with their inner edges in contact with the cylinder, and spacers between said coils and extending into said grooves, alternate coils having ducts near their inner edges, and the other coils being solid.

4. Electrical induction apparatus including an imperforate insulating cylinder, a plurality of spaced disk coils, alternate coils being solid and each having an edge in contact with the cylinder. there being a duct associated with each ofthe other coils and connecting the adjacent spaces near saidcylinder.

5. Electrical induction apparatus including an imperforate insulating cylinder, a plurality of spaced disk coils surrounding said cylinder, alternate coils being solid and each having its inner edge in contact with the cylinder, there being a duct associated with each of the other coils and connecting the adjacent spaces near said cylinder.

VINCENT M. MONTBINGER.