US885034A - Transformer. - Google Patents

Description

No. 885,034. PATENTED'APR. 21, 1908.

J. J. FRANK."

TRANSFORMER. APPLICATION FILED SEPT. 26, 1907- 2 SHEETS-SHEET 1.

\A/ITNELEISEE INVENTUR JEIH'N J'. FRANK- b q r ATTLl,

No .885,034. R v PATENTED APR. 21, 1908. v J.J.'FRANK. v

TRANSFORMER. APPLICATION FILED SEPT. 26, 1907.

2 SHEETS-SHBBT 2.

WITNhfifiEE INVENTEIR.

' I FRANK- .7 hq ATTL;

UNITED STATES PATENT OFFICE.

JOHN FRANK, OF SCHENECTADY, NEW YORK, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK. g

TRANSFORMER To all whom it may concern:

Be it known that I, JOHN J. FRANK; a citizen of the United States, residing at Schenectady, county of Schenectady, State of New York, have invented certain new and useful Improvements in Transformers, of which the following is a specification.

My invention relates to transformers which are especially intended for very high voltages, and has for its object an improvement in the insulation between the coils or the coils and the low-potential portions, such as conductors t at a high voltage may be main:

tained without a break-down of the insulation. If, however, the high potential stresses set up in that portion of the insulation adj acent to the high voltage portion of the condoctors can be distributed over a large area of the insulation surrounding the conductors, the amount of stress to which-an portion of such insulation will be then sub ect'ed .will be less, for the intensity of the stress will be decreased as it is extended over a large area. The insulation about such'high voltage conductorswill then be less liable to be broken down than if a smaller portion of the insulation be subjected to a greater stress.

The ob'ect of minvention .is' to decrease and distribute this igh potential stress which normally occurs over a small portion of the insulation over a greater portion of such insulation, and thus afford a better. rot'ection against short circuits in the transorrlner. I accomplish this by "surrounding the coils of high voltage conductors, which may alre'adv have their several turns insulated from adjacent turns, with parallel layers of a conducting materialiinterspersed with layers of an insulating material; the several la ers, of conducting material being insulate from each other. The conducting material then Specification of Letters Patent.

Application filed September 26, 1907. Serial No. 894,658.

Patented April 21, 1908..

ject to a certain potential per unit area, the

next-sheet is subject to a certain otential, but being a greater area than the st sheet, and distant from the first sheet, the otential' er unit area is much less than t lat of the rst sheet. By employing a number of these sheets the resulting otential stress per unit area of the insulation lietween the sheets, the conducting material and the final sheet may be made comparatively small, and thus the insulation between the final sheet and the conducting material adjacent to it may either be made small in quantity or a greater amount of a poorer quality of insulation may be employed.

While I may accomplish the object of my invention in many ways, I prefer to accomplish it bythe use of sheets consisting of a sheet of an insulating material, such for exam le as varnished cambric, to which is attac ed by a suitable adhesive substance, such as shellac, a thin sheet of some metallic substance, for exam le tin foil. These sheets may consist of one ayer of cambric and one layer of tin foil, or, if desired, of a number of alternate layers of varnished cambric' and tin foil to still better'equalize the otential stresses through the insulation. lac holding the tin foil to the varnished cambrie may be omitted but I prefer to use it or some other adhesive substance for convenience in manipulation. The compound insulatin sheet thus constructed may then be readily formed into any of the desired shapes required for insulating purposes, and, if desired, any number of t used to further increase the insulation.

In the accompan ing drawings attached'to and made a part 0 this specification, Figure 1 shows a vertical view ofa transformer with my improved insulation the surrounding case and one of the coils, with portions of the insulation'shown in section to obtain a better he shelese sheets may be understanding of my invention; Fig.2 shows a top view of the same transformer, with the to and terminal bushings removed, and Fig. 3 s ows a portion of my improved insulation.

While I may employ my new method of insulation with any type of transformer, I have shown it employed with an oil insulated coretype transformer, in which 1 represents the base of the transformer to which ma be attached by any suitable means a shel or casing 2 to which is attached the top 3 the j omts between 1 and 2 and 2 and 3 being formed in any well-known manner, so that they be oil-tight. The cover 3 has formed in it holes 4 and 4 to allow suitable terminals to be brought out from the transformer coils and other' holes, such as 4,which may be useful and necessary forinspecting the inside of the transformer, or putting in oil etc.

5 shows the core of the transformer, which may be formed of bundles of laminae in the well known fashion; the bundles being held together by bolts 6, passinathrough suitable crossieces 7 and fastened y nuts 8.

As t at portion of the structure of the transformer that relates to the retaining of the core and the coils, and the holding of the same together andto the casing is immaterial to my present invention, I shall riot further describe it; but shall confine my description to those portions of the transformer to which my invention relates.

9 is the primary or low-voltage winding closely fitting the core, and 10 the secondary or high-voltage windin this being shown as divided into short 00' s, for convenience in insulatin the .coils. These short coils are se arate from each' other by strips of an insu ating material 11, which are shown as not extending over the entire faces of the coils, but allowin spaces 12 to permit of a flow of cooling flui between the coils. I have shown the upper coils as' somewhat thicker than the lower as the insulation between the turns ma be increased'in the well-known. manner to urther provide against a short circuit be;- tween the several turns subjected to the high potential between the coils.

13 are blocks of wood, which serve as suports for the coils; the inside of the coil being ined by a strip of insulating material, '14, fiber, or an other suitable substance.

Terinina s 15 are shown leading from the grimary winding through suitable insulating ushings 16 to the exterior of the casin of the transformer, and terminals 17 lea ing from the secondary windings through suitable high-tension bushings 18 to the .exterior of the transformer.

Sheets of my improved insulation 19 are shown between the primary and secondary coils; these sheets being separated by suitable insu'latin space-blocks to makes aces 20 between -t e insulating sheets an the am le.

primary and secondary winding, through which spaces of insulating fluid mayv be allowed to flow. Insulating sheets 21 are also shown between the coils of the transformer, the sheets being supported bv insulating blocks 22 to provide spaces etween the sheets and the coils for the purpose previously described. All of these sheets are shown extending well beyond the ends of the coils and successively greater in area as they are s aced further from the high voltage conuctors, and sheets 21 are shown as extending in a horizontal direction well beyond the exterior faces of the coils, to give a, greater voltage creepage distance. I have also shown sheets of insulation 23 extending around the interior of the casing of the transformer and resting upon and se mated by insulating blocks 24 and spaceb ocks 25. I These sheets 23 I have shown as extending to the top of the casing, for while the terminals 17 are shown as insulated by the hi h-voltage bushings 18, it has been found t at frequently a short-circuit will occur between the terminals 17 and the casing and by extending' my improved insulation about the casing, well :above the terminals 17, and makin the sheets greater in area as they a proac the casing, I distribute and diminis the potential stress due to the terminalsover a wide area of insulation for the reasons previously described.

In Fig. 3, I have shown a portion of my insulation consistin materialv 26v attacIied to a thin conductin sheet 27; a cover of the sheet 27 be' rolle away from the insulating material. hile I have shown my insulation as consisting of one layer of conducting and one layer 'of insulating material, for greater clearness in illustration, I do not limit myself to a single sheet in each, but a number of sheets alter nately of a conducting and an insulating material-may be used if desired, and these ma or may not be fastened together 'by an a hesive substance, such as shellac, for exile I have shown my invention as applied to a certain type of apparatus, namely, an oil-insulated core-t e of transformer, it should be understood t at my invention is not limited to such an a paratus, but may be used with'any type of electrical apparatus where certain portions are subjected to a high voltage, substantiallyrfor the purpose and in the manner described.

What I claim as new and desire to secure by Letters Patent of the United States, is,

1. In an electric device containing conof a layer of insulating ductors subject to a high' voltage and adjacent to other conductors or conducting material, means for insulating the high-voltage conductors by interposing between them and the low-voltage conductor or the low-voltage conducting material adjacent to them parallel layers of an insulating and an insulated conducting substance.

2. In an electric device containing conductors subject to a high voltage and ads j acent to other conductors or conducting ma terial, means for insulating them from the low-voltage conductors or conducting material by surrounding them with insulated.

sively greater in area as they are successively spaced further from the high-voltage conductors and spaces bet-ween the sheets containing insulating fluid. I

4. In a transformer composed of a primary and a secondary winding, means-for decreasing and e ualizing the potential stresses due to one of t e windings over a large area of the insulation between the windings. l

5. In a transformer composed of a primary and a secondary winding, one winding having high potential in certain portions, a laminated core and an inclosing casing, means for decreasing and equalizing the otential stresses due to a portion of one of t e windings over a lar e area of the insulation be tween said win ing, the core and the casing. 6. In a transformer composed of a primary and a secondary winding with a laminated core and aninclosing casing, and high-potential terminals adjacent to the sides of the casing, means for decreasing and equalizing the potential stresses due to said terminals over a large area of the insulation of said casm 7. a transformer composed of a primary and a secondary winding, one of the windings having high potential in certain portions, an insulation composed of a plurality of parallel layers of an insulated conducting substance, and an insulating substance for decreasing the potential stresses due to one of said windings a iid e ualizing them over a large portion of the lnsu ation between said windlngs.

8.. In a transformer composed of a primary and a secondary winding with a laminated core and an inclosin casing, an nsulatlon composed of a plurality of arallel layers of an insulated conducting su stance, and an insulating substance for decreasing the potential stresses due to one of said windings,

and equalizing them over a large area of the insulation between .said winding, the core and the casing. L

9. In a transformer composed of a primary and a secondary winding, one of the windings having high potential in certain portions, an insulation composed of a plurality of parallel layers of an insulated conductin substance,

and an insulating substance, the ayers being successively greater in area as they are successively spaced further from the high-voltage winding, for decreasin the potential stresses due to one of sai windings and equalizing the stresses over a large portion of the insulation between said windings.

10. In a transformer composed of a primary and a secondary winding with a laminated core and an inclosing casing, an insulation composed of a plurality of arallel layers of an insulating conducted substance and an insulating substance, the layers being successively greater in area as they are successively spaced further from the high-voltage conductors for decreasing the otential stresses due to one of said windings and equalizing the stresses over a large area of the insulation between the said winding, the

core and the casing. 11. In a transformer composed of a primary and a secondary winding with a laminated coreand an inclosing casing, and highpotential terminals adjacent to the sides of the casing, an insulation composed of a plurality of 'parallel layers of an insulated conducting substance and an insulating substance for decreasing the stresses due to the potential of said terminals and equalizing the stresses over a large area of the insulation ad'acent to the casing.

12. n a transformer composed of a primary and a secondary winding with a laminated core and an inclosing casing and highpotential terminals adjacent to the sides of the casing, an insulation composed of a plurality of parallel layers of an insulated conducting substance and an insulating substance, the layers being successively greater in area as they are successively spaced further from the high-potential terminals for decreasing the stresses due to the otential of said terminals and equalizing t e stresses over a large area of the insulation adjacent to the casing.

13. The combination witha transformer consisting of a primary and a secondary windin of an insulating material inclosing said 'COIlS consisting of parallel layers of an insulating and a conducting substance.

14. The combination with a transformer consisting of a primary and a secondary Winding, a 'core and an inclosin casing, of an insulation composed of a plura ity of parallel layers of an insulating and a conducting material, the layers being successively greater in area as they are successively spaced further from the high-voltage conductors, and spaces of a core,

between said layers filled with an insulating fluid for increasing the insulation.

15. In a core-'type transformer consisting of .a core, primary and secondary windings inclosing the legs of said core substantially as said coils, the layers being successively greater in area as they are successivel spaced further from the high-voltage con uctors to decrease the potential stresses between said coils and equalize the stresses overa wide area of the insulation separating said coils.

16. In a core-type transformer consisting primary and secondary windings inclosing t e legs'of said core substantially as shown, one of said windings having a maxir'nunf potential at certain portions, and an inclosin casing, an insulatin material comosed o a plurality of aral el layers of an insulated conducting 's'u stance and' an insulating substance, the layers being successively greater in areaas they are successively spaced further from the high-voltage conductors to decrease the'potential stresses due to the high potential of one of saidwindings and equalize the stresses over a large area of the insulation between said windmg, the core and the easing. 7

17. In a core-type transformer consisting )of a core, primary and secondary windings inclosing the legs of said core substantially as shown, and high-potential terminals adj acent to said casing, an insulatin material consisting of a plurality of paralle layers of an insulated conducting substance and an insulating substance, the layers surrounding the inner srde'of said casing and being successively greater in area as they are successively spaced further from the high voltage conductors, for decreasin the potential stresses due to said termina s and equalizing the stresses over a wide area of the insulation adjacent the casing.

18. In combination with an oil insulated core-type transformer with a core, primary and secondary windings upon the legs of said core, an inclosing casing, high-voltage terminals brought out adjacent to the sides of JOHN J. FRANK,

Wit esses:

ELEN 'ORFORD, BENJAMIN B. HULL.

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