US1311507A - Vania - Google Patents

Description

G. HARLOW.

TRANsroRmER.

APPLICATION FILED JUNE 20. i916.

Patented' July 29, 1912).

INVENTOR WITNESSES ATTORNEY GEORGE HARLOW, OF ALTRINCHAM, ENGLAND,

ASSIGNOR T0 WESTINGHOUSE ELECTRIC MANUFACTURING COMPANY, A CORPORATION OF PENNSYL- VANIA.

TRANSFORMEB.

Specication of Letters Patent.

Patented July 29, 1919.

.Application led J une 20, 1916. Serial No. 104,794.

To all LU/wm z't may concern."

Be it known that I, GEORGE HARLow, a subject of the King of Great Britain, and a resident of IVoodgarth, Oldfield Road, Altrincham, in the county of Chester, England, have invented a new and useful Improvement in Transformers, of which the following is a specification.

My invention relates to electrical transf formers and particularly to core-type transformers in which the coils that constitute the windings are braced to resist permanent displacement resulting from any axial stresses that may be imposed upon them.

In core-type transformers, it is usual to wind the low-tension winding into a single coil for each core le and to dispose this coil closely adjacent to t ie iron core. The hightension winding is usually wound into a number of coils which are placed outside of the low-tension coils and arranged coaxially therewith. These high-tension coils, being superposed upon one another, are spaced from one another by means-of insulating blocks or insulating washers. If a short circuit occurs on the low-tension side of the transformer, in addition to the very heavy radial stresses set up between the windings, axial stresses are generated which tend to force the high-tension coils apart. Of course, axial stresses are imposed upon the low-tension coils which may be distorted also, but usually are Inot because of their form of construction. In order to secure the coils against axial movement and to resist the axial stresses that result from short circuits. it has been usual to provide heavy clamps at the top and bottom of the member to brace the coils against forces that may permanently displace them. It is found, however, that., although these clamps may be forced tightly against the coils when the transformer is built, the coils gradually become loosened after the transformer has been placed in service because of the shrinkage of the insulating material. IVhen the high-tension winding is composed of a large number of superimposed coils, this defect is especially noticeable.

According to 'the present invention. I provide means whereby the coils may be securely clamped under all conditions and which automatically compensates for any slackness resulting from the shrinkage of the insulating material. My clamping means permits the coils to be axially moved when subjected to axial stresses that, under ordinary conditions, would be dangerous to them. After the axial stresses have subsided, the coils are returned to their original position and firmly held in alinement. Moreover, any axial movement that the coils may partake of is damped in such manner as to preclude them from being suddenly pulled apart.

For a better understanding of the nature and scope of my invention, reference may be had to the following description and the accompanying drawing in which Figure 1 is a sectional view of the upper part of a coretype transformer embodying a formv of my invention, and Fig. 2is a similar view of a modified form of the structure shown in F ig.' 1.

Referring to the figures, a core leg 1 of a core-type transformer is embraced by a low-tension winding 2 which, in this instance, consists of a single coil for each core leg, and a high-tension winding which consists of a number of superposed coils 3. The low-tension winding 2 is spaced from the core leg 1 by means of an insulating barrier l and is separated from thc high-tension coils 3 by means of an insulating barrier Each coil 3 is provided with a suitable-insulating covering 6 which usually consists of a wrapping of impregnated tape or other insulating material.

In Fig. 1, the core member of the transformer is provided with two angle pieces 7 and 8 which are connected by a bolt 9 to clamp the yoke or top portion of the core member. Each of the angle pieces 7 and 8 is provided with a bolt 10 that is engaged by a lock nut 11. The shank of the bolt 10 projects into an opening providedin a head member 12. On top of the uppermost hightension coil 3 is placed a plurality of insulating washers 13 and a steel ring 1i which is slit in any suitable manner to prevent the circulation of eddy currents therein. Interposed between the head l2 and the steel ring 14 is a spacing member 15 ipon which is formed a flanged portion 16 that is alined with the head 12. A compression spring. 17 is interposed between the iianged portion of the head 12 and a flanged portion 16 of the spacing member 15. The spacing member 15 is provided also with an upwardly extending portion 18 that projects into, and forms a piston member to coperate with, a downwardly-extending cylinder -19 that is formed integrally with the head member 12. The piston member 18 and the cylinder '19 constitute a dash pot which is surrounded by the compression spring 17. Holes 20,

formed in the upper walls of the dash pot, provide means for regulating the damping eli'ect for which the dash pot is furnished by allowing the oil in which the whole mechanismis immersed to pass into 'and out of the dash pot cylinders. Of course, it will be understood that the dash pots and compression springs permitithe high-tension coils to be axially displaced but their movement is damped which precludes them from being rapidly separated when the transformer is subjected to any abnormal stresses. The springs 17 compensate for the shrinkage in the insulation and, under normal conditions, firmly hold the coils in fixed relationship. Any suitable number of dash pots and springs may be provided, depending upon the size of the transformer coils and the necessity for maintaining a substantially uniform compression upon them. v

In assembling the transformer, the bolts 10 are tightened up, thereby firmly holding the coils by compressing the spring members 17 and adding a suliicient number of insulating washers 13. The spacing member 15 .is so designed as not to affect or restrain the action of the dash pot and, therefore, suiicient room must be provided between the head of the cylinder and the top of the piston member 18. When the insulation shrinks, it is com ensated for by the springs 17, but any su den axial movement of the coils resulting from heavy magnetic stresses will be prevented by means of the dash pots,l since the oil contained in the cylinders 19 will be prevented from escaping too quickly from them by reason of the comparatively small diameters of the exit holes 20. If the whole transformer is not immersed in oil, the dash pots will have a damping action by reason of the compression of the air contained inthe cylinders 1 9.

In Fig. 2, I havexshow thecompression springs 17 and the dash pot members 18 and 19 placed intermediate the coils 3. The adjacent coils 3 are separated by the compression springs 17 located between split rings 21. and 22, and are held in place by means ofthe cylinders 19 which, as mentioned above, coact with the piston members '18 65y `upper ring 21. The compression of thesprings 17 may be adjusted when the trans-' 'i that, in this instance, are threaded into the former is being assembled by means of the usual clamping means at the top Aand bottom of the transformer core-members.

In the foregoing description, I have shown my invention applied tothe hightension windings only of the transformer,

but it will be appreciated that a similar structure may be provided for the lowtension winding.

Although I have shown only one form of my invention, it will be understood that` many modifications may be made without.A

departing from the spirit and scope of the appended claims.

'I claim as my invention: A

1. A transformer comprising a core member, current-carrying coils inductively related thereto, elastic means for normally holding and urging said coils together and means for substantially preventing yielding vmovement of said elastic means when sudden mechanical stresses are imposed on said coils. v

2. A transformer comprising a core inember, current-carrying coils inductively related tliereto, elastic means for normally holding said coils in fixed relationship, and retarding means for substantially preventing yielding movement of said elastic means l in a reverse direction from that in which the coils are normally urged, lwhen sudden j mechanical stresses are imposed on said coils:

3. A transformer comprising a core member, current-carrying coils linductively related thereto, elastic means for normally holding and urgin said coils together, and

a dash-pot mechanism which, when. sudden mechanical stresses are imposed on said coils, substantially prevents yielding movement in a reverse direction from that in whichsaid coils are normally urged.

4. A transformer comprising a core member and a plurality of superimposed currentcarrying coils that are subjected to magnetic stresses directedin axial directions, yielding members for normally holding the coils in firm engagement with one another but permitting them to move temporarily in axial directions to resist the imposed` magnetic stresses, and means for retarding the com-V pressive action of the springs to preclude abrupt separation of the coils.

5. A transformer comprising a core member, current-carrying coils therefor that are subjected to axial magnetic stresses, springs held in compression for normally holding the coils in fixed relationship to permit them tomove axially when subjected to abnormal, stresses, and dash pots enveloped by saidv springs for retarding the axial movement of subscribed my name this nineteenth day of the coils, whereby the motion of a coil in May, 1916. response to a slowly applied force is permitted but the motion occasioned by a sud- GEORGE HARLOW 5 denly applied force is substantially nega- Witnesses: tived. W. S. Torus,

In testimony whereof, I have hereunto E. JACKSON.

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