US1112908A - Transformer. - Google Patents

Description

A. S. HUBBARD. TRANSPORMER. APPLIOATION FILED SEPT. 24,1909.

kmim@ MfS/M Patented Oct. 6, 1914.

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BATTERY COMPANY, L CORPORATION OF NEW YORK.i

TRANSFORTJIER.

To alt who/m, it may concern Be it known that I, ALBERT S. HUBBARD, a citizen of the United States, and a resident of Belleville, county vof Essex, and State of New Jersey, have invented certain new and useful Improvements in Transformer-s, of which the following is a specification.

My invention relates to improvements in transformers, and especially to transformers which are particularly adapted for use as pieces of regulating apparatus in alternating current systems of distribution.

One object of my invention is to provide ai arrangement in which a number of turns in circuit of one'of the coils of the transformer may be gradually varied as distinguished from step by step variations, and at the saine time preventing any material loss of energy due to the self or mutual induction of a short-circuited turn.

A further object of my invention is to provide an arrangement whereby the resistance variations due to the contact with such a short-circuited turn, may be properly compensated for.

Further objects, features and advantages will more clearly appear from the detailed description given below, taken in connection with the accompanying drawing which forms a part of this specification, and which shows diagrammatically an arrangement embodying one foiin of my-invention.

In the drawing, 1 represents a laminated iron core forming a closed circuit for the iiux of a transformer provided on one side with the primary winding 2. r1`he secondary winding consists of a plurality of turns 3 in the Vform of a helix, which are/preferably turned up on a screw-cutting lathe. The helix 3 has secured thereto a short circuited slip ring 4 and a gear 5. Since the path of the transformerflux is wholly in iron all or most of the iiux passes through the ring 4. That is, the flux passing through the ring 4 is substantially the saine in amount as that passing through the turns of helix 3. The parts 3, 4 and 5 are all secured together and arranged to he rotated about the core 1 by means of a motor 6 and gear 7.

The helix 3 is electrically connected with the ring or turn/4 'at 8 and the ring or turn 4 consists of a short-circuited turn' of high resistance so that any current induced therein will be` small on account of the high re- Specification of Letters Patent.

Application led Sheptember 24, 1509.

Patented Oct. 6, 1914. serial No. 513,365.

sistance of the circuit. For this purpose the ring 4 may be made of carbon, resistance metal or other`well known relatively high resistance material or structure. r1`he high resistance of the ring 4 may be produced by making the ring of -high .resistance metal or in any other suitable Way. In other words, the resistance of the ring` or turn 4 is relatively large as compared with the turns of the helix 3. A brush 9 is arranged to contact with the surface of the slip ring 4 so as to form one terminal of a regulating circuit of which the conductor 10 forms a part. 11 .represents a brush forming the other terminal of the regulating circuit connected to the conductor 12, and the brush 11 is arranged to travel along the turns of the helix 3 as the same revolves to cut more or less of said. turns in circuit. The action of the brush 11 is not, however, step by step, but the brush moves gradually along each turn so that extremely fine adjustments may be had. i

Driven by the gear 7 is a gear 13 secured to shaft 14 which iii turn drives a disk 15 having around its periphery a slip ring 16 in all respects similar to the slip ring 4. Also upon the shaft 14 there is a small slip ring 17 of small resistance and a brush 18 is arranged to contact therewith to connect the same with one terminal of the regulating circuit by means of conductor 19. Bearing upon the periphery of the slip ring or short-circuited turn 16 is another brush 20 which is electrically connected with the con-- ductor 10.

If the ring 4 were made of low resistance metal then the large number of lines of force passing through the core 1, would induce a very heavy current in the slip ring 4, since it is short-circuited. This heavy current would thereforel cause a considerable loss of energy, and would very disadvantageously affect them operation of the transformer asa piece of regulating apparatus. But by forming the slip ring 4 of such material that it has a very high resistance only ay small current will 'flow therein dueto this induction. But since the ring 4 is of high resistance, it will be lapparent that as the helix 3 revolves and the point 8 moves farther away from the brush 9, that a considerable amount of resistance is inserted in series with the helix 3. In order to compensate for this variation in resistance, the

conductor 21, the conductor 21 being so ar- .5 ranged that it is connected to the slip ring 16 opposite the brush 2O when Vthe-point 8 is directly under the brush 9. 'Thus as the point 8 moves farther away from the brush 9, the point 22 comes nearer the brush 20 so 10 that the resistance of that portion of the ring 16 in the circuit is decreased Just as much as the resistance of that portion of the ring 4 'included in circuit is increased. I t

will be apparent also that as the point 8 1s brought nearer the brush 9, the point 22 will be carried farther away from the brush -20 so that correct compensation is always maintained.

From the above it will be apparent that 1 20 have provided an arrangement in which the transformer action may be adjusted evento the finest degree, and yet the deleterious 1nduction due to the short-circuited vturn is cut down so that it is immaterial.V The addition of the slip ring 16 provides means for compensating for any changes 1n the reslstance of the circuit due to the high resistance of the slip ring 4.

Although I have described my improvements in great detail, nevertheless I do not desire to be limited thereto except as specified hereinaIter in the claims, since many modiications within the spirit and scope of the invention will be apparent to those skilled in the art, but

Having fully and clearly described my invention, what I claim as new and desire to secure by Letters Patent, is:

1. A transformer having a core Jforming a closed magnetic circuit carrying primary and secondary windings, one of said windings having a short'eircuit turn forming one terminal of the winding, said winding and turn being rotatable with respect to the core but fixed longitudinally with respect to the core, a brush adapted to move longitudinally with respect to the core to contact with the various turns of the winding and form the other terminal thereof and means for compensating for variations in the resistance of the circuit due to the movement of the'brush with respect to the turn.

2. A transformer having a closed magnetic circuit and having a short-circuited turn of highv resistance for forming one terminal of the transformer winding, a brush engaging said terminal and movable relatively about the turn, and means for compensating for variations in the resistance of the circuit, due to the movement of f the brush with respect to the turn.

3. A transformer having a coil, a slip ring of high resistance formingone terminal of the coil, said slip ring being arranged to embrace the most of the transformer flux, a brush for said slip ring, and means for adjustin the resistance of the circuit of said coil 1n accordance with the relative positions of said brush and slip ring.

4. A transformer having a coil in the formajl cfa helix, ajshort-circuited. turn of high re'' sistance forming one terminal of the coil, said short-circuited turn bein arranged to inclose the most of the trans ormer flux, a brush for making electrical connection with said short-circuited turn, a second shortcircuited turn connected in circuit with the coil, a brush therefore, and means for adjusting the relative position of said last mentioned brush and short-circuited turn to regulate the resistance in circuit with the coil to compensate for resistance changes due t0 the rotation of said first mentioned shortcircuited turn.

5. A transformerhaving a coil in inductive relation thereon, a slip ring of 4high resistance forming one terminal of the coil, said slip ring being arranged to embrace the most of the transformer flux, a brush for said slip ring, and means for compensating for resistance changes due to the rotation` of said slip ring and responsive thereto.

6. A transformer having a coil, a slip ring of high resistance forming one terminal of the coil, said slip ring being arranged to embrace the most ofthe transformer flux, a brush for said slip ring, and l means for compensating for resistance changes due to the rotation of said slip ring, said means including a second slip ring of similar resistance, and means for including moe or less of the same in circuit with the co1 7. A transformer having a rotating coil, a brush, la 'conducting ring engaging said brush and forming one terminal of the coil and arranged to rotate therewith, said ring being arranged so that the most of the transformer flux passes therethrough, a brush arranged to slide along the turns of said coil as it revolves to cut more or less of the turns of the coil in circuit, a second conducting ring in circuit with the coil, and means for rotating said second conducting ring simultaneously with the rotation of the first conduct-ing ring, so that the variations in resistance in circuit with said coil may be compensated for.

8. A transformer 'having a rotating coil, a brush, a conducting ring engaging said brush and forming one terminal of the coil, and arranged to rotate therewith, said ring being arranged to embrace most of the transformer flux, a brush arranged to slide along the turns of the coil as it revolves to cut more or less of the turns of the coil in circuit, a second conducting ring in circuit with said coil, both of said conducting rings being of high resistance as compared with 130 the turns of said coil, and means for rotating said second conducting ring simultaneously with the rotation of the first conducting ring so that the variations in resistance in ircuit with said coil may be compensated 9. A transformer having a rotating coil, a brush,- a conducting ring engaging said brush and forming one terminal o the coil, and arranged to rotate therewith, said ring being arranged to embrace most of the transformer flux, a brush arranged to slide along the turns of the coil as it revolves to cut more or less of the turns of the coil in circuit, a second conducting ring in circuit with said coil, both of Vsaid conducting rings being of high resistance as compared with the turnsof said coil, and means for rotating said second conduct-ing aing simultaneously with the rotation of the rst conducting 1 ring so that the variations in resistance in circuit with said coil may be compensated for, and both of said rings being short circuited.

10. A transformer having a short circuited turn of high resistance, for forming one terminal thereof, said turn being arranged to embrace most of the transformer flux, a brush engaging said terminal and movable relatively thereto, and means for compensating for variations in the resistance of the circuit, due to the movement of the brush with respect to said turn.

In testimony Whereof,l have signed my name to this specification, in the presence of two subscribing Witnesses.

. ALBERT S. HUBBARD. litnesses z GORHAM CROSBY, EDWIN SEGER.

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