US1708775A - Transformer - Google Patents

Description

Patented Apr. 9, 1929.

UNITED ySTATES-PATENT OFFICE.

WILLIAM E. PAUL, F SCHENCTADY, NEW YORK, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

TRANSFORMER.

Application led May 18,

My invention relates to-transformers.v A transformer usually includes a magnetic core and primary and secondary windings. Current in the prim ary windin g induces magnetic vflux in the core and this flux induces in the secondary windinol a voltage which will cause a current to flow if a suitable path is provided between the secondary terminals. Itis sometimes desirable to limit the secondary current to some definite maximum value even when the values of the voltage and current in the primary winding are greater than necessary to produce this maximum secondary current. This result has been obtained to some degree by arranging the core to become saturated by the amount of flux necessary to produce the maximum secondary voltage and current. Any further increase in primary voltage and current will then produce y only leakage flux and the amount of this leakage flux will not be very great because the reluctance of the leakage Hux path is high. The

amount of this leakage flux, however, may be very appreciable and the general object of the invention is to provide an improved transformer of the saturated core type so arranged and constructed that the primary leakage flux will not substantially affect the secondary voltage and current.

rI'he invention will be better understood from the following description taken in connection with the accompanying drawing in which Fig. 1 is a perspective View of a transformer constructed in accordance with the invention, and Figs. 2 and 3 are explanatory views of the transformer shown in Fig. 1 with the windings shown in section.

-Like reference characters indicate similar parts in the different figures of the drawing. l In the particular construction shown in the drawing, the transformer includes a laminated magnetic core 10 having a. central leg 11 and two outer legs 12 connected at their ends by yokes. The central leg 11 is surrounded by a winding 13. Each outer leg 12 has two end sections 14 connected to an offset intermediate section 15 by short connecting sections 16 disposed at right angles to the central leg 11 and to the axis of thewinding 13. There are thus four of these connecting core sections 16. Windings 17v surround respectively the four connecting core sections 16. These windings '17 may be connected in any desired series or parallel or series-parallel 1928. Serial No. 278,844.

combination so that together they form a second wind-ing of the transformer.

The main magnetic flux fiowing through Vthe core is indicated bythe arrows in Figs. 2 and 3 and will be substantially the same whichever of the two windings 13 and 17 is used as the primary. When the number of ampere turns in the primary winding is greater than that necessary to saturate the core, a leakage flux field will appear and this field will be different depending upon which of the two windings 13 andV 17 is used as the primary. ]f the winding 13 on the central core leg 11 is the primary, the leakage fiux field 18V` indicated by broken lines in Fig. 2 will,` be produced. If the windings 17 on the outer core legs are connected to form the primary, leakage flux 19 as indicated by broken lines in Fig. 3 will be produced.

In the arrangement which has been described, the windings 17 are disposed beside the winding 13 and with their axes at right angles to the axis of this winding 13. The windings 17 are thus disposed in the leakage magnetic field 18 which may be produced when the winding 13 is used as the primary and the axes of the windings 17 are at right angles to the lines of force in the field 18. The voltages and currents in the windings 17 are therefore not affected by this magnetic field or by any increase in ampere turns in the primary winding 13 after the core is saturated. 1n some cases, it may be found desirable to extend the central core leg beyond the end yokes as shown in Figs. 2 and 3 t0 direct the lilies of force inthe magnetic held 18 more nearly at right angles to the axes of the windings 17 at all points within these windings.

The leakage magneticfields 19 shown in Fig. 3 are produced when the windings 17 are used as primary. If these fields reach the winding 13 which is now` the secondary, their axes will be at right angles to the axis of this secondary winding and the voltage and current in the secondary winding will therefore not be affected and cannot increase in response to any increase in ampere turns in the windings 17 after the core is saturated.

The invention has been explained by describing a specific form thereof but it will be apparent that various changes may be made without departing from the scope of the invention as defined in the appended claims.

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

1. A transformer including a magnetic core having a plurality of legs, a winding surroundingV one of said legs, a second leg having an end section and a section oil'set from its end section, and a second Winding surrounding said second leg between its end and its ofset sections, the axes of said two windings being at substantially right angles to each other.

2. A transformer including a magnetic core having a plurality of legs, a winding surrounding one of said legs, a second leg having two end sections and an mtermedlate section offset from its end sections, and windings surrounding said second leg between its end and intermediate sections, the axes of the windings on said second leg being at substantially right angles to the axis of the other winding.

3. A. transformer including a magnetic core having a central leg and two outer legs, a winding surrounding said central leg, each outer leg having two end sections and an intermediate section oiset from its end sections, and windings surrounding each outerleg between its end and intermediate sections, the axes of the windings on said outer legs being at substantially right angles to the axis of the winding on said central leg.

In witness whereof, I have hereunto set my hand this 17th day oi May, 1928.

WILLIAM E. PAUL.

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