GB335283A - Improvements in regulating transformers - Google Patents

Abstract

335,283. Thoma, H. June 27, 1929. Regulating transformers. - The brush of a regulating transformer is displaced longitudinally by a spindle positively coupled by gearing to the rotary coil of the transformer, and current is supplied to the coil by leads passing through cavities in the shaft and yoke. The core K, Fig. 1, carries the insulated flat copper winding F and is mounted to rotate between the yokes I, X. The ends A', A<2> of the winding are led through holes in the shaft and grooves N in the core. The brush contact B is mounted on a screw spindle Y which rotates when the core rotates, so that the brush always makes proper contact with the winding. Several brushes B may be mounted adjacent each other, and the connecting leads from the brushes are taken outside by insulated contact bars, so that the effect of the pulsating flux balances the voltage of one turn of the regulating winding. In the modification shown in Fig. 2, the slit core L is fixed to the yoke I so as not to rotate, while the short rotatable part D attached to the winding F is separated by air gaps from the part L and the yoke X. In this form a separate exciter winding R is arranged between the core L and the winding F. The-rotatable part D of the core may be omitted; the current lead M then has the form of a twisted bar, similar to the twisted bars used in generators, and passes through a simple air-gap. In another modification a pole-piece is attached to the core L. In another modification the core L, Fig. 4, carries the primary winding G, while the secondary F is wound on the insulating cylinder S, which extends through the yoke X and supports the slip rings U. The stampings V of the yoke X are slotted and separated by presspahn, the outer stampings being separated by thicker pieces of presspahn than the inner layers. Multiple leads for conducting the current may be used and are connected by suitable resistances or choking coils.