GB190707791A - Improvements in Electric Transformer Furnaces. - Google Patents

Abstract

7791. Gr÷nwall, E. A. A., Lindblad, A. R., and StÕlhane, O. April 3. Electric furnaces. -An induction furn a c e is provided with auxiliary coils supplied with alternating current, arranged to counteract magnetic leakage. Fig. 2 shows one of the arrangements described by way of example, in which two equal coils 8, 9 are placed round the transformer legs 1, 2 and are connected so as to be in magnetic opposition. The coils, 8, 9 are supplied with current of phase and frequency corresponding with that in the primary coil 5, either from an external source or, as shown, from the primary coil itself by the Hick system of transformation. In the latter case, one terminal 12 of the auxiliary coils 8, 9 is connected to a terminal 7 of the primary, and the other terminal 13 to a point 14 on the primary. The primary may be arranged differently, and may be subdivided. In another construction, a coil surrounds a face of the transformer core, to counteract leakage therefrom, and any number of such coils may be provided.