GB558022A - Improvements relating to self-starting synchronous motors of the hysteresis type - Google Patents

Abstract

558,022. Motors. FERRANTI, Ltd., and HOLMES, S. W. July 18, 1942, No. 10019. [Class 35] In a self-starting synchronous motor of the hysteresis type, such as described in Specification 436,145, the stator is formed of two annular dished member a, Fig. 1, fitted together at the outer edges and on their inner edges provided with interdigitated pole-forming members c, h. The members c are shaded by a shading coil d, which may be formed of laminae, and alternate with the members h. In the assembled position of the two parts of the stator, the pole members c, h and c', h<SP>1</SP>, Fig. 2, of the two parts are arranged so that the distance between a group c, h or c<SP>1</SP>, h<SP>1</SP> is more than half the distance between pole members c', h<SP>1</SP> or c, h on either side of it. According to another arrangement, Fig. 4 (not shown), the pole members are arranged in groups comprising h, c', h<SP>1</SP>, c in that order and the distance between the groups is greater than the distance between the individual members of a group. The unshaded pole members may be formed on a mild steel ring e or integrally with the member a being bent around the inner edge of the shading coil. Also they may be stepped to come opposite the tip of a shaded pole member of the opposite polarity, Fig. 6 (not shown).