IE33473B1 - Electrodynamic system comprising a variable reluctance machine - Google Patents

Abstract

1321110 Dynamo-electric machines ALLMANNA SVENSKA ELEKTRISKA AB 24 June 1970 [25 June 1969] 30644/70 Heading H2A An electric motor comprises a salient pole stator providing a set of stator pole faces, a rotor having a set of rotor pole faces, the pole faces of one of the sets being of greater arcuate length than those of the other, and stator windings M 1 , M 2 connected sequentially to a D.C. power supply under the control of a rotor position sensor, the path for the flux produced by the stator windings having, adjacent a stator/rotor interface, a zone of restricted cross-sectional area, which area increases from zero to a maximum during each pass of a rotor pole past a stator pole, the zone being such that this maximum occurs after the leading edge of the larger pole has passed the trailing edge of the smaller pole, and saturation occurring in the zone even at the maximum. In Fig. 1, the rotor poles are each twice the length of the stator poles 2, 3, 8, 9, but over the leading portion of each rotor pole part of the iron is removed, e.g. by punching holes 6 or omitting portions of alternate laminations (Fig. 2, not shown). When the leading edges of the rotor poles begin to overlap one pair of stator poles (say, 2, 3) the associated winding M 1 is connected to the supply so that the rotor is pulled anticlockwise into its minimum reluctance position. Owing to the punchings 6, this position is not reached until the trailing portions of the rotor poles are beneath the stator poles 2, 3, at which time the leading edges of the rotor poles are beginning to overlap the other stator poles 8, 9. The supply is thereupon switched from the winding M 1 to M 2 so that rotation continues. A thyristor-controlled switching circuit for the windings is disclosed (Fig. 3, not shown), which includes an arrangement for keeping the current supplied substantially constant. [GB1321110A]