GB1148911A - Synchronous dynamo electric machines - Google Patents

Abstract

1,148,911. Starting synchronous machines. ENGLISH ELECTRIC CO. Ltd. 3 May, 1966 [6 May, 1965], No. 19167/65. Heading H2A. In a synchronous dynamo-electric machine 10, e.g. generator, motor, condenser, or rotary converter, having stator and rotor members 11, 13 of which one, e.g. the stator, has an A.C. winding 12 and the other, e.g. the rotor, has a winding 16 disposed about an even number of discrete polar axes such that when D.C. energized the other member produces a like number of steady magnetic poles, the winding about at least some of the polar axes includes two separate windings 21, 22 which are wound in the same sense, have different resistances, and are connected or connectible in parallel to form closed loop circuits which act as induction motor secondary windings when the machine is started as an induction motor. As shown, the differing resistances result from the two windings having differing numbers of turns, but alternatively result from differing cross-sectional areas or specific resistances. Although shown on a salient pole rotor they may be alternatively on a cylindrical rotor, Fig. 7, or on the stator. Although shown as interleaved the windings may be partially or wholly axially spaced, Fig. 2, and the turns difference effected by an asymmetric crossconnection, Figs. 5, 6. In other modifications the parallel connection is made via slip rings by a switching means which thereby controls the torque speed characteristic.