GB1439991A - Synchronous stepping motors and control circuits therefor - Google Patents

Abstract

1439991 Control of stepping motors SOC INTERNATIONALE DE MECANIQUE INDUSTRIELLE SA 26 June 1973 [30 June 1972] 30391/73 Heading H2J A stepping motor having two groups I, II of stator coils 9 ... 16, each comprising two windings, e.g. 9a, 9b wound on a single core in mutually opposed senses, is controlled by an electronic circuit E consisting of a tripper circuit 1 feeding two bi-stable circuits 2a, 3a which are interconnected as shown and supply amplifiers 5a, 6a, 5b, 6b connected to the motor windings 9a... 16b and to a voltage stabilizer 17 through diodes 18 ... 21, the arrangement being such that the outputs of the amplifier pairs 5a, 6a and 5b, 6b are in anti-phase with each other and phase displaced by 90 degrees with respect to the corresponding one of the other pair, Figs 2-5 (not shown), whereby selected windings are sequentially energized from circuit E to generate a rotating magnetic field and those windings not momentarily energized are supplied with a small current from a D.C. source (+) via members 17... 21 to produce a small residual field opposing the rotating field and so create a braking torque to damp the motion of the motor rotor at the end of each step. The motor and its control circuit may be used in the supply network of a motor vehicle, in which case the D.C. source (+) may be the positive terminal of the battery and the circuit E, which is supplied from the stabilizer 17, is protected against transient voltages by the presence of coils 9 ... 16.