device for kommutieren of the coils of electrical motor durchfliessenden stream with electronic switches

摘要

1,263,861. Electric motors. LENCO A.G. 10 Feb., 1970 [11 Feb., 1969], No. 6261/70. Heading H2A. An electronic commutating circuit for selectively switching the field coils F of an electric motor comprises a separate switching stage for each field coil, each stage comprising an oscillatory circuit whose inductance value is cyclically changed by a control member rotatable with the motor rotor. In the embodiment shown, the oscillatory circuits are parallel resonant LC circuits connected through a common transistor TV to a high frequency oscillator, e.g. a frequency stabilized multivibrator, Fig. 5 (not shown). The control member is a ferromagnetic yoke in the shape of a segment of a circle, and when adjacent an inductance L, tunes the respective LC circuit to the operating frequency of the multivibrator. The output of each LC circuit is fed to a respective switching transistor TS through a rectifier D. In a modification, Fig. 7 (not shown) the common transistor TV is omitted and each diode is replaced by a common-emitter transistor operating in Class C. Series resonant circuits may be used in place of the parallel LC circuits shown.