SYNCHRONOUS MOTOR FIELD CONTROL DEVICE Russian patent published in 1998 - IPC

FIELD: electrical engineering. SUBSTANCE: device is, essentially, three-circuit automatic control system depending for its operation on slave control of coordinates. First slave circuit controlling field current incorporates current regulator, controlled thyristor valve, and current sensor. Second slave circuit controlling reactive current of synchronous motor includes reactive-current measuring transducer and reactive-current regulator; it functions to maintain stator reactive current at level set by voltage regulator output signal. Third one is main voltage-control circuit incorporating voltage measuring transducer and voltage regulator. Voltage feedback including threshold element, one-shot multivibrator, first aperiodic filter with controlled time constant, two Schmitt flip-flops of aperiodic filter and AND gate functions to raise field current setting value in case of heavy voltage fluctuations to ensure steady operation of motor. EFFECT: improved reliability of voltage control and reduced power loss in motor and in supply mains. 2 dwg