METHOD FOR REGULATION OF ROTATION FREQUENCY OF DOUBLE-SUPPLY ELECTRIC MOTOR AND DEVICE WHICH IMPLEMENTS SAID METHOD Russian patent published in 1997 - IPC

FIELD: double-supply electric motors. SUBSTANCE: method involves supply of stator windings of electric motor from three-phase line and supply of rotor windings from frequency converter. When electric motor reaches rotation frequency which is greater than stator field rotation, alternation of stator windings is changed, voltage which supplies rotor windings is altered simultaneously. Angle for conducting thyristors of inverter of frequency converter is kept constant, it is equal to 150 degrees during regulation of rotation frequency. Corresponding device has phase switching unit, which matches phase alternation in power circuit and in inverter control circuit. EFFECT: increased range of rotation frequency regulation. 2 cl, 3 dwg