Control of async. motor - uses thyristor rectifier bridge and thyristor oscillator receiving variable frequency three-phase supply

摘要

The appts. is for the control of an asynchronous motor powered by a three-phase electric network via a thyristor rectifying bridge. A filter circuit for rectified current comprises an inductance in series and a capacitor in parallel, and an oscillator switching thyristor bridge. The thyristors of the bridge are controlled by the pulses produced by a control circuit receiving an input signal proportional to the supply voltage of the oscillator bridge. The thyristors of the rectifying bridge are controlled by a threshold circuit receiving an input voltage controlled by a regulator receiving a voltage with a value proportional to the voltage at the terminals of the motor.