Bidirectional speed control for DC motor - has control circuit switching on two inverter groups operating with different pulse rates for different selected currents

摘要

The bidirectional speed control has a control circuit to switch on the two groups of static inverters. the inverter groups operate in a 3-pulse mode at selected low currents and in a 6-pulse mode at selected high currents. A polarity detector generates a signal whose magnitude and direction determine the selected current. The control circuit is connected to the polarity detector, to the speed controller and to a current measuring unit that constantly measures the actual current flowing in the motor's armature. The advantage lies in max. reliability and precision.