Turn-off circuit for thyristors in bidirectional controls - simplifies circuitry by using separate turn-off bus-bars for each direction

摘要

The turn-off circuit, for thyristors in bidirectional controls, has the terminals of the turn-off capacitors connected over diodes and ballast resistors to the turn-off bus-bar that determines direction reversal (of motor). A holding current circuit, separate from the main circuitry, is connected via a special bus-bar and diodes and ballast resistors to the cathodes of all the thyristors. The advantage lies in its simplifying the circuitry for direction reversal by connecting the turn-off voltage to two separate bus-bars corresponding to the two directions of rotation of the motor.