SWITCHING DEVICE AND METHOD FOR TERMINATING A BRAKING PROCESS OF A THREE-PHASE AC MOTOR

摘要

A switching device and method are disclosed for terminating a braking process of a three-phase AC motor. The braking process of the AC motor is performed by way of a first and second thyristor. During the braking process of the AC motor, in a first step the first thyristor is actuated in such a way that a braking current is fed to the AC motor, and therefore a torque which brakes the AC motor is produced. In a second step the second thyristor is actuated in such a way that, when the first thyristor is quenched, the braking current is taken on by the second thyristor and the braking torque is maintained. The two steps are repeated during the braking process; wherein the second step is suppressed during the braking process after a last actuation of the first thyristor.