| 摘要 |
PURPOSE:To protect a thyristor converting device from overcurrents, by changing the flows of currents by making an electromagnetic contactor for short-circuit operation by detecting the failure of the commutation of a thyristor. CONSTITUTION:When the preparation of operation is completed, an electromagnetic contactor 6 for acceleration is made. When operational instructions are emitted, a breaker 52 at the primary side of a motor is made and the motor is gradually accelerated, an electromagnetic contactor 42 for working a Scherbius device is closed when the speed of the motor reaches Scherbius operation making speed, and speed becomes constant at Scherbius operation set speed. Meanwhile, when commutation failure detecting signals are issued, an electromagnetic contactor 41 for secondary short-circuits is instantaneously closed, main circuit currents are moved at the short-circuit side at the secondary side and a thyristor Scherbius device is protected from overcurrents. |
