| 摘要 |
PURPOSE:To provide a residual voltage protection device which can prevent the application of an excessively high voltage across the winding of an induction motor which occurs at the time of restarting the motor and an excessively high torque applied to a mechanical system side. CONSTITUTION:The throwing of a circuit breaker 2 for motor in a time zone in which a residual voltage exists is interlocked by means of the normally- opened contact 12a of a voltage detector 12 which closes when the residual voltage on an induction motor 1 side drops from a prescribed value, the normally-opened contact 13a of a rotating speed detector 13 which closes when the rotating speed of the motor 1 becomes lower than the rotating speed when the residual voltage drops, throwing commanding switch 4, and normally-opened contact 2b of the circuit breaker 2 for motor. |
