| 摘要 |
A control system for an alternating current motor (40), such as an elevator hoisting induction motor, in response to failure of power supply (10), such as service interruption, phase open and so forth, performs in a first emergency control mode and in a second emergency control mode. In the first emergency control mode operation, dynamic braking is used to decelerate the motor (40). On the other hand, in the second emergency mode, triggered while the motor (40) is driven in regeneration mode to recirculate regenerated power to decelerate the motor (40), a mechanical brake is applied. During second emergency control mode operation, power supply condition is monitored to detect failure of the power supply (10) for switching control mode from the second emergency control mode to the first emergency control mode. Switching from the second emergency control mode to the first emergency control mode assures synchronous operation of an inverter and the motor (40) after resumption of power supply (10) to the motor (40) in cases where the power failure is short in duration. |
