| 摘要 |
PURPOSE:To start an induction motor by preventing unnecessary tripping by actively using the overcurrent stall preventing function of an inverter at the time of starting the induction motor from a freely running state by means of the inverter. CONSTITUTION:At the time of starting an induction motor 12 from a freely running state, a CT detects the electric current of the motor 12 and a current signal converter 13 detects a current signal I. Then a control circuit 11 starts the motor 12 by gradually lowering the output frequency of the motor 12 while the current signal I reaches a stall preventing level or gradually raising the output frequency when the current signal I becomes lower than the stall preventing level. |
