| 摘要 |
PURPOSE:To obtain smooth starting by separating a motor group after reducing the output voltages in a power unit for starting and that for normal operation when a hysteresis motor group is switched to a power unit for normal operation from that for starting. CONSTITUTION:A switch 143 is closed and a hysteresis motor 10 is started by the output in a power unit 13 for starting. When a rotary frequency B which is outputs from a rotary detector 15 synchronizes with the output frequency A in a power unit 11 for normal operation, a voltage reduction command D is sent to the power unit 13 for starting and that 11 for normal operation from a voltage reduction command circuit 17. A switching command circuit 18 receives the voltage reduction command D. and outputs a switching command E after predetermined time to open the switch 143 and to close the switch 141 as well. After that, the voltage reduction command D is off and the output voltage to the power units 11, 13 slowly returns to the rated value. |
