| 摘要 |
PURPOSE:To stably perform the operation stop and the resumption when service is momentarily interrupted by a method wherein a circuit is installed to stop the power inverter output and perform the electric discharge of the smoothing capacitor when the AC power source current is interrupted. CONSTITUTION:The electric discharge resistor 7 is connected through the switch 8 in parallel with the smoothing capacitor 2 to the inverter system in which the alternating current from the AC power source S is rectified through the rectifier 1, which is capable of phase control, and smoothed through the smoothing capacitor 2 and then, converted into the specified frequency through the inverter 3 to be supplied to the motor 4. When service interruption is caused by the AC power source S, then, this state is detected by the detecting circuit 10 through the transformer 9 and the service interruption detection signal PSF is emitted to the control circuit 11 and the switch 12. The control circuit 11 stops to emit the signals RF, INV which are for the purpose of controlling the rectifier 1 and the converter 3. And the switch 12 lets the switch 8 close. |
