| 摘要 |
PURPOSE:To prevent a decrease in the service life of a transistor composing an inverter by reducing the flow of an inrush current for restarting under abnormal condition such as a retention of motor. CONSTITUTION:An inverter protective circuit is provided with overvoltage detection circuits 60, 61 detecting the overvoltage exceeding a reference voltage through the voltage detection section in a DC power source composed of a converter circuit, overcurrent detection circuits 75, 76 detecting the overcurrent flowing into a switching circuit from the DC power source, and a V-F conversion voltage detection circuit sensing the transmission of a signal stopping a motor to a control signal circuit 55. When one detection signal at the least is transmitted by using the logical OR of the signals sent through each detection circuit, the switch circuit is turned OFF to interrupt the power supply to the motor. |
