| 摘要 |
PURPOSE:To protect a start failure of a motor by providing a power detecting circuit for a frequency converter for stopping energization of the motor in response to the detection signal from the power detecting circuit. CONSTITUTION:DC side voltage and current of the inverter 7 of a frequency converter 3 for controlling an induction motor 1 are detected by DC voltage and current detectors 21 and 22 respectively. A multiplier 23 multiplies the output signals from the DC voltage and current detecting circuits 21 and 22, thereby detecting the power supplied to the motor 1. When the control circuit 4 detects the start failure of the motor 1 by the output signal from the multiplier 23, it stops energization of the motor 1. |
