| 摘要 |
PURPOSE:To protect a motor from burning by comparing a power factor, obtained through comparison of the base-emitter voltage of a transistor and a reference signal, with a reference power factor and stopping output to a motor if overload or locked state of motor is detected. CONSTITUTION:An inverter control unit 7 compares a power factor, detected through comparison of the base-emitter voltage of a transistor at a inverter section 4 and a reference signal, with a reference power factor being set in order to detect overload or locked state of motor. When overload or locked state of an induction motor 6 is detected, control is made to stop the output to the induction motor 6. Consequently, overcurrent does not flow continuously and the induction motor 6 is protected from burning. |
