| 摘要 |
PURPOSE:To enhance brake performance and safety by exciting a brake means upon detection of interruption or voltage drop of AC input power to an inverter or detection of an abnormality in an inverter control circuit. CONSTITUTION:A brake means 39 is excited upon detection of interruption or voltage drop of AC input power to an inverter 17 or detection of an abnormality in the control circuit for the inverter 17. Consequently, the elevator door is braked even if input power supply is interrupted or lowered or an abnormality occurs in the control circuit for the inverter 17 during closing operation of a heavy door. Furthermore, power supply for the brake means 39 drops upon elapse of a predetermined time thus eliminating the holding torque of the brake means 39. According to the constitution, brake performance and safety are enhanced. |
