| 摘要 |
PURPOSE:To improve the safety and operability by setting up each driving control circuit driving a hoisting motor in parallel operation at respective input sides, and installing a switch connecting an ac power source to these driving control circuits and this ac power source supplying power to each of these control circuits separately. CONSTITUTION:When an elevator is in its operating state, if an inverter 12A of a first driving control circuit gets out of order for somereason or other and an overcurrent flows, it is detected by an overcurrent detector 13A, outputting a signal to an overcurrent protection circuit part, and thereby this circuit part opens a switch, contacts 24a-24e are opened, thereby stopping output of the circuit 10A. In addition, since the contact 24e of the switch is opened, a speed command generating circuit 16 generates a required speed command to an inverter control circuit 17. An inverter 12B being connected to a second driving control circuit 10B changes frequency of ac power to be converted in accordance with the said speed command, varying rotational frequency of a three-phase induction motor 5, and continues operation of the elevator at a speed conformed to capacity of the circuit 10B. |
