| 摘要 |
In an AC lift control system in which the voltage and frequency applied from an inverter unit (3) to an induction motor (4) driving a lift car (9) are controlled to control the operation of the car in a normal operation mode, a battery (18) is connected to the DC input terminals of the inverter unit for use in an emergency such as sudden service interruption, and a switching signal generator (16) operating in an emergency operation mode generates a switching signal for controlling the output of the inverter unit (3) in such a manner that the number of switching is smaller than that in the normal operation mode and the duty factor per unit switching is larger than that in the normal operation mode. Therefore, a battery (18) of low voltage and small size can be used. <IMAGE> |
