| 摘要 |
PURPOSE:To improve the operating performance of an elevator and also to improve its safety by invalidating the function of short-circuit prevention period correcting means when the elevator is in a rescue operating state and validating the function of the short-circuit prevention period correcting means when it is in a normal operating state. CONSTITUTION:During normal operation, the output states of switching elements 5a, 5b of an inverter portion 5 are detected to compensate the short-circuit prevention period by short-circuit prevention period correcting means. According ly, a bad effect due to the short-circuit prevention period for preventing a short- circuit phenomenon caused by the simultaneous ignition of upper and lower elements connected in a series among plural switching elements of the inverter portion 5 can be decreased so as to improve the operating performance of an elevator. In the case where abnormality occurs during operational control of the elevator, a safety circuit means detects the abnormality, a cage is moved at a low speed to a platform, a door is opened, and in case of rescue operation, the function of the short-circuit prevention period correcting means is invalidated so that passengers will not be shut up in the cage so as to improve the safety. |
