| 摘要 |
PURPOSE:To reduce the number of contactors without deteriorating the controlling performance of an induction motor controller which has a DC braking function, by improving the manner of connection of semiconductor rectifiers with the contactors. CONSTITUTION:When a three-phase induction motor 1 for driving an elevator is controlled, contacts 10a, 10b, 10c, 11a, 11b of contactors are closed in upward power running to perform single-phase control by thyristors 6, 7. In downward power running, contacts 10a, 10b, 10c, 12a, 12b of contactors are closed to rotate the motor 1 in the opposite direction to the ascent and perform single-phase control of the motor. In braking, the contacts 11a, 11b, 12a, 12b of the contactors are closed both in ascent and in descent to supply the motor 1 with DC power from a mixed bridge made of thyristors 6, 7 and diodes 8, 9 and apply DC braking to the motor. |
