| 摘要 |
PURPOSE:To reduce the vibration and the noise of a 3-phase induction motor by accelerating the motor by inserting antiparallel circuit of a thyristor into two phases and decelerating the motor by forming a full-wave rectifier with another of the diode of the thyristor. CONSTITUTION:A 3-phase induction motor 1 is accelerated by closing contactors 2a-2c, 3a-3c at normal revolution and by closing contactors 2a-3c, 4a-4c under two phase control of thyristors 6-9 at reverse revolution. The motor is further braked by closing contactors 3a-3c, 4a-4c and applying a DC current between the terminals U and V of the motor 1 by the 3-phase full-wave rectification of the thyristors 6-9 and diodes 10, 11. Accordingly, the number of using contactors can be minimized to simplify the arrangement, the pulsation rate of the motor current and the unbalance are reduced to reduce the vibration and the noise of the motor. |
