| 摘要 |
PURPOSE:To restart an AC motor without damaging a power converter by applying a DC voltage to a stator winding of an AC motor to perform a DC braking, and altering a drive voltage from a low frequency sequentially to a high frequency. CONSTITUTION:A switch 2 is opened, a switch 4 is closed at a starting time, the prescribed DC voltage from a DC power source 5 is applied to the stator winding of a motor 1 for the prescribed time to perform a DC braking at a rotor during inertial rotation. When the rotation of the rotor is stopped, the switch 4 is opened, the switch 2 is closed, and an AC drive voltage is applied from a power converter 3 to the motor 1 to restart it. Then, the frequency of the AC drive voltage is sequentially raised, and the rotating speed is accelerated to the target rotating speed. Thus, an AC motor which is shifting to the stopping state can be restarted without damaging a power converter. |
