| 摘要 |
PURPOSE:To abruptly reset a motor decelerated to a predetermined low speed to one before a malfunction by interrupting an inverter output by the malfunction detection of the inverter, coasting a motor, and DC-braking it to avoid the voltage rise of the inverter. CONSTITUTION:If a malfunction is detected by a malfunction detector 11 during operation of a motor 3, the output of an inverter 2 is interrupted, and the motor 3 is coasted. The value of a frequency command 7 of a malfunction detection point t0 is stored. After predetermined time is elapsed, a DC current is supplied to the motor 3 to DC-brake the motor 3 to abruptly decelerate it. The command 7 is checked at a time point t3 when the motor 3 becomes a set speed or less, and if the command 7 is applied, it is recovered to the rotating speed N at the time t0 of the malfunction detection, while if the command is reversely not applied, it can be stopped as it is. The motor can be recovered from a low speed state to that before the malfunction at an abrupt speed. |
