| 摘要 |
PURPOSE:To continue the normal operation of a DC motor without operating an overvoltage or overcurrent protecting circuit by applying a phase reduction command to a chopper when a voltage drop is detected and opening shortcircuiting means. CONSTITUTION:When a power source voltage is instantaneously interrupted, contacts 15a1, 15a2 are opened, and the coil 6c of shortcircuiting means is simultaneously demagnetized. Accordingly, a contact 4a is opened, a chopper phase reduction command 12G is outputted form a controller 12P, applied to a chopper, a motor current is attenuated, and becomes zero. On the other hand, the capacitor voltage of a filter capacitor is not jumped up nor become overvoltage as a conventional one since the chopper phase reduction command 12G is outputted from the controller 12P after the prescribed time is elapsed from when the contact 6a is opened. |
