| 摘要 |
PURPOSE:To compensate the change of frequency and phase characteristic of frequency command value before and after the instantaneous stoppage, by holding the inverter frequency command value before the instantaneous stoppage and by controlling the inverter on the basis of this command value after the circuit is reelectrified. CONSTITUTION:A source voltage detection circuit detects the instantaneous source voltage drop and moves correspondently. As a result, the detected point of contact 10a1 is opened and the inverter operational command VST is switched OFF. By opening the detected point of contact 10a2, the value of a cushion circuit 4 is kept in the same condition as before the instantaneous stoppage occurs. After reelectrification, by closing the points of contact 10a1 and 10a2, the inverter output frequency command value fref before the instantaneous stoppage is outputted from the cushion circuit 4 to an inverter 1. |
