DRIVE CONTROL DEVICE OF ALTERNATING-CURRENT MOTOR

An AC motor drive control device including: an inverter INV, having a plurality of switching elements subjected to on-off control, for converting a DC voltage to an AC voltage with a desired frequency to drive an AC motor 6; a motor opening contactor MMK connected between the inverter INV and the AC motor 6; a switching operation beforehand detection unit 55 for detecting a switching operation of the motor opening contactor MMK prior to the contact or detach of main contacts and outputting a switching operation beforehand detection signal; and a control unit 10A having an inverter control unit 70 for performing the on-off control for the plurality of switching elements and switching control for the motor opening contactor MMK, and controlling the inverter INV based on the switching operation beforehand detection signal.