Restart method of load motor at the time of the inverter after instantaneous power failure power recovery

摘要

PURPOSE:To allow a load motor to be controlled for restarting without a rotating detective device such as tachometer generator, etc., by using the prediction of an AC motor revolving speed in coasting deceleration and the increasing control of inverter supply voltage at the same time. CONSTITUTION:Various signals for control necessary for the restarting of a motor in inputting the inverter power supply to work from an input terminal CTL1 and a changeover control signal of inverter operation from an input terminal CTL2 are inputted respectively. The changeover signal to commercial operation from a relay 9 and the inverter operation starting signal from a relay 10 are outputted respectively. Thus, before the load motor is shifted to the constant control of the ratio of voltage supplied by an inverter CPU to the frequency, the frequency of supply voltage is set constant and its voltage value is gradually increased.