Commercial business operational inverter operational change control manner null of

摘要

PURPOSE:To realize smooth power changeover, which avoids the transient and excessive current increase and torque ripple in a motor at the time of changeover from the commercial power of an AC motor to an inverter. CONSTITUTION:There are set a limitation level, which can be varied according to the relative weight of load to an inverter output current, and a recovery level smaller than that limitation level. Inverter voltage of rated frequency, which increases from a low value in the free run of the Ac motor after breaking of a commercial power source is applied so as to reaccelerate that motor. When the output current of the inverter becomes above the limitation level, the output frequency is reduced, and when that output current becomes below the recovery level, the output frequency is increased toward the rated value. What is more, the inverter output voltage, when the ratio of the voltage to frequency reaches the specified value, is controller interlocking with the output frequency, keeping the specified ration since then.