Control apparatus for an induction motor.

摘要

A control apparatus for an induction motor (1) includes a microcomputer (39) which evaluates an optimum number of rotations at which the operation efficiency of the motor becomes a maximum when the frequency (f1) of an alternating current electric power applied to said induction motor is varied in accordance with a change of the load. An inverter circuit (40) is controlled by the microcomputer for adjusting the voltage outputted from the inverter circuit (40) such that the induction motor (1) rotates with the optimum number of rotations.