An error amplifier is connected to both a tachometer generator for an induction motor and a command speed generator to produce an error signal corresponding to the difference between the actual motor speed and a command motor speed. A current limit generator connected to the tachometer generator generates a current limit signal which is subtracted from a motor current signal from a current sensor for the motor. A multiplier imparts to the resulting difference signal the polarity opposite to that of the error signal as determined by a polarity discriminator. The difference signal is added to the error and actual speed signals by an adder to form a command frequency signal. An inverter controls the motor in response to the command frequency signal.