Abstract: A circuit for a polyphase motor which operates in response to undesirable operating conditions so as to prevent damage to the electric motor. The protection circuit converts current to voltage over a range of operating currents. The current sensitive voltage in response to an undesired current condition triggers the operation of a gating circuit to apply potential to an output switch which in turn controls the current supply and stops the motor. The gating circuit is also triggered by a detector circuit sensing a deficiency in motor current to thereby actuate the output switch and interrupt the motor operation and thus protect the motor. A timing circuit provides an inverse time function in conjunction with the voltage applied to the gating circuit. The timing circuit is adjustable to provide adjustability in the elapsed time for providing a triggering voltage to the gating circuit.