CONTROLLER OF SWITCHGEAR

The invention relates to an arrangement for influencing, particularly blocking, a switching apparatus, preferably a remotely controlled switching apparatus, in dependence on mains condition data by means of feeding in an external voltage and a subsequent evaluating circuit with setpoint and actual-value comparison. For the purpose of feeding in the external voltage, an impulse generator for generating test pulses and an evaluating circuit is provided here which determines the peak value of the instantaneous electric power converted in the motor. This allows short circuits, inter-turn shorts and interruptions in the feedline to be detected reliably and rapidly in a motor.