ELECTRONIC SYSTEM FOR CONTINUOUS CONTROL OF INSULATION CONDITION IN AN OPERATING ELECTRIC MOTOR AND FOR AUTOMATED SWITCHING OFF FROM HIGH VOLTAGE IN CASE OF INSULATION DAMAGE

摘要

The circuit arrangement is, in particular, intended for monitoring a three-phase asynchronous motor of a mining pump and is connected to the motor cable of the electric motor and, via a mains switch, to the high-voltage mains. In order to provide a protection system which avoids the central superordinate protection system, a thyristor isolating stage is inserted between the insulation measurement circuit of the circuit arrangement and the mains switch, the triggering unit of which stage is controlled by a triggering control unit which is synchronised with the mains frequency and is connected to the insulation measurement circuit. A tripping-detector circuit is connected to the motor cable and is in enable/inhibit connection to the insulation measurement circuit.