Overcurrent protection device for AC or DC network - with ohmic current monitoring and semiconductor current interrupter activated when max. current is exceeded

摘要

The overcurrent protection device uses a current measuring device and a current interrupter (5) which is activated when the permissible line current is exceeded. The current measuring device uses an ohmic current measuring path (4) coupled to a comparator circuit (6) for comparison with a preset reference valve (7), providing an output signal for the current interrupter (5). The interrupter pref. comprises a thyristor or a high current transistor, the comparator circuit (6) followed by a delay circuit with a variable time constant. ADVANTAGE - Min. number of components for reduced cost.