FAULT-CURRENT DETECTION DEVICE

摘要

The invention relates to a fault-current circuit breaker comprising a summation current transformer, through which AC fault currents induce a voltage in a secondary coil (32), wherein at the same time a square-wave generator (54) having a frequency which is higher than the mains frequency exposes the secondary coil (32) to square pulses and therefore regularly induces a voltage, wherein said induced voltage is influenced by a DC fault current. An evaluation device (50) detects the voltage dropping on an inductance (38) subordinated to the secondary winding to a ground connection (40). According to the invention, the evaluation device comprises an amplifier, the amplification factor of which is adjustable. Then the amplitude of fault currents at which the fault-current circuit breaker (10) should trip can be adjusted.