The system consists of a residual current monitor and a current transformer. If the content of the earth leakage current at the output exceeds the preset response value, the converter disengages.

If the converter is equipped with 2 outputs, both output cables must be led through the current transformer.

NB. If the converter is equipped with Neutral Conductor Rupture supervision (option 573929) the Z-wires from this supervision must also be lead through the current transformer.

The trip value of the RCM can be set to any value between 10 mA and 10 A. The response time can be delayed up to 10 seconds.

Please notice that aircraft connected to earth (as an example during refuelling) will have a leakage current that significantly exceeds 30 mA. The high leakage current is due to the additional current path to the 400 Hz neutral formed by the ground connection.