F074 fault in WEG CFW900 Drive indicates a Ground Fault. This means electrical current is leaking to the earth ground, usually due to damaged motor winding insulation or pinched output cables.
Cause:
- Short circuit to ground in one or more output phases.
- Motor cable capacitance is too large, resulting in current peaks at the output.
Note: This fault can be disabled by setting parameter C7.2.1 = 0 or 3.
Remedy:
Verify insulation of motor cables and motor winding. If cable capacitance is high, reduce cable length or add an output reactor.
