Output insulation and leakage detection

VFD motor cable and ground-fault path

Separates motor insulation, cable leakage, terminal contamination, output filters and internal sensing when a drive trips only after output voltage is applied.

Functional path

Output bridge

Output terminals

Output reactor/filter if fitted

Motor cable

Motor terminal box

Motor winding insulation

Ground-fault sensing

Diagnostic signals and checkpoints

Ground fault at runEarth leakage tripIntermittent wet-weather tripTrip after motor cable movement

Technician notes

Do not insulation-test through the drive.
Water ingress and conductive dust are common external causes.
A true output leakage problem can destroy modules if ignored.