Vacon · X4
The drive has detected a current imbalance between its output phases, and this imbalance is determined to be current flowing to ground. This is a critical fault indicating a direct path to ground from the motor or motor cabling. It poses an electrical hazard, potential equipment damage, and could trip upstream protective devices.
Click steps to track your progress.
1. De-energize and lock out the drive. Disconnect all motor output cables (U, V, W) from the drive terminals.
2. Perform an insulation resistance test (Megger test) on the motor cables (each phase to ground) at 500VDC to check for cable insulation breakdown.
3. Perform an insulation resistance test (Megger test) on the motor windings (each phase to motor frame ground) at 500VDC to check for internal motor ground faults.
4. Visually inspect the drive's output terminals (T1/U, T2/V, T3/W) for signs of arcing, carbon tracking, or contamination.
5. With motor and cables disconnected, power on the drive to determine if the fault clears. If it does, the fault is external to the drive.
6. If the fault persists with no motor or cables connected, replace the drive unit.