What can cause an OPF or Motor phase loss on the ATV312 drive?

The OPF (Output Phase Fault) indicates that the drive has detected a loss of current on one or more motor output phases. This fault is typically related to the motor, motor wiring, or output circuitry between the drive and the motor.

Common Causes

• One or more motor output phases are disconnected or open.
• Loose, damaged, or incorrectly wired motor connections.
• A damaged motor winding causing an imbalance in motor current.
• An undersized motor operating below the drive's motor phase loss detection threshold.
• Excessive contact resistance due to loose terminals or deteriorated connections.
• An output contactor opened while the drive was running.
• Incorrect motor parameter settings, particularly the motor rated current.
• A failed output IGBT or internal power stage issue within the drive.

Troubleshooting Steps

1. Verify all motor power connections at both the drive and motor terminals.
2. Inspect motor cables for damage, loose connections, or open conductors.
3. Measure motor winding resistance and check for phase-to-phase balance.
4. Confirm the motor nameplate data is correctly programmed in the drive.
5. Ensure no contactors or disconnect devices are opening between the drive and motor while the drive is running.
6. Test the motor and cable insulation using appropriate methods.
7. If available, run the drive with a known-good motor to isolate the issue.