Overcurrent
Schneider Electric · ALTIVAR 28 Variable Speed Drive
What does OCF mean?
This fault indicates an overcurrent condition in the drive controller, often caused by a ramp that is too short, excessive inertia or load, or a mechanical obstruction affecting the motor. If unresolved, this can lead to severe damage to the motor or the drive's power components.
Common Causes
- Motor shaft mechanically jammed or seized (e.g., bearing failure, debris).
- Acceleration ramp time (Parameter P0-11) set too short for the load's inertia.
- Instantaneous overload due to sudden heavy load application exceeding motor capacity.
- Motor phase-to-phase or phase-to-ground insulation breakdown causing low impedance.
- Incorrect motor parameters (e.g., P0-03, P0-04, P0-05) configured in the drive, leading to improper current control.
Repair Steps & Checklist
Click steps to track your progress.
- 1
1. Confirm motor shaft free movement by attempting to rotate it manually (power off).
- 2
2. Measure motor winding resistance between U-V, V-W, and W-U terminals; values should be balanced and within manufacturer specifications.
- 3
3. Increase acceleration ramp time (Parameter P0-11) by 20% and retest.
- 4
4. Verify motor nameplate data (Voltage, Current, RPM, kW/HP) against drive parameters (P0-03, P0-04, P0-05).
- 5
5. Monitor drive output current (display parameter P0-07) during start-up to identify peak current demand.