Yaskawa Fault oC — Overcurrent

What This Fault Means

The oC fault indicates the drive output current exceeded 200% of the drive's rated current. The drive shuts down immediately to protect the output transistors.

Common Causes

• Motor cable short circuit
• Motor winding failure
• Sudden mechanical overload or jam
• Acceleration time too aggressive (C1-01 too low)
• Motor auto-tune not performed after motor replacement

Recommended Fix

1. Check motor and cable insulation with a megger (>1 MΩ to ground).
2. Inspect the mechanical load — clear any jams.
3. Increase the acceleration time (C1-01).
4. Run motor auto-tune (T1-01) to update the drive's motor model.
5. If oC trips at start with no load, the drive may have an internal fault.