Cause : Overcurrent comes when the inverter momentary output current exceeded the overcurrent level. An Overcurrent Fault in a Fuji FRENIC-VG drive indicates that the drive has detected an excessive current flow in its output circuit. 

"Oc" fault in Fuji FRENIC-VG drive indicate "Overcurrent" condition. This means the drive has detected a current level exceeding its maximum rated capacity. This fault is a protective measure designed to prevent damage to the drive and motor from excessive current.

Troubleshooting Steps:

1. Check the Motor Load:

   • Verify that the motor is not overloaded and that it is operating within its rated capacity.
   • Inspect the connected load for any mechanical issues, such as binding or excessive friction, that could cause the motor to draw more current.

2. Inspect for Short Circuits:

   • Check the motor windings and power cables for signs of short circuits. Use a multimeter to test for continuity and resistance in the motor windings.
   • Inspect the drive's output terminals and internal components for any signs of short circuits or damage.

3. Review Drive Parameters:

   • Ensure that the drive's current limits, acceleration time, and torque settings are correctly configured for the motor and application.
   • Adjust the settings if necessary to prevent excessive current draw during startup or operation.

4. Examine the Power Supply:

   • Check the stability and quality of the power supply to the drive. Ensure that the voltage is within the specified range and that there are no significant fluctuations or drops.
   • If necessary, use a power conditioner or UPS (Uninterruptible Power Supply) to stabilize the input power.

5. Inspect Drive Components:

   • If the fault persists, the issue may be related to internal drive components, such as IGBTs or the power supply circuitry. This may require more in-depth diagnostics or the assistance of a qualified technician.
   • If internal damage is suspected, consider having the drive serviced or repaired by an authorized service center.

6. Check Wiring and Connections:

   • Inspect all wiring between the drive and motor to ensure it is in good condition, with no loose or damaged connections.
   • Verify that the wiring is appropriately sized for the current load and that all connections are secure.