Cause : Overspeed comes when the motor connected to the drive is operating at a speed that exceeds the permissible limit. This protective function prevents damage to the motor and drive.

"0s" fault in Fuji FRENIC-VG drive indicate "Overspeed" condition. This means the motor has exceeded its maximum allowable speed. This fault is triggered when the motor speed surpasses the set speed limit defined in the drive's parameters, which can lead to potential damage to the motor, drive, or connected equipment.

Troubleshooting Steps:

1. Check Speed Command Input:

   • Review the speed command being sent to the drive. Ensure it is within the allowable range for the motor and application.
   • Verify that any control system or operator inputs are set correctly and not commanding an excessively high speed.

2. Inspect the Encoder:

   • If the motor uses an encoder for speed feedback, check that the encoder is securely mounted and functioning properly.
   • Test the encoder for correct operation, and ensure that its signals are being correctly interpreted by the drive.

3. Review Drive Parameter Settings:

   • Check the drive’s parameters, particularly those related to maximum frequency, speed limits, and acceleration/deceleration rates.
   • Ensure these settings are correctly configured according to the motor's specifications and the application’s requirements.
   • Adjust the maximum speed or frequency limits if necessary to prevent overspeed.

4. Check for Load Issues:

   • Inspect the mechanical load connected to the motor. Ensure that no parts of the load have become disconnected or disengaged, which could lead to a sudden increase in speed.
   • If the load is variable, ensure the drive is correctly configured to handle such variations without causing overspeed.

5. Test the Speed Control Loop:

   • Verify that the drive’s speed control loop is operating correctly. Check for any issues in the control signals, feedback loops, or drive tuning parameters.
   • If the control loop is not stable, adjust the gain settings or other control parameters as needed.

6. Inspect the Inverter and Motor:

   • Check for any signs of malfunction in the inverter or motor that could cause abnormal speed behavior.
   • Look for overheating, unusual noise, or other symptoms that might indicate a problem.