Cause : Heat sink overheat comes when the heat sink within your Fuji FRENIC-VG drive has exceeded its safe operating temperature. This is a critical fault designed to protect the drive from damage.

"Oh1" fault in Fuji FRENIC-VG drive indicate "Heat sink overheat" condition. This means the temperature of the heat sink has exceeded the safe operating limit. The heat sink is responsible for dissipating the heat generated by the drive's power electronics, and overheating can lead to damage or reduced lifespan of the drive.

Troubleshooting Steps:

1. Check Cooling Fans and Ventilation:

   • Inspect the cooling fans to ensure they are functioning correctly. Replace any non-working or noisy fans.
   • Check that the drive's air filters and ventilation paths are clean and free from dust or obstructions. Clean or replace filters as needed.

2. Verify Ambient Temperature:

   • Measure the ambient temperature around the drive. Ensure it is within the manufacturer’s recommended operating range.
   • If the ambient temperature is too high, consider improving the ventilation, adding air conditioning, or relocating the drive to a cooler environment.

3. Reduce Load on the Drive:

   • Ensure the drive is not overloaded. Check the motor load and reduce it if necessary to prevent excessive heat generation.
   • Review the drive's operating conditions and consider whether the drive is appropriately sized for the application.

4. Clean the Heat Sink:

   • Power down the drive and safely access the heat sink. Clean it thoroughly to remove any dust, dirt, or debris that may be impeding heat dissipation.
   • Ensure there is no buildup of material that could be insulating the heat sink and preventing it from cooling properly.

5. Inspect the Temperature Sensor:

   • If the heat sink appears to be in good condition and properly cooled, the temperature sensor itself may be faulty. Test or replace the sensor if needed.
   • Ensure the sensor is correctly connected and calibrated according to the drive’s specifications.

6. Check Installation and Environment:

   • Verify that the drive is installed with sufficient clearance on all sides to allow for proper airflow.
   • Make sure that the drive is not installed in a confined or enclosed space where heat can build up.