Cause : Device overheating comes when the drive's internal temperature has exceeded the maximum allowable limit. This fault can occur due to various reasons, including inadequate cooling, excessive ambient temperature, or high power demands.

An "OHF" fault in Schneider ATV950 drive signifies "Device Overheating" Fault. This indicates the drive's internal heat sink temperature has surpassed the safe operating limit.

Steps to Address an "OHF Device Overheating" Fault:

1. Immediate Actions:

   • Stop Operation: If the drive is running, stop it immediately to prevent any potential damage or unsafe conditions.
   • Reset Error: Attempt to reset the error using the drive’s control panel. This may clear temporary issues.

2. Inspect the Cooling System:

   • Cooling Fans: Ensure that all cooling fans are operational. Check for any signs of malfunction or failure.
   • Air Vents: Ensure that all air vents are clear and not blocked by dust, debris, or obstructions.
   • Heat Sinks: Check that the heat sinks are clean and free from dust accumulation, which can impede heat dissipation.

3. Verify Ambient Conditions:

   • Ambient Temperature: Check the ambient temperature around the drive. Ensure it is within the drive's specified operating range.
   • Ventilation: Ensure there is adequate ventilation in the installation area to allow for proper airflow around the drive.

4. Check Drive Load:

   • Overloading: Ensure the drive is not overloaded. Verify that the motor and application are within the drive's capacity.
   • Duty Cycle: Check the duty cycle of the drive. Continuous high power demands can cause overheating.

5. Inspect Internal Components:

   • Thermal Sensors: Verify that the thermal sensors inside the drive are functioning correctly. Faulty sensors can give false overheating readings.
   • Component Inspection: If safe and possible, inspect the drive's internal components for any signs of damage, overheating, or wear.

6. Check Parameter Settings:

   • Thermal Protection: Ensure that the thermal protection settings in the drive are configured correctly.
   • Current Limits: Verify that the current limit settings are appropriate for the motor and application.

7. Run Diagnostics:

   • Diagnostic Tools: Use any diagnostic tools or software provided by Schneider Electric to perform a thorough check of the drive’s systems, including temperature monitoring.
   • Error Logs: Check the drive’s error logs for additional details about the overheating fault.

Example Approach to Resolving an OHF Device Overheating Fault:

1. Stop Operation: Halt the drive if it is running.
2. Reset Error: Attempt to reset the error using the control panel.
3. Inspect Cooling System: Ensure all cooling fans are operational, air vents are clear, and heat sinks are clean.
4. Verify Ambient Conditions: Check the ambient temperature and ensure adequate ventilation around the drive.
5. Check Drive Load: Ensure the drive is not overloaded and the duty cycle is within limits.
6. Inspect Internal Components: Verify the thermal sensors and inspect internal components for signs of damage or overheating.
7. Check Parameter Settings: Ensure thermal protection and current limit settings are correct.
8. Run Diagnostics: Use diagnostic tools and check error logs for details.