Drive Controller Overload / Overheat

What does -OHF mean?

This fault indicates that the drive controller's internal temperature has exceeded its safe operating limits, often due to sustained high motor current or insufficient cooling. This protects the drive's power components from thermal damage. The fault is triggered when the drive controller's thermal state estimate reaches 118%, necessitating a cooldown period.

• Ambient temperature around the drive controller exceeding its specified operating range (e.g., >40°C or 104°F) inside the enclosure.
• Blocked or dirty cooling fan on the drive's heatsink, significantly reducing essential airflow for heat dissipation.
• Restricted ventilation inside the electrical enclosure due to poor spacing, excessive cable routing, or blocked vents.
• Sustained operation at high motor current, approaching or exceeding the drive's rated output for extended periods.
• Drive heatsink fins clogged with dust, lint, or debris, creating an insulating layer and impairing heat transfer efficiency.

Click steps to track your progress.

1. 1

   Measure ambient temperature inside the electrical enclosure using a calibrated thermometer. Ensure it is within drive specifications.

2. 2

   Clean the drive's heatsink fins and cooling fan blades thoroughly with compressed air (power OFF, lockout/tagout).

3. 3

   Verify the drive's cooling fan is operating correctly (visually inspect rotation when powered ON) and free of obstructions.

4. 4

   Review drive's output current (Parameter P3-01) and actual motor current using the drive display. Reduce motor load if persistently high.

5. 5

   Ensure adequate spacing around the drive controller (e.g., 100mm top/bottom clearance) and check enclosure ventilation openings for blockage.