Drive overheat

What does OHF mean?

This fault signifies that the drive's internal temperature has exceeded its safe operating limits, indicating insufficient cooling, a blocked heatsink, or an excessive load condition. Continuous operation in an overheated state will lead to accelerated wear and potential failure of drive components (e.g., capacitors, power semiconductors). Prolonged overheating can result in complete drive breakdown.

• Blocked heatsink fins or cooling fan intake/exhaust vents with dust, lint, or debris, restricting airflow.
• Failed or degraded cooling fan, leading to insufficient airflow across the drive's internal heatsink.
• Ambient operating temperature inside the electrical enclosure exceeding the drive's specified maximum (e.g., above 40°C).
• Excessive continuous load on the motor, causing the drive's output stage (IGBTs) to generate more heat than the cooling system can dissipate.
• Incorrect mounting orientation of the drive, preventing natural convection or proper fan operation (e.g., horizontal mounting for a drive designed for vertical).

Click steps to track your progress.

1. 1

   1. Inspect drive's cooling fan for rotation and listen for unusual noises; measure current draw of fan motor if applicable (refer to drive schematic).

2. 2

   2. Shut down drive, disconnect power, and remove cover to physically inspect heatsink fins for dust and debris; clean thoroughly with dry compressed air.

3. 3

   3. Verify the ambient temperature inside the electrical enclosure using a calibrated thermometer; ensure it is within the drive's specified operating range (e.g., 0-50°C).

4. 4

   4. Check drive parameters related to current limits or motor nominal current (e.g., P2-01, P2-02) to ensure they are correctly set for the connected motor and application load.

5. 5

   5. Monitor the internal temperature of the drive using the diagnostic parameter (e.g., tHD1, r1.8) and compare it to the drive's maximum allowable temperature (e.g., 85°C for IGBT junction).

6. 6

   6. Confirm the drive is mounted vertically in the enclosure (if applicable) and that required clearances (e.g., 100mm top/bottom) are maintained for proper airflow.