Drive Overheating

What does OHF mean?

This fault indicates that the internal temperature of the drive has exceeded its safe operating threshold. Common causes include inadequate cooling due to blocked ventilation, a faulty cooling fan, high ambient temperatures, or sustained operation at current levels close to the drive's maximum rating. Persistent overheating can lead to premature failure of internal components.

• Inadequate cooling due to blocked ventilation ducts or heavily dust-laden heatsink fins.
• Malfunctioning cooling fan, indicated by no rotation or unusual noise, reducing airflow through the drive.
• Ambient temperature within the control panel exceeding the drive's maximum specified operating limit (e.g., above 50°C).
• Excessive drive switching frequency (Parameter P7-14) for the current load and ambient conditions, leading to higher internal losses.
• Overcurrent or sustained high load operation stressing the drive's thermal capacity, especially if motor current (P2-01) is close to drive nominal.

Click steps to track your progress.

1. 1

   1. Measure the ambient temperature at the drive's air intake vents (must be within the drive's specified operating range, e.g., 0-50°C).

2. 2

   2. Inspect the drive's heatsink fins and ventilation openings for any accumulation of dust, debris, or foreign objects. Clean thoroughly with compressed air.

3. 3

   3. Verify the cooling fan operation by observing its rotation or measuring its supply voltage (e.g., 24VDC) at the fan terminals. Replace the fan unit if faulty.

4. 4

   4. Review Parameter P7-14 (Switching Frequency) and P7-15 (Boost Current). If set excessively high, reduce these values, monitoring motor performance.

5. 5

   5. Measure the current draw on the motor output terminals (U, V, W) using a clamp meter to confirm it does not exceed the drive's continuous output current rating.