OHF

Drive Overheating

Schneider Electric · Altivar Machine ATV320 Variable Speed Drive

What does OHF mean?

The drive has detected an internal overheating condition. This occurs when the drive's internal temperature exceeds safe operating limits, often due to high ambient temperatures, blocked cooling fins, or failed cooling fans. Continued operation can lead to permanent damage to the drive's power components.

Common Causes

  • Ambient temperature around the drive exceeding its maximum specified operating temperature (e.g., > 40°C or 50°C).
  • Blocked or dirty heat sink fins restricting proper airflow through the drive's cooling passages.
  • Failure of one or more cooling fans within the drive (e.g., seized bearing, open winding, or debris blockage).
  • Drive enclosure lacking adequate ventilation, proper spacing from other heat-generating equipment, or incorrect mounting orientation.
  • Drive operating continuously at or near its maximum rated current, generating excessive internal heat beyond design limits.

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    Measure the ambient temperature within the enclosure containing the drive and verify it is below the drive's specified maximum (e.g., < 40°C).

  2. 2

    Inspect all cooling fan operation within the drive; verify fans rotate freely, move air effectively, and are not obstructed.

  3. 3

    Clean any dust or debris from the drive's heat sink fins and ventilation openings using compressed air or a vacuum cleaner.

  4. 4

    Check for adequate clearance around the drive as per installation guidelines (e.g., 100mm top/bottom, 50mm sides) and ensure unobstructed airflow.

  5. 5

    Monitor the drive's internal temperature via a display parameter (e.g., d0-07 "Drive Temp") and compare it to the documented trip threshold.

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Verified technical data. Last updated: March 2026

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Source: Schneider Electric Altivar Machine ATV320 Variable Speed Drive