36

Overtemperature

Danfoss · VLT 2800 Variable Speed Drive

What does 36 mean?

The heatsink temperature has risen above a critical threshold (167-185°F / 75-85°C). The drive initially issues a warning, and if the temperature continues to rise, it automatically reduces the switching frequency to mitigate heating. Prolonged high temperatures can lead to component degradation and drive failure.

Common Causes

  • Blocked or restricted airflow to the drive's heatsink due to dust accumulation, debris, or improper cabinet ventilation.
  • Cooling fans (internal or external) are faulty, jammed, or operating below optimal speed.
  • Ambient temperature in the enclosure or control room exceeds the drive's specified operating limits.
  • Drive is undersized for the application, causing it to operate continuously near its current limits, generating excessive heat.
  • Loose or degraded thermal paste/interface material between the power module and heatsink, reducing heat transfer efficiency.

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    Safely power down the drive. Open the enclosure and clear any dust, debris, or obstructions from the drive's heatsink fins and cooling fan inlets/outlets.

  2. 2

    Manually check cooling fan operation by observing blade rotation and airflow after reapplying power (ensure hands clear moving parts). Replace faulty fans if necessary.

  3. 3

    Measure the ambient temperature inside the electrical enclosure and compare it to the drive's maximum allowable operating temperature (typically 40-50°C).

  4. 4

    Verify the drive's current output (A) against the motor's rated current and the drive's nominal current rating (found on drive nameplate). Ensure it's not consistently overloaded.

  5. 5

    Check that the enclosure's ventilation system (e.g., exhaust fans, air conditioners) is fully functional and providing adequate airflow.

  6. 6

    Inspect thermal interface material (e.g., paste, pads) between the power module and heatsink if disassembly is required (advanced troubleshooting, qualified personnel only).

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Verified technical data. Last updated: March 2026

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Source: Danfoss VLT 2800 Variable Speed Drive