Cause : Heat sink temperature too high comes when the enclosure is IP 00 or IP 20/NEMA 1, the cut-out temperature of the heat-sink is 90°C. If IP 54 is used, the cut-out temperature is 80°C. The tolerance is ± 5°C.

1. The temperature fault cannot be reset, until the temperature of the heat-sink is below 60°C.
2. The fault could be the following:
   - Ambient temperature too high
   - Too long motor cable
   - Too high switching frequency.