Danfoss · VLT AutomationDrive FC 301/302
The electronic thermal protection (ETR) indicates the motor is too hot. The drive issues a warning or alarm when the internal counter exceeds 90% (depending on parameter 1-90) and trips when it reaches 100%, typically due to prolonged operation above 100% overload.
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Measure the actual motor current (e.g., using a clamp meter) and compare it to the motor's nameplate rated current.
Verify motor thermal protection parameters (e.g., P1-90, P1-92, P1-93) are correctly set according to motor specifications.
Inspect the motor's cooling fan for obstruction or damage and clean any accumulated dirt from the motor housing and fins.
Check for mechanical binding or excessive friction in the driven equipment by manually rotating the shaft (if safe).
Monitor the motor's winding temperature directly (if possible, with a thermal camera) to confirm actual overheating.