Danfoss VLT AutomationDrive FC 302 fault A10: Motor ETR Overtemperature
Alarm 10 on a Danfoss VLT FC 302 is Motor ETR Overtemperature: according to the drive’s electronic thermal protection (ETR), the motor is too hot because it has run with more than 100% overload for too long. Parameter 1-90 Motor Thermal Protection decides whether this warns or trips.
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Try Free Drive Diagnostic Upload a keypad photo, the fault history or a parameter export from your Danfoss VLT AutomationDrive FC 302. InduQT compares the evidence and suggests the next useful checks.
When it happens
- After long running at high load
- On repeated starts
- After motor data were changed or entered wrongly
Likely causes and checks
1Motor mechanically overloaded
- Points to it
- Motor current high; motor body hot to the touch; process load increased.
- Check
- Check the driven machine and compare motor current with the rating plate.
2Motor current or motor data set wrong
- Points to it
- Alarm appears with a normal-feeling motor; after commissioning or a motor change.
- Check
- Check 1-24 Motor Current and parameters 1-20 to 1-25 against the rating plate.
3External motor fan not declared
- Points to it
- Motor has a separately powered fan; alarm at low speed.
- Check
- If an external fan is used, check it is selected in 1-91 Motor External Fan.
4Drive not tuned to the motor
- Points to it
- AMA never run; motor runs hotter than expected.
- Check
- Run AMA (1-29); Danfoss notes it reduces thermal loading.
Telling it apart
- Alarm 10 is a calculated (ETR) motor temperature; Alarm 11 Motor Thermistor Overtemp comes from a real sensor in the motor.
- Alarm 9 is the drive’s own overload counter, not the motor’s.
- Danfoss states the ETR functions provide class 20 motor overload protection per the NEC.
Relevant parameters
| Parameter | Name | Why it matters |
|---|---|---|
| 1-90 | Motor Thermal Protection | Selects ETR or thermistor warning/trip options. |
| 1-24 | Motor Current | Must match the rating plate; the ETR model is based on it. |
| 1-91 | Motor External Fan | Select when the motor has a separately powered fan. |
| 1-29 | Automatic Motor Adaptation (AMA) | Improves the motor model. |
Evidence to collect
- 1-90 setting and motor thermal load reading
- Motor current vs rating plate
- Parameters 1-20 to 1-25 and 1-91
- Whether AMA was run
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