Motor thermistor overtemp

What does ALARM 11 mean?

The motor thermistor indicates an overtemperature condition, or it may be disconnected. The frequency converter can be configured to issue either a warning or an alarm based on parameter 1-90 Motor Thermal Protection. This fault protects the motor from thermal damage.

• Motor operating under excessive mechanical load, leading to winding overtemperature.
• Motor cooling fan failure or obstructed cooling fins.
• Thermistor cable breakage or loose connection at the motor or frequency converter terminals (e.g., terminals 53, 54, 55, or dedicated thermistor inputs).
• Faulty motor thermistor (PTC, NTC, KTY) sending an incorrect resistance signal.
• Incorrect parameter setting for P1-90 (Motor Thermistor Function) or P1-91 (Thermistor Source).

Click steps to track your progress.

1. 1

   Verify the motor temperature using an external non-contact thermometer to confirm actual overtemperature.

2. 2

   Measure the resistance of the motor thermistor at the frequency converter's thermistor input terminals (e.g., 53/54, or specific AIN) and compare to its datasheet values.

3. 3

   Check the wiring continuity and connections of the thermistor cable from the motor to the frequency converter.

4. 4

   Inspect the motor's cooling fan and cooling fins for blockages or damage.

5. 5

   Review parameter P1-90 (Motor Thermistor Function) to ensure it is correctly enabled and configured for the thermistor type.

6. 6

   Reduce the mechanical load on the motor or verify its sizing for the application.