THERMISTOR FAULT

What does 907 mean?

The thermistor used for temperature sensing is detected as either open or shorted. This fault can also occur if the ambient machine room temperature is below 0°C, causing the detected resistance to be abnormally high. On larger drives, an open thermostat will also trigger this fault. This fault will not shut down the drive.

• An open circuit in the thermistor or its wiring.
• A short circuit in the thermistor or its wiring.
• Ambient machine room temperature falling below 0°C, leading to excessively high thermistor resistance readings.
• An open thermostat on larger drive models.

Click steps to track your progress.

1. 1

   Check the thermistor and its wiring for open or short circuits; it should measure between 2K – 10K ohms at 20C room temperature.

2. 2

   Verify that the machine room ambient temperature is above 0°C.

3. 3

   On larger drives, inspect the thermostat for an open circuit.