Motor Overheat (PTC input)

What does oH4 mean?

The motor's internal PTC thermistor input has triggered, indicating that the motor has exceeded its safe operating temperature. This is another motor overheat detection, distinct from oH3 (001DH) but with the same name.

Click steps to track your progress.

1. 1

   Verify actual motor surface temperature using a thermal imager or contact thermometer to confirm an overheat condition.

2. 2

   Inspect motor cooling fan operation and ensure motor cooling fins/vents are free from obstruction.

3. 3

   Inspect PTC thermistor wiring from the motor to the drive's input terminals for damage, loose connections, or proper termination.

4. 4

   Measure the resistance of the PTC thermistor at the drive's input terminals (with power off and wiring disconnected) to verify sensor integrity and compare to specifications.

5. 5

   Verify drive parameters for PTC thermistor input configuration (e.g., H2-xx group) are correctly set according to the motor and application.