Motor Overheat Fault (Level 4)

What does OH4 mean?

This fault signifies a critical motor overtemperature condition where the analog temperature input (H3-09=E) has exceeded the OH4 fault threshold (2.34V). This level typically triggers a drive stop (based on L1-04) to prevent severe and permanent motor damage due to excessive heat.

Complete Troubleshooting Guide

1. 1

   Immediately stop the motor and allow it to cool down completely before attempting any restarts or further troubleshooting.

2. 2

   Investigate the root cause of excessive motor heating, such as sustained overload, inadequate ventilation, fan failure, or incorrect motor sizing for the application.

3. 3

   Verify the motor temperature sensor's calibration and ensure its proper connection and functionality.

4. 4

   Check parameter L1-04 (Motor Overheat Fault Operation Selection) to ensure the stopping method is appropriate for safety and process requirements.

5. 5

   Measure motor winding resistance and insulation resistance to check for internal motor damage that might have occurred from overheating.