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.

• Severe and prolonged mechanical overload on the motor, leading to critical and rapid overheating.
• Complete failure of the motor cooling system (e.g., fan motor seized, liquid cooling pump failure, blocked ducts).
• Motor winding insulation failure leading to internal short circuits and a rapid, uncontrolled temperature increase.
• Incorrectly calibrated or faulty analog temperature sensor providing erroneous high readings to input H3-09.
• Significant imbalance in drive output currents (U, V, W) indicating internal motor damage or phase loss.

Click steps to track your progress.

1. 1

   1. Immediately stop the motor and allow it to cool down to a safe temperature before any further inspection.

2. 2

   2. Measure the analog input voltage at H3-09 and verify it against the sensor's specifications for the current motor temperature.

3. 3

   3. Inspect the motor's cooling system (fan, fins, liquid cooling if applicable) for blockages or failures.

4. 4

   4. With power off, measure the motor winding resistance and insulation resistance to ground with a megohmmeter.

5. 5

   5. Using a clamp meter, measure and compare the drive output currents (U, V, W) for phase balance after a brief restart attempt.