Inverter Thermal Trip

What does E21 mean?

This fault indicates that the inverter's internal temperature has exceeded its safe operating threshold. The thermal sensor within the inverter module detects overheating of the power devices (IGBTs), causing the inverter to trip and shut down its output to prevent damage.

Additional Steps

Steps 1–2 are listed in Priority Fix.

1. 3

   Check the cooling fan control parameter (b092) to ensure the fan is operating correctly or set to 'Always ON' (00) if needed.

2. 4

   If the inverter is in an enclosed cabinet, ensure proper airflow and cooling capacity of the cabinet itself.

3. 5

   Reduce the load on the motor if operating conditions are continuously pushing the inverter to its thermal limits.