Abnormal Temperature (Main Circuit)

What does E21. mean?

This fault occurs when the temperature in the inverter's main circuit exceeds a specified maximum value. This is typically caused by high ambient temperatures, insufficient ventilation, or clogged cooling fins, leading to thermal stress on internal components. Prolonged exposure to abnormal temperatures can significantly shorten the inverter's lifespan and lead to irreversible damage.

• Ambient temperature inside the control panel exceeding the inverter's specified maximum operating temperature (e.g., 40°C or 50°C).
• Insufficient airflow around the inverter due to blocked cooling fan intake/exhaust vents or a failing cooling fan (low RPM or seized motor).
• Accumulated dust, debris, or foreign objects on the inverter's heat sinks and cooling fins, reducing heat dissipation efficiency.
• Continuous operation at high output current (e.g., above 110% of rated current) for extended periods without adequate cooling capacity.

Click steps to track your progress.

1. 1

   Measure the ambient temperature inside the control panel enclosure using a calibrated thermometer. Verify it is below the inverter's maximum operating temperature.

2. 2

   Inspect the inverter's cooling fan operation. Verify fan blades are rotating freely, listening for abnormal noises, and confirming strong airflow out of the exhaust.

3. 3

   Power off and disconnect the inverter. Clean cooling fins and vents thoroughly using compressed air or a soft brush to remove accumulated dust and debris.

4. 4

   Measure the actual motor load current using a True RMS clamp meter on the output (U, V, W) phases and compare it to the inverter's rated output current.

5. 5

   Confirm that enclosure ventilation fans are operating correctly, filters are clean, and the control panel enclosure provides adequate air exchange (e.g., 20 air changes per minute).