Brake Chopper IGBT Excess Temperature

What does A79C mean?

The Insulated Gate Bipolar Transistor (IGBT) within the brake chopper has exceeded its internal temperature warning limit. This indicates excessive heat generation due to sustained braking, inadequate cooling, or an overdriven chopper, risking damage to the power components and potentially causing drive failure.

• Excessive or prolonged regenerative braking due to short deceleration times (P21.02) or frequent start/stop cycles, leading to high duty cycle for the IGBT.
• Ambient temperature around the drive is too high, or the drive's cooling system (fans, heatsink) is compromised (e.g., blocked fins, failed fan).
• Drive installed in an enclosure with inadequate ventilation, causing heat buildup inside the cabinet.
• Internal fault within the brake chopper circuit (e.g., partial IGBT failure, gate driver issue) causing increased losses and heat generation.
• DC bus voltage (P06.01) consistently high due to unstable grid voltage or other anomalies, increasing stress on the brake chopper.

Click steps to track your progress.

1. 1

   1. Check the drive's cooling fan operation and ensure the heatsink fins are free from dust and debris, allowing for proper airflow.

2. 2

   2. Measure the ambient temperature immediately surrounding the drive and within the control cabinet to ensure it is within specified operating limits.

3. 3

   3. Increase the deceleration time (P21.02) if the application allows, to reduce the frequency and intensity of regenerative braking.

4. 4

   4. Monitor the drive's internal temperature readings (e.g., P06.18, P06.19 for module temperatures) to observe trends and identify specific hot spots.

5. 5

   5. Verify that the drive enclosure has adequate ventilation, and consider adding exhaust fans or an air conditioner if high ambient temperatures persist.