Cause: AFE IGBT over-heat error comes when the rectifier is operating beyond its rated capacity, leading to excessive current and heat generation. This fault typically indicate rectifier IGBT power stage overheating.

"tJF2" fault in Schneider ATV950 drive indicate "AFE IGBT over-heat" condition. This means the Insulated Gate Bipolar Transistors (IGBTs) in the rectifier section of the drive’s power stage are experiencing excessive temperatures. This can affect the performance and reliability of the drive. 

Here’s a structured approach to troubleshoot and resolve this issue:

1. Initial Checks:

• Restart the Drive: Power off the drive, wait for a few minutes, and then power it back on. This can sometimes clear transient faults.
• Check Fault Logs: Review the drive’s fault logs to gather more details about the overheating event and any associated conditions.

2. Inspect Cooling Systems:

• Cooling Fans: Check if the cooling fans in the drive are functioning correctly. Ensure they are not obstructed or clogged with dust.
• Airflow: Ensure that there is adequate airflow around the drive and that the cooling system is working efficiently.
• Heat Sink: Inspect the heat sinks and ensure they are properly attached and not clogged with dust or debris.

3. Verify Ambient Conditions:

• Temperature: Ensure that the drive is operating within its specified ambient temperature range. Measure the ambient temperature where the drive is installed.
• Ventilation: Verify that the drive is installed in a well-ventilated area and not exposed to excessive heat sources.

4. Check for Overloading:

• Load Conditions: Ensure that the drive is not operating beyond its rated load capacity. Overloading can lead to increased temperatures in the power stage.
• Current Limits: Verify that the drive’s current limits are properly set and not being exceeded.

5. Inspect Power Supply:

• Input Voltage: Ensure that the input voltage to the drive is stable and within the specified range. Voltage fluctuations can affect the power stage.
• Power Quality: Check for any issues with power quality that could lead to increased thermal stress on the IGBTs.