Power unit: Overtemperature thermal model

What does A05006 mean?

This alarm indicates that the thermal model for blocksize power units has detected an excessive temperature difference between the semiconductor chip and its heat sink. While it often resolves automatically, if the temperature continues to rise, it can lead to fault F30024. Sustained high temperature differences can reduce the lifespan of power unit components.

• Rapid load changes or transient overloads causing fast temperature rises in the semiconductor junction (chip) that the heat sink cannot dissipate quickly enough.
• Degraded thermal paste or inadequate contact between the semiconductor module and its heat sink, impeding efficient heat transfer.
• Localized airflow restrictions within the heat sink structure, leading to uneven cooling performance.
• Operating the drive close to its thermal limits with frequent acceleration/deceleration cycles (P1120, P1121).
• Possible inaccuracy in the thermal model parameters (e.g., P0290, P0291) not matching the application's thermal dynamics.

Click steps to track your progress.

1. 1

   Monitor the semiconductor temperature (e.g., r0035) and heat sink temperature (e.g., r0036) for significant, rapid differentials.

2. 2

   Review the application's load profile; consider extending acceleration/deceleration ramps (P1120, P1121) to reduce peak thermal stress.

3. 3

   Ensure clear airflow around the power unit's heat sink and verify proper installation in the cabinet.

4. 4

   Cycle power to the drive. If the alarm clears temporarily, it suggests a dynamic thermal issue rather than a hard fault.

5. 5

   If recurrence is frequent, and no other issues are found, consider verifying parameter P0290 (thermal model base temperature) and P0291 (thermal time constant).