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Member Post posted an update
Trane CVHE500 – AFD/VFD cabinet failure (looking for tech feedback / root cause
Our technician arrived onsite Monday and found the chiller offline. We located a catastrophic failure in the Trane Adaptive Frequency Drive (AFD) / starter cabinet. The damage is concentrated at the line/inlet side of the drive power section.
Both the chiller’s machine breaker was tripped and the MCC main was also tripped.
We isolated the compressor motor and meggered it — motor checked good.
Photos attached: unit nameplate, full AFD cabinet view, power module/board section, and the damaged area.
Unit info (from nameplate):
Trane CVHE500, 460V / 60Hz / 3PH, refrigerant R-123.Looking for feedback on:
- What are the most common causes you’ve seen that lead to a line-side drive cabinet event like this? (loose connection/bus, surge/transient, phase imbalance, failed input components, line reactor/filter issues, etc.)
- What checks do you consider “mandatory” before installing a replacement drive/module so it doesn’t repeat? (incoming power quality/imbalance, lug torque, upstream breaker/fusing, grounding/bonding, line reactor/harmonic filter, insulation tracking/carbon paths, cabinet contamination/moisture)
- When the visible damage is on the inlet side, where do you usually find the failure started — rectifier/input stage, DC bus components, or something else?
