I have a Trane RTAA Chiller tripping on the severe phase imbalance about twice a week. It is tripping out both circuits when this happens. It is usually very early in the morning. Usually compressor A will trip first, and then about 6 min later compressor C trips off. The fact that both are tripping around the same time I assumed that there was a power problem. After checking the voltages i noticed a imbalance, and higher than normal voltages. We called AEP, and they told us that they had a bad voltage regulator on the main lines into the building. After they changed it out the power appeared to be normal. Well the chiller went back down again yesterday. Is there something I can do about this? Everytime this thing goes down the Tracer calls the customer. The tenants in the building are getting upset. What can I do? Is there some other things I can check? I already checked all of the connections, and ohmed out the current transformers. I checked the contacts on the starters, and the compressor terminals. To me since the electric company had the problem before, they may still have a problem, but they claimed that they fixed it.
Any help on this will be appreciated.