Hi! I'm Aldrin and I'm new in this forum. I am an electrical service technician in a power generating set sales and services firm. I have a situation which might need your expertise or could relate to your previous experiences.
We have supplied a 350kW generating set to a condominium. This building has a 380V, 3-phase system and a 220V, 3-phase system. The 220V system is being distributed through a 3-phase step-down transformer. The power switching between the building's two main sources (Utility and Genset) is done with an automatic transfer switch (ATS). The problem is when the power is switched to the generator set during utility failure. When this occurs, all of the 3-phase 220V pump motors are running in reverse. We don't think the generator set is out of phase because the 3-phase, 380V motors (including the elevators and blowers) are running normally.
Is there anyone that has experienced this before and have pinpointed the main cause of trouble? Your thoughts would be much appreciated.