new ATS and now one downstream Breaker tripping

[toninocp]

hi all
this is the case
New ABB Zenith ZTG T Series 2600A replaced a GE Zenith ZTG 2600A in service from 2003 to September 2024.
Every time the Power goes out or it has a voltage dip, the ATS starts the Generator as expected but when it switches to S2 the 480V Breaker that feeds the busbar before a Transformer 480V/208V trips, the people in the Maintenace department of the building have to close it again, and when the ATS ABB Zenith is switching back to S1 it also trips. The Mains Breaker and the Generator Breaker are GE Power Break I, the Breaker that trips is a GE Power Break II 2000Amps with a 1000A rating plug, the average current normally is 400Amps. This breaker feeds mostly Inductive loads, (Chiller, Water pumps, AC HVAC, Elevators and other power systems. All the other breakers never trip when ATS operates.
As you may think, this issue is erratic and customer asks why this happens and it did not happen with the GE Zenith unit for 20 years
TY

 

[mparenteau]

Sounds like an inrush trip. Is your breaker feeding the transformer set properly?

Mike

 

[toninocp]

the only modification was ATS upgrade

 

[waross]

The new switch may be transferring faster than the old switch.
With less time for the transformer residual to decay, the inrush may at times be higher.
Raise the instantaneous setting on the breaker.

it did not happen with the GE Zenith unit for 20 years

Take that on advisement.
Such statements by customers are often less than accurate.
If I had a dollar for every time a customer gave me bad information, I would buy a new car.

 

[toninocp]

totally right, I would be billionaire.
I would understand the issue from S2 (gen) to S1 but transfer time from S1( utility) to S2 is 10.0s then residual voltage for trafo and motors in MCC should almost be nothing.
on next trip will try Inst setting, thanks.

 

[thermionic1]

Is there enough time for the motor loads to spin down before transferring? Is the new switch set up correctly?