ATS won't transfer back
ATS won't transfer back
(OP)
I currnetly have a square D ATS and I am almost positive it is a 3 pole 480v. The problem lies when I kill utility power the Gens fire up and and the ATS switches and life is good, but when Utility comes back the Transfer switch won't transfer back instead the open transisition starts to transfer then it stops halfway through and I have no power to my load, so I lost the data center. I am visiting the site next week I need a good plan of attack.
Could it possibly be a ground fault located somewhere preventing the return to utility?
Circulating currents on the ground?
Square D ATS are crap (Square D service techs have nothing)
Anybody experience anything like this?
Could it possibly be a ground fault located somewhere preventing the return to utility?
Circulating currents on the ground?
Square D ATS are crap (Square D service techs have nothing)
Anybody experience anything like this?






RE: ATS won't transfer back
Alan
"The engineer's first problem in any design situation is to discover what the problem really is." Unk.
RE: ATS won't transfer back
There may be a set of relay contacts that have failed.
On some types the operating pulse may be too long or maintained.
Ground faults, circulating current. Not likely. These would show up in normal operation.
There are so many types of ATSs and controllers that about the only thing I can suggest is don't waste time looking for an ephemeral ground fault and/or circulating current until you have spent a week checking everything else.
Bill
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"Why not the best?"
Jimmy Carter
RE: ATS won't transfer back
David Castor
www.cvoes.com
RE: ATS won't transfer back
Is this a true UL-1008 transfer switch or a pair of circuit breakers? If it is a breaker pair, check for a trip indication on the utility breaker. SqD had problems with nuisance trips on their Micrologic trip units. After a breaker opens, the trip unit could trip, preventing reclosure. Of course, if the normal breaker were tripped, you'd think the ATS controller would be smart enough to stay on generator. But like you said, SqD ATSs are crap.
Engineers are always honest in matters of technology and human relationships. That's why it's a good idea to keep engineers away from customers, romantic interests, and other people who can't handle the truth.
RE: ATS won't transfer back
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: ATS won't transfer back
RE: ATS won't transfer back
I can think of at least three types of transfer switch where this statement is not valid.
Bill
--------------------
"Why not the best?"
Jimmy Carter