----- Original Message -----
From: "Michael DeMan" <nanog@deman.com>
It is my understanding also that most commercial grade gensets have built into the ATS logic that when utility power comesback online, that the transfer back to utility power is coordinated with the ATS driving the generator until both frequency and phases are within a user specified range?
I don't believe that's actually true, Mike. In a *load transfer* configuration, it's really not all that critical if the power presented to the load skips phase a touch on the transfer; there's a 50-500ms gap in the power anyway, since such transfer switches are required by the NEC to be non-shorting, so they don't electrocute power workers. Cheers, -- jra -- Jay R. Ashworth Baylink jra@baylink.com Designer The Things I Think RFC 2100 Ashworth & Associates http://baylink.pitas.com 2000 Land Rover DII St Petersburg FL USA http://photo.imageinc.us +1 727 647 1274