"This is only bullet proof if you can measure the primary voltages. If you are measuring PTs this is a disaster waiting to happen."
- i agree and this is what we did using two sets of high voltage sticks and high voltage meters.
GenSwgrEng - what you said in the last part of your post is what we did to check the system. It worked great and it was very obvious that everything was rotating the same direction.
"Another way to check is to take two voltmeters, one across A-phase of both sources, and one across B-phase...
this is the part that was confusing me:
"However the part I still don't understand is even if one side had an incorrect phase sequence, wouldn't the A phase vectors be rotating in the opposite direction to each other if the generator is rotating in the wrong direction, thus only in synch for a...
well what happened here is some generator cables were changed out. two cables got crossed and we missed it on our phase checks. we DID NOT actually start and close the generator. i am just trying to figure out some what ifs as to whether or not the breaker would have closed if we had started...
All the sync relays i've ever seen take a single phase input from the running and line side. This particluar case is actually an auto syncronizer (with sync checking) so there is some ciruitry associated with it.
here's the scenario what would you expect to see?
a sync check relay monitors phase-phase voltage on both the incomming and running system. the incomming system is wired incorrectly with two of the generator wires crossed.
because of the crossed wires electrically the machine is rotating...
