Parelling generators to the bus

[Gallo22]

Of course you bring the generator up to speed and zero out the voltages and turn the syncroscope on and slowly raise the speed so the needle will slowly move in the clockwise direction as the speeds become equal to that of the oncoming bus the lamps will stay off which is when you want to close the breaker at top dead center or 12 o clock, when voltage between generator is the least. Now my question is when a generator breaker is closed a little out of phase they will be yanked in phase as then lots of current will flow in between them which could lead to mechanical and electrical damage but isn't this why we have protective relays? Also is it possible by paralleling the oncoming generator to the bus and close breaker a little out of phase could it cause vibration to the other generator that is already on the bus?

 

[waross]

Yes all of the above. You should have the 'scope moving slowly clockwise (slightly faster) so the incoming machine picks up a few percent of load to prevent a reverse power trip. I don't want to comment on the lights as there are several connection schemes. The lamps may be bright or dim, or both. Search this site. There was a recent discussion regarding the amount of allowable "Out of phase" when paralleling sets.

Bill
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"Why not the best?"
Jimmy Carter