On Tue, 18 Sep 2007 10:11:28 -0700, Jim Stewart
wrote:

Ignoramus29233 wrote:
Regarding a danger of backfeeding a generator, I have a question.

What if the generator has a circuit breaker? So the backfeeding power
goes in through a breaker? Would the breaker save the generator from
backfeeding damage, in this instance? (assuming properly sized
breaker)

Regarding Brian's article, there's no date so we
don't know the vintage of the electrical equipment.
Circuit breakers, especially in the old days,
depended on a minimal amount of resistance and
inductance between them and the source. They are
also limited as to the absolute maximum surge
current.

I can't think of a worse situation than strapping
together the two busbars of generators exactly
180 out of phase. You'd be producing a fault
current twice that of a hard short circuit. If
everything were sized for that, it's no surprise
something exploded.


On all the multi generator sets I have seen the generator connects to
a circuit breaker and then to the bus. The circuit breaker is what you
turn on when the frequencies are in phase.


Bruce in Bangkok
(brucepaigeATgmailDOTcom)