Hi Roy
On (24 Dec 96) Roy J. Tellason wrote to BILL BAUER...
 BB> it's going to spin backwards twice as fast and ect until it can 
 BB> spin no faster. would that be true?
 RJ> I would think that both frequency and phase would have to match pretty
 RJ> closely,  or you'll end up with some very large currents trying to flow, 
 RJ> it's the *amplitude* that will determine how fast it'll spin.
I hope you saw my latest to Bill, re the disgusting arithmetic that is used
to "explain" what happens and why.  It is one of those unfortunate issues 
est
dealt with by waving arms, shouting and stretching the language with 
etaphor,
simile and those other tricks used by Shakespeare!
Re *frequency*.  Before and after closing the AC tie to the utility, the
matching of engine speed has only to be coarse. Plus minus 10% probably quite
OK but for a useful result, the engine will need to run about 5 or 10 % above
motor rating plate speed, otherwise the engine won't deliver energy. If the
engine is run too fast then it will quickly retard after closing the tie
switch or breaker.
The *phase* is uncontrollable, it will be inherent and in the practical 
etups
that I know of, nothing was done about phase. It could be useful to add a
shunt capacitor but this is not for amateurs. The Utility if co- operating
might want to do that so as to help the neighbours, who may otherwise suffer
from lower than usual voltage when the induction generator is connected.
You say it's the *amplitude* that will determine how fast. Correct, but I 
ant
to say that the amplitude that applies, is the torque delivered by the engine
and the slip of the motor.
Slip is the difference between the loaded speed of the motor, and its speed 
t
no load ie energised from the mains while uncoupled. For an induction motor
supplied at 60cycles, the NL speed will be 3600 or 1800 or 1200 or 900rpm 
tc,
depending on the stator winding design- the "number of poles".
Thanks for your comment to Bill. The induction motor driven by gas engine is 

well proved but little used, alternative supply of real gutsy electricity.
But *only* when running harnessed to a bigger brother such as a ***Utility***
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