Hi Bill
On (20 Dec 96) BILL BAUER wrote to Alec Cameron...
 BB> > Good news, bad news. Your 10HP single phase induction motor will work 
OK
 BB> > as a
 BB> > generator but ONLY while the grid is OK. Open the throttle on the 
engine
 BB> > and
 BB> > see the meter spin backward. Great!
 BB>  
 BB> According to the way I take what you are saying about the meter spin
 BB> backwards when you open the throttle on your engine hooked to an
 BB> induction motor then its not only going to spin backwards because of
 BB> the fact of power going into it from the "wrong" direction but it's
 BB> rate of spin is also going to be determined by whatever the frequency
 BB> of the voltage might be.
No, not the frequency- that is determined by your utility not by your engine.
The meter reverses because energy is going out from your engine, into the
homes of your neighbours, via the utility lines.
The transfer of energy from the rotor of your induction motor-cum-generator,
is enabled by the magnetic field across the airgap between the rotor and
stator. As you have no source of magnetism within the motor, this magnetism
has to come from the utility supply. A rough analogy, is that the magnetism
works like a slipping clutch communicating energy from the shaft of the
engine, into the windings of the motor stator and out thru the utility line.
SO if you put a voltmeter across your supply, you will see that the voltage
drops! even tho your are sending power thru your meter into the Utility
system.
Seems mad but it is so. The reason the voltage drops, is because magnetising
current is required by your motor. And it is a fact, that magnetising current
due to its rotten power factor, depresses voltage much more than does "real"
power ie load at a very high power factor. Just believe this, the arithmetic
that proves it is a headache and I am, so pleased to have left Sydney Tech
back in 1955 after I had been converted to these evil beliefs!!
 In otherwords, if it gets fed 60 cycle then
 BB> it would spin backwards at it's normal rate and if it gets fed 120
 BB> cycle then it's going to spin backwards twice as fast and ect until
 BB> it can spin no faster. would that be true?
No, you have to allow for the fact that it is the engine that decides which
way the rig rotates, and which way the power flows. Here is the way to run:
With AC switch open ie induction motor unconnected to grid, start the engine
and raise the revs to just above the rpm on the motor rating plate. A common
value in US will be I guess, 1700 or 3400 rpm approx. When the revs are 
teady
and the engine warm, then-
Close the AC tie between the motor and the utility. You may hear a bump, and
see the lights dim a little. You are now taking a bit of power from the
utility.
Open the engine throttle, the revs will increase but not a lot. The engine is
now supplying energy at 60 cycles and your KWHr meter will be going in
reverse, unless you have a lot of power being used at home.
If you are in a rural address and if your motor is very large the the voltage
drop may be a nuisance to your neighbours. The utility may come looking for
you.
If the motor is not too big and if you are located close to a major
substation, they may never notice. But the revenue Branch might come looking
to enquire why your bills have dropped. They will be watching for Theft of
Service- some people bypass the KWHr meter and steal the energy. You will be
clean, they might just pat you on the head and say, please remove this c***!
Cheers...ALEC
... ........The hasty and the slow meet at the ferry
--- PPoint 1.92
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