Subject: Windpower 3 of 3



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(3566)   Sat 27 Jul 91 23:10                             
By: Terry Olsen
To: Don Kulha

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 QE 2.75 b9 & RA 1.01 2306@
MSGID: 1:125/12 4e309afe
One more thing Don, and I ask because you have posted some 
expertise in this area...do you know of a method to get 60 Hertz, 
120 VAC from a windmill?
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(3588)   Tue 30 Jul 91  0:30                             
By: Lou Schneider
To: Terry Olsen

> ...do you know of a method to get 60 Hertz, 120 VAC from a 
windmill?

I've never tried this, but if you excite the field of a
commutator-type DC generator with an AC signal, you should get an AC
output that's locked to the excitation signal, not the rotational
speed.  Voltage would be controlled in the normal manner, varying the
excitation voltage to control the output voltage, just like a DC
generator.
 
I can think of several possibilities - use a small inverter to excite
the generator and get large quantities of stable AC whenever the wind
blows.  Or use a sample from the PG&E grid and your wind generator
will be phase locked to PG&E (I think this is how commercial wind
generators feed back into the grid).
 
Or if you're using steam or hydro to power the generator run the
turbine at the most efficient speed for the load that's on it, and
vary the field to control the output.  You wouldn't have to keep the
speed at a constant 1800 or 3600 RPM.
 
One disadvantage would be the maintenance of the commutator and
brushes.  Of course, to minimize brush wear you could apply the
excitation to the armature and take the output from the stator coils.

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