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Posted by jk on July 18, 2008, 12:39 am
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>I remember mentioning the "any induction machine is a generator". I
>hope you've gotten more detail than just what I said!
>
Well in essence it is correct. You just have to spin it faster than
synchronous, AND be connected to the line.
>I think that if you have the motor spinning at around the synchronous
>speed when you apply power, or if you're using capacitor start, that yes
>you'll be successful.
He will have to have it spinning first, connected to the line. [
>
>You'll be demanding reactive VARs from the power line -- induction
>machines do put power back on the line when they're operated above their
>synchronous speed, but they also look like whopping big inductors and
WHich capacitors can eliminate. Given that they are probably at the
end (or middle) of a long line, they probably should use some..
>they may well generate some interesting harmonic currents in
>single-phase service.
There should be no significant harmonics, unless something saturates.
[Assuming they don't go into ferroressonance.]
> I just don't know if this would be an issue in
>your application -- if a heavy tank sporting your power company's logo
>appears outside your driveway one day, you can assume they have issues
>with it.
:)
But seriously, if they have a net metering contract, the power co
probably knows exactly what they are doing (or they think they know)
>
>I don't know just what you could expect from the other two phases for
>your local power.
3 phase power. Looked at that way, it is just a rotary converter, with
shaft pwoer input.
> I suspect that their voltages will be higher than
>what you're getting on the power line, but I couldn't tell you how much
I would expect lower. I could easially be wrong on this
>(other than the fact that I also suspect it'll get higher as the
>generator speed & hence power output gets higher, and that it may depend
>on the characteristics of the line from the power company).
>
>I wouldn't put anything sensitive on those lines until I'd done some
>careful scrutiny of the output with at least a voltmeter, if not with an
>oscilloscope. I might consider getting a low-voltage transformers of
>sufficiently hefty current ratings to use as buck transformers, either
>on the line from the power company to drop all the voltages, or on the
>lines that you'll use locally to drop the voltages that you use.
>
>I hope you document this all with text and pictures on a web page -- it
>sounds like interesting and useful information for the rest of the world.
jk
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>hope you've gotten more detail than just what I said!
>