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RE: ganging up cheap generators

Original poster: "Jim Mora" <jmora@xxxxxxxxxxx>

Hi Jim,

I have two generators that I have put together. One is single phase
utilizing a small Kubota diesel off Ebay and a dual belt driven Gen head
from Harbor Freight at ~10KVA. Easy to build.

The second one is a work in progress and is comprised of a Isuzu 240C
Industrial diesel prime mover and a Stanford - Newage three phase direct
drive gen head that required machining the flywheel, which is coupled
directly to a flex plate and thus the gen head. Again Ebay. Out of two
engines I got one good one :-^)

The costs are similar, the effort is much greater.

Best Regards,
Jim Mora

-----Original Message-----
From: Tesla list [mailto:tesla@xxxxxxxxxx]
Sent: Tuesday, January 09, 2007 11:08 PM
To: tesla@xxxxxxxxxx
Subject: Re: ganging up cheap generators

Original poster: Jim Lux <jimlux@xxxxxxxxxxxxx>

At 05:56 PM 1/9/2007, Tesla list wrote:
>Original poster: <davep@xxxxxxxx>
> > Actually, with a suitable zigzag transformer, apparently
> > synchronization is no worse than just paralleling them.
> >
> > Frequency/phase takes care of itself (the generator that wants to run  a
> > bit fast takes more load, slowing it down).
>      Which means it takes more of the load, so there is less than 3X
>      power available.
>      Also the underspeed.voltage units will tend to _absorb_
>      power, robbing the external load.

Well, that's why it's less optimum than a real 3 phase
generator.  But, finding a brand new 3 phase generator for $750 might
be a bit of a challenge.

> > There IS an issue when throwing the switch to connect them.
> >  Amplitude is a matter of regulators and throttles.
>      An current sruging baack and forth as the throttles
>      run the units up and down.  And the fact the voltage
>      regulation is less important than frequency regulation
>      when paralleling AC sources.  And the fact that 'identical'
>      regulators AND governors on three 'identical' units
>      won't be.  cf any text book on power system stability.

I didn't say it would be easy <grin>...

>      best
>       dwp