On Sat, 21 Nov 2009 14:14:35 -0800, Jon Anderson
wrote:

Ecnerwal wrote:

Makes little difference (land or marine) if you are just grabbing the
generator end. I can make a few suggestions about using a marine unit on
land if you went that route, as I am doing that.

IMHO, 1800 or 1200 RPM (for 60 hz) units are the only reliable ones out
there - 3600 tend to have short lifetimes.

Suggest away! Since I'll belt drive the generator from the 50hz motor, I
can handle any rpm, but would like to stay with lower rpm stuff.

Thanks,

Jon

If you want to make an electric motor driven motor-generator, I hope
you are made of money - that's going to cost a ton to run, when you
figure in the inefficiency of buying the power from the grid. Just
think about it - to start the main motor on a 10 HP machine your
converter needs to be (rough guess) 40 HP or better...

And belts for the step up drive (1500 RPM electric motor to 1800 RPM
generator head) will have to be adjustable, or your frequency is going
be way off - and with belts it will still sag and surge pretty bad.
You can't just adjust the throttle...

You could hard-couple the motor and generator with a Lovejoy
Coupling IF you can find a rotating field generator head
("Electronically Commutated") or the "Inverter" style (Honda EU line)
where engine RPM is not the frequency timebase.

A conventional genset with a diesel prime mover will make a lot more
sense. And the PTO Drive generator driven off a locally available
tractor is a close second.

-- Bruce --