Actually reducing the alternator RPM is the idea. This thing puts out
200Amps at an alternator speed under 2000 RPM. With the pulleys I have now
that is an engine speed of about 800 RPM. I need to get the engine turning
faster or the power will be all torque and no speed and Larry's prediction
of gloom and doom might come true. A pair of BX belts can handle plenty of
HP but not at such low speeds.

After some research I found some interesting things about this monster.
There are actually two rotors on the same shaft. One is high power
permanent magnets and the other is a regular Lundell claw & field coil.
With the field coil off the magnets will drive the alternator to 200 amps at
4,000 RPM. If more power is needed to maintain voltage the field coil is
energized to add to the flux and produce up to 305 amps. If less power is
needed the coil is reversed to cancel out the flux field. Net result is a
70% increase in efficiency and a corresponding reduction in heat build up
but to get minimum output the field coil has to be driven at full power
backwards.

The down side is you can't use a 3 stage regulator. This puppy is designed
to crank out power for lights, inverters and equipment. Control is strictly
on the output voltage so it stays in bulk stage until the batteries can't
take any more. This is going to take some more thought. For the price
though it would be a good temporary high output spare.

--
Glenn Ashmore

I'm building a 45' cutter in strip/composite. Watch my progress (or lack
there of) at: http://www.rutuonline.com
Shameless Commercial Division: http://www.spade-anchor-us.com

"Andina Marie" wrote in message
ps.com...
I hope you were increasing both pulleys so the alternator RPM was the
same?

If the alternator sucks up too many horsepower, especially when docking
or emergencies, a field disconnect switch can be added to remove the
load temporarily.