Posted by Johnny B Good on October 22, 2008, 4:45 pm
It's a nice idea (and I've, conceptually, toyed with the idea myself),
but it would only really be applicable to a larger micro-hydro power
project where the alternator's output was used directly as an AC supply
and a constant frequency was required.
In this instance, you'd reduce the no load consumption by the field
control circuit and hence the water power demand, conserving what might
be a limited resource and have less overhead from the control circuitry
under peak demand. Overall, a much welcomed improvement of efficiency.
Here, the aim would be to simply compensate for volt drop due to I2R and
other losses in the generator, the speed being entirely regulated by the
amount of water being admitted to the pelton wheel turbine.
In the more typical homepower case, where a battery bank or two is used
to store the energy and smooth out demand on the prime source, a PM
generator represents the optimum solution, in conjunction with a
switching voltage regulator, for most efficient extraction of wind or
Wind powered generators enjoy the most benefit from this technique (PM
alternator feeding a rectifier pack with a switching regulator) where
even just a trickle of power is considered a useful 'top up'.
The water powered case of maintaining a battery supply, where frequency
stability is not an issue, is also best served with a PM alternator.
Here, regulation of the voltage from the rectifier pack is best done by
control of the water consumption (a flywheel on the alternator shaft
helps smooth out speed variations). However, you need to have measures
in place to tame the resulting hydraulic surges any 'rapid response'
metering controls would place on the penstock plumbing.
Please remove the "ohggcyht" before replying.
The address has been munged to reject Spam-bots.
Posted by Vaughn Simon on October 22, 2008, 5:49 pm
Amazing! When do you sleep John?
Since cars are getting to the point where tiny improvements like this applied
fleetwide could make a noticeable difference in CAFE, you would think that this
would be a common item. It would add no weight and save (what?) about 50 watts
on average? In bulk, the additional price of the hybrid alternator along with
its special regulator could be negligible.
Posted by Ulysses on October 20, 2008, 6:05 pm
Is it a PM DC motor? Got any wind? I'll bet you could make some PVC blades
and put it on a rotating mast in less than 2 hours.
Posted by z on October 21, 2008, 5:29 pm
Not much wind here man, or i'd be all over it. I'm in a pretty sheltered
area. The only real wind I get is when a storm hits .. and then its way
too much wind.
I'd have to run around a mile of wire to get to a high ridge that is the
nearest spot .. and no road going up there so ..
Posted by Ulysses on October 21, 2008, 11:18 pm
So just put it on a one mile high pole! ;-)
My experience says if you can get around four volts by turning it by hand at
about one rpm then it should work. Maybe if you use a small two-blade prop
and only get some power from it during storms....