On Thu, 28 Aug 2003 14:43:06 -0700, Eric R Snow
wrote:

The motor I tested that comes closest to what I want is 2.25 long and
1.5 dia.. At 10,000 rpm it was putting out 9 volts @ 1.5 amps. It was
$10.00 at H.F.. It came complete with a drill chuck, batteries,
charger and a drill motor case wrapped around it. For 8 bucks they
have one with a keyed chuck. If two were connected in series then spun
to 15,000 rpm max then with a cheap regulator the batteries could be
charged and the lights lit. Now, if a similar sized motor came along
with a higher voltage output so only one would be needed then that
would be great. I'm curious to see what Ax-Man has.

They had several different sizes, including a couple of 24-volt
motors. Prices ranged between $5 and $10 for the smaller ones --
sizes like you describe and a bit larger. In general, the larger
the diameter you can use the more volts per rev you'll probably get
because there's more room for magnets and peripheral velocity is
greater for given RPM. I didn't see any 90-volt PM motors this time.

If you could find a power seat motor at a junkyard, that might work
very well. I have one here that's 2.56" dia and would be a little
under 4" long if one cut the wormgear drive off or made a new endcap.
It turns about 113 RPM thru 44:1 worm reduction, which makes me think
it would generate pretty close to 12 volts at about 5000 RPM. The
armature resistance is only 0.175 ohms so IR drop would be very low.
I think there's be no problem getting several amps out of it. It
draws about 15 amps before it starts slowing down noticably.

AxMan had some windshieldwiper motors with gearbox attached, but they
wanted way too much for them -- $19.95, I think, and you don't need
gear reduction.