Saturn starter motor

[Ben Bennett <greyhawk2@earthlink.net>]

As in my previous post the Saturn Starter is a PM motor with a
planetary reduction gear. For my first electric project, I'm
trying to build a cart (almost a wheelchair) That I can run around
swap meets in. I'm trying to make it look as much unlike a
wheelchair as I can.

Well I finally got it together enough to run some tests. The motor
is 2.5" in diameter and 8" long (overall, GR, endframe, and all),
very light, maybe less than a pound. The PGR is 11:1. I replaced
the Bendex with a 10 tooth sprocket (#41). I have a 39 tooth
sprocket on the 13" diameter front wheel. I figure that gives me a
final ratio of 42.9:1 The stall current is 56 amps. Running
current starts at 40 amps and goes down to 30. I was running it
directly on 12 Volts (one battery). Top speed? My 9 YO
granddaughter couldn't keep up, so I figure maybe 10 MPH. It does
very satisfactory burn outs too. I have 3, 12 volt, 26 AH, Gel
cells that I plan to use, made by Johnson Controls, Dynsty #
UPS12-100. Anybody know anything about these batteries? I found
them at a swap meet, I think they're for a computer UPS. I ran it
up the street and back a couple of times and the motor got just
barely warm, I could hold my hand on it with getting burned.

I guess the next step is a controller. I thought maybe a Micro
Processor driving a couple of MosFets. What would be a good choice
of MosFets?
On the cheep side. Hey, I'm on a fixed income here. I have a Micro
I can use, Probably most of the parts too. I figure the most of my
running will be less than 50% Duty Cycle (unless my GD gets on it)
so do you think I could get a hour running time out of the 3
batteries?

-- 
Ben Bennett
He who dies with the most toys is nonetheless dead
Http://home.earthlink.net/~greyhawk2/