Thanks for your input, everyone! The motor I have is a PMDC motor, normal non-hub arrangement. It was originally from a forklift steering mechnism, where it mated to a 43:1 gearbox. Check it out: http://www.majhost.com/gallery/Ned/misc/big_motor1.jpghttp://www.majhost.com/gallery/Ned/misc/big_motor2.jpghttp://www.majhost.com/gallery/Ned/misc/big_motor3.jpghttp://www.majhost.com/gallery/Ned/misc/big_motor_4.jpghttp://www.majhost.com/gallery/Ned/misc/big_motor_5.jpghttp://www.majhost.com/gallery/Ned/misc/big_motor6.jpg
It is rated for 1-1/3 HP, "Special duty". I think they might have had to made that duty cycle up because it would be very frequently reversing in its original application. I wonder if "special duty" is better than continuous, even. We'll see.
My current thought is to run it through a right angle gearbox and chain or belt drive to the rear wheel. It has a nice thick shaft- once the splines are turned off, probably 1/2". I couldn't use the gearbox from a standard 4.25" grinder (I have two dead ones that I could, if only) because the pinion is too small to accept the 1/2" shaft and I'm not willing to turn it down to 1/4" to make it fit. I have been on the prowl for a gearbox for a 9" grinder, but no luck so far.
Next question: the controller. What controllers would you all recommend? 1000 / 36 = ~28A, 75% efficiency (stab in the dark) makes it 37A. I'd like to have 2X that for surge, so I'll be looking for an 80A controller. Can anyone recommend an 80A 36v controller that can be had for cheap? I have an old Curtis 1505 80A controller, but sadly it's only good for 24v. I thought about running it at 24v just for a little while until I get the first kinks sorted out, and maybe I still will. It'd be a significant power drop. Power is the cube of voltage, right? So at 24v I'd only have something like 300W. I can't remember the formula off hand.
Wild idea: Can I just take an el-cheapo controller and wire up some well-heatsunk high-current MOSFETs were the old cheapie ones were? (probably remotely) Anyone ever tried that? I've been told that the big change in gate charge will really hurt my switching frequency and lose some efficiency. I wonder how much of an effect that would have, practically speaking.