PDA

View Full Version : What happened to all the surplus treadmill motors?



jacampb2
02-05-2010, 05:42 AM
I recently got it in my head to try to turn some inexpensive treadmill motors into DC servos... My thinking was, they are cheap enough to play around with, and if it doesn't work out, then the encoders can still be used for real servos.

So, I went to www.surpluscenter.com, they've had various treadmill motors in stock for the 8 years I've been shopping there, always thought about picking some up, but never bothered. They don't have anything listed on their web page. I looked in my '09 catalog, and there they were for $29 each, just as I remembered. I have an email in to them asking if any more will come in this year.

So then I checked out ebay, and find that used treadmill motors are going for $50+ and $20-$30 shipping, and finding 3 matched ones is about impossible. The best part is it looks like I may have stumbled on the reason they are getting scarce. They are all being sold as "wind power generators". Most of the sellers are incredibly optimistic about their power generation potential, about 90% of them claim that you can get 1.6Kw out of a 1.6Kw rated motor-- you might approach that if you could turn the thing at its rated 6000+ RPMs, I'd LOVE to see that home built turbine!

I just had to vent a little bit. It gets frustrating running into things like this. Probably 99% of the folks that bought one thinking they would build a turbine just set the dang thing on the shelf.

If anyone has some good surplus sources for used and inexpensive larger DC motors, please let me know. If anyone has 3 matching ones they want to unload for a reasonable price, let me know. I'm in a buying mood!

Thanks,
Jason

Doc Nickel
02-05-2010, 06:36 AM
That's interesting to hear. While I haven't looked for treadmill motors in a while (I've dismantled at least six in the past two years) I'd have thought they were all going to people repowering import mills and lathes, rather than windmills.

It's even more interesting because I got a massive 4HP 90VDC motor out of a big gymnasium-quality industrial treadmill. The built-in power supply was nigh-indecipherable to either myself (no surprise there) or any of the electrical types I asked or showed it to. It was all part and parcel of the control and computer, and if any of it was missing, none of it worked.

Anyway, I've kept my eyes open for a power supply for it, but something what that HP rating at only 90VDC either doesn't exist, or is absurdly rare, or violently expensive. Though the latter is only a guess as I haven't found one at any price yet. :D

I almost gave it to the scrapper last year- at ten cents a pound (remember, this is Alaska- transportation costs eat up most of the scrap price) it was only worth about six bucks (er, if I left the big flywheel on it :D ) but it was doing me no good, and I had no expectation I'd be able to sell it.

I wonder if I ought to try listing it as a DC windmill "generator"?

Doc.

cebump
02-05-2010, 08:12 AM
Doc
I have purchased controls for the motors you mention from http://www.beel.ca/ I have one on my southbend and a very large wood lathe I built. As far as finding motors, if you have an exercise equipment repair company in your area, touch base with them. Thats what I do for a living and I scrap treadmills all the time, usually for electronics being obsolete, not bad motors.
Brian

Evan
02-05-2010, 08:53 AM
I would guess that brushed DC PM motors are becoming obsolete. Most likely the treadmill manufacturers are switching to brushless motors. They will produce more output for less weight, especially at lower rpm. The controller may be built into the motor so the only external control is a speed pot and a one chip control for the pretty blinking lights.

wierdscience
02-05-2010, 09:05 AM
I would guess that brushed DC PM motors are becoming obsolete. Most likely the treadmill manufacturers are switching to brushless motors. They will produce more output for less weight, especially at lower rpm. The controller may be built into the motor so the only external control is a speed pot and a one chip control for the pretty blinking lights.

Actually yes and no,maybe.I made a part for a customer's new treadmill the other day,it was an Excell??? brand,bout a $1200 unit.

Staring at me from under the base taunting me was a 1.86KW 220vac 3~ motor and chassis mount VFD.I can't wait until they start showing up at yard sales:)

It had me so faint I didn't notice the tank top and leotard clad females prancing around:D

Peter.
02-05-2010, 09:06 AM
I'm thinking of butchering a treadmill for the motor for my milling machine. Are there any type which are NOT suitable?

ArkTinkerer
02-05-2010, 09:44 AM
You can also check if there are any wheelchair repair places near you. Lower speed DC motors are used in the powered wheelchairs. Tend to be lower voltage though...

ArkTinkerer

JanvanSaane
02-05-2010, 10:25 PM
There is a site called otherpower.com, about a year or two ago they had an article on the surplus sales of permanent magnet motors for wind power, after that the price skyrocketed. Personally I like the homebrew axial flux design better and if I ever get off the 12 hour days will pursue it a little more. John

cebump
02-06-2010, 09:58 AM
Wierdscience
I got a batch of treads in recently that had 3 h/p 3 phase motors with Reliance phase converters. They were missing the keypad, but I was able to find those on ebay. I know less than nothing about this kind of drive but with the manual I found on line I have one up and running. I suspect it will find its way onto my mill/drill in due time.
Peter,
as far as what is suitable, i think that depends on your application. The real low end treadmills breakdown/wear out real easy, so I would assume they would be a poor choice for use. Most of the higher end d/c drive units use Baldor, Leeson, Pacific Scientific, or McMillion brand motors. There are few others for sure. We also have quite a few variable speed AC drives out now.