Garbage Score: 2HP Treadmill Motor

[SteveHGraham]

This must be my lucky day. A neighbor threw out a treadmill, and I grabbed it. I scored a control board, a 2HP motor, and a rack and pinion type of thing which appears to be driven by a gearmotor. Not sure yet. It raises the treadmill.

Now...what do I do with it? Maybe I should make a bench grinder. I got my hands on one of those remote arbor things with a belt. It's a pillar sort of deal with a shaft and two arbors. It's old and sloppy, but I may be able to fix it up. The treadmill motor is open, so it's not idea for grinding anything, but I figure if it's a foot away from the wheels, it might be okay.

Better yet, I should turn it into a buffer. Less grit, and I don't have a stationary buffer.

I wonder if I could come up with a use for the rack and pinion.

I hope the motor is in working condition. I won't be able to hook it up until at least tomorrow.

[spro]

Parts for free is usually always good. If that is a brush motor, the problem may be the brushes or garbage between the commutators. Vacuum the motor and do a smell test. Burnt insulation is a lingering smell.

[SteveM]

One use for it is a variable speed setup for a bandsaw. My dad had variable speed (home brew control panel) on his and it was very useful when moving between cutting wood, plastic, aluminum and brass.

Steve

[SteveHGraham]

The saw thing is actually tempting. I have a Shop Fox 2HP saw with only 2 speeds. Still, I am not excited about using it for metal.

I hooked the motor up to 12V to see if it was okay, and it didn't move, but I don't know if it that's enough to make it turn, so I'm not drawing conclusions yet. It's rated for 149V, I believe.

The gearmotor thing is neat. I guess it's a linear actuator? It has a 115V trransformer. I think these things have limit switches somewhere in the chain of command. I wonder what I can do with a machine that pushes things about five inches, really hard.

I was thinking about building a small welding platform. Maybe this motor is strong enough to turn it, if I include a bearing.

This treadmill is a bonanza. It's full of steel I can cut up for welding. Not sure if it's useful for that. I know some Chinese steel is too hard to be welded and trusted. I also get some metal rollers and bearings.

The bracket the motor was attached to can be cut out of the frame, and I can trim it with plasma and the belt grinder. Then if I want to mount the motor somewhere, I won't have to make a bracket.

Hope some of this stuff works!

[ChipMaker4130]

Steve, a couple of things hard-learned:
1- 'treadmill' horsepower is not 'real' horsepower. They're rated with a pulsing load and it equates to around 1.3 - 1.5hp for your motor.
2- Do NOT remove the armature from the motor unless you push it out with a steel or iron 'keeper' slug of the same diameter (heavy wall pipe should work), leaving the slug in until it is pushed out when you re-insert the armature. If you leave an empty shell the magnets can lose a great deal of strength and it happens almost instantly. After that, the motor will run, but weakly, and draw huge current.

[Glenn Brooks]

Some people use 24 v treadmill motors to power trucks on their locomotives. Many reports of these things working quite well...

Gpb

[SteveHGraham]

Thanks for the assist, Chipmaker, but I have good news which conflicts with your information.

I had to Google a lot, but I finally found the truth: modern DC motor magnets do not lose magnetism simply because you remove the armatures.

The first magnets were iron, and after that, the alloy Alnico was popular. Both metals lost magnetism easily. Even the shaking encountered in motors and machines killed these types of magnets, and they required "keepers" (like the slug you mentioned) to prevent demagnetization when DC motors were disassembled.

Now the most common material is barium-ferrite, which is ceramic. According to a source, it is "almost immune" to demagnetization. It won't demagnetize if you drop it, and it doesn't require a keeper.

Instead of barium-ferrite, the best DC motors use rare earth magnets, which are more expensive. Although I seem to load up on them pretty cheaply on Ebay. God bless the Chinese.

Man, it's nice to find an authoritative source once in a while. I guess that's why we like Harold and Richard.

The HP issue is interesting. I found out that some treadmill motor makers rate their motors at very high speeds, so when you run them at lower speeds which are actually useful, the power is lower. Also, of course, "continuous duty" HP is the only figure worth looking at. I wonder how much you can compensate with small pulleys. I would guess that a motor that runs happily at 5000 RPM or more probably doesn't mind a small pulley, but I don't know.

The motor I have on my grinder is 0.75 HP, and while it's very nice for a 1" belt grinder, I find it hard to believe that it ever powered a decent treadmill. I think I might make a smaller pulley for it and crank it up higher.

If the motor I just scrounged produces even 1 HP, I'll have more power than I need to buff things.

[SteveHGraham]

I have some info which will be very useful to anyone who cuts up one of these treadmills.

First off, before you take the motor out, try to angle the bed or whatever it's called so the fasteners holding the motor in are accessible. In certain positions, it may obstruct your access, and that makes for a bad experience.

If you have a hard time removing the pulley from the motor, it may be because you're trying to turn it backwards. These things are held on with left-hand threads. To get a pulley off, clamp the pulley (not the motor) in a vise with padded jaws and use Vise Grips on the rear end of the shaft. Turn it clockwise, as if you're screwing it INTO the pulley. If it doesn't move, arrange your motor so the pulley is free and the motor is held tight. Heat the pulley hub with a torch WHILE trying to unscrew the shaft from the rear with Vise Grips. This way, you won't overheat the pulley. As soon as it gets hot enough to expand off the shaft, it will turn, and you can stop heating it.

If you want to be able to reverse your motor, just put a key in the pulley.

If you have an MC-60 controller, you're all set. Just hook up a potentiometer to the input, hook the motor to the output, connect the AC, and it will run. Do NOT ground the board to the heat sink. Forget about chokes and transformers. You don't need them.

You may need to snip a resistor in order to control the rotation. I had to do this. My motor either didn't run at all, or it ran full tilt. The number of the resistor evades me, but you can find it online somewhere.

If you have an MC-2100 controller, you have more work to do. It won't operate off a potentiometer input. You have to build a small circuit which provides PWM (Pulse Width Modulation) input. Don't ask me why. It requires two op amps and some other inexpensive items. You don't need an Arduino or a new control board.

The speed of the motor is solely dependent on voltage. The torque may drop if you don't provide enough current. I don't know if this will ever be a problem with a factory controller, but you might as well have the information.

The motors provide plenty of power, but they produce it at high speeds, so make yourself a small pulley with fan vanes to replace the huge factory pulley. If your motor seems weak, you're running it too slow.

You can also run a treadmill motor off a variac (autotransformer) and a diode bridge (rectifier), and that would certainly be cheaper than building a complicated circuit.

To test your motor, hook it to 12V DC from a battery charger. It will turn at low voltage if it's working properly. It just won't turn fast.

If you have two blue wires coming out of your motor, they go to a temperature cutoff inside the motor. You don't need this to run the motor, but it may prevent it from blowing up.

There are schematics and PDF's for both controllers on the web, so Google around.

[ChipMaker4130]

Steve, I was speaking from direct experience. The motors I screwed up were all the same brand, appeared to be well constructed and were NOS Icon treadmill motors (I think the brand name was SUD, with oomlauts over the U). This was just 3 years ago too. They ranged from 1.5-3 hp. I took the armature out with some significant effort, a LOT of effort, really, to check on other things. A few minutes later, I re-installed the armature but had to remove it again for some reason. This second time the removal was much easier (lower magnetic attraction). When I ran the motor, it was much, much weaker than it had been before disassembly, and drew much more current. Having no idea what happened, I bought another motor, did the same thing and got the same result. Only after ruining 3 units did I search the web and found out what I posted above.

Perhaps top-of-the-line motors no longer have this problem, but I doubt most are immune. If you dare, take yours apart for a few minutes and let us know how it turns out!

Even though these were unused, they could have been quite old, I don't know. When I gave up on them I broke the magnets out so I could use the shells, and the magnets broke much like a ceramic might. Maybe someone is familiar with these SUD motors and their construction?

[liveaboard]

Nothing like a good pile of free parts!
A buddy of mine scrapped a little ford escort diesel car because the body was rotten, so I took the motor.
I never did use it, it's been in my storage area for 15 years; but I took the gearbox apart. What a lot of nice gears I found in there!
The steel is a bit hard on the outside, but they can be cut and I've used a lot of them already.

[BadDog]

LOL, going OT, but that sounds so familiar. I took apart a Ford NP205 to get a large bearing 31 spline input for my "doubler" (stacked cases for compound low) intermediate. Anyway, I had a lot of otherwise "useless" big honking gears, shafts, shifter forks. They are all in a box of such things, along with the gear/shaft guts of a TH350 I broke the case in half on (I swear I'm going to whip something up with the planetary set some day! Just not sure what...). At this point, the stuff I've used from the bin I couldn't even tell you the original source, but it's been so useful, and the material used for those shafts is so VERY nice to turn. On a side note, if you need good material for smaller shafting cheap, gather up pull-off shocks from obvious sources (they have to pay to get rid of them). Cut the shafts off, and they make great 3/8" to 3/4" shafting sources, you just have to get under the hard chrome coating.

[SteveHGraham]

Chipmaker, I'm sorry to hear about your experience. I'm not an EE; just reporting what I learned. I had no problems with the Icon motor I took apart for machining.

I can give you a couple of references I found. See what you think. I keep reading that ceramic magnets don't require keepers. I'm wondering if something else is going on with your motors.

http://www.practicalmachinist.com/vb/re ... 6f%3Dfalse

http://www.rexresearch.com/monus/monus.htm#2

Depending on whether you still have the ruined motors, I have good news for you. They can be remagnetized. Here's an example of a page detailing a simple procedure that supposedly works. Some motor repair shops can do it. Now I'm wondering if my grinder would benefit from it!

http://www.nutsvolts.com/questions-and- ... magnetizer

I suppose it won't hurt me to scrounge up a piece of iron pipe to cram in there if I ever remove the armature.

Liveaboard, today I saw a guy in a pickup truck, stopping to take the steel I threw out. I wanted to keep it for welding, but I have so much junk already.