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[How do I?] Wiring Up A Treadmill Motor (i Know, I Know)

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hmwhitehead

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#61
I have made this modification to 2 speed controllers, one on my drill press and one on my band saw. I just cut the lead on the Q6 transistor collector (looking at the flat face of the transistor, it is the lead on the left), or you can cut the lead on the 5.6K resistor attached to the collector. I left it in place in case I had to go back. Now I can start the motor at whatever speed the pot is set at. Works great. Drawing is attached.
Not sure why the drawing did not get uploaded, I have not looked at this board in a while, so sorry for not getting the information out sooner. Here is the schmatic, hopefully it will be uploaded. MC-60 Motor Controller 1.jpg
 

QCaudill

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#64
I know this is an old thread, so I hope it's ok to post here. I'm just getting started in DC powering my wood lathe with an MC-60 controller. I know very little about metal, but quite accomplished with wood. Again, I hope it's ok to post here. My electronic knowledge is basic. A few questions:

1. I'm just wondering if the reverse switch needs to be 15-20 Amp at 90VDC or not (depending on your motor size. My motor is 18A). And if so, where did you find one? A 90VDC switch with that amperage seems to be hard to find. That is leading me down the relay road, which I would like to avoid. I'm thinking that unless the motor gets stalled it's not likely to draw more than 1/2 it's rating and then only on startup.
2. I see a lot of people use a 10k linear POT, but it seems the MC-60 normally has a 5k linear POT. Is there a reason for using a 10k POT?

Thanks,
Quiller
 

hman

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#65
Quiller -

1. Most any switch rated at 20 (or better, 25) amps should work, especially if you don't switch it under load. Turn off the power, let the motor coast down, throw the switch, then turn power back on. CAUTION - Treadmill motors are optimized for rotation in one direction. The brushes are offset several degrees (I forget the typical amount) in one direction with respect to the field magnets. Yes, you can reverse one, but it will run slower in reverse.

2. The value of the pot is not critical. The controller puts 12 volts across the outer terminals, and the wiper simply picks off the voltage at the set point. Both 5K and 10K will work fine. 10k are often easier to find. I'd not recommend going below 5k, as this might send too much current across the pot and shorten its life. By the way ... if you put a switch between the pot wiper and the MC-60, you can return to your previously set speed on startup without having to turn the pot all the way down. Opening the switch drops the "W" voltage to zero and deactivates the safety circuit that prevents a treadmill from starting up at speed.
 

QCaudill

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#66
Thanks so much for the quick reply. 20 amp AC switches are plentiful, 20 amp DC switches, not so much. None the less, I think you are saying what was my gut feeling is, that the motor will really never be at the rated amps and as you say, the reverse switch would never be thrown with power going to the motor. The motor I have is actually Reversible, and on a wood lathe the only time you ever run the lathe in reverse is when sanding so not much power needed.

I knew about adding the switch to the POT, but wasn't sure exactly where it went. Thanks for that information. I was thinking a small normally closed momentary switch would fit that role. Just push it before startup. It won't carry any current, to speak of, will it?

Thanks again.
 

Forty Niner

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#67
I use a treadmill motor on a small Taig metal lathe. The 5k POT works fine on mine.
I would recommend that you include the choke coil on the DC circuit to smooth out the DC. It will run without out it but not as smooth.
f.y.i. I have attached a diagram that may be some help.

Other items I included on mine are a "jog" button and a "pause/run" switch as well as a reversing switch. The jog button can be used setting up. The pause/run switch allows the motor to be shut off then turned back on without moving the speed control knob.

I really really like using the treadmill motor. It is smooth and powerful and runs a wide range of speeds. The one I have is 2.65HP, which is way more than the fractional hp motors normally used on small lathes. Never a problem cutting metal or wood.

Good luck.
 

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QCaudill

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#68
I use a treadmill motor on a small Taig metal lathe. The 5k POT works fine on mine.
I would recommend that you include the choke coil on the DC circuit to smooth out the DC. It will run without out it but not as smooth.
f.y.i. I have attached a diagram that may be some help.

Other items I included on mine are a "jog" button and a "pause/run" switch as well as a reversing switch. The jog button can be used setting up. The pause/run switch allows the motor to be shut off then turned back on without moving the speed control knob.

I really really like using the treadmill motor. It is smooth and powerful and runs a wide range of speeds. The one I have is 2.65HP, which is way more than the fractional hp motors normally used on small lathes. Never a problem cutting metal or wood.

Good luck.
What exactly does the jog button do?
 

FanMan

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#69
I'm getting ready to do my own conversion, with the motor and MC-2100 controller I pulled from a treadmill. I've seen it mentioned in several places about the motor brushes being angled and causing issues (either lower speed or premature wear) when the motor is run in reverse. How much of an issue is this? "Forward" in my mill is the opposite of the motor's normal rotation in the treadmill.
 

QCaudill

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#70
I'm getting ready to do my own conversion, with the motor and MC-2100 controller I pulled from a treadmill. I've seen it mentioned in several places about the motor brushes being angled and causing issues (either lower speed or premature wear) when the motor is run in reverse. How much of an issue is this? "Forward" in my mill is the opposite of the motor's normal rotation in the treadmill.
There are quite a few new treadmill motors on eBay that are reversable in varing sizes. Used too but harder to determine if rated reversable.

Sent from my SM-N920P using Tapatalk
 

Forty Niner

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#71
What exactly does the jog button do?
The "Jog" button is wired in parallel with the "pause" switch.
It is a spring loaded normally open momentary switch.
When the "pause" switch has the power cut to the wiper connection on the potentiometer, the "jog" button can be pressed to momentary send power to the motor. This can allow you to move the item in the chuck a bit to check alignment, etc...
 

Forty Niner

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#72
I'm getting ready to do my own conversion, with the motor and MC-2100 controller I pulled from a treadmill. I've seen it mentioned in several places about the motor brushes being angled and causing issues (either lower speed or premature wear) when the motor is run in reverse. How much of an issue is this? "Forward" in my mill is the opposite of the motor's normal rotation in the treadmill.
My treadmill motor powers my small lathe and runs happily in either direction. I don't even know which way it is "supposed" to run. I got the motor "bare." The direction that I normally use was determined solely by where I physically located the motor on my base.

However I must disclose that my treadmill motor HP (2.65) is way more than what the lathe requires! Maybe that is why it doesn't matter which way mine runs.
 

QCaudill

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#73
The "Jog" button is wired in parallel with the "pause" switch.
It is a spring loaded normally open momentary switch.
When the "pause" switch has the power cut to the wiper connection on the potentiometer, the "jog" button can be pressed to momentary send power to the motor. This can allow you to move the item in the chuck a bit to check alignment, etc...
Thanks,
Quiller
 

QCaudill

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#75
Guess I'm late to the party, but here are a few things I've stumbled onto (or into) while working with several treadmill conversions. Others have mentioned some of them. Three sets of motors and controls are in use on my lathe, mill, and drill press; and there's one slated for the vertical bandsaw and possibly another for the horizontal. I love these things.
  1. Almost all the motors have flywheels with 1/2-13 LH threads. Nuts and taps are readily available.
  2. The easy way to get the flywheel off is to run the motor forward and then stop the shaft suddenly. The easy way to do that is to set up a SPDT switch in one side of the line, wired so in one position it feeds the motor, and in the other, it opens the line and shorts the motor. (See below for more on this.) I do have a couple of 3 HP motors that use a keyed shaft.
  3. The flywheel will add momentum to the tool, for better or worse. It's kind of like using a sledgehammer instead of an engineer's hammer. It's harder to stop, which I wouldn't like if I were tapping a hole because it could break your tap if it bogged down. In fact, I'd rather have a slip clutch for tapping.
  4. The flywheel usually has fan blades that provide cooling in proportion to the speed. But the main point of using a DC motor with PWM is that you can create a lot of torque at low RPM, and that takes a lot of current that produces a lot of heat. Better to use a PC fan that runs full speed all the time, with the bonus of continuing to cool the motor down after it stops. This is another reason to lose the flywheel.
  5. These motors have incredibly strong permanent magnets. They're great for cleaning up your chips and filings around the shop - they'll pick up every last little shard. Problem is, they weren't designed for machine shops. I put duct tape over the openings as soon as I can get to them, and don't take it off until you have to. Part of the retrofit requires making some sort of shield and screen to keep stuff from getting drawn in by the combination of magnetism, cooling airflow, and Murphy's Law.
  6. The pot is usually 5K and always linear. The value isn't critical, but I wouldn't go below 1K or above 10K without some electronics investigation. It's important that it be linear, not audio or log, to keep the speed proportional to how far you turn the dial. (If you're into that stuff, the reason the resistance isn't critical is that the pot is a voltage divider feeding a high impedance, carrying little current, so value is not a big deal. And with the other nonlinear pots, the speed changes pretty fast at one end, and pretty slow at the other.)
  7. Treadmills can be shut down by the feedback loop that tells the controller how fast the motor is going. The controller compares this with the speed control setting (pot) and cranks up or down the juice as needed to maintain the target speed, even as the load varies. That can be helpful for things like avoiding chipping carbide tips. Say you're milling an irregular piece of stock that isn't uniformly hardened (think case-hardened, or unseasoned cast iron, for example), and the speed is bogging down so you crank the pot and the speed comes back up. Then if you hit a hollow or soft spot, the mill speeds way up almost instantly, and you slide right through the hollow only to have the tips hit the case-hardened surface on the other side, and bang! Carbide doesn't like shocks like that - though it's really hard and takes hi temp beautifully, it just can't handle impact.
  8. Some controllers will shut the motor down if they don't get a signal back indicating that it's moving. Most treadmills use a magnet or stripes on the flywheel and a coil or phototransistor nearby on the frame to create the signal. Problem comes after you remove the flywheel and lost the signal generator. You can fabricate a substitute, too complicated to go into here, but I would be glad to explain offline.
  9. About stopping the motor with a switch: Actually, this is pretty effective. Here's how it works: a motor and a generator and one and the same, though optimized differently. A spinning motor generates a voltage proportional to its speed. If you disconnect the power and then put a low resistance across the motor terminals, current flows with the effect of slowing the motor down rapidly. I’ve got a kill switch on my lathe that does just this, and it stops the chuck in less than 1 second.
  10. Most switches and relays can't handle nearly as much current when it's DC as when it's AC. Look for switches rated at least 10 amps at 110 VDC. They can be hard to find, and you may have to settle for something less. Just be aware that they can overheat, open the circuit (cutting power to the motor), short the power (could fry the controller, although you can minimize the risk by putting a fuse between the controller and the reversing or shorting switch going to the motor; or - perhaps worst of all, it could flake out and suddenly turn on when you have it in the off position.
  11. Because unintended start-up could be disastrous to the operator, as well as the tooling, the machine, and the work, I would ALWAYS PUT A RELIABLE, ADEQUATELY RATED DPDT SWITCH IN THE AC LINE BEFORE THE CONTROLLER, IN A VERY HANDY LOCATION, AND ALWAYS SWITCH IT OFF WHEN NOT USING THE MOTOR. This is the only way to be sure the motor won't start up without warning.
  12. About opening the pot's center lead to turn the motor off: I would use the same AC line switch as above to kill the power absolutely for sure before assuming the motor will never start up on its own. I don't pretend to know a lot about machining, or everything about electronics, but I do have a lot of years worth of surprises and scars because I assumed circuitry was dead when it wasn't. Components fail, solder joints break - both aggravated by the vibration that machines inevitably create.
A couple of fusing questions. What size should the fuse be between the reversing switch and the controller, and also the size of the fuse/circuit breaker after the main power switch.
Thanks,
Quiller
 

FanMan

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#76
A couple of fusing questions. What size should the fuse be between the reversing switch and the controller, and also the size of the fuse/circuit breaker after the main power switch.
I'm wiring mine with the original circuit breaker from the treadmill on the AC supply line to the controller... dunno the rating but the treadmill manufacturer presumably knew what they were doing. There was and is is no fuse between the controller and the motor.
 

QCaudill

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#77
I'm wiring mine with the original circuit breaker from the treadmill on the AC supply line to the controller... dunno the rating but the treadmill manufacturer presumably knew what they were doing. There was and is is no fuse between the controller and the motor.
My motor says it's 18 amps, I thought I would use a 15 amp circuit breaker on the AC supply line. It seems like that's what most treadmills have on them. I wanted to put a fuse or circuit-breaker between the reversing switch and the controller in case the motor ever got reversed without coming to a stop first.

Sent from my SM-N920P using Tapatalk
 

QCaudill

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#78
I'm wiring mine with the original circuit breaker from the treadmill on the AC supply line to the controller... dunno the rating but the treadmill manufacturer presumably knew what they were doing. There was and is is no fuse between the controller and the motor.
My motor says it's 18 amps, I thought I would use a 15 amp circuit breaker on the AC supply line. It seems like that's what most treadmills have on them. I wanted to put a fuse or circuit-breaker between the reversing switch and the controller in case the motor ever got reversed without coming to a stop first.

Sent from my SM-N920P using Tapatalk
 

QCaudill

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#79
I'm wiring mine with the original circuit breaker from the treadmill on the AC supply line to the controller... dunno the rating but the treadmill manufacturer presumably knew what they were doing. There was and is is no fuse between the controller and the motor.
My motor says it's 18 amps, I thought I would use a 15 amp circuit breaker on the AC supply line. It seems like that's what most treadmills have on them. I wanted to put a fuse or circuit-breaker between the reversing switch and the controller in case the motor ever got reversed without coming to a stop first.

Sent from my SM-N920P using Tapatalk
 

FanMan

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#80
My motor says it's 18 amps, I thought I would use a 15 amp circuit breaker on the AC supply line. It seems like that's what most treadmills have on them. I wanted to put a fuse or circuit-breaker between the reversing switch and the controller in case the motor ever got reversed without coming to a stop first.
Good point.

Mine doesn't list the amperage explicitly, but the nameplate says 2.60HP cont. duty @ 110VDC/1940 watts, which is 17.6A... but it also says 2.80HP "treadmill duty" (which is apparently some arbitrary number somewhere between the continuous and peak duty ratings) @ 130VDC. 17.6*2.8/2.6=18.99, so a 20A fast blowing fuse ought to do it. Or maybe a 15 to be safe, and have a 20A on hand in case the 15 doesn't do it.

Though I will have the reversing switch on the box holding the controller on the back of the machine where I can't reach it easily, far away from the other controls.
 

QCaudill

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#81
Good point.

Mine doesn't list the amperage explicitly, but the nameplate says 2.60HP cont. duty @ 110VDC/1940 watts, which is 17.6A... but it also says 2.80HP "treadmill duty" (which is apparently some arbitrary number somewhere between the continuous and peak duty ratings) @ 130VDC. 17.6*2.8/2.6=18.99, so a 20A fast blowing fuse ought to do it. Or maybe a 15 to be safe, and have a 20A on hand in case the 15 doesn't do it.

Though I will have the reversing switch on the box holding the controller on the back of the machine where I can't reach it easily, far away from the other controls.
Sounds right, but I'm still wonering what the proper value would be for a fuse between the reversing switch and the controller.

Sent from my SM-N920P using Tapatalk
 

FanMan

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#82
Sounds right, but I'm still wonering what the proper value would be for a fuse between the reversing switch and the controller.

Sent from my SM-N920P using Tapatalk
That's what I was talking about, could need as much as 20A... but no harm starting smaller, then upping the size if it blows during normal use. The real question is what can the board take?
 

QCaudill

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#83
Yes that is exactly the question what can the board take, not what it can put out. The only time the board would get any current back to it is if the motor was reversed without coming to a stop first. I can't believe that it could withstand anything near 15 or 20 amps. Maybe I'm not thinking right?

Sent from my SM-N920P using Tapatalk
 
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