Use a Treadmill DC Drive Motor and PWM Speed Controller for Powering Tools




Posted in TechnologyTools

Introduction: Use a Treadmill DC Drive Motor and PWM Speed Controller for Powering Tools

About: I like to learn new things.CNC, foundry, Screenprinting, anything electronics related. I like to tear things apart to see how they tick. Unless I can't resist the challenge-rarely do I ever put back together...

Power tools such as Metal cutting mills and lathes, Drill presses, bandsaws, sanders and more may require .5HP to 2HP motors with the ability to fine tune the speed while maintaining torque.

Coincidentally most Treadmills use a 80-260 VDC motor with a suitable HP rating and a PWM motor speed controller to allow the user to change the belt speed and keep a good constant speed and torque while running on it.

There are Commercial DC Motor/PWM controllers available or you can build the PWM circuit from scratch and buy all the components seperately but you will spend a lot of time and money either way. All the parts you need are on the treadmill.

Tear your own apart or get one on Ebay.
(shameless self-promotion below)

Motor/controller combos on Ebay

Safety and Disclaimers- You should have some knowledge of electricity and the dangers of household current and know your abilities/inabilities. Serious injury may occur to you or others from use/misuse of these motor set-up. If you are in doubt DO NOT ATTEMPT. IT CAN KILL YOU. Any Crazy Ideas found here REQUIRE your testing. Your appliction and use of any ideas here are all on you and you agree I cannot be held liable. You equipment should have On/Off safety switches, Fuse protection, ground wires on your machine as required and your power source should have ground fault interupters, circuit breakers,properly grounded sockets and cords and always unplug equipment before tinkering and any other safety practise I am forgetting to mention.

Step 1: Motor Vid

Testing the motor/controller

Step 2: The PWM Circuit Board

For a complicated description of a treadmill PWM (Pulse-Width-Modulation) controller you can visit
You can visit wikipedia for a better definition of PWM.

But basically (as best I can understand) it's an efficient speed controlling circuit that pulses the Voltage and the width of the signal to the motor off and on thousands of times per second. This transfers more power to the load and wastes less power to heat than a resistive type speed controller.

PWM style controller Trim Pots- located near one of the edges of the board.Each Set for specific motor

MIN (Minimum speed-Touch if you dare) adjusting MIN Trimpot may affect MAX, may be necessary to adjust both until desired levels are achieved

MAX (Maximum speed-Touch if you dare) Note that MAX adjustment may affect MIN

IR COMP (Inrush compensation-Don't touch)Improves load regulation by providing minimal speed fluctuation due to changing loads. If the load presented to the motor does not vary substantially,the IR adjustment set at a minimum level. Excessive IR comp will cause control to become
unstable causing motor cogging.

CL (Current Limiting-Don't touch)The CL Trimpot sets the current which limits the maximum current to the motor. Also limits the AC line inrush current to a safe level during startup.

ACCEL (Acceleration Time Period, 0-full speed in seconds)I've never seen one on a treadmill circuit card, only on commercial PWM DC motor controllers. There must be something on the treadmill board that sets the time value..resistor perhaps?

Step 3: The Speed Pot

PWM circuits uses a Pot (Potentiometer)to adjust the speed from 0 RPM to Max RPM . The Potentiometer can be of the rotary type or linear sliding type. The potentiometer is usually rated 5 or 10K Ohms. Typically 0 Ohms is no movement and 10K Ohms is full speed (unless you have your Pot High and Low wires swapped...then it's visa versa). Keep in mind the motor may not even begin moving till 2 or 3 K Ohms (actual value varies) and you can't really start the pot at 2 or 3K Ohm position either because the treadmill motor controller requires 0 Ohms on start-up (Kind of annoying).

The Pot talks to the circuit board through 3 terminals usually marked High,Wiper and Low (or H,W,L).

Some controllers use a digital console to change the motor speed. You dont want to scroll through programmable selections, excercise routines and heart beat monitors just to change the motor speed on your lathe.
Solution: Throw it away and replace it with an appropriate Pot(usually 5 or 10K Ohm Pot). The digital console interfaces the PWM Circuit board the same way that The speed Pot does. through those 3 terminals (on some marked G O H or L W H and colored black, white and red or S1,S2,S3, colored Blue, Grey, Orange.

You should also use a switch for ON and OFF. The Pot is for speed control once the machine is running.

Step 4: Types of Treadmill Motors

I have seen 3 types of motors.

DC Permanent Magnet with PWM controller (Great for torque at all speeds).2 wires to the motor (Usually).

DC motor with Armature-voltage DC Motor Control. (Great for torque at all speeds).4 wires to the motor. 2 run to the shunt-field current , 2 run to the armature. Vary the voltage applied to the armature, vary the speed. Not all 4 wire motors are Armature Voltage controlled. Some have 2 wires that are part of a thermal protective circuit. The ones I have seen are usually both blue.

AC motors. (Probably not any better than the AC motor your'e thinking of replacing).Motors are running at a constant. Incorporates a special sliding pulley.Changing the belt speed is done manually-controlled with a cable that changes the size of the pulley's diameter. Larger motor pulley diameter faster belt speed, smaller pulley slower belt speed (I think).

The DC motors vary in size but most are Permanent Magnet,have brushes, a flywheel,and have either tapped holes or a bracket or flange welded to the case for mouting. They typically can range from 80-120VDC but as high as 260VDC. The HP's 1/2 to 3.5HP (treadmill duty rating), Upper end RPM 2500-6000, 5-20 Amps.

The Max RPM isn't as critical when you can adjust to any RPM within the range and keep a near constant torque.

You can reverse the direction on the DC motors by reversing the polarity. Simply swap the 2 motor wires (usually Black & White or Black & Red)at the terminals on the PWM circuit card. Remember if you reverse the direction of the motor you can't use the flywheel as it is. Because of left hand threads it could come off. Drill tap and set-screw the flywheel to the shaft

Step 5: Drive Pulleys and Belts

Most treadmill motor flywheels serve also as the pulley. They fit a fancy flat belt with 5-10 "v" grooves. The driven pulley that mates with this belt originally drove the large roller that the treadmill belt rode on. Reusing the plastic roller pulley is near impossible. Very few motors actually come with the common Automotive 4L style belt pulley. Solution: Remove flywheel and replace with normal V-belt pulley. *If the flywheel you take off had fins for cooling the motor, replace it with either a blade mounted to the shaft or an externally powered fan*

Taking the flywheel off can be a pain. The flywheel are left-hand 4m thread and can really be cinched down or corroded onto the shaft. Chuck the flywheel end in a vise and turn the shaft on the opposing end Clock-wise and the flywheel may come off.

Some Motors don't have 2 shafts. The shaft on the brush side is usually hidden under the bearing housing. For the stubborn or single shaft motors I use a hacksaw and run the motor on low speed and use it like a metal lathe and saw the pulley through once or twice. It always comes off easily when you turn the nut into 3 thinner nuts rather than one wide nut. Just make sure you don't cut into the motor shaft. Eyeball it close and then test it by turning it with a pair of vise grips until you are through the threaded portion.

Or.... If you don't mind the flywheel...
You can use the motor(at a very low speed) as a metal lathe and carve a suitable groove to fit the belt of your choice. It can be a bit tricky (dangerous) as your cutting tool is not fixed. ** USE eye protection, gloves, faceshield etc.**
A rat tail file will work for a round belt or a small bastard file can carve a v shaped groove for the common automotive style belt.

Remember again- If you reverse the direction of the motor you can't use the flywheel as it is. Because of left hand threads it could come off. Drill tap and set-screw it.

Step 6: More Idiosyncrasies

There are some small but solveable problems using these set-ups. I think a lot of these issues could be fixed with trim pot settings but the exact amount of adjustment and the values for each vary too much, are vague and unpublished or unknown to the average person. If you come up with better solutions PLEASE let me know so I can update them.

problem 1) Treadmill motors have a 3-4 pound fywheel. Engineers calculate the energy stored by spinning this heavy flywheel to obtain Horsepower ratings referred to as "Treadmill Duty Horsepower". Any quick changes in speed aren't noticed because of the kinetic energy still stored in the flywheel. Sometimes you can hear the motor totally turn off till the flywheel spools down and balances the motors RPM with the respective setting on the rheostat. If the load is restored or the speed setting raised above the motor's present speed, the motor turns right back on. Solution: remove the flywheel. Some of that kinetic energy will be stored in the piece of equipment you are powering but if not then some horsepower could be lost.

problem 2) When starting up a treadmill you wouldn't want it to start up at full speed while you are on it. If the rheostat is not set to the lower end of the resistance value the circuit will not start. Now you have the Motor/controller combo on your drill press or mill and it won't start because the rheostat is not set in the start position.
Solution: Turn the rheostat to the start position before turning on.

Step 7: My Treadmill Powered Tools

This is my Drill press converted to a mill. I got it at the junkyard for $10. It had a bad AC motor. The Crossfeed table is from Enco and the new motor is off of a treadmill also from the junkyard. The motor and belts drive it just like the original motor did. It drills and mills fine. The treadmill motor mount was identical to the original AC motor mount. I experimented with the original 2 belts but quickly got rid of the extra belt and step pulley and went with one belt. There was no need for moving belts up and down the step pulley anymore. The motor keeps good torque at all speeds.

[ My Treadmill powered Mill/Drill]

(Future pics of Sewing machine mod will be here)
The machine is the 1940 style heavy duty leather machine and had its own 4 ft bench and a 50 LB friction clutch motor hooked up to a treadle. The machine and bench just would not fit in my garage. am fitting it with one of these set-ups and have tested it enough to know it will work. The foot control is off of a newer sewing machine that used an AC motor speed control circuit also utilizing a Pot. I tore out the rest of the circuit and replaced the Pot with the 10K Ohm Pot my treadmill motor speed control needed. Now I can operate the sewing machine in my living room like a normal portable machine. It has as much torque as the original clutch motor and will sew right up your arm.

Step 8: Motor Mount Styles

This is 4 of the styles I have found. All pictured are DC motors. All except the last one are the permanent magnet type. The lower left motor image has a mount almost identical to the mounts on the AC motors found on drillpresses and such.

Step 9: Foot Speed Control

This is a sewing machine foot control that I modified to run a motor set-up I plan on powering an old industrial sewing machine with. The circuit inside was originally for controlling an AC motor so it is only good for mounting your potentiometer. Remove all the circuitry of the original controller (i.e. resistors, pot SCR's and such)and mount your speed Pot. It takes some adjustment of the placement but it can be done. I can now control the treadmill motor with my foot from a few RPM to full 4000 RPM.

Step 10: Schematics/Pics

This is some Schematics and Pics I have collected. Most Treadmills have one taped to the plastic belly panel. If you have a schematic you would like to contribute email me. The PDF's download very slow but the detail is worth the wait so be patient. Just right click it and open in another window and check out the rest of the instructable while it downloads.

Step 11: Reader Submitted Contraptions

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I got my first treadmill motor a couple of years ago. It is a PM type. I tore the treadmill apart myself,so,I know I have all the pieces, and labeled them, so it is put together correctly.

I needed to make a custom mount, but before I took the motor apart, I made sure it worked, out of the treadmill. It worked perfectly.

I disassembled the motor, made slight mods to the end caps, fab'd the mounts I needed, (made everything out of SS so it wouldn't affect the PM motor), then put it back together.

When I fire it up, it 'chugs' at fairly steady interval through out the RPM range. Then it shuts down with an error code.

I have talked with treadmill techs, and no one can tell me the problem. One guy suggested it was the reed switch, but I can't find a reed switch anywhere, and besides, I didn't NOT use a reed switch after making the mount. It ran fine, for 5-10 minutes before I took it apart.

Any ideas as to what the problem might be?




Ok ChrisL358 as stated in my reply to you I do have pictures now that I can post. I would appreciate any help I can get from anyone on how to wire all this mess up, motor, pot, toggle switch and maybe a digital read out somewhere to show speed.

The first 3 pics are of the actual speed controller board it's a very old board 1976 to be exact. If it were a MC60 0r a MC 2100 board the wiring would be much easier have Youtube vids for that. There are no markings to per say what kinda board it is other than a manufacturer number and the year on one of the pics. As you can see it's a mess.

The last 3 pics are the motor with the specs and the wiring, notice the middle wire connects to nothing as the 3rd pic shows have no idea what it goes to. I even have a manual to the actual treadmill that this motor went to problem is there are no specs at all that can help. Did a google search for specs on the board and motor and found nothing that could help, you can call Lifefitness and still no help for they change part numbers way to often so they really have no specs on the motor.

I am no electrician but do know basic stuff if anyone can help please let me know in "layman's" terms or LOL I'll get lost. Thanks

My speed control ebay 1.jpgMy speed control ebay 2.jpgMy speed control ebay 3.jpgMy speed control ebay 4.jpgMy treadmill specs.jpgtreadmill motor wiring 1.jpgtreadmill motor wiring 2.jpg
8 replies

Hi SpinnerOfWood, I just picked up a free Life Fitness treadmill that uses that same board, but the motor is slightly different than yours. I'm going to use the motor to power a bead roller. If you want, I will let you know how I adapt that board once I figure it out!

Yes please anything that would help. Even a simple schematic would help greatly as you can see on that board I have so many wires going to nothing I just have no idea what goes to where. Just a fyi I am going to use this is a replacement motor for my woodturning lathe , it already has a speed control on it and a good motor but the motor was a 3 phase and I had to have a electrician figure out how to convert the speed controller to where it brought down the motor to 1 phase(math was way beyond me), prob was that converting down to 1 phase I lost too much torque so I couldn't/can't turn anything very big, hence switching to a DC motor I figure I will get the torgue I least I hope.

I will do my best, but I'm no tech guy, just someone trying to make use of a good DC motor! Is that motor out of the same treadmill as the control board? Mine is similar but a little different looking. Do you know what that small white connector by the motor plugs into? I'll take some pics of mine before I tear it apart. Maybe that will help.

OK first thanks for the pics they may help a bit even tho your motor is made by a different company, secondly to answer you question the motor and the board were bought separately yet they are made by the same company "Life Fitness" I have a feeling that the motor is newer than the board= 1996. No idea what the white wire hooks to. I have watched some youtube videos on the subject but they tend to be confusing since all I had seen were #1. different motors #2. different boards, #3. Most spoke techy stuff that was way over my head, lastly nearly all I had seen were way newer boards than what I have. I will say my search won't stop I had seen a guys website that seemed to be very helpful hopefully I will find it again and even leave a link here. Good luck with your endeavors.

Well, I messed with this thing for a while now and could not get it to run with just a pot. The only way I can run this thing is through the control panel that came with the treadmill. I started watching craigslist for another treadmill and ended up buying one for $30 that had a board I could use to run my motor. It was a cheapy Weslo treadmill, but it has a good control for modding to use for projects. It's an MC-1000 board, witch is similar to an MC-60. So I now have it wired up and running fine. Plus, I have an extra motor now!

My advice to you would be to watch craigslist like a hawk, and try to grab a treadmill from the free section. They do come up from time to time. If you have time to check it out online to see what type of controller it uses, you could end up getting the one you need for free!

Two wires are + and - DC drive to the motor and should labeled as such on the board. Two wires to the motor are over temp sensor. Should be three wires or terminals labeled "H", "L", "W". These wires hook to a potentiometer to control speed. H wire goes to one side of the variable resistor, L goes to the other of the pot, W wire goes to the center or wiper terminal. 10K variable resistor should work good. A higher value may make more sensitive and lower may less sensitive to speed changes. Two wires attach to AC power to the hi-lo terminals or labeled AC.

Thank you for your answer.Sorry so long to answer I'm just not on here very much when I comes time to rig all these up I will try what you say. By chance any way you could provide a simple schematic when you have time please if you could.

OK, here are some pics before disassembly. Hope this helps!


I was wondering if you could advise me how to bypass my console on my nordic track x7i incline trainer. All i need is the treadmill; no need for incline. I feel as though what little i know of all things electrical.... i would not want attempt with out some guidance. Thank you


I have a treadmill (ProfForm 385Ex) with MC-60 motor controller which runs uncontrollably. As soon as the power/safety switch is turned on the motor starts rotating and the belt starts fast (not crawls). The sliding potentiometer does not seem to impact slow speed but I can increase the speed with the potentiometer but cannot decrease it beyond a limit.

I unplugged all the 3 wires (high, wiper, slow) of the potentiometer and switched ON the power - the motor still runs at a certain constant speed (medium) without the poteniometer.

What could be wrong ? that the motor does not slow down or controllable by the pontetiometer for slow speeds? Thanks much for help.

a DC motor can also be a generator. a spinning DC motor generates a current and voltage. The difference between applied power to the motor and generated power from the motor determines the motor drive. The controller measures the motor feedback to determine the speed of the motor. A variable resistor or circuit controls desired drive to the motor. The controller balances the applied drive and feedback signal to control drive to the motor attaining a more or less somewhat constant speed. The controller adds drive signal to maintain speed by applying more drive as needed up to the maximum drive available from the controller in maintaining constant speed. The feedback from the motor is somewhat out of phase from the controller drive which is how the controller determines the proper amount of applied drive signal.

First off thank you so very much for this article. I'm new here and realize this is a old article but hope I can get some answers.

I am looking to make my own large bowl woodturning lathe( here: and have searched tirelessly for information on building one on a budget. I have just a few questions and have some examples of a speed controller and motor I looking at on eBay.

1. Are treadmill motors capable of high torgue? Reason why I ask is I need a dc motor that can handle being able to turn large blanks for bowls.

2. Do you think this setup would work and this is just a example of the motor I plan on trying to buy or scrap one from a used treadmill.

3. I realize that using all the electronics from a treadmill to control the speed etc. would be cheaper but while this is a excellent article I am no genius at electronics. So this is the speed controller I am looking to buy

I have a speed controller on my old lathe that I modified also with a new motor but the thing was so complicated to figure out going from a 3 phase motor to 1 phase I had to hire a electrician to figure it out( trigonometry involved LOL hurt my brain)

Anyhow if anyone can help me here with answers I would greatly appreciate it.

2 replies

1) Treadmills have excellent torque. Most electric motors develop close to full torque all the way from 0 RPM up.

2) You can often buy motor/controller "pairs" off ebay for treadmills, that supposedly just need to be connected together and work. I'm not fond of canabalizing PCBs like that, especially if you're going to put it into a dusty woodworking shop and use it for hours at a time. Most treadmill controllers have a startup delay, which could be a bit of a hazard/annoyance in a shop. I'm searching for a purpose-built separate DC drive now. The MC-60 and KBIC-120 look promising.

3) That speed controller is a VFD, VFDs are for AC (usually 3 phase) motors. It won't work with DC motors (most treadmill motors).

Thank you Chris for you reply. I have learned all since I made the post such as the difference between VFD drives and DC drives. I was lucky to meet a guy on eBay that is a electrical engineer for a huge company out of New Jersey. He is helping me allot but has limited time so slow going for now.

I did buy the above treadmill motor and a separate treadmill speed control board. Problem I am facing at this time is figuring out how to wire the motor,pot, and toggle switch to the board I have. Reason why I went ahead and bought the motor and control board separately is I got a heckva deal on both from eBay, paid $60 for the motor and $12 for the speed control board. I seen the guy selling the combo rigs on eBay but #1 he had none rigged with a 3hp motor #2 prices anywhere from $125 to $145 so I think I got a better deal just have to figure out the wiring.

Right now typing this I am on my laptop so I have no pics of the speed control or motor on here. I do however have pics on my desktop and will post them so maybe I can get some help with the wiring. Give me some time and I will make a separate post. The board is ancient 1976 exact and has wires everywhere guy left them all on it not to mention it has the biggest capacitor I have ever seen on any of these treadmill boards. Anyhow give me a few and I'll post some pics.


I have a 4 wire AC powered treadmill motor and when i press start, the motor runs for 1-2seconds and then stop, after fully stoped in static position it can run again for 1-2sec... where can be the problem? In the motor? 4wire - 2blue , 1black and 1red. 2 blue wire are for AC power supply 220V . For what are black and red? Is PWM wait information from them?

Please help me!

Thank you?

1 reply

The problem you are experiencing it related to an additional sensor that is built into the circuitry of the treadmill's control panel. (I see this same behavior on the treadmill motor and panel that I just recently tore apart.)

Newer treadmills have a speed sensor (typically photo or magnetic) and either a magnet or disk with black/mirror stripes attached to the front roller. When the controller spins up the motor, it checks the speed sensor to see if the roller spins up as expected. If the controller detects no speed, it shuts the motor down. On many treadmills, the control panel also displays an error code. If so, you can google the code and confirm that this is the problem you are experiencing.

If this is what you are experiencing, the easiest fix is to move the spinning magnet or disk from the roller to the motor's shaft and set up the sensor to detect that rotation.

So are these DC motors actually servos or not?
I am assuming there must be some kind of signal coming out of the motor to the control board if the motors turn on and off to maintain a set seed. At least with the 4-wire units, and the two wire I guess would have an internal circuit to adjust to speed.
Anybody know for sure?
I am trying to find an fordable servo to power a bench-top lathe and I require spindle feedback to the control software for treading.

Thanks for any guidance!!

2 replies

Stepper motors will do that good and they don't cost very much

you could use one for the main drive & one for the secondary drive

the software will keep they instep with each other

you have to use more than the control board and motor then. There is a magnet that sits on the end of the front roller. On mine it feeds back to the control board and shows the actual machine speed to adjust the voltage to maintain the correct rpm. I have never went that far to use one, so I cannot offer that advice. If you can read and understand the wiring schematic for your treadmill, you may be able to get it to work for you.