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

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: 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 2: Motor Vid

Testing the motor/controller

Step 3: The PWM Circuit Board

For a complicated description of a treadmill PWM (Pulse-Width-Modulation) controller you can visit
http://www.freepatentsonline.com/6731082.html
or
You can visit wikipedia for a better definition of PWM.

http://en.wikipedia.org/w/index.php?title=Pulse-width_modulation&oldid=71190555/

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- I’ve only ever adjusted on my sewing machine so far.. I needed to be able to stop in 1-2 stitches and the original treadmill settings were too high. Note: adjusting MIN Trimpot may affect MAX, may be necessary to adjust both until desired levels are achieved

MAX Maximum speed-Touch, I found that on my sewing machine I needed less than say my drill press: Note that MAX adjustment may affect MIN

IR COMP (Inrush compensation-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. Ive never adjusted this yet to even be able to tell you how or when you’d want to adjust it.

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 4: 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 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.

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 or turn the min adjustment down some

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 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 for what I do.

I’ve included a step below of my latest treadmill powered sewing machine in the last pages.

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.
UPDATE: I found it easier to piggyback the potentiometer that my treadmill motor requires next to the SCR based AC motor controller POT, rather than rip the old one out. See my sewing machine conversion towards the end.

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: Industrial Sewing Machine Powered by Treadmill Motor

I had a Janome DB-J706 that I found at the junkyard without a clutch motor or table for $15 and the lifestyler 8.0 with a 1.5hp motor was free off marketplace. I couldn’t tell if the machine worked without a motor and I didn’t want to spend a lot finding out. It was a huge success and after timing the shuttle and replacing the tensioner for one I salvaged off an old serger, it stitches beautifully and I am sewing through 2 layers of TM (treadmill) rubberized canvas belt material like butter. I also am using spider-wire “spectra” fishing line for thread.
Originally the sewing machine was made to run in a special bench that had a special clutch motor. The clutch motor runs all the time and a foot pedal attached to a linkage engages a friction clutch. The whole setup takes up a large space, is heavy, and clutch motors are expensive and touchy and didn’t come with mine anyways. I built my new sewing Machine base with pieces from the TM tubing frame.
The square tubing on TM’s are fairly heavy gauge, mild steel, and weld easily after you sand or grind off any plastic powder coat or paint. I cut off the existing Motor mount and welded it to my new sewing machine frame-base and used a piece of all-thread that can be adjusted with nuts to force the motor away from the frame, tensioning the original belt and motor pulley. Notice the welded pulley to shaft...had to reverse polarity which naturally wanted to unthread the left-hand thread pulley... easy enough problem to fix. As you can see I also power hack-sawed off the flywheel. Can’t have all that inertia causing the machine to keep sewing. This hack also requires lowering the minimum speed adjustment on the TM controller and the maximum adjustment. Treadmills don’t have to stop on a dime like sewing machines. With these adjustments, the machine was responsive enough to sew one stitch at a time, or full speed ahead and still managed stop in a stitch or two. As you can see I also used the original TM belt pulley by 3D printing an adapter that mated it to the sewing machine drive shaft.
The controller and power supply board fit nicely into a plastic container. The harness that went to the original TM controller only had 8 or 10 wires but only 2 wires were needed. When shorted they closed the relay that supplied AC power-in . The original TM digital board that controlled the speed was scrapped and controlled right from the main controller board instead with 3 wires and a 10K him sliding potentiometer. The speed control foot I found at the second-hand store was for a thyristor-based AC sewing machine . While the circuit was useless and the sliding potentiometer was not useable, I was able to piggy-back and epoxy a 10k Ohm sliding Pot right next to the original in wire it to my controller board for speed control. The digital displays really throw people off when they are trying to incorporate TM controllers into their project. But if you look at the main controller there is usually 3 lugs that will hook up to a POT and in this case a 10K ohm worked great.
One thing this foot pedal had was a micro switch built into the circuit that could prob be used to incorporate Dynamic breaking by inserting a resistor across the DC motor when you let your foot off...this could help with stopping on a single stitch without having to lower the controller Min setting and may be my next endeavor but for now the torque, even though greatly reduced, is far more torque than the sewing machine needs.

Step 12: Tablesaw Running on Treadmill Motor

I finally got tired of trying to rip 2X4’s with my tablesaw’s 1hp AC motor . I found a treadmill on FB marketplace for $10. It had a 2.7HP motor and it mounted easily to my saws existing brackets. I found this 3 ribbed serpentine belt that fit my V grooved tablesaw pulley and the stock pulley on the treadmill motor. Like most newer treadmills this one had digital controls so I had to install my own 10K ohm pot that I mounted to the front. The power board and controller are mounted inside Tupperware to keep it safe from dust. Works like a champ and my tablesaw rips studs like butter

Step 13: Reader Submitted Contraptions

Ball Pitching Machinehttp://www.youtube.com/watch?v=oEUYII-SYGg

Comments

[acheide]

To remove a threaded flywheel, reverse the power wires, hold on to the flywheel, turn it on. You will be left holding the flywheel. Mine came off very easily.
I found this tip at https://www.youtube.com/watch?v=qZ6uyskDIZc
Thanks for your information.
Abraham.

[fred slifer]

Have a new 3 hp treadmill motor using 120v ac through a $20 scr motor controller with a rectifier for dc to the motor. Have tried two of these controllers and various potetiometers from 5k ohm to 250k ohm and I cannot change the speed of the motor. 120v ac in always produces 120v ac out to the rectifier.
What is wrong?
Thank you,
Fred

[DavidF15]

Another option for the pulleys is to use a plain flat pulley. If you are going from the ~1" pulley on the motor to a much larger diameter to increase torque and reduce speed, the belt will tend to slip on the smaller diameter pulley before it slips on the bigger pulley.

I found that my M-215392 2.8HP 130V/2089W peak/ 1.75HP continuous 100V/1305W treadmill motor's pulley is a Micro-V 10-groove 28mm (1.1") pulley with a 8PJ483 belt (an 8 band, J-form Micro-V belt that is 483mm in circumference) hooking up to the 88mm (3.5") 10-groove plastic pulley on the treadmill drive bar. The 88mm:28mm ratio triples the torque and scales the speed range down from the 2500-6000 top speed to a more useful 800-1900 RPM.

I can buy a 6-strand, 60" circumference 600J6 (US numbering scheme) belt for ~$11, and gear down to a simple, plain 12" flat pulley (plywood, crowned a little bit) and get 10x the torque at 10x slower/safer top speeds.

I tried fiddling with my treadmill's PWM mc-2100 controller board, (reverse engineered circuit and documentation out on the web) but I really like my HQ-SXPWM-A PWM controller box. With a couple hidden buttons, you can limit the top voltage, adjust max current, ramp up and ramp down, and use the I-R feature. It also displays the voltage and current dynamically under operation. I adjusted mine up from the factory default of 8A to 10A max current for testing, so I could ramp up quickly without hitting the overload fault. Unloaded at 100V, my motor only takes 0.3A.

[jjmcquoid]

Trying to figure out which wires are to be use for the pot can you help? Also concerned about whether or not this will work without the lift motor and speed sensor hooked up

[mullermc]

i want to make a portable water well drilling rig, which motor should i consider suitable for the job?

[erronius]

I've only seen one little one-person portable drill rig, and it was hydraulically powered instead of electrical -brand name "Big Beaver". Our drillers that we use for engineering and environmental work only used it for tight locations; and the maximum depth of penetration depended heavily on the soil type and compaction. The manufacturer said it could go up to 100 feet, but we rarely got beyond 15 or 20 feet in our rocky desert soil.

[Intructee]

HELP
"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."
I did this, and it worked perfectly at first. A couple hours later, i plugged it back in, and it blew the power socket. What went wrong?? Per the safety warning, I'll probably call an electrician now...

[JoeG124]

Check the motor badge as not all DC motors are bidirectional. It may say "CW" for clock wise or "CCW" ...for counter clock wise.

[Kevinslot]

Is there a good economical switch to use to get forward and reverse directions from a 2.25hp 130VDC treadmill motor? I want to add a switch to my control box instead of having to switch wires every time. I plan to use a SCR motor controller with a bridge rectifier. Thankyou in advance.

[rccipriani]

I was running a treadmill motor on my drill press with an MC-60 speed control that died. Any suggestions for a low-cost replacement? Reviews for some of the cheap ones give me pause. I could build one if I had a good schematic.

[GeoNOregon]

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?

Thanks,

GeoD

[DonS174]

I think there might have been a choke coil inline with the motor and you left it out. Looks like a transformer but only two wires.It might even have been a capacitor board. Some motors may not run well if wired backwards due to the brushes.Hope this helps.

[squared59]

I had an older treadmill that matched the wiring diagram VITAMASTER8711BP.pdf and it works great. Mine had 2 circuit boards. One was the motor controller and the other was for the display and linear actuator that changed the incline. I unplugged all of the cables that went to the display, any 120v power to the 2nd board and all of the speed pickups. Totally unneccesary.

[Alanm206]

Hi i have a treadmill motor and controller that i want to use as a wood lathe variable speed motor. The pwm has a connector as attached, can i connect a pot to this to control the speed?

[HilbornJ]

I have a DC 130 volt, 2 HP, 17 Amp treadmill motor that I want to use on my wood lathe. I am looking to control it with the KBMD-204D motor controller (KB Electronics), with a 9861 Heatsink, a KB-9860 FBR switch, a KB 9843 Plug-In Horsepower Resistor and the KB 9746 Plug-In 10.0 amp fuse. These were all recommended by a KB Electronics distributor.

I spoke with a tech support specialist from KB Electronics and he advised me that the KBMD-204D will not work because the motor is 2 HP, 130 volts DC and 17 Amps.

Yet on YouTube there are several videos that recommend using the configuration I want to use.

I am confused, please help.

I am no longer confused.

I purchased all the component and integrated them into my wood lathe. Everything works perfectly, I couldn't be happier. The lathe runs real sweet from 0 - 3200 RPM.

I had the flywheel shaft turned down to 1" and had a 5/16 set screw hole drilled to accommodate a standard sheave pulley and set set screw. The set screw is to prevent the fly wheel from spinning off when in reverse. I also had a 7/8" bore sheave pulley bored out to .95" to fit on the lathe head stock shaft.

In hind sight I think I could have used the treadmill's MC-60 motor controller and just purchased the FBR switch. I would have saved about $130.00.

[SpinnerOfWood]

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

[Sporty45]

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!

[SpinnerOfWood]

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 need...at least I hope.

[Sporty45]

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.

[SpinnerOfWood]

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.