SCR Motor Speed Controller: amzn.to/3ovlFAV Bridge Rectifier: amzn.to/3wipA6R I found these links very informative, as they show the HP rating of many treadmill motors: www.treadmilltalk.com/ www.treadmilltalk.com/treadmill-comparison-chart-1.html under $500 www.treadmilltalk.com/treadmill-comparison-chart-2.html $500 - $1k www.treadmilltalk.com/treadmill-comparison-chart-3.html $1k - $2k www.treadmilltalk.com/treadmill-comparison-chart-4.html $2k - $3k www.treadmilltalk.com/treadmill-comparison-chart-5.html $3k - $4k + www.treadmilltalk.com/treadmill-reviews.html#Reviews
Todd, thank you much for sharing this. I just salvaged a 2.3 HP 130V treadmill motor and plan on incorporating it into my drill press. I have some background in electronics so I already understand what the components you mention are but still need some expert guidance in doing what you have done here. Thanks again.
Thanks for this, this looks like the most approachable means of controlling a treadmill motor yet. I look forward to follow on videos. Thank you for sharing!
Hi Alexios! Where are you located? If you do this, just be sure to use good quality, hi-wattage components, heat sinks, and adequate ventilation. Be sure to let us know what you do, and give us feed-back and comments! Best of luck!
Interesting. Looks like Mike's video predates mine by about 3 months. I'm sure if you keep researching you will find even more videos with similar content and information. I like mine better though. ;-)
Short answer: Nope. / Long answer: I read a lot of bad things regarding converting a wood-cutting band saw to a metal cutting one, so I ended up buying a Horizontal/Vertical Metal-cutting band saw from harbor freight. I still plan on using this motor in a project, but it will probably be a 2"x72" Belt Grinder now. I just finished my Forge, and want to focus on getting some Christmas gifts hammered out - and after the Holidays I hope to focus on the Belt Grinder.
An additional update. While researching DIY belt grinders, I learned that many treadmill motors are not of the TEFC (Totally Enclosed Fan Cooled) variety. Including the motor seen in this video. The grinder dust would just get sucked into this motor, and quickly ruin it. I'll probably end up using this treadmill motor on my drill-press now. :-P (You can see the motor I will be using on my 2"x72" Belt Grinder in part one of that video series.)
i did the same thing and used the motir on my 20 inch band saw. i bought a 1000w scr and some 200k potentiometers and it worked well untill i installed the motor in the band saw. now that its movin some weight it must be drawing some more amps than the 1000w scr likes. if i just turn it on with the switch and dont turn the speed down first it blows the 20a glass fuse in the scr. or if i leave it run about half speed for a while the fuse blows. do you think a 10000w scr would fix this? im not sure if they all have the same size fuse. im not experienced with electronics I just made this off of another video I seen
The one I purchased via Ebay was rated for 220v (still works with 110v) / 10,000 watts. Looks like the price went up a couple dollars since I purchased mine: www.ebay.com/itm/321432206220
If you take the flywheel off you also remove the cooling fan on most of these motors .So you need to provide another means of cooling if you load them to full power with no cooling they will not last long
Hi Mike! You say that you made your own IGBT controller, but you are asking ME if it will control an AC motor? Unfortunately, this is a question best asked of the person who designed the circuit for your Insulated Gate Bipolar Transistor based controller - not me. If I have misunderstood, and you are asking if the SCR controller in this video will control an AC motor, then the answer is YES. Just leave out the Bridge Rectifier. Good luck!
Great video. I was wondering how many watts your potentiometer is rated for and if 200k ohm a reasonable choice. Also if you used an inductor coil to increase motor life. Thanks. Would like to see your bandsaw set up!
Hi there! Since this video was recorded I've swapped out the potentiometer a few times, looking for the one that gives me the greatest amount of speed adjustment range. The potentiometers I have been using have all been 2 watts, because that is what my local shop has. Not sure if I should look for a higher wattage - what do you think? Anyways - In this video, I had replaced the 470K ohm with a 200K ohm. The 200K ohm was still too big, so I replaced it with a 100K ohm as another subscriber had suggested. 100K seemed too small (the motor ran too fast at the lowest setting), so it now has a 150K ohm pot hooked up. The motor still runs with the pot at the lowest setting, so I am eventually going to try a 175K ohm pot to see if it is any better. I am also considering using a multi-turn potentiometer once I have determined what size is the best.
Sorry for the delay in replying. Had a house full of people during xmas and lost my frig on friday and my heat xmas eve. Now that things are quieter I can work on the fun stuff. I could not find any specs on the scrs listed on ebay as far as pot wattage requirements. I usually use the largest wattage pot that will fit just to avoid smelling smoke. Are there any markings on the original scr pot indicating wattage? At this point I'll try a 150k and 175k and both are available in 5 watts. The 2 motors I was given came from a unit that had a 5mH inductor coil, but I don't have the original. I found some used ones on ebay for $10 I think I'll try. The coil should provide a more stable current for the motor. Am also looking for specs on the motors I have, there is little nameplate info. Was wondering if you might know a site for specs.The name on the motor is Magnetek ,model 4630D-15, 15 AMPS, 90 VOLTS, 4800 RPM but is no hp rating. It came off of a extinct Sears brand called Vitalife Roadway. I am looking for something that is over 1 hp.
Hello again! The 2 watt pots have been OK for me so far, but I do not run the motor long enough to heat things up much. I'm usually just making small cuts. I would imagine that if a 5 watt pot was too big to fit in the SCR case you would just have to extend the wires and mount it somewhere else - external to the SCR case. Have you tried looking at the Sears website for treadmill parts or the User Manual? You might find the specs for the motor that way.
@@vicjs216 approximately 1.8hp based on ohms law. P=IxE Power (watts/horsepower) is equal to amperage (I) x voltage (E) 15 amps, 90 volts, 746 watts per horsepower 15x90=1350 watts 1350 watts/ 746= 1.809 hp Simple formula for those who may run across this in the future and need to calculate motor size
I had a fairly cheap SCR from eBay, AC input, AC output with a potentiometer like yours. I am not a electrician and got in a hurry and forgot to use the rectifier bridge before going to a DC PWM motor controller. Blew the breaker where it was plugged in at. Potentiometer no longer works on the SCR, I don't if the current made it to the DC motor controller and if it did I'm not sure how to meter it out. I guess in my ignorance and not being familiar with electronics I screwed up big time. Lesson learned. I have a variable AC transformer (Cheap) from eBay that I used to test the motor from a electric wheelchair 24v. I was able to dial in the 24v to the motor and it worked great. Thank you for the video and sharing what and how you used The SCR
@@ToddMcMahon Well Todd I have learned a lot for an old retired disabled welder. I looked at my Potentiometer and it's a 250 ohm, I have several 100 ohm pots so I'm going to use one and hope it works better if I didn't burn it all out. I'm going to hook it all back up with the bridge in place and see if it works, my wall plug blew so it might have tripped before any damage was done, don't know but what have I got to lose other than giving it another go. I just had a friend give me a 2.5 hp treadmill motor and control panel. Before I have to learn from another TH-cam how to separate the the controller out of the panel I will continue to use the SCR like you are doing. I want to put it on my drill press. The old AC motor is weak, can't even drill with a 1/4" hole before stalling. Keep up the good work and again, thanks for sharing.
Whenever there is an unused pin on a potentiometer it typically just hangs open. You can cover it with heat-shrink tubeing if you like, As long as it doesn't short out against anything, it will be fine.
when I wire my scr the way you do. I changed the pot to 150k and set the rpm of motor to what I want and after about 5 times turning motor on and off with switch the motor goes to full rpm and can not control speed by the pot. can you tell me what is going wrong. motor is a permanent magnet 90v dc 1.0 hp 2500 rpm motor
Hi Gary. Are you using the same type of SCR motor speed controller like I have, or are you using something different? What wattage SCR are you using? Mine is 10k Watt / 220 Volt. It sounds to me like your SCR is getting too hot - and way too quickly. Perhaps it is just a poor quality SCR? Try to ensure that your SCR is staying cool (mount it to a big thick chunk of metal as a heat sink). Maybe put a fan on it. With these symptoms, I doubt that your SCR will last very long. You will probably burn out a component soon making the SCR unusable. Keep me informed, and good luck.
Todd, is there a way to make this programmable (instead of manually turning the potentiometer, is it possible to use Arduino or Raspberry Pi to program it). Thanks for the video.
Hi Yogi! Let me make sure I understand you correctly... You are asking how to use an external digital device (Arduino, etc.) to produce a variable resistance, thereby providing an analog voltage range to feed into the Analog to Digital Converter on another digital device (the SCR) which is then generating a pseudo-analog control output, which needs to pass thru a full-wave rectifier so it can drive a DC motor?? Sorry - it just seems to me that we're going out of our way to make this motor controller as complicated and expensive as possible, when it was meant to be a cheap and simple solution. To answer your question - I suppose that you might be able to find a Digital Potentiometer chip that could survive the voltage and power requirements of the circuit under load (check DigiKey.com), but I have no idea how to design and integrate the necessary circuitry to control that Digital Potentiometer via an Arduino. In my opinion, there would be so much time, effort, and cost involved that I would probably look for some off-the-shelf motor controller that provides the feature-functionality that I was looking for. Did you try checking the Arduino and/or Raspberry Pi forums? I'm sure someone somewhere has already figured all of this out already! ;-)
@@ToddMcMahon You are right! Solution is to use an SCR (AC 220V 10kW) controller in combination with full-wave bridge rectifier (50A 1000V) and a digital 200k pot (AD5262BRU200 IC POT DUAL 200K 256POS 16TSSOP; on eBay costs ~ $5) which can be controlled with Arduino (www.arduino.cc/en/Tutorial/DigitalPotentiometer). However, there are couple of unknowns: (a) I need to isolate Arduino from high currents/voltages (it fries if >5V and >600mA, may be an isolator like LTM2892 would work) (b) need to figure out power dissipation in this setup (power loss [thus heat produced] may be too high). Overall cost is probably going to be about $30, but I couldn't find any other alternatives that come close. MC-60 or MC-61 motor control board is ~$100 and any PWM programmable controllers go well above $50. Not much info was found online based on my search so far.
Todd, Basically, I am looking for a cheap way to program treadmill motor. Anything to do with the output of rectifier is looking expensive, so I have to everything before the rectifier. Unless I get some other "cheap" ideas, I have to feed rectifier output to the motor as-is.
Great video, thank you! What would you say the LOWEST functioning RPMs would be you could sustain with a good control setup like you show? (slow speed application) I only need about 1/3 to 1/2 hp, but hopefully under 100 rpm, or maybe closer to 50, before I step down with sprockets and chain. Is that even possible? (in a treadmill, aren't the lowest speed settings in this low rpm range?) Also, when you say SCR, is what you use there the same as a PWM? I guess I have to go figure out how to determine proper ohms needed and also about the ferrite core in line, AND about replacing the potentiometer. I guess I have more studying to do! lol I appreciate any info you might care to add here! Thank you so much!
I'm no expert, but if I understand things correctly, both SCR (with a rectifier) and PWM motor speed controllers (which are quite different) are capable of low speeds and good torque with DC motors. The SCR solutions have fewer components, and are therefore typically smaller, and cheaper than PWM. If good quality components are used in the SCR controller, it will also be a bit more robust for the same reasons (apparently there are some pretty crappy SCRs out there - so be sure to check the reviews). In answer to your question - the PWM is supposedly capable of lower sustained speeds - but again, more components, more expensive, and according to what I have read, it could be less durable than SCR. I have not used a PWM yet, but I might some day - just to compare.
@@ToddMcMahon thank you for the information! Thanks again for your video too! I'm just learning about all this and want to understand what I'm doing as or before I do it :) A month ago, I was planning to use the whole treadmill display and everything, but the more I learn, the simpler it gets. I'm still not sure what the low end RPMs would be, but might just pick one up and test it or contact a mfr for their specs. thanks again!
I have table top pottery wheel that I am trying to fix for a friend, which has a control board with two thyristors on it, (which makes it a triac) and the resistor going to one of the thuristors gates was burned out, so I replaced it, tested it, and it worked. - the first time anyway. but when I went to test it again, the thyristor exploded with a loud bang. FUN!
So now I am looking for a new motor controller... the motor appears to be a DC motor. The motor doesnt have any specs about it stamped on it, so I had to do some testing to figure out what it was... Connecting it to my volt meter and spinning it by hand gives me a positive dc voltage one way and negative in reverse. The motor drives a pulley via a belt, and the ratio is about 10 to 1. Spinning the flywheel at 180rpms gave me an output voltage from the motor of about 70-75v. which equates to about 2200rpms at 90volts. the owners manual says it is a 1/3hp motor, and the online store says the pottery wheel can go up to 220rpms, which, multiplied by ten is conveniently 2200 rpms from the motor. Perfect... So now I need a motor controller that can convert AC voltage into DC, 0-90v... am I right? - what does changing the potentiometer from the 450k to 250k, or 200k do for it? how is 450k too big? what effect does it have...
Yikes! Simply replacing the resistor would be like replacing a FUSE unless you find out what caused the resistor to fail. Sometimes putting a larger wattage resistor is enough to resolve the problem, but then again sometimes a larger wattage resistor just allows some other component to fail next time.
i have the same set up as you do. i am running a treadmill motor that uses 130vdc. how do i wire it for 110v? right now i have the positive running on the 2 out side terminals, and the ground wired direct out side of the SCR.
If you will notice, MY motor is also rated for 130vdc. This setup that I used and as described works fine with 110/120 AC input. The Full-Wave Bridge Rectifier converts the AC output of the SCR into DC. The only issue is that the motor will not get up to its highest speed at this supplied voltage, but I haven't seen any problems so far.
Hi Ronald, I think that it will depend on the age, make and model. Very Old Treadmills (20 years+) probably have A/C motors. If it is a newer treadmill with a digital control user interface, it probably has a DC motor. There are some very heavy duty (non-folding) treadmills made for commercial use that have 220v A/C motors - so be careful. Look for a residential-use treadmill (one with a running board that folds up for storage) with a digital user interface. What HP are you looking for? I found these links very informative as well, as they show the HP rating of many motors: www.treadmilltalk.com/ www.treadmilltalk.com/treadmill-comparison-chart-1.html under $500 www.treadmilltalk.com/treadmill-comparison-chart-2.html $500 - $1k www.treadmilltalk.com/treadmill-comparison-chart-3.html $1k - $2k www.treadmilltalk.com/treadmill-comparison-chart-4.html $2k - $3k www.treadmilltalk.com/treadmill-comparison-chart-5.html $3k - $4k + www.treadmilltalk.com/treadmill-reviews.html#Reviews
A typical potentiometer has 2 or 3 connectors. One on one or both ends of the internal "resistor" winding, and one for the "center tap". You will want one of the ends and the tap. This is pretty basic stuff though, you may want to ask a friend who knows more about electronics for some help. You don't want to make a mistake that could burn something up.
I have this setup on my lathe but my AC wire and SCR and getting very hot, also I don't know how much damage is being done to the SCR circut with inductive load that pumps back voltage as motor free spins and slows down
Is your SCR the 10k watt / 220-volt version, or smaller? How are the reviews on your SCR? Is it a good quality one, or did you just buy the cheapest? Are you using fans and heat-sinks? Can you increase the wire diameter / gauge? You could install a switch to cut off the motor from the rest of the circuit when it spins down. Just give it some thought, work it out! ;-)
Hello Todd, nice video, Thanks. You know, I was trying with a similar controller but It fails immediately as soon as I connect it so that the motor runs at full speed, I mean the controller doesn't controll the speed. It is the second controll that I spoil. My motor is a variable speed motor , 90 V DC, 11 amp. Could you help me?
You say that your controller is "similar", but this is apparently not the case. Don't pick the "cheapest". Buy the BEST you can afford. This specific solution only works with an SCR type speed controller, which has to be of sufficient wattage to survive the power surge at start-up. This is why I use a 10K-watt, 220-Volt SCR even though our power here is 115-volt. You also need to have a strong enough bridge rectifier. Mine is a 1000-Volt Diode Bridge Rectifier, 50 Amp, with a metal case. Good luck!
@@ToddMcMahon Hi Todd, thank you very much for your promp response. Acordind to your sugestios, now I know I had some misstakes about the parts I used, like the Triac. I will make the necessary corrections to fix the controller, You are very polite guy, I have learned something interesting thanks to you. Best wishes for you)
I haven't had a problem with it so far. Seems to be working well enough. Hasn't bogged down or stalled. This being said, I haven't cut any thing big or super hard (yet). Time will tell though!
Hmmm... Good question. I haven't actually checked. I have it in my band saw, and I also do not run it for extended periods of time. It has a fan in the SCR controller unit itself (you can hear it when I touched the cover), and I have an additional fan in the box that it is mounted in. My guess is that it gets enough air flow to stay within the normal operating temperature range. Time will tell! I plan on using the same configuration for a belt grinder later on. Now THAT device will run for extended periods of time, so I will have to ensure that it does remain cool.
I also have a fan in the SCR controller. It does fine but the bridge rectifier gets extremely hot. I got two when I ordered them and they're both bad now. I'm going to order more and hook them up against the metal of the belt sander so it dissipates the heat a little. I run the belt sander in my garage in the summer and its already 85-90 degrees out there.
I think that is a good idea. A belt sander/belt grinder probably pulls a lot of current, and it's typically running for longer periods of time when being used as well. Be sure to use some Heat-Sink Compound on the mounting surface. Did you get the 10k watt / 220 volt version SCR (it will still work with 110v) ?
You can probably eliminate the hum and some other undesirable effects by filtering the output of that bridge with some big caps to create a more “DC” signal.
True, but I don't know how to size it. I set this project aside, planning to do some more research - and then come back to it, but then I discovered that it wasn't an optimal motor for the belt grinder or the bandsaw due to ventilation concerns. ¯\_(ツ)_/¯ Anyways, when I finally decide to take it back out of storage and actually USE this motor again, I will do that research and optimize the circuit. These days I'm thinking about using it on my drill-press - LOL! (Maybe.) ;-)
I wired up a treadmill motor to run my treadmill with control mechanism as you described it work momentarily and then the diode bridge shorted out this happened twice I hooked up to third diode bridge and it has operated fine I’m suspicious that some diode bridges are susceptible to inductive loads.
Hi Paul! What was your bridge rectifier rated for? Do you have the Manufacturer Name and Part Number? I always try to buy good or high quality component parts rather than trying to simply find the cheapest. There are also some manufacturers that I try to avoid due to "quality" issues with their electronic components.
I have a question. I used this video to put a treadmill motor on my old ShopSmith and it works great. My question is that when I try to read the output of the rectifier sending current to the motor, I get no readings at all. Any ideas on this?
Hi Stephen, What are you using to measure Amps draw? I know of two methods, but have only used the (very) old-school "Pass-Thru" method where your current must pass thru the meter (in-line) that you are using to measure the Amps. This requires a meter and cables that are rated for that amount of current and voltage passing thru it - or better. There are newer methods where some type of "induction" (?) sensor is clamped around the cable - but I've never used this method. Also, keep in mind that the induction method might only work with alternating current, so you would have to measure on the A/C side rather than the D/C side. Hope this helps.
@@ToddMcMahon I used the clamp meter and got similar readings on the AC and the DC wiring. As I first bring up the speed, the amps max out at about 20amps, but then almost immediately settle to 4 or 5 and stay there. Very interesting.
@@stephenwalker2195 - Yes, this is typical with all motors. There is always more current draw as a motor starts and gets up to speed. From that point on the momentum helps the motor to keep rotating, and it requires less power to operate. This is the benefit of a flywheel, while it takes more energy to start, it requires much less energy to keep operating. Part of Newtons law - an object in motion tends to stay in motion until a force acts against it.
thanks, just what I am trying to do. Except my motor is 120 VDC and 21 Amps. Just ordered the parts, will need to order a pot, later on in the comments you said you might switch to a 175 ohm, did you mean 175K? thanks
I can't seem to find a 175K, so hoping a 200K will be good. I have almost the same motor, its 3.5 HP continuous, 130VDC, mine does not have amps marked, but about 2500 watts, so around 20 amps. I don't know a lot about this, but I have read that the maximum voltage from 110AC to DC is around 90 volts. How much affect will this have on the motor power? I am planning on putting this on a lathe. thx
You might want to get a 150K as well, and try them both to see which one works best with your setup. Fortunately, pots are relatively inexpensive. With regards to the output power - I don't really know much either. :-P
Many flywheels (like the one in my video) have integrated cooling fan blades. If yours has fan blades in its design, then you MUST provide some additional cooling if you remove the flywheel. I found it easier to keep the flywheel and belt.
Am cool. Hope u are doing well. Actually this question I was asking you course during that time I dint have AC motor. I was workin with a 3 face motor. I test it's yesturday and it's working cool without getting hot. The the IGBT I use and the Highy voltage Cree. Guy I would advice u to use it. It's handling 1900 Vdc and it's a 3 pin not the solid IGBT. Next week I will upload my VD. Thenx bro 4 ur assistance yeah
Hi... I have the same setup and am having a bit of trouble with wireing mine up. Would it be possible to upload the wireing diagram from your setup somehow from everything from the same type of scr motor controller to the bridge rectifier to hooking up a on off switch? Or perhaps email me a drawing. If so that would be awesome.😎
Hi Mitchell. Let me think about that for a while, and I'll let you know what I decide. In my opinion, this is a very simple setup, and if you are having difficulties it tells me that you do not yet have the knowledge/skills for this type of project. At this moment, I do not feel comfortable with that for liability reasons. Sorry.
I have a 4000 watt scr unit smaller than yours? My treadmill motor is 180 volts dc at 5 amps? Surely it should run? Any reply appreciated. Cheers from Australia 🙂👍👍👍.BTW 1.25 horsepower
I had read comments when I was doing research prior to doing this that while lower Watt SCRs would work for a while, they had a tendency to burn out. Since the 10k watt version wasn't that much more expensive, I decided that I would just start out with the higher rated SCR. Better safe than sorry. My understanding is that "Start-up Current" and "High Usage Loads" are what kill these SCRs. Since you already have the 4k Watt SCR, I guess you might as well try it - unless it's still un-used and you can return it or sell it, and get a higher rated one?
@@dragan3290 - I have purchased two so far, for different projects. One came from Amazon, the other from eBay. I would presume that the Amazon version at least would be shippable to Australia. This being said, they're all made in China - so perhaps "Alibaba.com" might be an option as well. Good Luck!
trying the same thing, but getting what looks like more than full speed, sparks are flying out of back... Potentiometer doesn't do anything... using the 4000w SCR, 50a 1000V rectifier and 200k pot...what am i doing wrong?
Another subscriber mentioned that he was also seeing sparks. His motor had "brushes", while mine does not. Eventually, he added an induction coil that was from the treadmill, and placed it in-line; as well as ferrite choke rings. He also removed the brushes and ground them flat before reinstalling them. After these modifications the sparks stopped (I think cleaning up the brushes helped the most). Does your motor have brushes? If yes, grind them flat and try again - or replace them with new brushes. Additionally, in my opinion "bigger is better" so I would recommend using the 10k-watt SCR (220 volt), as it will still work even at 115 volts. If the potentiometer isn't working, it might be connected wrong. Remove it and check the pins with an ohm meter. If the Pot tests OK, the problem may be with the SCR itself. Perhaps the SCR was under-sized at 4k-watt and is now defective? Please let us know what you find out. Good luck! (edited for clarity, and to add additional info).
Hi, I have a 180 volt 3 hp DC treadmill motor that runs on 220/ 230 volt single phase. Would you have a diagram on how to wire this? I already have a 10,000 watt SCR, a large rectifier, switch, 1- AC ferrite choke, etc. but with having 2-110 volt legs and 1- ground wire I am struggling to figure it all out. Thanks for any help you may provide.
Can you give me the Manufacturer and Model Number of the motor? Do you know what the brand and model was of the treadmill it came from? Any additional info would help.
Sorry this took so long, Baldor DC, Landice INC. 3HP, 15 Amps, 180 Volt 3200 RPM. The treadmill is Landice Model 8700, Volts 220, Phase 1, Herts 60, Amps 15. I took pictures but don't know how to attach them. Sorry I am old and slow. @@ToddMcMahon
I'm trying to do this but when i measure output AC voltage at src output and turn potentiometer, it keeps reading 125V consistently... What could be wrong?
Im trying to reproduce the power supply that you demonstrated for the tread mill motor but the lathe motor im using is90 volt dc 12 amp and i keep blowing the motor control was the motor control you used able to handle the power without blow up you said you used a 12 dollar controller. I’ve been use 18 dollar ones. What im doing wrong?
The cost of the controller is simply a matter of economics - you pay the price that the seller believes they can sell the most units for the greatest profit. The fact that I paid $12 and you paid $18 makes no difference at all. The real issue is the quality of the controller and its components. Were there any reviews? You could pay a lot of money for a crappy controller. Another thing to remember is that it's important to start out with a motor that is known to be running well and is problem free. If the motor has a problem, the project will fail. Lastly, if the power draw is too great, you might need a different solution, like a PWM (Pulse-Width Modulation) controller, which are capable of low speeds and good torque with DC motors.
@@ToddMcMahon i agree completely on what you saying. Idid check my motor out . I even powerd it up straight to the bridge rectifier and it run without flaws . After some thought i was thinkin i pushing to much power through the one motor controller so im stepping up to a high voltage controller. On amazon it the scr un 90 uniquegoods 10000 w. What do you think of this approach? Please respond soon Thank for your help and time and recent response.
@@MrMikeinbc - If you notice, I used the 220volt, 10k Watt controller, even though my power here is 120volt. Seems to work for me, but I have no clue if it will work for you with whatever loads you are putting on the motor. If this one blows too, you might need a more professional solution as opposed to this cheap solution.
I am using a treadmill motor on a metal lathe. The controller on the treadmill worked really well, but seems to have bitten the dust. I need a speed range from about 100 to 1200 rpm. I got a Harborfreght tools router controller, and hooked it up to a rectifier, and it works, but runs way to fast with not a lot of control. The pot in the unit is 150k; adding 200k slowed it some, but not enough, and higher values do not work. I am waiting for an SCR controller from China. What do you suggest to get the speed range I need?
I suppose it really depends on what you are trying to do. I will presume that you are trying to control a DC motor like I am doing in my video (You wouldn't need the bridge rectifier for an AC motor). All that I can tell you is what I am using, but I have no idea if what I used will also work for your application. I am using a KBPC5010 that I purchased on eBay. It is a 1000 Volt Diode Bridge Rectifier, 50 Amp, with a Metal Case. It's pretty strong, so it will probably work for most projects. Be sure to have it bolted to a heat-sink!
@@ToddMcMahon I was thinking more along the lines of installing the components in a plastic/pvc electrical box and mounting wherever would be convenient.
@@williamemerson1799 - I suppose it's possible. Seemed like a lot of work to me - which is why I went this route. If you do this, be sure to take photographs (or video) and document the steps you took, so that others can be inspired by your work! Let us know how it goes! :-) Good luck!
No smoothing cap after the bridge rectifier, Todd? You're feeding the motor with PULSING DC at 120Hz. The consequent widely varying motor current makes the motor noisy - as yours is at low speed. And inefficient There will also be harmonics of the fundamental - not only do these produce RF interference, they can feed back into your mains supply. The unit cost $13? Is that a home build? If so, is it a non-isolated (transformerless) design? Most European PM treadmill motors run at 180v maximum. Running off 230 volt mains is a challenging hobby build.
LOL! I never said I was an electronics expert! What would you suggest I use as a "smoothing cap" and where would it be placed? I am presuming that it would be in between the positive and negative lines to the motor?
Hi Jafar, Sorry, but I do not think this will work on a 3 Phase motor - but if you search Google for "3 Phase SCR Motor Controller" I am sure you will find something. My post was created to show that an SCR motor controller could be used to control a DC motor. With regards to minimum RPM, I think that would depend on the motor, and how much current it needs to drive it.
I think what you need is a 3-phase variable frequency drive for that application. You can dial in exactly the speed you want. Should be available for about $US150.
I found a VFD that works with a 3-phase motor that I have in my shop. I bought it from Amazon.com for a little over $100: www.amazon.com/gp/product/B07D76365G
I just received the SCR I ordered and they shipped a 4000W unit vs 10000w like I ordered. Didnt think it would really matter much...but maybe it does? Cannot get the motor up to much speed before it pops the fuse. I shorted the fuse block and tried again and it sparked a bit so I backed off. Couldnt tell where the sparks were coming from but it seemed like it was in the pot. Motor specs. 90v / 30a 4000rpm/3hp Do you think I just have a defective SCR or that this motor overloads it at only 4000w ?
Hi Jeremy! In my opinion a 4k watt SCR probably will not last very long. You should have returned it as soon as you saw it was not what you ordered. Shorting the fuse block removes that protection from your circuit, which means that some other component will be destroyed when it gets overloaded. Does your motor have brushes? It could be that the sparks come from there. If there are brushes, clean them up and try again. What pot are you using? Do you have a ferrite core in-line?
@@ToddMcMahon pot that came with it and no ferrite. It's a brushed motor but the sparks were in the box somewhere, not at the motor...I dont know the math for ac to dc but I would have thought 4k watts would hold up at least a little while. I think this one must be defective because it got sideways with barely any load on it
@@jzahirniak: The price difference between the 4k and 10k watt versions was minimal, and the higher wattage (and voltage) limitations meant that the components were going to be of better quality. These limitations are probably the "failure point", rather than normal operational condition, which means that the normal operating conditions are probably HALF of what the stated limitation is... if you are lucky.
Hi Kenndra. For liability reasons I am not providing such details. This is a simple project. Everything you need to know is either in the video or in some of the comments. As I have told others, if you need "instructions" then you probably do not have the skills or knowledge necessary to attempt a project such as this. Sorry.
For liability reasons I am not providing such details. This is a simple project. Everything you need to know is either in the video or in some of the comments. As I have told others, if you need "instructions" then you probably do not have the skills or knowledge necessary to attempt a project such as this. Sorry.
As far as treadmill motors are concerned, this one is fairly powerful, and probably would have had no problem with a 200 pound load in its original configuration. This being said, if I were trying to replace a broken controller on a treadmill, I would probably first look on Ebay for an OEM replacement control board to be able to retain all the features and functionality. If the costs were prohibitive, I'd probably look for a PWM (Pulse Width Modulation) controller next, rather than this low-end SCR controller. The starts and stops under load would worry me too much otherwise.
Hi Glen! No sparking/crackling that I have noticed. I ran the motor for several minutes yesterday to see if the motor was getting warm at all, but it remained cool. No sparks or crackling noises either. This being said, I have not ran the motor with any "load" or resistance yet either. I will post another comment if I see anything like what you describe. [edited for clarity]
Thanks, I used this method with a 130 volt, 2.25 HP tread mill motor and found that there was a lot of sparking. Particularly when I was changing the speed. It was suggested that an inductor might help reduce this. Great video, thanks for contributing.
Hello again Glen! I wonder if there may be differences in the motor design or construction. Does your motor have brushes? Mine appears to be brushless as far as I can tell. quantumdevices.wordpress.com/2010/08/27/brushless-motors-vs-brush-motors-whats-the-difference/
Hi Glen. Yeah, I figured as much. I tried a 2nd motor that I have (2.5 HP) which also appears to be brushless, and again no sparks or crackling sounds.
The SCR is AC, but the "Full Bridge Rectifier" converts the AC output to DC for the treadmill motor. It's simplistic, and a bit crude, but it works. Note: Your results may vary. ;-)
I salvaged this motor from a Life Fitness Treadmill. The motor is made specifically for the Life Fitness company by MagnaDrive Corporation. I would recommend that you do what I did, and just start picking up used treadmills. I have picked up several defective ones (for free), but the motors were always still functional. :-)
Hi. Maybe I expressed myself incorrectly, in the previous comment, I referred to the circuit of the control box, I already had control, just that I have a small inconvenience, the engine has a sound, I know it's a parasite signal, when even the revolutions increases that sound and when I decrease the revolutions stops listening, as filter that unwanted signal, use a potentiometer of 250K, the 200K can not get it you support me with the request is a hug.
Does your motor have "brushes"? If yes, you should replace them with new ones, or grind the brushes flat. Most noisy motors I have seen have been due to bad brushes. Another thing you can do is place a large coil with a ferrite core in-line, as that might help as well.
I don't understand why your feeding an SCR into a bridge rectifier. The output from an SCR is already DC. I expect that your controller is actually a triac, triacs provide a phase controlled AC output and that would make sense of the bridge rectify after your controller. Thanks for sharing.
@@petertyrrell6690 - Before spending any money, be sure to look into PWM (Pulse Width Modulation) controllers. More expensive, but in many situations they are a better fit. Worth looking into though!
@@ToddMcMahon Yes. I am building a PWM unit. Pretty simple, I am using a PIC micro controller to control PWM out, monitor current and speed. I did order similar voltage controllers to yours, from AliExpress, mainly to study them. I am still confused as to why these voltage controllers are called SCR as they use triacs.
I think that is the exact motor I found 3hp open const. 130vdc/2238 watts Thermally protected L. 17.2 amps 30lbs. And it says RPM 5265 . If I could hook up a Rectifier and hook up a variable speed controller with Potentiometer I think it would go to work . Am I right ? The only thing is how big does this stuff need to be ?
Hi Sam! Congrats! That is a really good motor. Please note that the flywheel has an integrated cooling fan on the back, so if you remove it you will need to provide cooling. I used a 10k watt SCR rated for 220 Volts; and swapped out the potentiometer with a 150k ohm version (the SCR came with a 470k ohm which was way too big, but the 250k that I replaced it with was still too big, 100k and 150k seemed too small ). I am currently thinking about replacing it with a 175k ohm - Multi-turn version. Be sure to provide the SCR with cooling, and mount it to something that can act as a heat sink. (edited to add "k" to a couple of the pot values)
Have 2 treadmill motors. Using to build belt sander. The issue I am having is knowing the size of the shaft and threads. The best I could find is a 7/16x14 left-hand thread. Looked for hours online for each motor specs but found nothing on the thread size. Ordered tap.die 7/17x14
Finding motor specs can sometimes be a daunting task, especially if the motor is no longer being manufactured, or the manufacturer goes out of business or is sold. Not fun. Good luck with your build.
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SCR Motor Speed Controller: amzn.to/3ovlFAV
Bridge Rectifier: amzn.to/3wipA6R
I found these links very informative, as they show the HP rating of many treadmill motors:
www.treadmilltalk.com/
www.treadmilltalk.com/treadmill-comparison-chart-1.html under $500
www.treadmilltalk.com/treadmill-comparison-chart-2.html $500 - $1k
www.treadmilltalk.com/treadmill-comparison-chart-3.html $1k - $2k
www.treadmilltalk.com/treadmill-comparison-chart-4.html $2k - $3k
www.treadmilltalk.com/treadmill-comparison-chart-5.html $3k - $4k +
www.treadmilltalk.com/treadmill-reviews.html#Reviews
Todd, thank you much for sharing this. I just salvaged a 2.3 HP 130V treadmill motor and plan on incorporating it into my drill press. I have some background in electronics so I already understand what the components you mention are but still need some expert guidance in doing what you have done here. Thanks again.
Thank you for the nice comments. Please share your drill press upgrade with us! 🙂
Thanks for this, this looks like the most approachable means of controlling a treadmill motor yet. I look forward to follow on videos. Thank you for sharing!
Hi Doug! Thank you for your comments. I'm looking forward to making more videos as well. :-)
I like the last sentence flywheel, they named like that cuz it could fly away
That was exactly my point! (Humor... It is a difficult concept.)
Thanks for the walk through mate, very easy to understand. 😃
Glad you liked it! :-)
Flywheel is also the integrated fan. Removing it will reduce cooling and may cause heat issues if used for prolonged period of time.
Yes, that is often true. While I neglect to talk about that in the video, I did mention it in one of my comments below.
Thanks for sharing. Really appreciated!
Glad it was helpful!
Awesome!!! thank you so much!
Hi Alexios! Where are you located? If you do this, just be sure to use good quality, hi-wattage components, heat sinks, and adequate ventilation. Be sure to let us know what you do, and give us feed-back and comments! Best of luck!
It seems as if it was a shared script with mikemanmade Low Cost DC Motor Controller. Both very instructional and useful info. Thanks.
Interesting. Looks like Mike's video predates mine by about 3 months. I'm sure if you keep researching you will find even more videos with similar content and information. I like mine better though. ;-)
Awesome!
What type of speed regulator can I use to control a (230v)single Phase 1hp Ac gear motor, max rpm 150
Have you looked on Amazon? How about Google?
Hey Todd, did you ever hook that DC motor up to your band saw? Haven't seen a video of it & winder d if you did & how it turned out. Thanks
Short answer: Nope. / Long answer: I read a lot of bad things regarding converting a wood-cutting band saw to a metal cutting one, so I ended up buying a Horizontal/Vertical Metal-cutting band saw from harbor freight. I still plan on using this motor in a project, but it will probably be a 2"x72" Belt Grinder now. I just finished my Forge, and want to focus on getting some Christmas gifts hammered out - and after the Holidays I hope to focus on the Belt Grinder.
An additional update. While researching DIY belt grinders, I learned that many treadmill motors are not of the TEFC (Totally Enclosed Fan Cooled) variety. Including the motor seen in this video. The grinder dust would just get sucked into this motor, and quickly ruin it. I'll probably end up using this treadmill motor on my drill-press now. :-P (You can see the motor I will be using on my 2"x72" Belt Grinder in part one of that video series.)
i did the same thing and used the motir on my 20 inch band saw. i bought a 1000w scr and some 200k potentiometers and it worked well untill i installed the motor in the band saw. now that its movin some weight it must be drawing some more amps than the 1000w scr likes. if i just turn it on with the switch and dont turn the speed down first it blows the 20a glass fuse in the scr. or if i leave it run about half speed for a while the fuse blows. do you think a 10000w scr would fix this? im not sure if they all have the same size fuse. im not experienced with electronics I just made this off of another video I seen
The one I purchased via Ebay was rated for 220v (still works with 110v) / 10,000 watts. Looks like the price went up a couple dollars since I purchased mine: www.ebay.com/itm/321432206220
If you take the flywheel off you also remove the cooling fan on most of these motors .So you need to provide another means of cooling if you load them to full power with no cooling they will not last long
Very true. I believe that I mentioned something to that effect in one of my other comments in this thread.
Good job bro keep it up. Let me ask u. I made myself IGBT controller can it controls AC motor??
Hi Mike! You say that you made your own IGBT controller, but you are asking ME if it will control an AC motor? Unfortunately, this is a question best asked of the person who designed the circuit for your Insulated Gate Bipolar Transistor based controller - not me. If I have misunderstood, and you are asking if the SCR controller in this video will control an AC motor, then the answer is YES. Just leave out the Bridge Rectifier. Good luck!
Great video. I was wondering how many watts your potentiometer is rated for and if 200k ohm a reasonable choice. Also if you used an inductor coil to increase motor life. Thanks. Would like to see your bandsaw set up!
Hi there! Since this video was recorded I've swapped out the potentiometer a few times, looking for the one that gives me the greatest amount of speed adjustment range. The potentiometers I have been using have all been 2 watts, because that is what my local shop has. Not sure if I should look for a higher wattage - what do you think? Anyways - In this video, I had replaced the 470K ohm with a 200K ohm. The 200K ohm was still too big, so I replaced it with a 100K ohm as another subscriber had suggested. 100K seemed too small (the motor ran too fast at the lowest setting), so it now has a 150K ohm pot hooked up. The motor still runs with the pot at the lowest setting, so I am eventually going to try a 175K ohm pot to see if it is any better. I am also considering using a multi-turn potentiometer once I have determined what size is the best.
Sorry for the delay in replying. Had a house full of people during xmas and lost my frig on friday and my heat xmas eve. Now that things are quieter I can work on the fun stuff.
I could not find any specs on the scrs listed on ebay as far as pot wattage requirements. I usually use the largest wattage pot that will fit just to avoid smelling smoke. Are there any markings on the original scr pot indicating wattage? At this point I'll try a 150k and 175k and both are available in 5 watts. The 2 motors I was given came from a unit that had a 5mH inductor coil, but I don't have the original. I found some used ones on ebay for $10 I think I'll try. The coil should provide a more stable current for the motor.
Am also looking for specs on the motors I have, there is little nameplate info. Was wondering if you might know a site for specs.The name on the motor is Magnetek ,model 4630D-15, 15 AMPS, 90 VOLTS, 4800 RPM but is no hp rating. It came off of a extinct Sears brand called Vitalife Roadway. I am looking for something that is over 1 hp.
Hello again! The 2 watt pots have been OK for me so far, but I do not run the motor long enough to heat things up much. I'm usually just making small cuts. I would imagine that if a 5 watt pot was too big to fit in the SCR case you would just have to extend the wires and mount it somewhere else - external to the SCR case. Have you tried looking at the Sears website for treadmill parts or the User Manual? You might find the specs for the motor that way.
Tried at Sears and could not find a users manual. On item on ebay said a similar motor "probably" was about 2hp.
@@vicjs216 approximately 1.8hp based on ohms law.
P=IxE
Power (watts/horsepower) is equal to amperage (I) x voltage (E)
15 amps, 90 volts, 746 watts per horsepower
15x90=1350 watts
1350 watts/ 746= 1.809 hp
Simple formula for those who may run across this in the future and need to calculate motor size
I had a fairly cheap SCR from eBay, AC input, AC output with a potentiometer like yours. I am not a electrician and got in a hurry and forgot to use the rectifier bridge before going to a DC PWM motor controller. Blew the breaker where it was plugged in at. Potentiometer no longer works on the SCR, I don't if the current made it to the DC motor controller and if it did I'm not sure how to meter it out. I guess in my ignorance and not being familiar with electronics I screwed up big time. Lesson learned. I have a variable AC transformer (Cheap) from eBay that I used to test the motor from a electric wheelchair 24v. I was able to dial in the 24v to the motor and it worked great. Thank you for the video and sharing what and how you used The SCR
Sorry to hear about your troubles. Good thing the SCR was inexpensive! Glad to hear that you found a solution that works for you. Thanks for sharing!
@@ToddMcMahon Well Todd I have learned a lot for an old retired disabled welder. I looked at my Potentiometer and it's a 250 ohm, I have several 100 ohm pots so I'm going to use one and hope it works better if I didn't burn it all out. I'm going to hook it all back up with the bridge in place and see if it works, my wall plug blew so it might have tripped before any damage was done, don't know but what have I got to lose other than giving it another go. I just had a friend give me a 2.5 hp treadmill motor and control panel. Before I have to learn from another TH-cam how to separate the the controller out of the panel I will continue to use the SCR like you are doing. I want to put it on my drill press. The old AC motor is weak, can't even drill with a 1/4" hole before stalling. Keep up the good work and again, thanks for sharing.
How did you wire your three wire new pot into your SCR which has only two wires? What did you do with the Hurd terminal on your new pot?
Thanks
Whenever there is an unused pin on a potentiometer it typically just hangs open. You can cover it with heat-shrink tubeing if you like, As long as it doesn't short out against anything, it will be fine.
when I wire my scr the way you do. I changed the pot to 150k and set the rpm of motor to what I want and after about 5 times turning motor on and off with switch the motor goes to full rpm and can not control speed by the pot. can you tell me what is going wrong. motor is a permanent magnet 90v dc 1.0 hp 2500 rpm motor
Hi Gary. Are you using the same type of SCR motor speed controller like I have, or are you using something different? What wattage SCR are you using? Mine is 10k Watt / 220 Volt. It sounds to me like your SCR is getting too hot - and way too quickly. Perhaps it is just a poor quality SCR? Try to ensure that your SCR is staying cool (mount it to a big thick chunk of metal as a heat sink). Maybe put a fan on it. With these symptoms, I doubt that your SCR will last very long. You will probably burn out a component soon making the SCR unusable. Keep me informed, and good luck.
Todd, is there a way to make this programmable (instead of manually turning the potentiometer, is it possible to use Arduino or Raspberry Pi to program it). Thanks for the video.
Hi Yogi!
Let me make sure I understand you correctly... You are asking how to use an external digital device (Arduino, etc.) to produce a variable resistance, thereby providing an analog voltage range to feed into the Analog to Digital Converter on another digital device (the SCR) which is then generating a pseudo-analog control output, which needs to pass thru a full-wave rectifier so it can drive a DC motor?? Sorry - it just seems to me that we're going out of our way to make this motor controller as complicated and expensive as possible, when it was meant to be a cheap and simple solution.
To answer your question - I suppose that you might be able to find a Digital Potentiometer chip that could survive the voltage and power requirements of the circuit under load (check DigiKey.com), but I have no idea how to design and integrate the necessary circuitry to control that Digital Potentiometer via an Arduino. In my opinion, there would be so much time, effort, and cost involved that I would probably look for some off-the-shelf motor controller that provides the feature-functionality that I was looking for. Did you try checking the Arduino and/or Raspberry Pi forums? I'm sure someone somewhere has already figured all of this out already! ;-)
@@ToddMcMahon
You are right!
Solution is to use an SCR (AC 220V 10kW) controller in combination with full-wave bridge rectifier (50A 1000V) and a digital 200k pot (AD5262BRU200 IC POT DUAL 200K 256POS 16TSSOP; on eBay costs ~ $5) which can be controlled with Arduino (www.arduino.cc/en/Tutorial/DigitalPotentiometer).
However, there are couple of unknowns: (a) I need to isolate Arduino from high currents/voltages (it fries if >5V and >600mA, may be an isolator like LTM2892 would work) (b) need to figure out power dissipation in this setup (power loss [thus heat produced] may be too high). Overall cost is probably going to be about $30, but I couldn't find any other alternatives that come close. MC-60 or MC-61 motor control board is ~$100 and any PWM programmable controllers go well above $50. Not much info was found online based on my search so far.
Todd, Basically, I am looking for a cheap way to program treadmill motor. Anything to do with the output of rectifier is looking expensive, so I have to everything before the rectifier. Unless I get some other "cheap" ideas, I have to feed rectifier output to the motor as-is.
Good luck! Let us know what you come up with! :-)
Great video, thank you! What would you say the LOWEST functioning RPMs would be you could sustain with a good control setup like you show? (slow speed application) I only need about 1/3 to 1/2 hp, but hopefully under 100 rpm, or maybe closer to 50, before I step down with sprockets and chain. Is that even possible? (in a treadmill, aren't the lowest speed settings in this low rpm range?)
Also, when you say SCR, is what you use there the same as a PWM? I guess I have to go figure out how to determine proper ohms needed and also about the ferrite core in line, AND about replacing the potentiometer. I guess I have more studying to do! lol
I appreciate any info you might care to add here! Thank you so much!
I'm no expert, but if I understand things correctly, both SCR (with a rectifier) and PWM motor speed controllers (which are quite different) are capable of low speeds and good torque with DC motors. The SCR solutions have fewer components, and are therefore typically smaller, and cheaper than PWM. If good quality components are used in the SCR controller, it will also be a bit more robust for the same reasons (apparently there are some pretty crappy SCRs out there - so be sure to check the reviews). In answer to your question - the PWM is supposedly capable of lower sustained speeds - but again, more components, more expensive, and according to what I have read, it could be less durable than SCR. I have not used a PWM yet, but I might some day - just to compare.
@@ToddMcMahon thank you for the information! Thanks again for your video too! I'm just learning about all this and want to understand what I'm doing as or before I do it :) A month ago, I was planning to use the whole treadmill display and everything, but the more I learn, the simpler it gets. I'm still not sure what the low end RPMs would be, but might just pick one up and test it or contact a mfr for their specs. thanks again!
If your motor doesn't have a RPM sensor, you could always rig up something like THIS: amzn.to/3KCJjYU
@@ToddMcMahon Thank you for the link. It looks affordable! Much appreciated!
I did a speed test on mine a few weeks ago. Slowest it saw was about 750rpm. Video @ th-cam.com/video/qZ6uyskDIZc/w-d-xo.htmlm44s
I have table top pottery wheel that I am trying to fix for a friend, which has a control board with two thyristors on it, (which makes it a triac) and the resistor going to one of the thuristors gates was burned out, so I replaced it, tested it, and it worked. - the first time anyway. but when I went to test it again, the thyristor exploded with a loud bang. FUN!
So now I am looking for a new motor controller... the motor appears to be a DC motor. The motor doesnt have any specs about it stamped on it, so I had to do some testing to figure out what it was... Connecting it to my volt meter and spinning it by hand gives me a positive dc voltage one way and negative in reverse. The motor drives a pulley via a belt, and the ratio is about 10 to 1. Spinning the flywheel at 180rpms gave me an output voltage from the motor of about 70-75v. which equates to about 2200rpms at 90volts. the owners manual says it is a 1/3hp motor, and the online store says the pottery wheel can go up to 220rpms, which, multiplied by ten is conveniently 2200 rpms from the motor. Perfect... So now I need a motor controller that can convert AC voltage into DC, 0-90v... am I right? - what does changing the potentiometer from the 450k to 250k, or 200k do for it? how is 450k too big? what effect does it have...
Yikes! Simply replacing the resistor would be like replacing a FUSE unless you find out what caused the resistor to fail. Sometimes putting a larger wattage resistor is enough to resolve the problem, but then again sometimes a larger wattage resistor just allows some other component to fail next time.
Changing the potentiometer provided me with a larger range of control.
i have the same set up as you do. i am running a treadmill motor that uses 130vdc. how do i wire it for 110v? right now i have the positive running on the 2 out side terminals, and the ground wired direct out side of the SCR.
If you will notice, MY motor is also rated for 130vdc. This setup that I used and as described works fine with 110/120 AC input. The Full-Wave Bridge Rectifier converts the AC output of the SCR into DC. The only issue is that the motor will not get up to its highest speed at this supplied voltage, but I haven't seen any problems so far.
Question ? are most treadmill dc motors. I need a controllable DC motor to operating a function on my Sawmill Its DC
Hi Ronald,
I think that it will depend on the age, make and model. Very Old Treadmills (20 years+) probably have A/C motors. If it is a newer treadmill with a digital control user interface, it probably has a DC motor. There are some very heavy duty (non-folding) treadmills made for commercial use that have 220v A/C motors - so be careful. Look for a residential-use treadmill (one with a running board that folds up for storage) with a digital user interface. What HP are you looking for?
I found these links very informative as well, as they show the HP rating of many motors:
www.treadmilltalk.com/
www.treadmilltalk.com/treadmill-comparison-chart-1.html under $500
www.treadmilltalk.com/treadmill-comparison-chart-2.html $500 - $1k
www.treadmilltalk.com/treadmill-comparison-chart-3.html $1k - $2k
www.treadmilltalk.com/treadmill-comparison-chart-4.html $2k - $3k
www.treadmilltalk.com/treadmill-comparison-chart-5.html $3k - $4k +
www.treadmilltalk.com/treadmill-reviews.html#Reviews
The fins on the fly wheel also provide much needed cooling for the motor. Best to leave it.
Yes... I mention that in one of the comments below.
The pot only has 2 terminals connected on the speed control. The new lower pot has 3. Which terminals do we use on the new pot?
A typical potentiometer has 2 or 3 connectors. One on one or both ends of the internal "resistor" winding, and one for the "center tap". You will want one of the ends and the tap. This is pretty basic stuff though, you may want to ask a friend who knows more about electronics for some help. You don't want to make a mistake that could burn something up.
I have this setup on my lathe but my AC wire and SCR and getting very hot, also I don't know how much damage is being done to the SCR circut with inductive load that pumps back voltage as motor free spins and slows down
Is your SCR the 10k watt / 220-volt version, or smaller? How are the reviews on your SCR? Is it a good quality one, or did you just buy the cheapest? Are you using fans and heat-sinks? Can you increase the wire diameter / gauge? You could install a switch to cut off the motor from the rest of the circuit when it spins down. Just give it some thought, work it out! ;-)
Hello Todd, nice video, Thanks. You know, I was trying with a similar controller but It fails immediately as soon as I connect it so that the motor runs at full speed, I mean the controller doesn't controll the speed. It is the second controll that I spoil. My motor is a variable speed motor , 90 V DC, 11 amp. Could you help me?
You say that your controller is "similar", but this is apparently not the case. Don't pick the "cheapest". Buy the BEST you can afford. This specific solution only works with an SCR type speed controller, which has to be of sufficient wattage to survive the power surge at start-up. This is why I use a 10K-watt, 220-Volt SCR even though our power here is 115-volt. You also need to have a strong enough bridge rectifier. Mine is a 1000-Volt Diode Bridge Rectifier, 50 Amp, with a metal case. Good luck!
@@ToddMcMahon Hi Todd, thank you very much for your promp response. Acordind to your sugestios, now I know I had some misstakes about the parts I used, like the Triac. I will make the necessary corrections to fix the controller, You are very polite guy, I have learned something interesting thanks to you. Best wishes for you)
does it have much torque(power) at the low rpm range?
I haven't had a problem with it so far. Seems to be working well enough. Hasn't bogged down or stalled. This being said, I haven't cut any thing big or super hard (yet). Time will tell though!
"Get it fly wheel" XD
Humor is such a difficult concept. ;-)
Todd McMahon 👍
@@ToddMcMahon got it immediately 👍 ... and chuckled a litte ;)
I have the exact same set up. Does your rectifier get very hot?
Hmmm... Good question. I haven't actually checked. I have it in my band saw, and I also do not run it for extended periods of time. It has a fan in the SCR controller unit itself (you can hear it when I touched the cover), and I have an additional fan in the box that it is mounted in. My guess is that it gets enough air flow to stay within the normal operating temperature range. Time will tell! I plan on using the same configuration for a belt grinder later on. Now THAT device will run for extended periods of time, so I will have to ensure that it does remain cool.
I also have a fan in the SCR controller. It does fine but the bridge rectifier gets extremely hot. I got two when I ordered them and they're both bad now. I'm going to order more and hook them up against the metal of the belt sander so it dissipates the heat a little. I run the belt sander in my garage in the summer and its already 85-90 degrees out there.
I think that is a good idea. A belt sander/belt grinder probably pulls a lot of current, and it's typically running for longer periods of time when being used as well. Be sure to use some Heat-Sink Compound on the mounting surface. Did you get the 10k watt / 220 volt version SCR (it will still work with 110v) ?
You can probably eliminate the hum and some other undesirable effects by filtering the output of that bridge with some big caps to create a more “DC” signal.
True, but I don't know how to size it. I set this project aside, planning to do some more research - and then come back to it, but then I discovered that it wasn't an optimal motor for the belt grinder or the bandsaw due to ventilation concerns. ¯\_(ツ)_/¯ Anyways, when I finally decide to take it back out of storage and actually USE this motor again, I will do that research and optimize the circuit. These days I'm thinking about using it on my drill-press - LOL! (Maybe.) ;-)
Hi. Is it possible to use this motor in the carpet wash machine ????
LOL! That is an interesting question. I have no idea.
what size is your scr. I find 10000 watt and 4000 watt. what are you using? THX
I use the 10k watt rated for 220 volts (it still works for 110v).
I wired up a treadmill motor to run my treadmill with control mechanism as you described it work momentarily and then the diode bridge shorted out this happened twice I hooked up to third diode bridge and it has operated fine I’m suspicious that some diode bridges are susceptible to inductive loads.
Hi Paul! What was your bridge rectifier rated for? Do you have the Manufacturer Name and Part Number? I always try to buy good or high quality component parts rather than trying to simply find the cheapest. There are also some manufacturers that I try to avoid due to "quality" issues with their electronic components.
I have a question. I used this video to put a treadmill motor on my old ShopSmith and it works great. My question is that when I try to read the output of the rectifier sending current to the motor, I get no readings at all. Any ideas on this?
Hi Stephen, What are you using to measure Amps draw? I know of two methods, but have only used the (very) old-school "Pass-Thru" method where your current must pass thru the meter (in-line) that you are using to measure the Amps. This requires a meter and cables that are rated for that amount of current and voltage passing thru it - or better. There are newer methods where some type of "induction" (?) sensor is clamped around the cable - but I've never used this method. Also, keep in mind that the induction method might only work with alternating current, so you would have to measure on the A/C side rather than the D/C side. Hope this helps.
@@ToddMcMahon I used the clamp meter and got similar readings on the AC and the DC wiring. As I first bring up the speed, the amps max out at about 20amps, but then almost immediately settle to 4 or 5 and stay there. Very interesting.
@@stephenwalker2195 - Yes, this is typical with all motors. There is always more current draw as a motor starts and gets up to speed. From that point on the momentum helps the motor to keep rotating, and it requires less power to operate. This is the benefit of a flywheel, while it takes more energy to start, it requires much less energy to keep operating. Part of Newtons law - an object in motion tends to stay in motion until a force acts against it.
Why did you put a smaller potentiometer in the controller. What happens if you leave the higher ohm potentiometer in the controller ?
The larger value potentiometer doesn't provide fine control of the motor speed. The original wasn't much better than a power switch.
I have a brushless 90 volt dc motor. What motor control works for it hooked with a bridge rectifier??
This treadmill motor is brushless, and it works fine with the controller featured in this video.
thanks, just what I am trying to do. Except my motor is 120 VDC and 21 Amps. Just ordered the parts, will need to order a pot, later on in the comments you said you might switch to a 175 ohm, did you mean 175K? thanks
Great catch! YES! 175k ohm. Still haven't done that yet though.
I can't seem to find a 175K, so hoping a 200K will be good. I have almost the same motor, its 3.5 HP continuous, 130VDC, mine does not have amps marked, but about 2500 watts, so around 20 amps. I don't know a lot about this, but I have read that the maximum voltage from 110AC to DC is around 90 volts. How much affect will this have on the motor power? I am planning on putting this on a lathe. thx
You might want to get a 150K as well, and try them both to see which one works best with your setup. Fortunately, pots are relatively inexpensive. With regards to the output power - I don't really know much either. :-P
Todd McMahon now just need to get flywheel off
Many flywheels (like the one in my video) have integrated cooling fan blades. If yours has fan blades in its design, then you MUST provide some additional cooling if you remove the flywheel. I found it easier to keep the flywheel and belt.
Am cool. Hope u are doing well. Actually this question I was asking you course during that time I dint have AC motor. I was workin with a 3 face motor. I test it's yesturday and it's working cool without getting hot. The the IGBT I use and the Highy voltage Cree. Guy I would advice u to use it. It's handling 1900 Vdc and it's a 3 pin not the solid IGBT. Next week I will upload my VD. Thenx bro 4 ur assistance yeah
Sounds interesting! Be sure to send me a link to your video once you have it posted. Be sure to mention how much you spent! :-)
Mike: Did you ever make that video?
On Today, I already testing SCR motor speed controller and diode without Filter Capacitor. Motor was operation and so out breaking noises.
Thanks for sharing
Hi... I have the same setup and am having a bit of trouble with wireing mine up. Would it be possible to upload the wireing diagram from your setup somehow from everything from the same type of scr motor controller to the bridge rectifier to hooking up a on off switch? Or perhaps email me a drawing. If so that would be awesome.😎
Hi Mitchell. Let me think about that for a while, and I'll let you know what I decide. In my opinion, this is a very simple setup, and if you are having difficulties it tells me that you do not yet have the knowledge/skills for this type of project. At this moment, I do not feel comfortable with that for liability reasons. Sorry.
I have a 4000 watt scr unit smaller than yours? My treadmill motor is 180 volts dc at 5 amps? Surely it should run? Any reply appreciated. Cheers from Australia 🙂👍👍👍.BTW 1.25 horsepower
I had read comments when I was doing research prior to doing this that while lower Watt SCRs would work for a while, they had a tendency to burn out. Since the 10k watt version wasn't that much more expensive, I decided that I would just start out with the higher rated SCR. Better safe than sorry. My understanding is that "Start-up Current" and "High Usage Loads" are what kill these SCRs. Since you already have the 4k Watt SCR, I guess you might as well try it - unless it's still un-used and you can return it or sell it, and get a higher rated one?
@@ToddMcMahon thanks heaps for the quick reply. I actually can't find the 10000 watt version? Maybe no shipping to Australia? Cheers 🙂
@@dragan3290 - I have purchased two so far, for different projects. One came from Amazon, the other from eBay. I would presume that the Amazon version at least would be shippable to Australia. This being said, they're all made in China - so perhaps "Alibaba.com" might be an option as well. Good Luck!
@@ToddMcMahon thank you! I can purchase asap!
trying the same thing, but getting what looks like more than full speed, sparks are flying out of back... Potentiometer doesn't do anything... using the 4000w SCR, 50a 1000V rectifier and 200k pot...what am i doing wrong?
Another subscriber mentioned that he was also seeing sparks. His motor had "brushes", while mine does not. Eventually, he added an induction coil that was from the treadmill, and placed it in-line; as well as ferrite choke rings. He also removed the brushes and ground them flat before reinstalling them. After these modifications the sparks stopped (I think cleaning up the brushes helped the most). Does your motor have brushes? If yes, grind them flat and try again - or replace them with new brushes. Additionally, in my opinion "bigger is better" so I would recommend using the 10k-watt SCR (220 volt), as it will still work even at 115 volts. If the potentiometer isn't working, it might be connected wrong. Remove it and check the pins with an ohm meter. If the Pot tests OK, the problem may be with the SCR itself. Perhaps the SCR was under-sized at 4k-watt and is now defective? Please let us know what you find out. Good luck! (edited for clarity, and to add additional info).
Have you checked your DC voltage output, you may be over speeding the motor!
Hi, I have a 180 volt 3 hp DC treadmill motor that runs on 220/ 230 volt single phase. Would you have a diagram on how to wire this? I already have a 10,000 watt SCR, a large rectifier, switch, 1- AC ferrite choke, etc. but with having 2-110 volt legs and 1- ground wire I am struggling to figure it all out. Thanks for any help you may provide.
Can you give me the Manufacturer and Model Number of the motor? Do you know what the brand and model was of the treadmill it came from? Any additional info would help.
Sorry this took so long, Baldor DC, Landice INC. 3HP, 15 Amps, 180 Volt 3200 RPM. The treadmill is Landice Model 8700, Volts 220, Phase 1, Herts 60, Amps 15. I took pictures but don't know how to attach them. Sorry I am old and slow. @@ToddMcMahon
I'm trying to do this but when i measure output AC voltage at src output and turn potentiometer, it keeps reading 125V consistently... What could be wrong?
Sounds like you have the SCR wired up incorrectly, or your SCR might be defective.
With SCR you control current ,always you see AC voltage in the output terminal,with TRIAC you control voltage
Im trying to reproduce the power supply that you demonstrated for the tread mill motor but the lathe motor im using is90 volt dc 12 amp and i keep blowing the motor control was the motor control you used able to handle the power without blow up you said you used a 12 dollar controller.
I’ve been use 18 dollar ones.
What im doing wrong?
The cost of the controller is simply a matter of economics - you pay the price that the seller believes they can sell the most units for the greatest profit. The fact that I paid $12 and you paid $18 makes no difference at all. The real issue is the quality of the controller and its components. Were there any reviews? You could pay a lot of money for a crappy controller. Another thing to remember is that it's important to start out with a motor that is known to be running well and is problem free. If the motor has a problem, the project will fail. Lastly, if the power draw is too great, you might need a different solution, like a PWM (Pulse-Width Modulation) controller, which are capable of low speeds and good torque with DC motors.
@@ToddMcMahon i agree completely on what you saying. Idid check my motor out . I even powerd it up straight to the bridge rectifier and it run without flaws .
After some thought i was thinkin i pushing to much power through the one motor controller so im stepping up to a high voltage controller.
On amazon it the scr un 90 uniquegoods 10000 w.
What do you think of this approach?
Please respond soon
Thank for your help and time and recent response.
Correction the un 390
@@MrMikeinbc - If you notice, I used the 220volt, 10k Watt controller, even though my power here is 120volt. Seems to work for me, but I have no clue if it will work for you with whatever loads you are putting on the motor. If this one blows too, you might need a more professional solution as opposed to this cheap solution.
I thought you were jamie Hynaman from mythbusters to start with lol
Thanks Tony! I absolutely LOVE that guy (and I still follow Adam Savage as well). Hope you liked the video! :-)
I am using a treadmill motor on a metal lathe. The controller on the treadmill worked really well, but seems to have bitten the dust. I need a speed range from about 100 to 1200 rpm. I got a Harborfreght tools router controller, and hooked it up to a rectifier, and it works, but runs way to fast with not a lot of control. The pot in the unit is 150k; adding 200k slowed it some, but not enough, and higher values do not work. I am waiting for an SCR controller from China. What do you suggest to get the speed range I need?
For sustained low RPMs you might want to consider a PWM type controller.
What volt bridge rectifier should I use for this
I suppose it really depends on what you are trying to do. I will presume that you are trying to control a DC motor like I am doing in my video (You wouldn't need the bridge rectifier for an AC motor). All that I can tell you is what I am using, but I have no idea if what I used will also work for your application. I am using a KBPC5010 that I purchased on eBay. It is a 1000 Volt Diode Bridge Rectifier, 50 Amp, with a Metal Case. It's pretty strong, so it will probably work for most projects. Be sure to have it bolted to a heat-sink!
why to mentioned this ---- Be sure to have it bolted to a heat-sink! ???
It may get hot in use if it's passing a lot of power. A heat sink (even just a big aluminum plate) helps keep it cool and not burn out.
@@kameshp9549 Because it gets HOT!
Since the treadmill is getting dissected anyway, can't you use the speed controls from the machine?
Yes, you can. I simply didn't want a huge treadmill panel getting in the way.
@@ToddMcMahon I was thinking more along the lines of installing the components in a plastic/pvc electrical box and mounting wherever would be convenient.
@@williamemerson1799 - I suppose it's possible. Seemed like a lot of work to me - which is why I went this route. If you do this, be sure to take photographs (or video) and document the steps you took, so that others can be inspired by your work! Let us know how it goes! :-) Good luck!
No smoothing cap after the bridge rectifier, Todd? You're feeding the motor with PULSING DC at 120Hz. The consequent widely varying motor current makes the motor noisy - as yours is at low speed. And inefficient There will also be harmonics of the fundamental - not only do these produce RF interference, they can feed back into your mains supply. The unit cost $13? Is that a home build? If so, is it a non-isolated (transformerless) design?
Most European PM treadmill motors run at 180v maximum. Running off 230 volt mains is a challenging hobby build.
LOL! I never said I was an electronics expert! What would you suggest I use as a "smoothing cap" and where would it be placed? I am presuming that it would be in between the positive and negative lines to the motor?
sir can it work on 2hp 3 phase motor...and minimum rpm I want is 960..what is the minimum rpm on this device we can control...
Hi Jafar, Sorry, but I do not think this will work on a 3 Phase motor - but if you search Google for "3 Phase SCR Motor Controller" I am sure you will find something. My post was created to show that an SCR motor controller could be used to control a DC motor. With regards to minimum RPM, I think that would depend on the motor, and how much current it needs to drive it.
ok... thank u sir for the suggestion..I will search on Google... thank u
Jafar Shaikh Interestingly enough the windings for a d.c. Inductive motor and a three phase a.c. motor are similar. TH-cam search both motors.
I think what you need is a 3-phase variable frequency drive for that application. You can dial in exactly the speed you want. Should be available for about $US150.
I found a VFD that works with a 3-phase motor that I have in my shop. I bought it from Amazon.com for a little over $100: www.amazon.com/gp/product/B07D76365G
I just received the SCR I ordered and they shipped a 4000W unit vs 10000w like I ordered. Didnt think it would really matter much...but maybe it does? Cannot get the motor up to much speed before it pops the fuse. I shorted the fuse block and tried again and it sparked a bit so I backed off. Couldnt tell where the sparks were coming from but it seemed like it was in the pot.
Motor specs. 90v / 30a 4000rpm/3hp Do you think I just have a defective SCR or that this motor overloads it at only 4000w ?
Hi Jeremy! In my opinion a 4k watt SCR probably will not last very long. You should have returned it as soon as you saw it was not what you ordered. Shorting the fuse block removes that protection from your circuit, which means that some other component will be destroyed when it gets overloaded. Does your motor have brushes? It could be that the sparks come from there. If there are brushes, clean them up and try again. What pot are you using? Do you have a ferrite core in-line?
@@ToddMcMahon pot that came with it and no ferrite. It's a brushed motor but the sparks were in the box somewhere, not at the motor...I dont know the math for ac to dc but I would have thought 4k watts would hold up at least a little while. I think this one must be defective because it got sideways with barely any load on it
@@jzahirniak: The price difference between the 4k and 10k watt versions was minimal, and the higher wattage (and voltage) limitations meant that the components were going to be of better quality. These limitations are probably the "failure point", rather than normal operational condition, which means that the normal operating conditions are probably HALF of what the stated limitation is... if you are lucky.
Hi. You'd be so kind to give me the file on how to make it, it's all thanks
Hi Kenndra. For liability reasons I am not providing such details. This is a simple project. Everything you need to know is either in the video or in some of the comments. As I have told others, if you need "instructions" then you probably do not have the skills or knowledge necessary to attempt a project such as this. Sorry.
Sir kindly send me the SCR DC Motor Controller Diagram with details . Thanks
For liability reasons I am not providing such details. This is a simple project. Everything you need to know is either in the video or in some of the comments. As I have told others, if you need "instructions" then you probably do not have the skills or knowledge necessary to attempt a project such as this. Sorry.
This pleases me
If you should put that concept back on a treadmill can it pull a 200lb person on it
As far as treadmill motors are concerned, this one is fairly powerful, and probably would have had no problem with a 200 pound load in its original configuration. This being said, if I were trying to replace a broken controller on a treadmill, I would probably first look on Ebay for an OEM replacement control board to be able to retain all the features and functionality. If the costs were prohibitive, I'd probably look for a PWM (Pulse Width Modulation) controller next, rather than this low-end SCR controller. The starts and stops under load would worry me too much otherwise.
Do you get a lot of sparking and crackling in the motor?
Hi Glen! No sparking/crackling that I have noticed. I ran the motor for several minutes yesterday to see if the motor was getting warm at all, but it remained cool. No sparks or crackling noises either. This being said, I have not ran the motor with any "load" or resistance yet either. I will post another comment if I see anything like what you describe. [edited for clarity]
Thanks, I used this method with a 130 volt, 2.25 HP tread mill motor and found that there was a lot of sparking. Particularly when I was changing the speed. It was suggested that an inductor might help reduce this. Great video, thanks for contributing.
Hello again Glen! I wonder if there may be differences in the motor design or construction. Does your motor have brushes? Mine appears to be brushless as far as I can tell. quantumdevices.wordpress.com/2010/08/27/brushless-motors-vs-brush-motors-whats-the-difference/
It has brushes, that might make the difference. Thanks.
Hi Glen. Yeah, I figured as much. I tried a 2nd motor that I have (2.5 HP) which also appears to be brushless, and again no sparks or crackling sounds.
Dimmer speed ac or dc?
The SCR is AC, but the "Full Bridge Rectifier" converts the AC output to DC for the treadmill motor. It's simplistic, and a bit crude, but it works. Note: Your results may vary. ;-)
@@ToddMcMahon Thanks for the explanation
@@ToddMcMahon but i want to ask one thing,
how many volt ampere dimmer speed ac do you use??
@@sctasikmalaya4218 - No problem. :-)
@@sctasikmalaya4218 - This is what I used: amzn.to/3t6SHKH
Company of this motor plzz
I salvaged this motor from a Life Fitness Treadmill. The motor is made specifically for the Life Fitness company by MagnaDrive Corporation. I would recommend that you do what I did, and just start picking up used treadmills. I have picked up several defective ones (for free), but the motors were always still functional. :-)
Hi. Maybe I expressed myself incorrectly, in the previous comment, I referred to the circuit of the control box, I already had control, just that I have a small inconvenience, the engine has a sound, I know it's a parasite signal, when even the revolutions increases that sound and when I decrease the revolutions stops listening, as filter that unwanted signal, use a potentiometer of 250K, the 200K can not get it you support me with the request is a hug.
Does your motor have "brushes"? If yes, you should replace them with new ones, or grind the brushes flat. Most noisy motors I have seen have been due to bad brushes. Another thing you can do is place a large coil with a ferrite core in-line, as that might help as well.
I don't understand why your feeding an SCR into a bridge rectifier. The output from an SCR is already DC. I expect that your controller is actually a triac, triacs provide a phase controlled AC output and that would make sense of the bridge rectify after your controller. Thanks for sharing.
The SCR that I am using has an AC output. amzn.to/3PUVfs3
@@ToddMcMahon The unit must use two SCR connected in ant-parallel. I may purchase one. Thank you for providing a link.
@@petertyrrell6690 - Before spending any money, be sure to look into PWM (Pulse Width Modulation) controllers. More expensive, but in many situations they are a better fit. Worth looking into though!
@@ToddMcMahon Yes. I am building a PWM unit. Pretty simple, I am using a PIC micro controller to control PWM out, monitor current and speed.
I did order similar voltage controllers to yours, from AliExpress, mainly to study them. I am still confused as to why these voltage controllers are called SCR as they use triacs.
@3:38 Anyone else stain their chair? What was that sound?
LOL! My dog was walking past my legs, and knocked over something off-camera. So sorry. Maybe your volume was a bit high? ;-)
How powerful is that motor
It is made by MagnaDrive specifically for LifeFitness. The motor is a whopping 3 HP continuous duty cycle, with a rating of 6 HP Peak :-)
I think that is the exact motor I found 3hp open const. 130vdc/2238 watts Thermally protected L. 17.2 amps 30lbs. And it says RPM 5265 . If I could hook up a Rectifier and hook up a variable speed controller with Potentiometer I think it would go to work . Am I right ? The only thing is how big does this stuff need to be ?
Hi Sam!
Congrats! That is a really good motor. Please note that the flywheel has an integrated cooling fan on the back, so if you remove it you will need to provide cooling. I used a 10k watt SCR rated for 220 Volts; and swapped out the potentiometer with a 150k ohm version (the SCR came with a 470k ohm which was way too big, but the 250k that I replaced it with was still too big, 100k and 150k seemed too small ). I am currently thinking about replacing it with a 175k ohm - Multi-turn version. Be sure to provide the SCR with cooling, and mount it to something that can act as a heat sink. (edited to add "k" to a couple of the pot values)
Thank you for your help. I need all I can get
Don't we all?? ;-)
Have 2 treadmill motors. Using to build belt sander. The issue I am having is knowing the size of the shaft and threads. The best I could find is a 7/16x14 left-hand thread. Looked for hours online for each motor specs but found nothing on the thread size. Ordered tap.die 7/17x14
Finding motor specs can sometimes be a daunting task, especially if the motor is no longer being manufactured, or the manufacturer goes out of business or is sold. Not fun. Good luck with your build.