Variable Speed Treadmill Motor Power Supply Shootout: SCR, Variac, & MC-2100 Which one is the BEST?

[@blender_unleashed]

Only a few years ago finding this information was nearly impossible. Glad to see you making these videos. Okay that's enough sorry lol

[@dazecars]

happy to do it

[@mr.makeit4037]

I'm with you if I'm hearing you correctly. The SCR is route to go with shop tool applications. I'm building a basic shop metal lathe and already have purchased those scrs, for many projects to come. I will focus on cleaning the scr power output with the proper chokes and caps. Also will use your course and fine speed control adjustments using the potentiometers. Great job once again. Explained well. I'm thinking that you were a high school shop and or science teacher. Keep it up.

[@dazecars]

I am very happy with the SCRs on my tools. Making this video got me thinking that I may actually try the MC-2100 on my bandsaw. The tac input needs more investigation and I like the idea of having a set number for a specific material I am cutting. We will see, too many projects not enough time. Not a shop teacher just a self taught fabricator and electronics hobbyist.

[@blender_unleashed]

Promising results. For the difficulty to set up the variac seems reasonable. Using the variac was my first idea when converting a tool to a treadmill motor and thought it couldnt possibly be that easy.

[@dazecars]

Thanks for suggesting it. I am going to use mine as a bench top DC power supply for other projects and tests.

[@Strider396]

Excellent analysis of the 3 options for a treadmill power supply! As most of your criteria pretty much ends in a wash, the real question is: What is the long term life span of each under average general use? To be clear, this is not something you can provide an immediate answer to as much as much you may want to and would be too much to ask for anyway. Please do not take this as a negative response as your knowledge, time, and generous effort in sharing all this technical research is more than greatly appreciated especially by myself and no doubt many others. Looking forward to what you have coming next!

[@dazecars]

no offense at all. Just like you predicted I don't have enough real world data to say which one will last the longest, but I am sure they can be ranked 1, 2, & 3. The reality is I don't think it is important. While each one has a level of robustness (as i ranked) I don't think any of them are "fragile" under normal non extreme use. So even if the best one lasted twice as long as the worst one, if the worst one has a lifespan of 10 years (making that number up but it is probably a reasonable minimum assumption) under regular use that is long enough to "get your moneys worth" I think the better way to look at my analysis is to use the 2-4 criteria that are most important to you for the specific project you are working on, and then a clear winner likely emerges for your application or at least one drops out.

[@williamlanphar630]

So far , i think given the cleanness of power, robustness, and relatively simplicity involved with using the variac unit is which direction i am leaning towards. Even if it is large and a bit more costly, i think i prefer this. Thank you, again , for doing the comparisons so that a person , such as myself with almost zero preknowledge of such things, can make a more informed decision.

[@dazecars]

my pleasure

[@aguycalledlucas]

Daze, thanks for going through that exercise. We appreciate it. I need to rewatch the breaking videos. I don’t recall where you ended up on the motor brake.

[@dazecars]

my pleasure!! I worked out all the bugs on the bench but have not had time to do the final install on the lathe.

[@blender_unleashed]

I can't think of a scenario where such precise speed control would be necessary other than threading maybe? Great video fair comparison

[@dazecars]

threading would be it. I like to thread at 100 RPM and having to start at 150 might be a bit much and then as soon as you hit the gutter and tool pressure drops speed will go back up.

[@jimsloane5834]

One advantage of the variac that needs to be pointed out is that it can be used for other applications where variable ac voltage might be required or desired. I am a ham operator and one of these puppies would be a real asset

[@dazecars]

Excellent point but beyond the scope of this video. The same can be said of an SCR as it can be used for lots of things besides treadmill motors. If I added a lot of pros and cons of each unit outside of running a treadmill motor we end up with a list that is more confusing than helpful. Also someone that has a different use for one of these devices, like you, will know that, and can figure that into their own decision making.

[@DaveIngle1]

Again, another great video... I can't believe you won't quit your Day Job to do more video's... that is just selfish. I'm going on a limb and assuming that you could still add the forward reverse, auto brake, emergency stop, and you showed the RPM gauge with the Variac. The really slow speed might be vary useful when applying finishes to the wood lathe projects. From a previous video I posted I'm adding all this to an old lathe my Father had. If I determine wood turning is a hobby I want to pursue my next low budget step would be to buy the Harbor Freight lathe with the reeves drive and convert it using the parts from project one. Thanks Again, keep them coming!

[@dazecars]

this should help with your direction switch question kzbin.info/www/bejne/eGLTm2aEZq9lrMk

[@FunctionalPrintFriday]

Great job! Thx for sharing so quickly.

[@dazecars]

My pleasure!

[@markmiller6817]

Thanks for another great video , you are giving me much to think about .

[@dazecars]

Glad to hear it!

[@samehdarawshi3537]

great great video. summs it up in the best way. many thanks. now after you mentioned you have diy mill building i have to look for it :)

[@dazecars]

There are 4 videos in the play list kzbin.info/www/bejne/eWPTZ6OGg6eDo8k

[@samehdarawshi3537]

thank you

[@dazecars]

@@samehdarawshi3537 my pleasure

[@johnorr9404]

Look at KB electronics for a dc drive to match your motor. Even without a tach on the motor my 1 hp treadmill motor is nearly stall proof even running less than 50 rpm. Been running one on my jet 9x20 for 20 years or so and no problems. It uses current/voltage feedback on the motor to determine if the speed is slowing under load and cranks up the drive. There is an adjustment for that.

[@dazecars]

My concern with ther power supplies is they are fewer amps than a lot of the motors which means you will never have max torque. With that said I make that conclusion based on the numbers and how amps effect torque but I have never actually used one.

[@zjtr10since80]

Thanks for sharing your experience

[@dazecars]

My pleasure

[@jwdory]

Great video! Thanks for the links.

[@dazecars]

No problem!

[@blender_unleashed]

I'm pretty sure you can smooth out the signal of the variac in a similar way to the scr esc you built. Because ac constantly shifts polarity your signal will essentially pulse 60 times a second. I know when people convert ac welders to DC they often add a capacitor and a choke in addition to the rectifier for that reason

[@dazecars]

Because of how the rectifier works it actually pulses 120 times. The pulse in AC is a total polarity shift 60 times a second, but because of the rectifier as soon as it hits 0 it begins to go back up doubling the pulses. Here is a linked picture to better illustrate qph.cf2.quoracdn.net/main-qimg-0295ebdbeb5ad6e53f2383c6909f4c72 . A PWM like the MC-2100 effectively does the same thing, pulsing rapidly. The reason the SCR's pulsing is dirty is the on off action doesn't line up with the sine wave so the power is choppy instead of smooth up and down. My experience with capacitors is they cause surging under a load. I can see where smoothing out out would be needed for welder, but not needed for a motor.

[@blender_unleashed]

One thing to consider is if you draw to many amps on the variac, especially at higher voltages, it's very possible to short the coil. I've done it before. Also it's probably not as effecient as the others, they can get hot

[@mr.makeit4037]

I'm wondering if the fuse protection would work before reaching that critical point?

[@dazecars]

didn't think about heat and long term use. A fan could help there.

[@dazecars]

it would help if it was a high amp situation but not if heat was the problem.

[@dizzolve]

great round up

[@dazecars]

Thanks

[@markhedquist9597]

Hey, this was helpful. Thanks for the info.

[@dazecars]

No problem!

[@Tex260Z]

So with all these conversions seems like a nice op for for an electronics type to retune these original boards for purpose, you have to figure they are pretty rugged considering the original use? BTW, are all these motors brush type?

[@dazecars]

The motors are brush type. As to your other question, the ruggedness of the treadmill boards leaves much to be desired. I took the time to convert my bandsaw to a treadmill motor using an MC2100. I was excited to use the tach input to help regulate speed. First time I stuck the blade I fried the board. There is not a huge load on a treadmill so it is not as rugged as one might think. For shop equipment IMHO the SCR is a far better option than the original treadmill control board. kzbin.info/www/bejne/r37OiGWJjdGSqaM

[@edswagemakers5365]

Hi, first off, I need to say that your videos are an excellent source of information. I have watched some of them several times. I have recently managed to obtain another treadmill, and this one has a board in it that I haven’t seen before. It is a KING-I BC-1070(6). Like the MC 2100 it requires a PWM control. I have ordered one online and will receive it in the next couple of days. I wanted to put a couple of photos into the comment, but I couldn’t work out how to do it. Looking at the seven pin connector I really only have one choice. I believe for the PWN controller which is for the PWM signal to go into the S/W connection, have you ever seen one of these control boards and if so is it possible for you to give me some advice. Thank you.

[@dazecars]

I have not seen that board. You can send pix by emailing me through my website.

[@aguycalledlucas]

I really like the fine and course potentiometers.

[@dazecars]

Me too!!!

[@bobreichel]

The treadmill, I got free? Has on the Board, U V W. I understand that's 3 phase. Can I still use the power controller the same way, as a single phase?

[@dazecars]

no you can not VFD is the only effective option.

[@tomnorton8218]

Question for you. Is it possible to install a" remote/larger" on/off switch on a PWM?

[@dazecars]

anything is possible. My question is why? The reason I ask is changing the main button would probably be more trouble than it is worth but depending on what you are trying to accomplish you may be able to put a switch on one of the connecting wires

[@Chris-io2cs]

how does the other common controller taken from treadmills (mc60?) compare to these?

[@dazecars]

The MC60 is an SCR voltage controller and is not as versitle or as good as the one I show in this video. kzbin.info/www/bejne/bHiWcmWgd6d_fbM

[@georgedubrik280]

Thanks brother great video. I love your channel, it's very informative and logically presented. It would have been interesting to see how the voltage and amps fluctuated during the tests. In particular, I wonder if you know what the volts and amp readings were from the variac to get the 18 RPM minimum speed you mention in the video (@26:32)? I'm motorizing a small rolling mill (for jewellery/silver) where the priority is low RPM (target final drive roller speed of 5-20 RPM). Of course torque is a factor but this is a hand rolling mill with a built in 4:1 gear ratio (still hard work for an old guy ). I could skip the variable speed altogether if I can work out what voltage and current, I need to achieve 5 RPM. I'm counting on gearing the motor drive down probably about 5:1. From what I've gleaned from your videos, I'm thinking of trying a fixed 12 volt supply from a salvaged ATX power supply which has about 30 amps available. I realize that this limits the max power and therefore the torque available, but it should be enough. The treadmill motor I’m using is - DC permanent magnet, 220V, 4.8 amps, 1.5 HP Don’t sweat it if you don’t have time to answer this as I know you have a lot going on given the depth of your channel, but in any case, thanks again, I’ve learnt so much from you already

[@dazecars]

I have not done any testing of specific volts-speed. The problem is there is no one size fits all answer. I have scrapped 18 treadmills and every motor is a little different. To make it even harder even if comparing two identical motors the application is going to change how that motor functions given specific volts and amps. My advice would be to run your motor at 1/3-1/2 the volts listed on the motor making sure the power supply has adequate amp put put so you don't lose torque and then gear it reach the desired RPM. At those speeds you should have full torque from the motor, even more torque from the gearing and most importantly enough airflow to keep the motor cool. Please don't hesitate to reach out if I can be of any further assistance.

[@georgedubrik280]

@@dazecars thanks! Good advice man, I do recall you saying that at very low voltages the ability to maintain a linear torque characteristic my not hold true regardless of the current thats available. ...and I hadn't even thought about the impact of low RPM on heat dissipation.👍

[@georgedubrik280]

hey brother...ok I built an SCR speed control as per your vids and it's working great (thanks man!). When i turn up the pot on the SCR the motor kicks in at about 170 RPM which is lower than I expected , but still not low enough for my application ( target 50 RPM). As you've said, I can use gearing to achieve the final destination RPM, but my question is what if I put a resistor after the DC choke to reduce voltage, to "step down" the output voltage going to the motor and subsequently reduce the speed of the motor further. Is this worth pursuing this tack, or am I missing something. By the way, as you've noted in your earlier reply, I understand the rotational speed of the motor impacts on fan speed and therefore the motor's ability to provide self cooling, but for my application (a previously hand powered rolling mill for silver and other non ferrous metals) the duty cycles are short and the power requirements are relatively modest.

[@dazecars]

I just saw this reply sorry I didn't get back sooner. In theory if the resistor was big enough to handle the high wattage it would do as you said but it will also limit amps which will in effect limit torque. Gearing is the way to go

[@Kevin.L_]

Excellent comparison. The results are interesting. Happy to see the Variac actually be useful. I was expecting a bigger loss on the Variac. Guess I didn't take into account the gear reduction. Any idea how much load the motor was under? Amp reading in and out of cut?

[@dazecars]

I didn't take any amp reedings. When I build the dyno I will include an amp gauge so that I have that info as well.

[@daithioyeah]

Fantastic video as usual, so informative and entertaining👍 Have you come across the DC-51 Speed Controller which is widely available from multiple sources and is great value. It takes in mains power and connects straight to the motor. I would love to hear your opinion on it compared to the other options in the video. Keep up the good work 👍

[@dazecars]

I have never used one so I went and looked at the specs. I see two issues first the listings say "only suitable for the motor below 1800rpm" which may or may not be an actual issues. My bigger concern is that says watts is 400 max and that is not nearly enough. At 90V that's less than 5 amps meaning you will not be anywhere near the max torque of even cheap low power treadmill motors most around 15 amps a good treadmill motor is closer to 25 amps.

[@daithioyeah]

@@dazecars Shame it’s not strong enough to drive a treadmill motor. Would have been a great solution.

[@dazecars]

@@daithioyeah if it was easy and effective, it would be a lot more expensive 😁

[@zafarimamalvi6203]

Dear Teacher, I wish you to kindly add a closed loop feedback speed governor for treadmill dc motor, please.

[@dazecars]

That is a good idea but is beyond the scope of this channel. The video I just uploaded this morning is about as close as I will likely come to using electronic feedback.

[@paulshermet535]

I was shocked to find the SCR held on to the speed. I ordered a $120 aftermarket treadmill controller for up to 4HP, mine is 2.5 which I will never use. It will let me plug in my motor speed sensor. After hearing everyone complain about no torque at low rpm, I went overboard and added 3 five groove pulleys. Probably a waste of money however the spindle will go from 50rpm to 25000 rpm. Not doing that, ever. Next one, maybe my wood lathe, will be the SCR. It has a variable belt drive which bottoms out at 625 rpm, too fast for a 12" wood bowl.

[@dazecars]

I was amazed at how well all of them did. I didn't expect to be so close

[@kensherwin4544]

Which one did you get?

[@paulshermet535]

@@kensherwin4544 None of them, just commenting on the test.

[@dazecars]

👍

[@paulshermet535]

@@dazecars I changed it to your scr schematic. Like it way better. That SCR can switch from the mill to the lathe which now has a 3hp treadmill motor, and the Clough 42 ELS. I made a short update kzbin.info/www/bejne/g6itqpqQeJdkeLssi=_Y9O3GmcSPDHnXWm

[@minskmade]

im a fan of the original board and the pwm generator...its seems to work incredibly well..with a very clean signal..and should be easy to add to a work box...though the lowest speed is 300 rpms on my setup with an icon board...

[@dazecars]

My machine is geared at 3.5:1 so my 65 is in fact 228 at the motor and I started faster and dropped it down to get the minimum. cold start would likely be more than that.

[@tcalcut]

All I have is a MC 2100 which I got for free. I guess I'll just have to go with that and like it ... !!!

[@dazecars]

It should get the job done

[@KD0CAC]

An amp-meter would have completed the test setup , I think . Thanks

[@dazecars]

agreed and I will be adding one to the dyno build

[@kellyjones334]

On a DC motor if you don't hook any power to it and just spin it and you take a Amp reading of the leads of the motor that should tell you how many amps it you putting out or will it not. It's a suggestion that I thought of but I'm no expert on this kind of stuff. I'll let you answer it and see if that would work.

[@dazecars]

sadly it doesn't work that way. You would need to load the electrical system while its spinning to determine max amps.