# Proper motor controller for treadmill motor

#### reharik

Joined Nov 4, 2019
23
Hi, I'm pretty new at this. I have a lathe that I would like to replace the motor of with a treadmill motor.
The motor I purchased has this description
1.75 HP Continuous Duty @ 90 VDC
Amps 15
4200 RPM @ 90 VDC
I have read about someone doing the old treadmill motor conversion on a lathe using this motor controller
https://www.amazon.com/Motor-Controller-Variable-Adjust-Control/dp/B07JMK63LP/ref=sr_1_7?crid=31K99XKHDK4JE&keywords=dc+motor+speed+controller+90v&qid=1572884423&sprefix=dc+motor+speed,aps,171&sr=8-7Which is described as this ( incase the link is blocked )
AC 110V 400W Knob Motor Speed Controller DC 0-90V Variable Adjust Lathe Control
However, my understanding is that the wattage for a treadmill motor would be closer to 1500 W.
So my question is, will this style controller ( the 400w one above ) work for me? If not is there another, preferably nicely contained all in one converter and speed control, unit that will work for me? I read about people taking them out of treadmills and hooking them all up, and/or fabricating their own component cases etc. I'm a software engineer, and kinda woodworker, I don't have metal fabrication tools or really the skills to make a box and hook up a bunch of pieces. That said, if that's my only option I will figure it out, but any help people could give me would be really great.
Thank,
Raif

#### Alec_t

Joined Sep 17, 2013
10,905
Welcome to AAC!
400W (~4.5A) is woefully inadequate for that motor. Bear in mind that the starting (stalled) current of a DC motor is several times its rated running current.

#### jpanhalt

Joined Jan 18, 2008
8,724

Joined Jul 18, 2013
19,997
I think you will find that is a simple Triac controller with a DC bridge.
Most faced with this application use a T.M. controller, MC-60 SCR bridge or the superior PWM MC2100, there is also KB DC motor controllers out there also on Ebay etc.
The above have the advantage of accel/decel features.
For these drives you would need an encosure of some kind. Either plastic or metalic.
The metallic version should be earth grounded.
Max.

#### reharik

Joined Nov 4, 2019
23
Hi! Thank you all for responding.
I'm afraid I'm still a bit confused. It seems like these controllers are going to be in the $80 -$120 range. And that most of them come as just a circuit board.
My first question is are all of these devices that you mention, the minarik MM23001c the MC-60 SCR or the PWM MC2100, are they all both AC->DC converters and speed controls? If so then would I also need to by a potometer? Are there other pieces I would need? I'm afraid I may need one of you to kind of spell this out for me.
Thanks,
R

Joined Jul 18, 2013
19,997
The KB controllers and the MC-60 just require a 5k pot.
The MC2100 requires an add on board that provides a 50Hz PWM signal, the add-on board also has a pot control.
Max.

#### jpanhalt

Joined Jan 18, 2008
8,724
Hi! Thank you all for responding.
I'm afraid I'm still a bit confused. It seems like these controllers are going to be in the $80 -$120 range. And that most of them come as just a circuit board.
My first question is are all of these devices that you mention, the minarik MM23001c the MC-60 SCR or the PWM MC2100, are they all both AC->DC converters and speed controls? If so then would I also need to by a potometer? Are there other pieces I would need? I'm afraid I may need one of you to kind of spell this out for me.
Thanks,
R
You can get one in a nice box for 3X the price. I built my KB controller into the base of the lathe. If money is a factor, it seems to me that putting a big value on a nice box is misplaced.

Here's the front:

And here's the bottom:

Albeit, it's a very small lathe,but I needed something I could haul up to the second floor of a temporary apartment.

#### reharik

Joined Nov 4, 2019
23
Ok cool. I wonder if someone has a link to a sort intro to puttin stuff in a box post Or you know just an intro type site.

Joined Jul 18, 2013
19,997
When you get into machine control circuits and/or enclosures, there are a few things to observe, safety, e.g. Machine E_Stop etc.
Also proper grounding of all metallic enclosures etc.
Max.

#### reharik

Joined Nov 4, 2019
23
Hi all,
I have decided to got with a mc-60 from ebay. After your posts and reading a bunch on the topic I feel I'm much better equipped.
1) I have seen a video that shows that having an inducer attached to the board makes the motor start and stop with less strain. As I am not hacking this thing out of a treadmill my self, I wont have that inducer. Do you think it's a good idea to add one and if so how would I know which to get?
2) I understand that the board has a soft start feature which resets the speed to 0 when you turn off the motor. This makes sense for a treadmill but for a lathe it will be a big pain. I read that you can add a switch to the high end wire of the pot and that will bypass this reset. Is the this the best way to do it? Would it make sense to make that switch the main power switch for the motor?
Thanks,
Raif

Joined Jul 18, 2013
19,997
Do you mean inductor, commonly known as a choke, if so, yes a series choke is an advantage with this type of drive, (120hz ripple).
The way to defeat turning the pot to zero is remove a resistor, I would have to look it up, but I believe there are a few old posts here that would show it.
Max.

#### reharik

Joined Nov 4, 2019
23
Hi, thanks for the link and the info. Yes inductor . I figured that wasn't quite right. Just two letters off. However, I have searched for those terms and have not found anything. I think inductor must be a pretty cool word cuz I keep getting laptops and video games. Could you give me a bit more to go on?
As for the link, I had seen that one, but a) the op post seems a bit complicated and the second post was just "remove r19" which I wouldn't know how to do. Also I've read posts about people clipping all manner of stuff off their boars and it not working. I'd be willing to give it a try but I'd need a pretty detailed description of which thing to cut off.
What do you think about putting a switch inline on the potometer?

Not sure what you mean that soft-start is a pain on a lathe. Can you give some more information on that?
So one starts and stops a lathe somewhat frequently, so each time you'd be bringing it back up to an aproximation of the speed you were at before. I just feel like that's going to be off putting to have to adjust to the speed of the lathe each time.

Thanks all,
Raif

Joined Jul 18, 2013
19,997
IIRC the resistor is the closest to the centre (slider) connection for the pot, if you have a soldering iron you could just lift one end out if not wishing to cut off completely, to try.
The board should have the resistor designation on it next to the resistor.
Do a search on ebay for Treadmill Choke. Several hits.
The KB style controllers have an Inhibit input which allows the same effect when stopping the motor/drive.
Max.

#### reharik

Joined Nov 4, 2019
23
Ah, you are right, I searched for all the wrong things. So none of them really give any details except for the type of treadmill they came out of. I'm guessing/hoping that they should mostly all work.
I don't actually have my board yet so I can't look at it but you've inspired me to give only R19 a try. HOWEVER, I would like your thoughts on using a switch on one of the legs of the 5hz pot, both to kill the slow start and as an over all power switch, just in case I can't get r19 to work.
Thanks again for all the advice. You all are a super help.
R