Selecting a Variable Speed Motor for Test Set-Ups

[Lloyd-ss]

First, let me say that I am posting here because this seems like the most appropriate place for the question,
and two, let me be honest, I'd like to keep this cheap, like from ebay or a surplus house.

I want to get a variable speed motor and control, fractional HP (150 watt??), maybe 1500 rpm max, to use for making test rigs. Like to drive a cam or rotate a dummy set-up. Not for driving cutting tools or anything abusive like that. I don't need a stepper motor (at least I don't think so at this time, but might end up kicking myself later.)

I am thinking AC that can just be plugged in, and then a speed control either on the motor or in a separate box. I don't know if it even has to control to a specific RPM. I can use a tach of some kind to find the RPM, unless having a speed indication on the control is more appropriate.

I look at what's available in the market, and it makes my head spin. I just need some guidance to help me zero in on something. Or if there are controllers on ebay that would match with any motors also on ebay, that could work too.

Any and all help is appreciated.
Lloyd

 

[Vietti]

I like old tread mill motors. You can usually find a cheap tread mill or free. Some have remarkably small motors.. with a vfd they can run very slow with plenty of torque. Cheap vfds are more of a problem-ebay?

 

[Lloyd-ss]

I like old tread mill motors. You can usually find a cheap tread mill or free. Some have remarkably small motors.. with a vfd they can run very slow with plenty of torque. Cheap vfds are more of a problem-ebay?

Great idea. I hadn't thought about those. My daughter is good at finding that kind of thing on the Buy-Nothing facebook groups. I'll have her poke around for one.
Thanks, Lloyd

 

[abby]

Look on the Bangood website , they have DC motors with control units very cheap.
I bought a 500 watt motor for my instrument lathe for about £50 including the speed controller.
Dan.

 

[petertha]

I keep eyeing what they call 'spindle' motor packages likes these but have not pulled the pin. 500-600watts seems to be about the max in this configuration, then next stop is ~1500 watt motors VFD driven. Having an ER collet was beneficial to my projects, but from what I can tell, its basically an add-on to the motor's standard output shaft. Guessing the brushless may be a bit better than brushed in terms of efficiency and torque at lower rpm, but that's more a guess or wishful thinking. They don't really publish curves or talk much about bearings. I've seen some YouTube videos of them running & occassional disassembly but not a lot of data to go on. Let s know what you get in the end.

https://www.ebay.ca/str/toniyang123/CNC-Spindle-Motor/_i.html?store_cat=29198550018

 

[Toymaker]

Electric scooters typically have motors and controllers in the 200 to 1500 watt range. You may be able to find one at a garage sale on the cheap, (or have your daughter shop around for you ). You can either use the batteries that come with it, or replace the batteries with a power supply from eBay.

 

[jim333us]

First, let me say that I am posting here because this seems like the most appropriate place for the question,
and two, let me be honest, I'd like to keep this cheap, like from ebay or a surplus house.

I want to get a variable speed motor and control, fractional HP (150 watt??), maybe 1500 rpm max, to use for making test rigs. Like to drive a cam or rotate a dummy set-up. Not for driving cutting tools or anything abusive like that. I don't need a stepper motor (at least I don't think so at this time, but might end up kicking myself later.)

I am thinking AC that can just be plugged in, and then a speed control either on the motor or in a separate box. I don't know if it even has to control to a specific RPM. I can use a tach of some kind to find the RPM, unless having a speed indication on the control is more appropriate.

I look at what's available in the market, and it makes my head spin. I just need some guidance to help me zero in on something. Or if there are controllers on ebay that would match with any motors also on ebay, that could work too.

Any and all help is appreciated.
Lloyd

How about a new cheap variable speed drill? They're pretty cheap and readily available at Harbor Freight (no affiliation). That would probably be fairly versatile with either a 3/8" or a 1/2" chuck. Some drills are still variable with the trigger locked. You might even own a drill already too. Treadmills are great for higher power levels than a drill can provide. Jim

 

[Madsciguy]

I second the suggestion of DC brushed motors from recycled treadmills. They can be up to 2hp @ 3000 rpm and combined with an SCR speed controller ( eg. KB-controls) can be a great variable speed solution.

 

[petertha]

I've heard of people harvesting treadmill motors but seems like the critical bit was also getting the associated controller. In the absence of finding a treadmill to cannibalize, I hunted around Ebay for used/refurb parts. Not exhaustively, some were not exactly cheap. But is the gist of it you can basically plug it into 110VAC & you have variable speed capability?

 

[bluejets]

150w @ 1500 rpm one can easily get from a low voltage (12V) brushless motor.
Speed controlled via an ESC and a 2 bob servo tester.

Or, a straight up brushed motor with a gearbox. Same deal, only pwm speed control and again 12v supply.
If there is not a lot of load, an old pc power supply or a gel cell battery.

Just another line of thought........keeps mains away from the hobby bench.

All available on fleabay etc for low cost.

 

[Toymaker]

Your local auto junkyard will have several different fractional HP 12V DC motors to choose from; fan motors used to circulate air in the car, windshield wiper motors, & electric window motors. You can easily find a 12VDC speed controller & 12VDC power supply on eBay.

 

[Lloyd-ss]

If you look at OEM treadmill motors and controllers, the prices are going to be high. There are lots of youtube videos about re-purposing treadmill motors and building or using cheap aftermarket controllers. Sounds like an attractive option.

But the problem that many of us mechanical types have is that we are way behind on the learning curve on electronic stuff in general. The buzz words and jargon and acronyms are daunting, especially when several of them are used in one sentence.

Honestly, it makes it seem like unless you know the secret handshake to get in the door, you are stuck with having to buy expensive pre-engineered packages where the correct motors and controllers and power supplies are already working in perfect harmony inside the little black box that they come in.

First, there is the problem of motor selection. AC, DC, brushed, brushless??? Where does the DC power come from? What if I feel that batteries are a PITA and just want to plug something into the wall. 12vdc, 90vdc, battery, power supply, mains (another gotcha, LOL), AC, 110v, 220v, 50Hz, 60Hz?? Controllers, pwm,SCR, TRIACs, and on and on. So, what works with what? Obviously, there are more wrong combinations than there are right combinations. Do you electronic types see how us mechanicals are intimidated by all this?
I know, I know, I should stop whining, but I am just trying to get a point across.

Luckily, I worked at a fairly big company with a lot of really smart people who were happy to share their knowledge. I found out that..... no offense intended..... the electronic types were sand bagging their knowledge behind the mystery lingo. (And I am sure the reverse is true, too.) Once somebody explained some of the electronic basics, it was fairly easy to continue on from there, and come back occasionally with a question i couldn't find the answer to.

So, as a couple of you have recommended, I am going to investigate the treadmill motor route via youtube. I don't know whether I will buy or build the controller. Building one can be fun, but sometimes its not cost effective if you can buy just the right thing.

This will be fun, as all of this should be.
And truly, ALL of the comments are helpful, no matter how much I whine. ha ha.
Lloyd
P.S. This is all meant as good natured fun, and the learning that goes with it.

 

[Toymaker]

<snip>

So, as a couple of you have recommended, I am going to investigate the treadmill motor route via youtube. I don't know whether I will buy or build the controller. Building one can be fun, but sometimes its not cost effective if you can buy just the right thing.

This will be fun, as all of this should be.
And truly, ALL of the comments are helpful, no matter how much I whine. ha ha.
Lloyd
P.S. This is all meant as good natured fun, and the learning that goes with it.

A few thoughts about safety,....

In your original post, you stated you wanted a fractional HP motor, something around 150W. I doubt you will find a treadmill motor under 1 HP (745 Watts); their typical range is between 1.5 HP to 4 HP. All treadmill motors will be MUCH larger than what you first stated you were looking for.

Treadmill motors typically use at least 90 Volts DC and many use 125 Volts DC and above; that's a high enough voltage to kill you if you accidentally touch the wrong wires.

Smaller DC motors from cordless drills, scooters, cars, etc., all use much lower voltages that wont hurt you if you make a mistake while you're learning.

 

[SteveM]

This set-up looks like it might fit the bill. For close to $90 delivered you get a 3/4 HP motor with speed control via an actuation lever or control box, all easily mountable with solid brackets.

This is the link to it: Motor & Controller

 

[Lloyd-ss]

This set-up looks like it might fit the bill. For close to $90 delivered you get a 3/4 HP motor with speed control via an actuation lever or control box, all easily mountable with solid brackets.

This is the link to it: Motor & Controller

View attachment 139910

Steve, that is actually better than what I had in mind, and for less money, too! The RPM readout is a BIG plus for my applications. I should have it in about a week.
The 0-4500 rpm range is nice but it looks like a toothed belt could be added for speed reduction. Or possibly adapt the planetary set from an old (but sturdy) drill.
$91 and nothing to cobble up. That is great! Thank you!
Lloyd

 

[Lloyd-ss]

A few thoughts about safety,....

In your original post, you stated you wanted a fractional HP motor, something around 150W. I doubt you will find a treadmill motor under 1 HP (745 Watts); their typical range is between 1.5 HP to 4 HP. All treadmill motors will be MUCH larger than what you first stated you were looking for.

Treadmill motors typically use at least 90 Volts DC and many use 125 Volts DC and above; that's a high enough voltage to kill you if you accidentally touch the wrong wires.

Smaller DC motors from cordless drills, scooters, cars, etc., all use much lower voltages that wont hurt you if you make a mistake while you're learning.

Toymaker, (and all)
Thanks for the info and the safety reminder. A close call, with no damage to person or property is the ultimate safety wake-up call, and hopefully, they are few and far between.

I ordered the set-up that Steve found on ebay.
But I do enjoy tinkering with mechanical and electrical projects. A big one I did involved converting an a old golf cart from 36v lead acid batteries to Li batteries (56vdc at full charge) from a Nissan Leaf. It really was a gut job on the electricals but I found another tinkerer who bought everything I took out, including the old motor. Building this gave me a lot of experience but I over-engineered some of the safety interlocks, but they work.

Here is a picture of my bench-test set-up before final installation. I weighed everything and getting rid of the lead-acid batts saved almost 300 pounds. Since this is used as a utility cart around our very hilly property, that is a big deal. You can't see it in the pic, but I have a dummy 3,000 watt resistance load made from the coils from some old electrical heaters. The 7 batteries are in the bin on the left.




The old 36v motor wasn't up to the task so I got a new hightorque motor from D&D in NY. You can change the speed and torque maps in the SPM controller via a laptop and since my wife loves to cruise along at one mile an hour admiring her landscaping handiwork, the tune up in the video had to be cut back significantly before anybody got upset.

 

[SteveM]

Steve, that is actually better than what I had in mind, and for less money, too! The RPM readout is a BIG plus for my applications. I should have it in about a week.
The 0-4500 rpm range is nice but it looks like a toothed belt could be added for speed reduction. Or possibly adapt the planetary set from an old (but sturdy) drill.
$91 and nothing to cobble up. That is great! Thank you!
Lloyd

You're most welcome Lloyd, and it'd be nice to see the motor in action once you have it set up. Good luck!

 

[SteveM]

Lloyd, I thought you might be interested to see the YouTube video that sprang to mind when I saw your post. I think the motor and controller are identical and he adds a smaller diameter poly-v pulley for speed reduction.
Also - that ex golf cart is awesome!!

Brushless Motor for a Mini-Lathe

 

[Lloyd-ss]

I received the motor today (picture is in post #14) but have not yet plugged it in. There is the front and back of a sheet of paper with various parameters you can set, but some of them won't apply. I will prbly try to set some of the parameters in the controller before connecting the cable from the controller to motor.

First impression is that it is a nice looking unit. Well finished, nice castings, machined aluminum belt pulley, good connectors. The motor looks small for a 3/4 HP unit. The motor and controller labels say 110vac, 550w, 4500rpm. But the spec listings on ebay are 3/4 HP, 3A, 4NM. No matter how you look at it, there is some confusion in the various conversions.

But unless it is a total bust, I will definitely keep it. It looks quite versatile and has an output for an LED light and some other stuff. Ramp up speed, braking, max top speed, etc. I will do some testing on it see what it is, but it is off to a good start for $92.

I have been watching some of the youtube videos about using treadmill motors and there is a lot of info, and a lot of it is in conflict. But after hashing thru the discrepancies, they look like a viable option for higher powered applications, if you can find a free motor.

Here is a picture of what I received. It came in a box with a custom molded Styrofoam interior.

I will let you know how it goes.
Lloyd

 

[petertha]

That looks super useful, keep us posted.