Selecting a Variable Speed Motor for Test Set-Ups

[Lloyd-ss]

That looks super useful, keep us posted.

Well, this is looking very promising.
I fiddled around with setting the parameters, and that was super easy and relatively fast.

Default motor rotation direction is set with a parameter, but you can also toggle it with a single button from the controller.
Max speed is another parameter that is easy to set.

Anyway, I hooked it up and it works flawlessly so far.

But here is the really cool part. I jury rigged up a prony brake with a couple of hard wood dowels and a big thumb screw. I used a light duty spring scale (whose accuracy I verified) to hold the rotation as I screwed the thumbscrew to clamp the dowels tighter and tighter into the v-groove of the pulley. It took some diddling to get smooth at it.
I had set the max rpm to 1,000, so that I could press the speed control lever all the way and it would hold at 1,000 rpm. While I was getting the hang of starting it smoothly, I popped the wall recpt GFI a couple of times. I don't know if that was over current or something internal in the controller. But I was cautious to not abuse the motor or controller too much.

I only tested at 1,000 rpm because its getting late and I don't want to ruin anything.

These are the real numbers, although it might seem like I faked them. I plan on doing a little video about this.
Torque arm was 9.5". I ran it at 1,000 rpm and held the spring scale and and turned the motor off as soon as it felt like the rpm was just dropping off to stall. The tell-tale on the spring scale read about exactly 5 pounds (1/8 pound graduations).

9.5" x 5 lbs = 47.5 inch lbs = 3.96 ft lbs
3.96 ft lbs x 1,000 rpm / 5252 = .75 HP

The motor was advertised as 3/4 hp, and that is what it gave, but I have not checked current draw, but I bet it was on the edge. But then again, it is also advertised as 550 watts, which is .74 HP.

All in all, so far, I am super pleased at this purchase!!
Lloyd
P.S. pictures and video coming in a few days.

 

[william_b_noble]

Beware of treadmill motors, the can be used, and can be controlled by a suitable controller, but they are generally open to the environment and not designed fot sustained power. Many tomes the power rating is optimistic. You are almost always better off with an industrial motor

 

[Ken I]

Beware of treadmill motors, the can be used, and can be controlled by a suitable controller, but they are generally open to the environment and not designed fot sustained power. Many tomes the power rating is optimistic. You are almost always better off with an industrial motor

Check if the motor rating plate is marked with duty cycle or rating
Rating S1 is 100% duty cycle rated.
Rating S2 is for Intermittent Duty - probably fine for home workshop lathe use - but keep an eye on temperature if run hard for more than 20 minutes.
Rating S3 is for Light Duty - Limited run at max power - run below average power for less than 50% of time

Regards, Ken

 

[Toymaker]

Beware of treadmill motors, the can be used, and can be controlled by a suitable controller, but they are generally open to the environment and not designed fot sustained power. Many tomes the power rating is optimistic. You are almost always better off with an industrial motor

For most of us using treadmill motors and controllers for our DIY projects, cost is the driving factor between buying an industrial motor vs a treadmill motor. Entire treadmills can be picked up at yard sales for pennies on the dollar, compared to hundreds, or even thousands, of dollars for a new industrial motor that doesn't come with a controller.

I've been using my DIY CNC lathe with it's 2.5 HP Leeson treadmill motor for 6 years without a bit of trouble, and because my lathe is a CNC machine, there have been several times when the lathe worked continuously for several hours while I sat back and watched

 

[Lloyd-ss]

For most of us using treadmill motors and controllers for our DIY projects, cost is the driving factor between buying an industrial motor vs a treadmill motor. Entire treadmills can be picked up at yard sales for pennies on the dollar, compared to hundreds, or even thousands, of dollars for a new industrial motor that doesn't come with a controller.

I've been using my DIY CNC lathe with it's 2.5 HP Leeson treadmill motor for 6 years without a bit of trouble, and because my lathe is a CNC machine, there have been several times when the lathe worked continuously for several hours while I sat back and watched

I agree. Everyone on this forum is a tinkerer. We take a pile of nothing and turn it into something beautiful, and that is something that very few people can do. And we have a right to be proud of it.

This motor is unusual for me because I bought it as a complete black box that I didn't have to build or finish. But it was less than $100. If my options were all over $200, I would have acquired a bunch of cheap used junk, spent 20 hours on it and ended up with something similar.
It's been a while since I bought something that was cheap, completely finished, and worked well.
It feels good.
Lloyd

EDIT - P.S. I just thought of another good "complete blackbox." The HF small size Predator gas engine for $99. What a dream. I've been using that for 2 years now and it is the best engine I have ever had.

 

[ajoeiam]

Beware of treadmill motors, the can be used, and can be controlled by a suitable controller, but they are generally open to the environment and not designed fot sustained power. Many tomes the power rating is optimistic. You are almost always better off with an industrial motor

Hmmmmm - - - you will find that if you look at the specifications for most (maybe almost all) CNC equipment that the motors are rated for a 20 or 30 minute period with a lower rating for continuous - - - so - - - grin - - - this treadmill motor usage merely moves one into the 'pro' category (LOL - - - !)

 

[william_b_noble]

I am speaking from second hand exprience - I sold a bunch of treadmill motors at one point in time, as sold they had inadequate cooling and were ok for an occasional use drill press but certainly not for a lathe or mill where they would run for an hour or two. As for CNC motors, I don't have room for a CNC, but I do know the motors on my mill, metal and wood lathe are all rated for continuous use and they do run for an hour at a time when I'm in hte groove. also on my air compressor - when using air tools, that 5 HP motor runs steadily - an air drill really chews through the air, often 15 to 19 cfm

 

[timo_gross]

For most of us using treadmill motors and controllers for our DIY projects, cost is the driving factor between buying an industrial motor vs a treadmill motor. Entire treadmills can be picked up at yard sales for pennies on the dollar, compared to hundreds, or even thousands, of dollars for a new industrial motor that doesn't come with a controller.

I've been using my DIY CNC lathe with it's 2.5 HP Leeson treadmill motor for 6 years without a bit of trouble, and because my lathe is a CNC machine, there have been several times when the lathe worked continuously for several hours while I sat back and watched

Depends on what you exactly want to do and what your budget is, also what you already have.
Just some thoughts.
I stopped salvaging old motors a little, because sometimes the time wasted to get it up and running totally eats up the money saved. By the time I figured out power supply, driver electronics and all that I rather spent some money.

• (DC or BLDC) motor kit for a bigger RC car?

Maybe you will need another gear reduction of some sort, because they rotate fast. You do not need a remote control to run those, there are servo testers and other pwm gear to adjust the speed for those BLDC drivers.

• a sewing machine motor, or the entire sewing machine? it has a "throttle" for speed control.

• Use the Drillpress or lathe, for test setups. Just put a rod with pulley in the chuck and drive the test setup with it.
• I paid about 100 USD for a 2nd hand VFD (brand name with instructions downloadable form Internet) a small 3-phase motor came about 50 USD, the inverter can be used for different motors, so it is not gathering dust.
• A youtube channel with some good advice on recycled motors.
• Windscreen wiper motor from car, with lab power supply.

Greetings Timo

 

[ajoeiam]

I am speaking from second hand exprience - I sold a bunch of treadmill motors at one point in time, as sold they had inadequate cooling and were ok for an occasional use drill press but certainly not for a lathe or mill where they would run for an hour or two. As for CNC motors, I don't have room for a CNC, but I do know the motors on my mill, metal and wood lathe are all rated for continuous use and they do run for an hour at a time when I'm in hte groove. also on my air compressor - when using air tools, that 5 HP motor runs steadily - an air drill really chews through the air, often 15 to 19 cfm

Hmmmmmmmm - - - re: your air compressor

If you find that you are running your air compressor a lot - - - well they are designed for something like a 80% on time - - - and that's the industrial brand level ones (cheap ones just aren't as robust). If you are running a reciprocating air compressor at greater than that level on a regular basis you should be considering either moving to a larger compressor or getting a rotary style (these will be more energy efficient at the larger usage ratios(especially if you choose one made by a company that is into energy efficiency!!)) IIRC plumbing in a larger reservoir can help with this somewhat.
I'm thinking of changing my system to a large tank where I can add air pressure using possibly multiple inputs. So like a central air storage and piping the air to various locations.

 

[Lloyd-ss]

Prony Brake test of the motor and controller
I did a pretty extensive prony brake test of this motor and controller here:
Performance was quite decent. I didn't want to double post the video.

https://www.homemodelenginemachinis...st-a-3-4-hp-sewing-machine-motor-video.34494/

 

[Toymaker]

Hmmmmmmmm - - - re: your air compressor

If you find that you are running your air compressor a lot - - - well they are designed for something like a 80% on time - - - and that's the industrial brand level ones (cheap ones just aren't as robust). If you are running a reciprocating air compressor at greater than that level on a regular basis you should be considering either moving to a larger compressor or getting a rotary style (these will be more energy efficient at the larger usage ratios(especially if you choose one made by a company that is into energy efficiency!!)) IIRC plumbing in a larger reservoir can help with this somewhat.
I'm thinking of changing my system to a large tank where I can add air pressure using possibly multiple inputs. So like a central air storage and piping the air to various locations.

OK, I can't resist jumping in on this topic. Being an in-curable DIYer and tinkerer, a few months ago I built an air compressor using an automotive A/C compressor. A/C compressors come in lots of different sizes and pumping capacities, so pick one that's right for your needs. As long as you give an A/C compressor a little oil in the air intake they'll run forever. DIY Air Compressor

 

[Lloyd-ss]

OK, I can't resist jumping in on this topic. Being an in-curable DIYer and tinkerer, ...........................................

Golly, I am so sorry to hear that. I have the same affliction, and it can lead to more serious complications. But more than for you, my sympathy goes out to your family. They bear much of the burden.

My wife no longer even asks what I am working on in the shop. Instead she posts a picture to her facebook group under the hashtag #married to an engineer. She makes it a guessing game as to what I am working(wasting my time) on. She usually doesn't have a clue. Toymaker, are you subjected to that kind of emotional abuse because of you tinkerer affliction? Very sad.

 

[ajoeiam]

Golly, I am so sorry to hear that. I have the same affliction, and it can lead to more serious complications. But more than for you, my sympathy goes out to your family. They bear much of the burden.

My wife no longer even asks what I am working on in the shop. Instead she posts a picture to her facebook group under the hashtag #married to an engineer. She makes it a guessing game as to what I am working(wasting my time) on. She usually doesn't have a clue. Toymaker, are you subjected to that kind of emotional abuse because of you tinkerer affliction? Very sad.

My wife is getting even buy adding to her 'gone nova' yarn stash and her own projects. (LOL)

 

[william_b_noble]

ok, on my air compressor specifically, it is a Quincy (I don't remember the model #), it's an industrial unit with an oil pump and gauge, 80 gallon tank and I have it set for 160 psi, it will deliver about 21 CFM at that pressure if I remember the specs correctly. It does not get annoyed or bothered when it runs straight for several hours while I paint, or sand a car. The smaller (8 cfm) Craftsman compressor that preceeded it got hot enough from painting a car that the paint burned off the cylinder head, the rings cracked, and it needed a rebuild. This Quincy just doesn't do that - on the other hand it weighs about 800 to 900 pounds and it's kinda hard to move around. I do find that a nice quality air compressor is a great luxury. And it's much quieter than the small cheap ones. in the 30 years or more that I've had this (I got it used from an industiral supplier), it has had the capacitors fail due to vibration (e.g. a mechanical not electrical failure) and I had to replace a pressure relief valve that started to leak, and I've changed the oil once. The compressor I have is a much older unit that is vaguely like this one Quincy 253DS80HCB23 QT Pro 5-HP 80-Gallon Two-Stage Air Compressor 230V 3-Phase.
~
if you are buying a compressor, do not look at the HP, look at the CFM at your anticipated working pressure. I have seen "5hp" compressors that delivered less air than the 2 hp sears compressor that I stopped using. A good industrial compressor is generally 1000% better than the best thing at a big box consumer store, adn 100,000% better than Harbor Freight (or equivalent). Hyperbole for emphasis.