I have never seen a major commercial CNC manufacturer use steppers, and I have been retro-fitting them since the late 80's.
The old Getty's and Fanuc DC servo's could achieve 2000rpm at that time and controlled down to zero.
They had no Heatsink on them.
They were controlled at the manufactures constant torque.
There are VFD's out there that can position a 3phase motor induction motor, as in gantry crane lift motor and also they have been used on elevator control.
Max.

You guys are making me want to get a CNC mill, and I don't have room for one! Cut it out!

 

You guys are making me want to get a CNC mill, and I don't have room for one! Cut it out!

Even a non-CNC mill is a wonderful tool, but I don't have room for one either. And an interesting thing is that I have turned a number of round parts on a Bridgeport mill at my last employers shop, since they did not own a lathe at that location. Not many EEs can make that claim!

 

Even a non-CNC mill is a wonderful tool, but I don't have room for one either. And an interesting thing is that I have turned a number of round parts on a Bridgeport mill at my last employers shop, since they did not own a lathe at that location. Not many EEs can make that claim!

Yes, I have, in the grand plan, an outbuilding as shop. It will do wood, metal, electronics, and, though magic I have not yet worked out, be a photography studio as well. It's several years out on the plan, however.

 

You guys are making me want to get a CNC mill, and I don't have room for one! Cut it out!

One reason I purchased this house was it had a shop and garage combined, I picked up a couple of XLO knee mills that had obsolete CNC controls and retrofitted them as well as converting a 39" Chinese lathe to CNC.
Max..

 

One reason I purchased this house was it had a shop and garage combined, I picked up a couple of XLO knee mills that had obsolete CNC controls and retrofitted them as well as converting a 39" Chinese lathe to CNC.
Max..

Our house is really wonderful, but it was built in 1941 to retire into, so the garage is... not adequate. The property used to be twice as large, but they subdivided it and built a house on the other half in the 70s.

Still, it's a wonderful house, I call it my "terminal residence" because I will be carried out of it in a box if I ever leave it permanently. So, if there is going to be a decent shop, I am going to have to cleverly build it. It is why my electronics bench is compact, though that will expand when I shift the lab/photo studio to one of the larger rooms.

 

So, if there is going to be a decent shop, I am going to have to cleverly build it.

Post has wandered a little, but it is surprising what you can do with some of the small bench-top CNC's now.
Max.

 

Post has wandered a little, but it is surprising what you can do with some of the small bench-top CNC's now.
Max.

Perhaps this an off-topic threadlet.

 

Still, it's a wonderful house, I call it my "terminal residence"

I am hanging in there as long as possible, as SWMBO keeps on giving very pointed hints we should down-size!
Max.

 

I am hanging in there as long as possible, as SWMBO keeps on giving very pointed hints we should down-size!
Max.

Well, we chose a house that could accommodate our visiting children and their children, and a house the grandkids will remember as a great place from their childhood.

 

Plus, normally motors that are designed to run at low RPM have a higher number of windings (poles) in them.

To get back on track and just to make a point here, the Johnson T.M. DC motors I favour, have 32 comm segments, and 16 poles.
Compare this to a BLDC servo motor which at the typical maximum is 8 pole.
I was once told by a salesman when BLDC came out that I would need gearing to use as a servo due to 'cogging' at low rpm's, I have since used them in CNC applications with direct drive, open loop yes, but once you have a decent PID controller they are smooth as silk.
Max.

 

Not really 'Old' they are used in current machines replacing the old induction ones!
Max.

By "old" I meant don't go out and buy a new one. Often you can pick up a "used" one for next to nothing, although the Fisher and Paykel motors are very popular for wind and hydro generators, so there is quite a demand for the,.

 

I very much doubt you'll find any motor ,short of a gear motor that will like going that slow. That is the reason they make gear motors and things like belts, pulleys, chains and sprockets. You still haven't addressed what you're trying to do.

well the sewing machine motor went slow...

I suppose I could just find out what kind of motor the sewing machine motor is and also what kind of speed controller the the foot pedal is. just had that idea I think I could go that route.

 

The very old ones were Universal motors with a variable resistance in the pedal, pretty crude, the latest ones typically use BLDC motors, with much better control.
Max.

 

well the sewing machine motor went slow...

I suppose I could just find out what kind of motor the sewing machine motor is and also what kind of speed controller the the foot pedal is. just had that idea I think I could go that route.

And the sewing machine motor only works for seconds or minutes at a time. And if run for many hours will get very hot. And Max probably guessed what type motor you have. If it looks like this -


Not trying to be nosy but why won't you say what your "experiment" is? Then people can give a real answer not a bunch of guesses. And that is all we're doing for you, guessing by long distance!

 

To get back on track and just to make a point here, the Johnson T.M. DC motors I favour, have 32 comm segments, and 16 poles.
Compare this to a BLDC servo motor which at the typical maximum is 8 pole.
I was once told by a salesman when BLDC came out that I would need gearing to use as a servo due to 'cogging' at low rpm's, I have since used them in CNC applications with direct drive, open loop yes, but once you have a decent PID controller they are smooth as silk.
Max.

So is there a specific kind of speed controller I would need for one of those? basically could I slowly rev it up? I just need to be able to slowly rev it up and control its speed.

And the sewing machine motor only works for seconds or minutes at a time. And if run for many hours will get very hot. And Max probably guessed what type motor you have. If it looks like this -
View attachment 171837

Not trying to be nosy but why won't you say what your "experiment" is? Then people can give a real answer not a bunch of guesses. And that is all we're doing for you, guessing by long distance!

Yes that's the exact motor I have. I think youre right it got extremely hot quickly. I just need a motor and a controller that can be controlled like this motor.

The motor is going to power a contraption I've been working on for over a year. Basically I don't really want to explain it. I tried to tell you the closest example to it which is a ball mill. Sorry. ​

 

Have you thought of using a variable speed electric drill to power the top secret?

 

So is there a specific kind of speed controller I would need for one of those? basically could I slowly rev it up? I just need to be able to slowly rev it up and control its speed.

The T.M. motor and controller is one that is often used by the machining community.
The controllers for these come in two types, SCR bridge and PWM, the latter being the better selection.
They have some degree of RPM/current control in them. If you want very precise control you would need to go with some kind of closed loop.
Some leave the flywheel on these motors for stable rpm, but you loose the ability for fast response (accel/decel).
Max.

 

I've seen ball mills from 10 in. dia. 3 lb. loaded to 10 ft. X 30 ft. in cement plant.; which is yours?

 

I've seen ball mills from 10 in. dia. 3 lb. loaded to 10 ft. X 30 ft. in cement plant.; which is yours?

He could tell you, but then he'd need to kill you.

 

The T.M. motor and controller is one that is often used by the machining community.
The controllers for these come in two types, SCR bridge and PWM, the latter being the better selection.
They have some degree of RPM/current control in them. If you want very precise control you would need to go with some kind of closed loop.
Some leave the flywheel on these motors for stable rpm, but you loose the ability for fast response (accel/decel).
Max.

What does T.M. stand for? also what about SCR and PWM? I couldn't seem to get a good example on google for T.M. other than torque motor but even then I wasn't able to find much on those either doesn't seem like an actual type of motor.

What do you mean by closed loop? Also I have no need for fast response times all that matters is the ability to gradually turn up the speed.

Thanks for helping me

He could tell you, but then he'd need to kill you.

I've seen ball mills from 10 in. dia. 3 lb. loaded to 10 ft. X 30 ft. in cement plant.; which is yours?

It an infusion device. Used to infuse stuff under vacuum. The whole thing spins and has a glass distillation flask on it. Its similar to a ball mill only its held securely in a fixed position that can rotate in either direction. Since I'm only experimenting with it I need to explore the full range of rpms and since I haven't gotten it to work yet I don't know how fast I even need it to go yet hence the need for higher rpms than a normal ball mill would need. Sorry I didn't say this before I just have depression and find it hard to think sometimes.​