Variable speed control

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K

KJohn Woodworks

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Oct 27, 2017
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Location
Ravenna Ohio
Hello everyone. Quick question. I have an old Rockwell lathe that is belt driven. Speed is controlled by changing the belt on the pulleys. Can I incorporate a speed controller if I set the pulleys on the highest speed?
Thank you
 
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Key is there is not a quick cheap way to make a fixed speed induction motor into a variable sped motor.

The variable speed controllers used with routers and sewing machines (universal motors) do not work with motors built to run at a constant sped.

The lowest cost rectified dc motors lose torque severely at lower rpms and lathes with these motors have fewer pullies, typically 3 rather than 6.
 
I'm not sure what size your lathe is, but Penn State Industries has a variable speed motor kit for midi-sized lathes. I put one on my Delta Midi when the old motor started to give out and I really like the new variable speed. Super easy to install and works great with a turn of a knob to change the speed. https://www.pennstateind.com/store/TCLVSKIT.html

Just a thought...

Jim Smith
 
Yes it's a one speed lathe, but I am not sure your getting the picture. Most but not all variable speed lathes still have pulleys for low, med and high speeds but incorporate a special motor and a speed drive to power it. As said in previous responses the cost to change your lathe over will exceed the price of a new one. Believe me I have done it.
Lin
 
I have 2 of those lathes, they are the Delta Rockwell 46-111. The belt change system is so simple that spending the money on a variable speed motor would be wasted dollars. If you think you have to, look at industrial sewing machine servo motors. But beware, you loose all kinds of power at the slower speeds.
 
Your motor can't be made to do variable speed. You would need to buy a 3 Phase delta wound 220 volt motor. They are common in industry and are relatively inexpensive. To make it variable speed you will have to buy a variable Frequency Drive (VFD) to mate up with the new motor. The VFD takes the single phase house current and changes it to three phase and allows you to adjust the output to run the motor faster or slower. The existing motor is 1/3 horse power so you might want to get a more powerful one like a 3/4. So it should be about $200 or less especially if you can find a used or surplus one. You can get a good VFD from China for under $200 to your door. You would then need to hook up the wiring and then figure out how to setup/program the VFD. Mine came with a manual of almost 100 pages. Most of which is for advanced stuff it can do but you only need 10% of that. You would need to set up the maximum speed, startup, shutdown rates, reverse (only if you know that a chuck can unwind itself if it does't have a lock) and maybe pre-program some speeds you use the most. Simple if you are into that kind of stuff and something to pass on to a buddy if you aren't. As Kryn says it starts making a new lathe look good.
 
I understand now. For the little time it takes to change the belt to a different pulley it's not worth changing the motor out. At some point I may upgrade but being fairly new to turning this is good enough. Thanks for all the responses.
 
I have the small possibly discontinued Harbor Freight Mini VS lathe and I can't imagine moving a belt to change speed. If/when I move up I'm going to get a VS lathe either electrical or mechanical.

But...... could a DC motor and controller be removed from an old tread mill. I swear I have heard of doing this.
 
Last edited:
chartle said:
I have the small possibly discontinued Harbor Freight Mini VS lathe and I can't imagine moving a belt to change speed. If/when I move up I'm going to get a VS lathe either electrical or mechanical.

But...... could a DC motor and controller be removed from an old tread mill. I swear I have heard of doing this.
Click to expand...

Absolutly it can and has been done. There are a few challenges including mounting the motor as they are normally face mounted, handling the cooling fan commonly mounted on the shaft, and dealing with quirks of treadmill controls.

One can also adapt wheelchair motors.....

One has to really like working with adapting fitting rather than turning as it takes a fair amount of time and effort.
 
Jim Smith said:
I'm not sure what size your lathe is, but Penn State Industries has a variable speed motor kit for midi-sized lathes. I put one on my Delta Midi when the old motor started to give out and I really like the new variable speed. Super easy to install and works great with a turn of a knob to change the speed. https://www.pennstateind.com/store/TCLVSKIT.html

Just a thought...

Jim Smith
Click to expand...



Hi Jim

I have been considering upgrading my delta midi. I am just worried that the penn state upgrade is only 1/2 hp. Have you had any issues with the lower power.


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