# AC to DC conversion.



## dr. awsome (Nov 17, 2009)

The motor on my old craftsman lathe bound up on me last week. I thought this would be a good time to try and swap to an DC motor so I can have a variable speed motor. I've heard it's common to use a treadmill since it already has the AC to DC converter, motor, and speed controller. Has anyone here done this swap? I have a buddy that has a treadmill he's going to give me for this, but I want to get as much info on the swap before I start tearing into it.


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## SpudsMcGirt (Feb 9, 2010)

*DC conversion*

This might not be worth it, but you can get an AC VFD for your lathe. AutomationDirect.com sells a 1/2HP VFD for less than $120. You need a 3phase AC motor, but if you can scrounge one, worth it from my experience.


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## mranum (Mar 27, 2008)

Not sure if you have or haven't done this yet since this is an older post(and I don't get on here as often as I should), however I just did the treadmill conversion to my Shopsmith in January. 

It went very well, I was able to find a treadmill for free that had a 1.5hp DC motor in it. I stripped the entire treadmill of its components and basically all I did was shorten up the wiring and move the components to a different box. I left the flywheel on the motor and decided to use it for my pulley. I clamped the motor to my bench, hooked all the wiring up and turned it on and ran it slow while I took a bastard file and cut a groove into the pulley. It took a little while, maybe 30 min or so to get it where I wanted it. The control board had 4 POT adjustments on it, 2 were for speed(low and high end) the others I figured out were for torque and governor response to a load.

Overall I have to say that I love the results, especially considering the conversion cost me a whole $15. I have the speed range set from roughly 100rpm -3000rpm with good response to loads. I have another old Shopsmith that is waiting for its overhaul and I will be doing the same conversion to that one as well. I have only 1 complaint, and that is it has a built in time delay on start up. Turn it on and count to 5 then it starts nice and slow. Not really much of a pain just takes some getting used to.

The gray box with the dial is my control box.


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## dr. awsome (Nov 17, 2009)

Thanks for the reply! Your the first person I've been able to find that has done this to their lathe. I haven't had time to do the swap yet since I've had to much to do on the house and other projects. Hopefully I'll be able to work on it soon.


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## john lucas (Sep 18, 2007)

Back on Woodcentral several years ago there was a discussion about using treadmill motors. You might be able to do a search there and find the info. www.woodcentral.com go to the turning messageboard. 
There was also a way to bypass the slow start function. I bought 3 of the motors and controllers but was only successful in getting one of them to work. I had controller problems with the other 2 and have never been able to even get the motors to work. 
If you use one straight from the machine without modification It should work fine.


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