Usually the bearings (AKA CHEAP Bushings) wear out, letting the motor armature touch the field coils, and lock them up.
Sometimes you can "Fill in" the low spot on the bushing with whatever you can get to stick in the low spot=JB Weld, pop/beer can metal, or anything that you can get to center the shaft of the armature.
Some motors can be dis-assembled and bearings fitted to replace the bushings??, but is it worth it??==Your choice.
My choice==Dillon==I have the large (On the second motor) and the small model..BTW: The small model Dillon uses the same motor as the large model, and seems?? to last longer..
My Dillon tumblers have A LOT of hours on them..Bill.
PS: The Dillon tumblers DO use bearings on the motor shafts...
All of the tumblers I've seen use a simple "shaded pole" motor with a weight that makes the whole thing out of balance. Because of the out of balance condition, the bearings fail.... All of those motors I've seen use standard skate board bearings (i.e. 608 zz)which you can get 10 for $10 on Amazon pretty easily. I rebuilt my Franklin Arsenal one several times. Just watch out in that the armature looks like it could be reversed, but if you do, then the motor doesn't have the ability to start spinning. (Don't ask me how I know )
I tried to repair a different brand. I assumed my decades in the electrical field would allow me to fix it. Wrong. The proprietary motor had worn through the sleeve bearing and bearing holder. The motor was welded and staked together and a new motor would cost as much as a new cleaner, especially when there are "like new" cleaners listed in the classifieds all the time. Toss it and get a new one.
lol. just checked back on this. I got as far as taking to bowl off of it and got side tracked yesterday. I do have a dillon CV-2001 that i'm using now...
Here is a source for many different AC and D.C. Motors. Never know what they will have. Www.surpluscenter.com. Often have low rpm and shaded pole motors.