Repair lathe motor?

Well you would always have the cheap spare even if you replace the current motor with a better one. A motor like that would be a spare for several small pieces of equipment. Whatever keeps you going for now is probably what's best. The repulsion induction motors were truly head and shoulders above the others in their day, but we do all get older. It has been many years since i have seen one of those still in use. I found several of my old electric motor repair books and would gladly copy you or send it to you to use and return when you are done. It's a pretty comphrensive book though i didn't have time to go through it last night to see how well it covered the repulsion motors. If you have an interest in it i will look through it and see if it looks like it would be worth the postage to get it to you. Let me know where you are at with it and i will try to help if i can. Good luck!
 
Kevinb71 said:
Well you would always have the cheap spare even if you replace the current motor with a better one. A motor like that would be a spare for several small pieces of equipment. Whatever keeps you going for now is probably what's best. The repulsion induction motors were truly head and shoulders above the others in their day, but we do all get older. It has been many years since i have seen one of those still in use. I found several of my old electric motor repair books and would gladly copy you or send it to you to use and return when you are done. It's a pretty comphrensive book though i didn't have time to go through it last night to see how well it covered the repulsion motors. If you have an interest in it i will look through it and see if it looks like it would be worth the postage to get it to you. Let me know where you are at with it and i will try to help if i can. Good luck!
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Thank you very much Kevin. Don't go out of your way but if you happen to get bored and are looking through the repair books and find something that may help, let me know. I'd be more than happy to foot the cost of getting that info. It may be enough to let me know the book you find the info in as I may be able to track it down myself. If not, we aren't too far from each other so it shouldn't be too bad to work something out.

-Ron
 
I will second that. I when I went through this I C clamped a dime a dozen washing machine motor on
my SB I dont know if you have F&Reverse just make sure to mark these wires. Rather than fool with it
a local motor shop did it up for $30 must have been something simple, anyways I ran the lathe all
summer with that freebe motor. i never use reverse anyways sam
 
I'm not seeing any photos or drawings, so will have to go with the written descriptions. Repulsion motors were popular back in the days of 30-amp house entrances for running refrigerators, since they have a lot of starting torque without drawing much extra current (typically, as I recall, 150% of full-load current). Wagner motors were repulsion-induction, meaning they started as repulsion motors and then lifted the brushes at speed, while a ring of copper segments expanded inside the commutator to short the bars, converting the rotor to a squirrel-cage, and then the motor ran as an induction motor.

I know GE made straight repulsion motors (with no brush-lifting mechanism) because I have a 2HP running my belt sander. They may have made R-I motors too. In a straight repulsion motor, the brushes (probably two, at 90 degrees to each other) are fixed in the motor frame. It's not unusual for brushes to stick in their holders and not contact the commutator properly. Brush springs can lose their tension also if they are carrying electrical current (there is supposed to be a copper braided pigtail for that).

Commutators can be faced in a lathe, as noted, but the copper is soft and doesn't machine cleanly. Back when I worked summers in a motor shop I don't recall that we ever repaired small R-I motors; it wasn't economical. Undercutting the mica can be done by hand, with a broken hacksaw blade ground to width and with a hook on the end; you pull it toward you. It's slow work but you're not paying shop time.
 
Interesting, thanks. I'm thinking that what I'm going to do is to find a nice single phase motor to put on the lathe. Once I get that swapped out I can worry about rebuilding the old one at my leisure.

Any recommendations on a "good" motor? U.S. made?

-Ron
 
ScrapMetal said:
Interesting, thanks. I'm thinking that what I'm going to do is to find a nice single phase motor to put on the lathe. Once I get that swapped out I can worry about rebuilding the old one at my leisure.
Click to expand...

Good idea. :D

Any recommendations on a "good" motor? U.S. made?
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Those are not necessarily equivalent things. It may be very difficult to find a new motor made in the US, period. If you do, be prepared to pay 3x-5x the price of otherwise.

You have some choices to make.
1. AC or DC?
DC gives variable speed and high torque at all speeds.

AC is easier to find, (usually) has lower starting torque, and is harder to vary speed on - which may not matter to you.

2. Same or larger power rating/voltage/etc.
- If you're buying a horse, you *may* want a bigger one.
- measure the physical sizes of the motor, shafts, and mounts of the one you have if you want a semi-drop-in, then read the spec sheets on the proposed replacements to see how hard it will be to make it fit and what you have to machine to do this.

3. If AC, what kind?
- 3 phase is the premium in terms of smooth power and torque, but hard to power; may need static converters, VFDs, rotating converters, etc.
- 1 phase is easier, but needs help to start quickly and run smoothly. Capacitor start makes it have higher starting torque. Capacitor run makes it have more and smoother torque at speed.
 
Thanks R.G.

Yes, lots to consider. About the only reason I was tending towards AC single phase is cost. While the 3-phase and DC motors might not be all that much more expensive than an AC single phase (I don't really know as I haven't tried to price anything as of yet - so guessing here.) if I were to go with DC or AC 3-phase I would need other equipment to be able to use those motors.

It is my understanding that a DC motor also needs some kind of controller as well. Since I don't have 3-phase in my shop/garage (even though I'm only about 50' from the nearest transformer) I would either need to have it run at my expense or purchase a VFD or converter. How do these real stack up against each other cost wise?

Sorry about the "good" and "U.S. made" thing, that was really a poor choice of phrasing on my part. I know there are some beautiful motors of foreign manufacture and that "U.S made" is not the "end all" of everything. On the other hand, I do prefer to buy American made goods as longs as they are of equal or superior quality and are available at a competitive price. The quality of the component is the major deciding factor, not necessarily where it is made.


Thanks,

-Ron
 
Ron why don't you check out ebay for a motor? You mite find a older one made in the USA. I have gotten a few period motors off of there.

Paul
 
Good idea. I just spent the last hour going through the e-bay "selection". Not as much there as one might think. Funny thing, the couple of newer motors I saw on there linked back to Northern Tools (I was looking through their catalog last night.)

I need to measure the current motor shaft to see if I can use the same pulley. It might not hurt to get measure the bolt pattern, clearances, etc. either. :thinking: Always seem to need "more information". :rolleyes:

No comments on the comparative price - AC - DC - 3/1 phase thing?

-Ron
 
I will check and see what I have in my spare motor pile after you post the size info.
 
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