Repair lathe motor?

Having worked in a motor shop 25 yrs ago while I was going to school I will tell you what I learned.
Before doing anything else check how much "up and down" and "in and out" play there is on the shaft. Then pull off the capicitor as mentioned by R.G. A motor shop or some electricians can test this with a meter. If that all is ok then do the following.
1. Next write down how the wires are hooked up now. By color code or on a motor of that age by number on the wires! GE was always a little different than everybody else.
2. Before you pull the four long bolts holding the end bells to the middle(stator) section scrib a line fom the end bell on to the main body. One line on the shaft end bel and main body and two lines on the opposite end(start switch end. These are for reference later to get the end bells back on in the same position. Some of these older motors weren't always machined perfectly and if you get them "out of line" you can mess up the clearance of the rotor to the stator and it's hard to sort out.
3. Take and tap the end bell shaft end loose from the main body and slide the rotor and end bell out of the stator. That way you don't have to fight with/break the start switch and wiring. It's all at the "non shaft" end. There will be a centrifigal switch operator on the end of the rotor. It probably has two springs and a flat plate/washer that you should be able to push in on and it will pop back out on it's own. This operates the start switch.
4. Take a look inside at the motor windings. It's usually fairly obvious if the windings are burned out. Some will be bright or maybe a dark copper color and some will be "BLACK". If the are portions that are black you would probably need a different motor. They can be rewound(i did it ) but it is harder than I can explain here plus you have to find the right size wire.
5. Tap the other end bell loose carefully and watch how the wires are routed to the switch and windings. carefully lay the end bell down interior side up. The start switch will be mounted to the end bell. There are usually one or two contacts on the switch. Do they appear good and clean or dark and burned? Think points on a car(if you are old enough to know what they are:biggrin:.
iF ALL THIS APPEARS GOOD. How much play in and out play was there? Sometimes they wear out fiber washers(on the shaft between the shaft and end bell) and to much play won't let the start switch work properly.

The old motors like this one really are the best ones ever built (LOOK AT HOW OLD IT IS NOW) and if you can get it back up and purring that's how I'd go.

Post a picture or two of the inside if you question how something looks.
 
If it spins freely, and has no grit, resistance, or slop, you just saved yourself a fair amount of trouble. Bearings only need rebuilding if they're bad, and if they're not bad, rebuilding doesn't help at all.


That would be a help. Bad connections/wires can be a problem; so can the start and/or run caps.

It is possible that there is a bum contact that only opens or shorts when it warms up. I've run into that.

Are you familiar with an ohmmeter? This is one of the settings on most electric multimeters. This can tell you if there is any electrical connection between the two probes. It's used for measuring resistance (ohms) and also for detecting the difference between open circuits and short circuits (that is, very low resistances). The motor should have two or more wires going in, and a third wire attached to the motor frame or one end bell. Neither of the power wires should be connected (shorted) to the frame, either end bell, the shaft, or the third wire safety ground. If either one shows resistance under maybe 1 megohm, the motor windings are compromised. If they're both over 1M, it's something else.

See if you can find out the value of the start and/or run capacitor, which should be in the "bulge" outside the motor frame.

Having worked in a motor shop 25 yrs ago while I was going to school I will tell you what I learned.
Before doing anything else check how much "up and down" and "in and out" play there is on the shaft. Then pull off the capicitor as mentioned by R.G. A motor shop or some electricians can test this with a meter. If that all is ok then do the following.
1. Next write down how the wires are hooked up now. By color code or on a motor of that age by number on the wires! GE was always a little different than everybody else.
2. Before you pull the four long bolts holding the end bells to the middle(stator) section scrib a line fom the end bell on to the main body. One line on the shaft end bel and main body and two lines on the opposite end(start switch end. These are for reference later to get the end bells back on in the same position. Some of these older motors weren't always machined perfectly and if you get them "out of line" you can mess up the clearance of the rotor to the stator and it's hard to sort out.
3. Take and tap the end bell shaft end loose from the main body and slide the rotor and end bell out of the stator. That way you don't have to fight with/break the start switch and wiring. It's all at the "non shaft" end. There will be a centrifigal switch operator on the end of the rotor. It probably has two springs and a flat plate/washer that you should be able to push in on and it will pop back out on it's own. This operates the start switch.
4. Take a look inside at the motor windings. It's usually fairly obvious if the windings are burned out. Some will be bright or maybe a dark copper color and some will be "BLACK". If the are portions that are black you would probably need a different motor. They can be rewound(i did it ) but it is harder than I can explain here plus you have to find the right size wire.
5. Tap the other end bell loose carefully and watch how the wires are routed to the switch and windings. carefully lay the end bell down interior side up. The start switch will be mounted to the end bell. There are usually one or two contacts on the switch. Do they appear good and clean or dark and burned? Think points on a car(if you are old enough to know what they are:biggrin:.
iF ALL THIS APPEARS GOOD. How much play in and out play was there? Sometimes they wear out fiber washers(on the shaft between the shaft and end bell) and to much play won't let the start switch work properly.

The old motors like this one really are the best ones ever built (LOOK AT HOW OLD IT IS NOW) and if you can get it back up and purring that's how I'd go.

Post a picture or two of the inside if you question how something looks.

R.G. - Yep, I'm familiar with ohmmeters, I don't have a Simpson 260 sitting around but I can pull out my Fluke 87 and get pretty much the same thing done. :p:lmao: (Sorry, had to mess with you a bit even though you have no way of knowing that I majored in electronics engineering some 25 -30 years ago. :biggrin:) Good advice given. I'm not familiar with the layout of this old of motor though. I will be trying to get some good pics tomorrow. I may even be able to get some pics on the interior (wife got me an electronic bore-scope for Christmas that I haven't had a chance to use yet). Oh and no real "bulge" on the motor itself, pictures again. ;)

Kevin - Where to start? Okay, write down the wire hookups? All black. :banghead: Wait 'til you see the pics, you'll love it. :p The motor shaft itself it rock solid, no extraneous movement up, down, in or out. I really like the attitude, "The old motors like this one really are the best ones ever built". :thumbzup: I'd like to save it too.

Pics to come shortly,

-Ron
 
R.G. - Yep, I'm familiar with ohmmeters, I don't have a Simpson 260 sitting around but I can pull out my Fluke 87 and get pretty much the same thing done. :p:lmao: (Sorry, had to mess with you a bit even though you have no way of knowing that I majored in electronics engineering some 25 -30 years ago. :biggrin:)
Another EE? Ok. And may God have mercy on your soul. :D I do have a Simpson 260, but it was given to me as a legacy.

no real "bulge" on the motor itself
Mmmmm. That probably means they got self-starting with a resistance-split phase. The lower-end induction motors bypass the motor start and run caps with a high resistance winding. At startup, the main power winding is low resistance and appears highly inductive, and the high-resistance winding keeps a nearly resistive impedance. This makes for a partial second phase, enough out to let the rotating magnetic field get the rotor moving, and after that, induction takes over and the reaction of the rotor field keeps it running like it would if it had a start cap that dropped out.

That gets you lower starting torque than a capacitor start or run motor. Still, it's been working for you. That opens your range of replacements a bit. If it were me, I'd look for a cap-start or cap-run motor to replace it. These versions have better starting torque.

I bring this up because the lack of a capacitor phase split means that it's not as simple as clipping in another cap. If it's a resistive-split phase, that puts it into the rewind or replace category, because there's only the windings doing the work. I'm not a motors expert, but I played one back in the power supply design lab. :D


Kevin's advice is really, really good. Pictures, lots of pictures, and disassemble so you can find and fix.

However, at this point, my 'it's gotta work by tonight' demon prods me and says that you oughta buy a physical replacement motor used and cheap, install it in the lathe, and then work on refitting the old iron.
 
You know, I wonder if the motor is jumperable 110/220 and the jumpers have corroded.

And I wonder if the continuous increase in wall-socket voltage is just flat overvolting it. Wall sockets used to provide 110Vac, as the name plate says. Over time this has increased until I get 125Vac out on the end of a long, skinny, rural distribution wire. This is a common problem in vintage guitar amps (I deal with these in my day job) and can wear them out pronto. In a motor, it would lead to heating, and the cumulative effect could be to burn wire insulation.

Just speculation.
 
NO PICKING ON THE 260's!!! I have a fleet, and a couple of 160's as well. I use a 260 regularly.
 
oh man! it is getting thick now! ( and creamy!):biggrin:

another vintage amp guy... can`t beat glowing tubes!!:thumbzup:

Make that another :+1:



Also have a Matamp Minimat and the wife bought me a Mesa Transatlantic TA-30 Combo for Christmas. :biggrin:

NO PICKING ON THE 260's!!! I have a fleet, and a couple of 160's as well. I use a 260 regularly.

:lmao: No problem Tony. Most of my experience with them was back in school and their survival rate was horrendous with many of the students (true "dip sticks" ) switching ranges without disconnecting and frying them left and right.

Okay guys, I promised some pics today. Here goes.





Under the little "oval" plate is access to the brushes. I couldn't get a clear picture of them so I didn't bother to post the resulting blur.





And finally, my favorite...



Nice installation huh? :rolleyes: :lmao: I haven't dared to take off the old cloth electrical tape as it's a little "crunchy" and I'd rather keep the lathe "runable" 'til I'm prepared to actually do something about it.

-Ron
 
Make that another :+1:
You're doomed. At least you haven't developed a taste for JMI Vox amps. Might as well like absinthe.

Comments on pictures:
(rating plate)
OK, 1/2Hp, 110V 60 cycle 1780rpm (that's good), foot mounted. If you'll measure the shaft diameter and footprint hole pattern, you can pretty much directly pick a replacement. I think...

Under the little "oval" plate is access to the brushes. I couldn't get a clear picture of them so I didn't bother to post the resulting blur.
... brushes... ?? There are brushes in there?? Are you sure?? One of the reasons to use a split phase induction motor is that it doesn't need brushes at all, so there's nothing to wear out.

Is there a commutator or slip rings in there?

Are you sure it has brushes?? Brushes make it into a different animal. If there is a commutator in there, it's a big "universal" type. If there are slip rings, it's a wound-rotor type. I've read about wound-rotor induction types, but I don't think I've ever actually seen one.

Is that maybe access to a centrifugal switch to switch out the start winding?

Brushes... AAACCKK!!! Brushes...

Nice installation huh? :rolleyes: :lmao: I haven't dared to take off the old cloth electrical tape as it's a little "crunchy" and I'd rather keep the lathe "runable" 'til I'm prepared to actually do something about it.
That last run of comments flips my advice over to "find a used replacement motor and put it in. Then do your rebuilding at a leisurely pace."

Look here: http://austin.craigslist.org/tls/2877966495.html
I think numbers 3 and 4 might drop in if they are foot mounted. Can't tell from the pictures.
 
Hah! I ran the model number through Google. I got 10 hits, all originating from HM. :lmao: There's not much info on that motor on the net.

Is it possible that what you are seeing under the oval plate is the start switch mechanism? You don't usually see a universal motor in that size. (At least, not any more.) If it was for brushes, I'd expect to see another plate on the underside.

If the start switch is not opening, it will keep the start winding in play all the time. This will definitely cause quick heating. Try removing the oval plate and watch the switch mechanism while it is starting up. If it is opening, you will usually see a spark and hear a click when the start winding drops out. If not, check for grunge on and around the mechanism, broken springs, or pieces obviously out of place.

According to the plate, it is 110 Volt only. The fact that there are four leads coming out to the JB shows that it is likely reversible.

If you do take the connections apart, pick up some screw terminals large enough to take all the necessary wires. They come is strips of 12 and can be cut to length.
P4210014a.jpg

P4210014a.jpg
 
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