# Repair lathe motor?



## ScrapMetal (Mar 29, 2012)

I have (as best I can read off the tag) a GE, Model# 5SCA65AA6, Type SCA, 1/2 HP, single phase, 110v motor powering my SB 11".



The motor gets very hot and it does it rather quickly.  It will start to make "strained" noises short time which can be alleviated by oiling the bearings but it only lasts for a short time.  Applying the oil to the bearings is like dumping it on the ground as the oil just runs through it.  Yes, I can switch to a higher viscosity oil but I'm pretty sure the bearings need some work.

 How much effort is it to rebuild one on these?  Am I looking at bearings or bushings?  Is it "worth it" to try and rebuild this motor or just go with a newer and probably more efficient option?

I'd like to hear some opinions.

Thanks,

-Ron


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## Tony Wells (Mar 29, 2012)

Likely sleeve bearings, which are babbit plated steel. You could make some new ones of bronze, but you would need another lathe. Unlikely, but not impossible that a motor shop would sell you some. They press in, which of course means knock the old ones out with a drift, and press in the new ones, aligning the oil hole.


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## 8ntsane (Mar 29, 2012)

Ron
I would look around, and get a general idea of price for a motor in your area. If new is out of the price range for you , a used motor might be worth looking in to.
I maybe wrong, but the bearings would normally be greased,No?  I would also guess the bearing , or bushings should be fairly inexpensive, and shouldnt break the bank.

The only bummer about this, is once you pull the motor and tear it down, your lathe is down too. And you know the deal, thats just when you might need it.
Regardless, it might be worth taking it apart, just so you know what it needs, and how bad it looks inside. This might save you the BS of ordering bearings / bushings and wishing you just looked for another motor to start with.

Might check the local craigslist for a good used replacement first.


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## Tony Wells (Mar 29, 2012)

If you have a mill, you don't need a lathe to make new bushings, if it is a bushing as I suspect because of the oilers. You'll have to tear it down to see. I'm another who prefers repairing old motors if possible.


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## R.G. (Mar 30, 2012)

If it were mine, I'd pull that belt off the motor pulley and turn it by hand - er, power off, of course. If it's the bearings, you can feel it, and see how long it spins after being given a turn by hand. If it spins easily and smoothly, it's not the bearings. If it's hard to turn, yep, bearings or some built-up drag mechanism inside.

It could well be the motor start/run cap going bad. If that has not been replaced in your memory, it wouldn't be all that bad an idea to just replace it if the rest of the motor checks out. Motor caps are $5 to $20 items at HVAC supply places. This could cause the heat all by itself in some cases. A *shorted* or going-low-resistance motor cap causes a big electrical drag on the motor's rotation, as well as pulling a lot of current. 

The other option is to trouble shoot by telephone. I'd spend an hour calling motor rewinding shops within a reasonable driving distance. I've had alternators rewound in the past; this cost in the range of $30-50. I don't know about induction motors. 

Electrical motors are highly standardized. If you can get the motor speed  off the rating plate as well as the other numbers, any 1/2HP 120Vac --same speed-- rated motor with similar mounting will work, and may be cheaper as a surplus item.

A quick look at ebay shows:
http://www.ebay.com/itm/ELECTRIC-MO...601?pt=LH_DefaultDomain_0&hash=item3a698c7029 : 1/2HP 120vac 1ph 1800rpm, $110 including shipping, new, 5yr guarantee
http://www.ebay.com/itm/1-2-HP-ELEC...789?pt=LH_DefaultDomain_0&hash=item3a6b4ce97d : 1/2HP 120VAC 125rpm, $100 including shipping, reversable

searching on "electric motor 1/2HP"  turns up 13 pages of motors. You have to match the voltage, phases, power and speed, as well as the mounting, which is a foot type on yours. 

And, just because the devil is sitting on my shoulder tonight, if you were to buy a DC motor, you'd get infinitely variable speed. You'd have to get one rated for the same or higher HP (note, treadmill motors are notoriously overrated) and about the same speed, you'd only have to adapt it and a DC motor controller to get really wide speed variation.


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## ScrapMetal (Mar 30, 2012)

Thanks guys.  I personally like the idea of rebuilding but, as mentioned a few times, once I pull the motor my lathe is kaput.  If I had a mill that would simplify things but the closest things I have at the moment are a crappy drill press and a huge doorstop that looks kind of like a shaper.

I don't know any of the history of this motor as it was bought with the lathe, from the widow of the previous owner.  

Tony voiced what I was already thinking, "if it is a bushing as I suspect because of the oilers".  The only way to know for sure will be to pull it apart.

Looks like that is going to have to be the place to start though it's going to kill be to "disable" my lathe.

Now, if I were to replace it, that opens up a whole new "can o' worms" as I have both 115v and 230v readily available and, darn you R.G. :biggrin:, the possibility of going to a D.C. system.

I'll let you guys know what I find.

-Ron


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## R.G. (Mar 30, 2012)

Do try spinning the motor by hand with the belt off. It will tell you semi-instantly if the bearings are binding.

I threw in that comment about capacitors because they often fail. It might be worth your time to take off the capacitor cover and pull out the cap for testing/replacement if you can get to it. Motor start and run caps (those are different) are cheap and easy. 

One thing I forgot last night was craiglist. There's a guy on my local craigslist (which probably doesn't help you much) who is selling his accumulation of motors for $25 - $40 each. You might check your local craigslist for motors.


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## Hawkeye (Mar 30, 2012)

I think the ultimate solution would be to find a used motor and install it, then use the lathe as required to rebuild the old one. Even a yard-sale motor would keep you running. Just make sure it's got all the connections brought out to the junction box so it can be reversed.


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## ScrapMetal (Mar 30, 2012)

That's a good point Mike.  If a guy could pick up a used motor cheap enough it would make perfect sense.

I did pull the belt off today and spun the motor shaft by hand.  Doesn't seem gritty at all and the shaft is rock solid with no "slop" what so ever.  The "electronics" seemed questionable at best.  I'll take my camera in tomorrow so I can take a couple of pics as it's kind of hard to describe.

-Ron


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## R.G. (Mar 30, 2012)

ScrapMetal said:


> I did pull the belt off today and spun the motor shaft by hand.  Doesn't seem gritty at all and the shaft is rock solid with no "slop" what so ever.


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. 



> The "electronics" seemed questionable at best.  I'll take my camera in tomorrow so I can take a couple of pics as it's kind of hard to describe.


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.


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## Kevinb71 (Mar 30, 2012)

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.


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## ScrapMetal (Mar 31, 2012)

R.G. said:


> 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.
> ...





Kevinb71 said:


> 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.
> ...



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. :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.   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


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## R.G. (Mar 31, 2012)

ScrapMetal said:


> 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. :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.    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. 


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.


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## R.G. (Mar 31, 2012)

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.


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## R.G. (Mar 31, 2012)

http://www.dreisilker.com/Documents/Ctrl_Hyperlink/8_uid121420091225102.pdf

GE AC motor selection guide. Good info for anyone dealing with electric motors.


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## R.G. (Mar 31, 2012)

1200rpm said:


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



Real amps glow in the dark.

'Course, when welders do it, sparks fly. :biggrin:


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## Tony Wells (Mar 31, 2012)

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


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## ScrapMetal (Mar 31, 2012)

1200rpm said:


> 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:



Tony Wells said:


> 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?  :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


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## R.G. (Mar 31, 2012)

ScrapMetal said:


> 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?  :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.


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## Hawkeye (Mar 31, 2012)

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.


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## ScrapMetal (Mar 31, 2012)

I should have made a sketch when I was looking at it (By the way, my bore scope sucks!) but here's a rough drawing of what I saw under that nice little cover:



I could only see the top side, of course, so I can't say what else is going on in there.

-Ron


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## Hawkeye (Mar 31, 2012)

Yup. That's a universal, all right. Does it look like there is any kind of rotational adjustment in the brush arrangement? Some large frame brush motors were 'tunable' at one time - I think that's how some were reversed.


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## R.G. (Mar 31, 2012)

A series wound motor is a horse of an entirely different complexion.  

First: bummer - it's a natural for a speed control setup, just like a DC motor (which it is).
Second: maybe it'll be easy. Bad brushes and commutator would do what you're seeing.
Third: maybe it'll be very hard. I have no clue how common brushes are.

I'll go do some looking.

It would be GREAT if you could refurb it, as you'd get the possibility of variable speed control easily.


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## ScrapMetal (Mar 31, 2012)

Hawkeye said:


> Yup. That's a universal, all right. Does it look like there is any kind of rotational adjustment in the brush arrangement? Some large frame brush motors were 'tunable' at one time - I think that's how some were reversed.



I couldn't really tell.  The way my setup is it's a little difficult to get in at that area.  I'll have to remove the lathe's switch in order to get a bit closer.



Hawkeye said:


> 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.
> 
> 
> 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.



I couldn't find much on it either.  Not sure how it relates to the internal wiring but if you look at the motor plate there is a line on there that states "ELECT. REV."



-Ron


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## R.G. (Mar 31, 2012)

ScrapMetal said:


> I couldn't find much on it either.  Not sure how it relates to the internal wiring but if you look at the motor plate there is a line on there that states "ELECT. REV."


That means "electrically reversable", which is is. Reversing the connections of either of the two series windings while leaving the other one alone reverses the rotation direction. 

I did a quick scan through ebay and failed to turn up even one likely suspect.


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## Hawkeye (Mar 31, 2012)

I couldn't open the manual, but the front page mentions a "brush lifting" motor. Fascinating. The commutator is only in play during start-up. If this is what you have, you should see some type of centrifugal mechanism connected to the brushes that will lift them at speed.

Just for reference, I wouldn't advise using a series motor (which R.G. mentioned) in any application other than direct connection. They have the strongest torque of any brush motor, but, if the output becomes broken i.e., a belt comes off), they will "accelerate to destruction".


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## ScrapMetal (Apr 1, 2012)

CluelessNewB said:


> I believe that is an RI (repulsion start induction run motor) not a universal.  The link below is
> for a Wagner Electric Manual for their RI motors which may be of some help.
> 
> 
> http://www.vintagemachinery.org/pubs/detail.aspx?id=3918



Very interesting.  I have some reading to do tonight.

Thanks much.



Hawkeye said:


> I couldn't open the manual, but the front page mentions a "brush lifting" motor. Fascinating. The commutator is only in play during start-up. If this is what you have, you should see some type of centrifugal mechanism connected to the brushes that will lift them at speed.
> 
> Just for reference, I wouldn't advise using a series motor (which R.G. mentioned) in any application other than direct connection. They have the strongest torque of any brush motor, but, if the output becomes broken i.e., a belt comes off), they will "accelerate to destruction".



Got it!  example: "runaway diesel" - not good.   It makes sense, now that you mention it, with no load there is nothing to limit the acceleration 'til things get exciting and parts start whizzing past your nose.  Oh, and try downloading it from this link: http://68.227.91.247/machines/WagnerRepStartInd.pdf  It's off my server and I saved it in a slightly different way.  Hopefully you can open it.

Thanks Hawkeye

-Ron


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## R.G. (Apr 1, 2012)

A bit more info:

http://www.practicalmachinist.com/v...ntury-repulsion-start-induction-motor-101312/

[url]http://www.youtube.com/watch?v=47cAbiLqP60

[/URL]http://www.practicalmachinist.com/vb/antique-machinery-history/induction-repulsion-motors-169102/


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## Kevinb71 (Apr 2, 2012)

Ron
I was gone over the weekend and followed up this morning on the progress. Since this is a wound rotor motor it's even better if it's not toast. With a wound rotor the commutator typically has segments on it with mica separating each segment from the next. As the brush's wear down they also wear into the commutator section. The copper/brass section wears down quicker than the mica does causing the mica to lift the brush's as they pass from segment to segment. I have attached a crude attempt at a drawing showing this(i was laughed out of art class in high school. They let me go to shop class instead!) This can be turned down on a latheto flatten it back out, but you need a tiny slot cutter to cut the mica down between segments(only a few thou). Brush's should be available at a motor shop locally. If not I have some yet from back when. PM me and I will give you my address to send me an old one to match up. In the mean time try to find a used motor for a backup and then fix this one if you can. You can use your lathe to do it. The only hard part is getting the Mics cut down. A dremel with a slotting cutter mounted to your tool post somehow should do it fine. Since your an EE this will all make sense to you. Didn't mean to be so basic in my first reply. There's lot's of other good sources of info in the posts since my first reply.


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## ScrapMetal (Apr 2, 2012)

I like your drawing Kevin, has kind of a "Salvador Dali" feel to it. 

It seems counter intuitive that the mica would wear less than the copper but what you say makes perfect sense.  Before I go tearing apart this motor though, I am thinking that I need to get a better handle on exactly what type of motor I'm dealing with and it's operation.  It may seem a bit odd or overly cautious but this strikes me as opening up a "can o' worms" and it's my nature to try and handle a job as efficiently (least work ) as possible.  I'd hate to buy a cheap, used motor as a temp with the plan to rebuild the original then "hit a wall" on the rebuild for some reason.  I'd then have to buy a "good" motor to replace the crappy one (again, it's my nature ) and be left with an extra crappy motor as well as a pile of parts that used to be an old motor.  Or something along those lines.

That's a great offer on the "brushes" and I may end up taking you up on that but I'm going to do a little more research before I reach that point.

Thanks again,

-Ron


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## Kevinb71 (Apr 3, 2012)

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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## ScrapMetal (Apr 3, 2012)

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!



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


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## GK1918 (Apr 4, 2012)

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


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## Alan Douglas (Apr 5, 2012)

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.


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## ScrapMetal (Apr 5, 2012)

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


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## R.G. (Apr 6, 2012)

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.



Good idea. 



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


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.


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## ScrapMetal (Apr 6, 2012)

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


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## Old Iron (Apr 6, 2012)

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


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## ScrapMetal (Apr 6, 2012)

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". 

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

-Ron


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## Gary Max (Apr 6, 2012)

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


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## R.G. (Apr 6, 2012)

ScrapMetal said:


> 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.


No problem on that - I agree with you totally. I just wanted to be sure you were considering all possible sources for your motor, best deal (i.e. Quality/$) for you. 



> 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.


That's very rational. Single phase AC, especially capacitor-start and capacitor-run are kind of where the whole world has settled if there is no overriding other factor. Overriding factors might be total power (better with 3 phase), smoothness of power (better with 3P and DC), need for variable speed (very, very hard to do with single phase), perhaps others. 

There are more 1P motors around because there are more of them made. On the other hand, 3P motors in an equal power rating are much cheaper to buy used, because no one wants to cope with the problems of getting 3P power to them, as you noticed. 



> 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?


IMHO, 3P is not a good idea unless you already have 3P wiring or intend to go to a VFD anyway. VFDs can be had for about $100-$150 if you look hard - I know of some on ebay, but haven't yet bought one. I *do* have a 1/2 HP 3P motor I bought for my lathe, intending to go variable speed. It cost me $30.

DC is about the same price as new 1P or 3P in similar sizes; you're talking about $180-$300 depending.  DC does need a speed controller. This is available as the KBPC-19PM for about $40-50, or more expensive if you want. 

These are just my off-the-cuff opinions, but I have been looking at this issue for a while. 


> 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".


There's never enough info available. Measuring the length, diameter, weight, shaft size and length, etc. would be a real step forward to getting a good replacement. As noted, there may be one in a junk pile...

Oh - forgot. Ventilation style. What's the cooling air like where that motor lives? Does it have dust, perhaps conductive dust, coming down on it from the lathe? Swarf-bearing oil drops?  Electric motors come in some standardized ventilation styles. 

Air-over is bad for machine tools. That term means that it has to have cooling air coming over it all the time. This is great for a blower or fan motor, deadly for motors without fans. 

"Drip proof" means that the top surface is sealed up, and relatively immune to specifically drips from one direction. Not a good idea if the cooling air contains dusty contaminants.

TEFC = Totally Enclosed Fan Cooled; these have a built in fan that blows air over the motor, but are otherwise enclosed.

TENV = Totally Enclosed Non-Ventilated; no openings for contamination to enter.

I would want one of the last two for my lathe.


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## ScrapMetal (Apr 7, 2012)

"spare motor pile" - I like that.  Everyone needs one of those.  

Nice run-down of options there R.G. gives me a lot more to work with.  You brought up, in a round a bout way, one of the frustrations with looking for something like this on the 'bay.  For the most part, and especially with used motors, some of the necessary information is not to be had.  They don't usually post the information and just try asking a vendor if the motor is drip-proof or the kind of ventilation it uses.  Most of them have no idea of what exactly they're trying to sell. - Sorry, rant over. -

Again, thanks guys.  I'll see if I can't get some of that allusive "info" tomorrow. 

-Ron


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## R.G. (Apr 7, 2012)

I always assume the seller is clueless or worse on ebay. So I take the approach that (1) if it doesn't have a model number sufficient for me to go look up exactly what it is, I don't even read the description any more and (2) I go look up the manufacturer's data sheet to see if it does what I want. Google is our friend. 

I'm sure I miss a lot of good deals that way, but I also don't wind up with such a big pile of stuff that maybe I'll find a use for someday.


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## ScrapMetal (Apr 7, 2012)

I know a little more today.  The shaft is 3/4" and keyed for the pulley.  The bolts pattern along the axis parallel to the shaft measures 5".  Width or perpendicular to the shaft is over 6" but variable as the mount has long slots.  As we could see on the pic of the motor tag RPM is 1780 and the motor type is SCA.  Anyone able to tell me what "SCA" means?

I'll be doing some searching/reading on the internet for motors tonight. 

-Ron


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## ScrapMetal (Apr 8, 2012)

Nice deal.  You have basically a 4-speed lathe then (whether you use it or not).  Very "uptown".   Did you have troubles with mounting and thus the plywood base?

Thanks,

-Ron


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## R.G. (Apr 26, 2012)

So - what happened? Does it work? New motor? Refurbed motor? 

Inquiring minds want to know.


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## ScrapMetal (Apr 26, 2012)

{Lost posts}

I've been sidetracked by a number of other higher priority "projects" but I should be returning to this one shortly.  I've done quite a bit of research on motors and narrowed down the choices a bit.  For ease of installation I am looking for something in a 145T configuration.

As was mentioned (and now lost) I've looked at Surplus Supply quite a bit.  Turns out they are based in Lincoln, NE which is only about a 45 minute drive from where I live - bonus!

Despite other projects I do need to just "bite the bullet" and get something ordered.  

-Ron


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## martik777 (Apr 28, 2012)

Those old GE motors are almost indestructible - hope you can fix it.

Looking at your sig, I see you have at least 3 temporarily suitable (free) motors right on your shop:   The shaper, 4x6 bandsaw and drillpress, probably less HP but rpm should be about the same.


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## ScrapMetal (Apr 28, 2012)

martik777 said:


> Those old GE motors are almost indestructible - hope you can fix it.
> 
> Looking at your sig, I see you have at least 3 temporarily suitable (free) motors right on your shop:   The shaper, 4x6 bandsaw and drillpress, probably less HP but rpm should be about the same.



I hadn't really considered that. Interesting to say the least and a great tip if I get myself in to an "emergency" - motor down type situation.

Make that only two though.  The motor on the shaper is huge in comparison.  It's case alone is about 14" in diameter.  It would take some serious re-engineering of the lathe/drive to fit that puppy in there. 

Thanks,

-Ron


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