Restoring an Old Electrical Motor
#1
  
This is a spinoff thread from my long thread on Restoring an Old Drill Press. Since motors are much more general than just for DPs, it makes sense to give it it's own space so that it can go in whatever direction is appropriate about old motors.

The motor I'm working on is a nice 1/2hp single phase 1750 rpm Walker-Turner motor. IIRC, these were made by Kingston-Conley, who made motors for a lot of manufacturers. These are very highly regarded motors, heavy, solid, and attractive. The tags have a very nice design, and the little mounting feet that are built into the endbell castings are just way too cool. These motors are also famous for their "crinkled" paint jobs on the endbells.

In any event, I need to get the motor apart to clean out the insides and to replace the bearings. I've done a dozen or two motors over the years, a number of different sizes, styles, manufacturers, etc., but am only mediocre at best at this. There are a lot of real experts out there who know these things inside and out.

Here is the motor as I'm ready to start. If all goes well, it should take maybe an hour to get it apart at least to the point of getting the bearings off. But every motor has its idiosyncrasies, so no telling how long or what will be involved if it's not straightforward. That's probably likely.





Since I'm going to be ordering bearings, I'm hoping to pull these two others apart as well to order bearings for all... a 1/2hp Craftsman and a 1/3hp Delta. Delusions of grandeur, best laid plans, and all that...



Looking at this a little closer, the two cast iron end bells have little screws, probably set screws of some sort, for some reason, in locations where you typically see oiler holes for sleeve bearing motors. No idea what they're for on this one.



First things first, make alignment marks on the endbells and the center band for reassembly later. The components need to go back together exactly as they came apart. Most folks probably use a punch to make dimples, I prefer to use a drill to be a little more gentle. Just be sure not to drill through anything... a little mark is all that's needed. I also try to do them on the lower back area rather than out in the visible sides.





Remove the tie rods that pull the three major sections together. The design of these can take many forms. Most times, you'll find through rods with some form of hex cap or slotted head on one end and a nut on the other. These have threaded sections for nuts on both ends. Some motors don't use through rods, but use machine screws on both endbells that are threaded into the main housing.





Now, to pry the endbells loose. For the record, I'm showing using a wooden block as a tapper. Others, ahem, may use a punch, a screwdriver, a stud, whatever... but for purposes of this thread, I'll make the point that it is recommended not to use any steel device when tapping against cast iron. On this particular motor, the edge of the endbells stand slightly higher than the center band... that's a good thing. On some, most notably a lot of old Deltas (see the one above), the endbells are lower than center band so there is nothing to get a bite on to tap against. Discussion of how to approach those is left to other posts.



Anyways, you need to work your way around the edges of both endbells and gradually work them loose. Sometimes it can be productive to use the motor shaft to drive against the opposite endbell, but don't get carried away.



Success on one end, at least to the point where now I can get a screwdriver in and pry it loose a bit more easily.



A little more work in the other direction and both endbells are loosened somewhat, tho neither is yet off.



Working on the end that does not have all the electricals, one endbell comes right off, leaving the bearing on the shaft.



Now things get more complicated as we turn to the end with the electricals and the enclosed (blind) bearing well. These can be a real PITA. The leads from the motor are going to be connected to the contacts and centrifugal switch, which is going to be bolted to the endbell. That's pretty much a given. That means the endbell won't be able to pull very far from the center section because the leads will bind. Let's see what's up.

First, I notice for the first time that the design on this motor brings the start winding to and from the capacitor through a port in the endbell. That means we have to remove the capacitor if I want to completely remove the endbell. Damn. I much prefer leaving the capacitor attached when it's connected through the center section, and just tape it off for painting. Can't do that here.



Look inside the cap and see that the leads are soldered on rather than spade connectors. Not a surprise, but double-damn. Get the soldering gun and disconnect them. It was possible to just cut the wire for now, but since I'll have to resolder them eventually I might as well do it right... especially since the wire leads sometimes don't have much excess length.





Now let's look at what's going on with other aspects of the wiring. First, inside the junction box. This is really funky and a mess. I have no idea what's up with all of these connectors, jumpers, etc., but need to take a couple photos because it may matter later. It is certainly not the straightforward set of leads usually seen.





Now, to the endbell with all the circuitry. The working space is only about an inch gap, maybe two. Inside, there are two small slotted head machine screws that attach the switch to the endbell.



It's always a pain to get to these screws, and especially so when (a) you don't have much working room, and (b) you don't want to stress old crusty wiring. Fortunately, the cloth wiring in this one is pretty solid and has some flex, so I can stretch it to its max length. First, I took a couple of 90-degree screwdrivers to see if I could reach in and work from a right angle... nope, neither quite fit/reached. So then I took a long thin flat screwdriver to see if I could get to the heads. Sort of, but the tip couldn't get a bite on the screw head. Off to the grinder to sharpen/thin the screwdriver head to get a little better grip. Finally, they both slowly can be rotated out and removed.



You can't tell it from this photo, but the entire circuitry assembly is now free from the endbell. Whew, that means the endbell is free to come off the rotor shaft, assuming either the bearing will pull out of the well or the shaft will come out of the bearing, leaving the bearing in the well. Either way, it's finally ready to come off.

Twist, tap, pry, lube, curse, nope... that sucker's stuck in there. And I still can't see much because one wire seems to be binding, which keeps me from taking the endbell WITH the rotor out in the direction of the endbell. Trace that wire back, and we find that it's one of the leads that come into the j-box. This thing is really starting to kick my butt, but fine, let's pull that lead out of the j-box wiring and let it go with the switch.





Finally, the endbell and rotor are free to pull from the main housing and armature. Ughh... that's much uglier than I was expecting to see, considering the nice condition of the motor's exterior.



And a much better view inside that endbell. All the electrical components are disconnected, and I cannot see or feel a retaining screw that you sometimes find as a bearing retainer. Does anybody know if I'm missing something in there? The bearing/shaft just does not want to come out. The rotor assembly wobbles/rocks a little bit back and forth, but won't pull out.



It's a blind well, as seen here from the outside, so there's no way to get at it from the other side to tap it out.



So that's where I'm at. As I said, this thing is kicking my butt at the moment. From another post in the main DP thread, it seems that the shaft should most likely slide out of the bearing rather than the bearing come out of the well. That also makes sense because it would account for the shaft being able to wiggle somewhat. But it ain't happened yet, so I came in to take a break and look for some more info on this. It doesn't look like I'll be ordering bearings today.

More later.
Bill
Know, think, choose, do -- Ender's Shadow
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#2
  Response to: Restoring an Old Electrical Motor by skizzo (This is a spinoff th...)
Can you rotate and/or lift the switch to see the actual bearing? At any rate the shaft of the rotor should come out now. If it were me, I'd hold the rotor and whack the end bell with a plastic hammer. Patience is in short supply in my shop though.
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#3
  Response to: Re: Restoring an Old Electrical Motor by Jonny Rocket (Can you rotate and/o...)
Jonny Rocket said:
If it were me, I'd hold the rotor and whack the end bell with a plastic hammer.



Ding, ding, ding... we have a winner. Wooden mallet actually, took about 10 seconds. Buckeroo had said the same thing. I just needed to make sure there wasn't a retaining screw behind that plate where I couldn't see anything. BTW, Buckeroo, that plate on the centrifugal switch does, indeed, sit on top of the brass ring (i.e., switch side), not underneath it. Sounds like yours has a problem.





Now to try and pull the bearing out. I knew I had read somewhere about a little homemade rig for doing this, and Buckeroo reminded me that it was one of Bob Vaughan's incredibly cool posts, as usual.

http://owwm.org/viewtopic.php?t=48112
Bill
Know, think, choose, do -- Ender's Shadow
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#4
  Response to: Restoring an Old Electrical Motor by skizzo (This is a spinoff th...)
I take it those two screws on the housing aren't holding the bearing in the bell.

Cheers,
Andrew
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#5
  Response to: Re: Restoring an Old Electrical Motor by MrMhor (I take it those two ...)
That's kind of what we figure they do. There's just a fraction of an inch of the back side of the outer race that comes into that hole. So they must be some form of little set screw, but they can't do much since it's at most 1/16" bite on the outermost edge. Actually, as I think about it more, they're more likely to be a stop to keep the bearing from going too far into the well, as opposed to a set screw to hold it in place.
Bill
Know, think, choose, do -- Ender's Shadow
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#6
  Response to: Re: Restoring an Old Electrical Motor by skizzo (That's kind of what ...)
Got it. That bugger was in there. I first tried to do something along the lines that Bob's owwm thread showed, but the bearing was too small to find any respectable washer that would even fit through the bore. There was no way a tiny washer would ever tolerate enough force that would be necessary to be successful.

As usual, start by cleaning up the mating surfaces and drench with penetrant.



So next, it's time to look around the various drawers and parts bin. Aha, how about these inside calipers with little hooks on the end? Stick them in through the bore, open them up, and yank on them, beat on the endbell, see what happens.





What happens? The cast iron and bearing get a little chuckle out of the feeble attempt, bend the calipers, and say "next?" Ok, so I'm gonna have to smack it with something. How about one of those 90-degree drivers I was using before? This one just barely squeezes through the bore and pivots up to lever against the back side of the bearing. This has promise.





After a couple dozen whacks, starting to seem hopeless, suddenly there's an ominous/promising POP. Hope that wasn't the endbell. Take a close look, woohoo, movement!



Renewed enthusiasm at last. A couple whacks, rotate the endbell 90 degrees, a couple more, rinse & repeat. <trumpets please>



And we're out.



Whereas progress the other day on the drill press was way faster and more successful than expected, this effort gave it all back. The conclusion: you never know how it's going to go. But the good news is, I now have both bearings accessible, and I need to go pull the other one off the shaft. That'll come next.

I hope y'all don't mind my rambling on about this stuff... I'm just laying out my thoughts and ideas, just slightly more organized than stream of consciousness. Comments and suggestions are always appreciated.
Bill
Know, think, choose, do -- Ender's Shadow
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#7
  Response to: Re: Restoring an Old Electrical Motor by skizzo (Got it. That bugger...)
My one encounter with a stuck bearing came out with some long jawed vise grips:



Note: I wasn't trying to save that bearing. I pried the shield off and pulled it out.

Bill, I think those screws might be grease points? Are the bearings open on the sides facing the screws?
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#8
  Response to: Re: Restoring an Old Electrical Motor by skizzo (Got it. That bugger...)
Outstanding!
Had to laugh about the calipers. I could see me trying that approach...if I'd have been able to find some. Both you guys are creative. I can be, but I got frustrated and gave up so bought the puller instead.
Always good to see how others skin the proverbial cat.
Buck

Business Meetings - None of us is as dumb as all of us.
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#9
  Response to: Re: Restoring an Old Electrical Motor by Jonny Rocket (My one encounter wit...)
Jonny Rocket said:
Note: I wasn't trying to save that bearing. I pried the shield off and pulled it out.

Bill, I think those screws might be grease points? Are the bearings open on the sides facing the screws?



Nice, Jonny. I wasn't trying to save the bearing either, and was just a couple minutes away from pulling out the Dremel and cutting my way through the bearing. I didn't think of removing the shield, but I don't think I'd have been able to just pull the bearing out anyways because of how adhered it was. I'm still working to clean up the inside of those castings. Nasty.

The bearings are shielded on both sides, and the well is hollow behind the bearing. They're certainly not for grease or oil. The bearing in the blind well sits against a shoulder in the back, so there's no reason for the screw to be a stop... I guess it must be a little safety precaution against the bearing outer race spinning in the retainer.
Bill
Know, think, choose, do -- Ender's Shadow
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#10
  Response to: Re: Restoring an Old Electrical Motor by skizzo ()
bill
those blind brg. pullers are the cats meow for that job.
harbour freight used to have pilot brg. pullers probably still have them.
i have cupple diffrent stiles made buy OTC one is two jaws the other just a hook tool some what like you used but heavy duty .they are used on a small slide hammer
Otc also has push pullers that you can put blind hole pullers on and pull brgs.
im enjoying the great job your doing with both the posts edit to add this
bill are the set screws used to set the rotor end play ??I do not see them in the picture but just wondering seeing as you explain they just set partualy in the bottom of the brg. bore
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