Restoring an Old Electrical Motor

[skizzo]

Thanks Oakey, I'm always kinda wondering if anyone other than the few of us who are posting have any interest. It feels pretty weird rambling on like some of these posts do, and just replying to myself. Oh well... on we go.

So having gotten through that major hassle, we're getting back on track. Use a bearing puller to pull the other bearing off the rotor shaft, no problem there.





The two bearings turn out to be different sizes, which I haven't seen all that often, compared to motors with the same bearings on both ends. The smaller one, which was in the blind well, is an SKF 6301 and the larger one from the shaft is an MRC 203. According the Accurate Bearing Parts Interchange site both of those should be readily available off-the-shelf bearings.



Spend a little time cleaning up the other internal parts, starting with chucking up the rotor assembly in the lathe. First do the main rotor, centrifugal switch, and shaft end, then turn it around and do the other. It cleans up ok with some WD40 and a scotchbrite.





Next up is the switch contact device. I can't remember having had to disconnect one of these from the motor leads before, but that's the result of this afternoon's problems. This part works in conjunction with the centrifugal switch that is seen on the one end of the rotor shaft above. I'll show how those work together later when I put the whole thing back together... uh, assuming I'm able to get to that point.



We often hear people ask questions about why a motor just hums or buzzes when they try to start it up. Frequently the answer is to blow out the starter or the end of the motor with the contacts. If blowing it out doesn't work, then the next step is to pull the switch and clean up corroded contacts. Here are a couple shots of the starter contacts and the quick approach to sanding them back to conductive surfaces.

These are the start contacts open, which is the state while the motor is running.



These are the contacts closed, which is the state while the motor is off.



To clean the surfaces, I just take a piece of 320 grit sandpaper, fold it in half to use both surfaces, insert it between the contacts and hold them lightly closed, and slide the sandpaper around a little bit.



Finally, the switch is cleaned and the contacts freshened up. Note that the two wires are taped and labeled to show where they go respectively when reassembled... the one labeled "switch" being that problematic one that goes to the junction box, and the other one to the start capacitor.



Thanks all. Now on to prepping the motor parts for painting, hopefully tomorrow.

[Warptboard]

Groovy thread

More pics! More pics!!

[rsstreet]

Nice thread Bill. Definitely following along.

Randy

[SceneryMaker]

skizzo said:

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I'm always kinda wondering if anyone other than the few of us who are posting have any interest. It feels pretty weird rambling on like some of these posts do, and just replying to myself.

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PLEASE continue with these updates. Consider that this post already has 241 views in the 18 hours it has been up, with a title that nobody would open accidentally. In other words, you have an audience that cares about what you are doing, even if we are not vocal about it. For that, I apologize. It is probably taking more time and effort to document and post the process than it takes to do the work, so thank you and keep it up.

[TK'sDust]

Nice pictorial on an older motor with it's challenges. It's going nice with my morning coffee...

[skizzo]

SceneryMaker said:

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It is probably taking more time and effort to document and post the process than it takes to do the work, so thank you and keep it up.

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Thanks for the feeback, guys, that's good to know. I got a couple PMs as well, much appreciated. And nobody's called me a crackpot yet, either, so I took that as a good sign.

I've always taken a lot of photos on my projects... both woodworking and machines... but have never chronicled them as I went along. It turns out that the time to document is almost exactly equal to the time doing the work. An hour or two of work takes an hour or two to manage photos and put up a post, etc. It's not a surprise at all and I expected it going in, but I think it's interesting that it's pretty much a 1:1 relationship every time.

Gotta do a BORG run for supplies (wire wheels and scotchbrites), then plan to get the motor parts painted today and the base/column cleaned. I know I can't replicate the WT crinkled black, so I'm going to use black satin on the endbells and black gloss on the center band. I got them cleaned and stripped last night, so only have a bit of taping and final prep before painting.

Thanks again.

[oakey]

Bill
yes you can replicate the finnish its called wrinkle paint just google it one co is plastikote.com avalible from some auto parts stores. of course regular old paint going to be nice to .
waiting to see this finnished keep up the posts

[SceneryMaker]

skizzo said:

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I know I can't replicate the WT crinkled black

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Just practice on some scrap first because the coarseness of the texture is governed by how thick you apply it. I've used this and it works.

[Anak]

Very cool thread (or threads, as I also appreciate the DP teardown).

It's no crackpot who can figure out how to disassemble and rehabilitate old rusty equipment.

Another tool to add to the "toolbox" for pulling out those blind bearings would be the simple trick my grandfather taught me for pulling pilot bearings: Pack the blind hole with grease and then drive the bearing outward by driving the grease inward with a dowel or solid rod of the correct diameter.

Sizing the dowel/rod correctly is not always as easy as it sounds, but the technique has worked for me, and it is fairly low tech and doesn't require much in terms of fancy tools. If it gets someone out of a bind once it pretty much pays for itself.

[Brian in Boise]

Bill, let me add my "yes" to this great thread. The pictures and comments are excellent! When this project is done, I wonder if you'd be willing to start another note on how you put the pictures/notes together for posting. I'll bet there's a place here where that's explained, but doubt that I'm the only one who could benefit from your instruction. I really like the large, well photographed step-by-step presentation, and appreciate your sense of humor, too. Thanks!!