Restoring an Old Electrical Motor
oakey said:

yes you can replicate the finnish its called wrinkle paint just google it one co is avalible from some auto parts stores.

Sweet, thanks oakey and SceneryMaker. I never thought to look before, but I found a Krylon alternative in the automotive section of the hardware and paint store I go to. It's called wrinkled black... duh. I picked up a can, plus two other possible colors in the regular rattlecan cabinet, and did a color test when I got home. The two photos below show the following three colors, L-R: Rustoleum Black Night Metallic, Rustoleum Hammered Black, and VHT High Temperature Wrinkle Plus Black. The wrinkled is generally intended for automotive engine parts, so I would guess it's pretty durable. But does anyone have any experience or thoughts as to how it wears? It looks great, BTW, and isn't the salt-and-pepper look that appears in the photos... just a matte black.

I don't like the hammered much at all, but the metallic black is a nice dark charcoal black and will get used at some point for sure. It would go nice on these end bells along with a gloss black center, too.

Thanks... nice find today.
Know, think, choose, do -- Ender's Shadow
I have been following both posts. Really like the pics and detailed descriptions - thats's alot of effort.


"A dull mind uses dull tools" - my Uncle Jim RIP
Thanks Bob, glad some folks are interested.

The motor painting went pretty easily today. The wrinkle black paint for the end bells is really cool, I just hope it's durable. It definitely replicates the old WT wrinkled paint. I had already prepped the end bells and center band over the past couple of days. First I cleaned out the inside of the endbells, even though they don't get painted. A bit of hand scrubbing, particularly down into the bearing wells, got them acceptable. Then a scrub and wipedown on the outside with mineral spirits cleans and prepares the painted surfaces. They were wire-wheeled extensively a couple days ago to strip to raw cast iron.

Next up is the center section. This thing is a bit heavy, clunky, and always stays together with the sides just stuffed with paper to protect the coils and electricals, and gets taped off. Right. When I tipped it on its side one time, I heard a clunk and looked over and saw a little curved metal bar laying on the bench. Uh oh. The internal section and wiring were also sliding around inside the exterior band. darn... again. I guess it's going to have to come apart this time, another first. It turns out the little metal piece is the bar that slips inside the outer band to provide a threaded connector for the start capacitor bracket. You can see the bar sitting in place in the second photo.

Oh well, it'll make it a little easier to paint because it's only the outer band and can be hung and rotated in place, which is harder to do when the whole thing is together. After stripping paint on a wire wheel, then wiping with mineral spirits to clean everything up, it's time to tape off the badges. Tape extra wide and cut, then roll the tape under the edges of the tags so that the sides of the tags don't get overspray.

Quick run of the threads on the little set screw holes on the endbells, and pack the holes to keep the paint out.

Ready to go. Set up in the yard again, one table for pieces that get the black wrinkle, another table for the gloss black parts. Putting each part on its own little block allows them to move around independently. The center band hangs off to the side. The endbells can be either stood on end or laid flat on the inner edge.

A coat of primer on everything, using Rustoleum Rusty Metal rattlecan. Note the taping job on the inner edge of the endbells... if those get any paint on the surface, they have no hope of going back together with the center section during reassembly. Also, a rolled paper sleeve goes in the shaft bore to keep paint out of there as well.

Within about 10 minutes of spraying the primer, it is dry to the touch, but is still very soft. My approach is to quickly apply a first light coat of paint at this point, then several more coats at about 10 minute intervals. That leaves half a dozen layered coats of primer and paint, all very soft, but bonding to each other. The rattlecan instructions say to reapply each next coat either within one hour or after 48 hours, so I get it all done right away. Total painting time from the application of the primer to the final (usually about fourth) coat is about an hour. Then I let it flash dry for a couple hours, bring it inside for safekeeping, and don't touch it for three days. It seems to work reasonably well. Jasper is back there again as usual, keeping an eye on my work.

Here are parts inside a couple hours later, with the wrinkled paint doing its job really nicely. I have lots of other things to work on for the next few days, so these are going to cure until probably the end of this week before getting any more attention.

I'll be ordering bearings tomorrow and working on other stuff for the rest of the week, then hope to put the motor together probably next weekend. Back to the rest of the drill press.
Know, think, choose, do -- Ender's Shadow
There is another way to get bearings out of a dead end housing. It might not be the optimum way for old cast iron, however.

Find/make a flat ended rod just smaller than the inside diameter of the bearing. I've made them on a DP with round mild steel rod and a file.

Pack heavy grease(with a dose of WD-40(etc) first into the dead end housing. Place the punch in the bearing bore and hit it with a hammer.

I did blow out the housing on one old motor I was using for practice, but that was more a problem with support while hammering. (I think). And I was seeing how hard I should hit the punch--had a 5 pound maul)

Have also used a press in the same way. That---using the press---has a LOT of pucker factor and can be HUGELY dangerous. The press I used actually had an operator guard(1/4" thick steel plate) behind which the operator would stand during use.
Ok, back to the motor. Finally time to see if this thing will go back together. This is a long post that goes from start to finish on the entire assembly. Total time spent was a bit over two hours,which includes some do-over time a couple places.

The bearings came in last week from Accurate Bearing, total cost $10 shipped. One was three bucks, one was five, and two bucks postage. Quality sealed Nachi bearings made in Japan. As always, the price and service is unparalleled.

Here are the parts all ready to go.

Start by installing the new bearings. I just use a socket and mallet to drive them on, using the smallest socket that fits over the shaft so that it only engages the inner race. On the longer end, I use an extended reach socket and a piece of pipe to get the bearing all the way down to its seat.

Five minutes later, both bearings are installed.

Now a quick couple shots and brief explanation (as I understand it) of how the centrifugal switch works in these single phase motors. The contacts that are on the little brass ring, which I showed earlier during disassembly, work together with the switch assembly that is mounted on the motor shaft. In the first photo below, the contacts are closed because the spring on the switch is pressing the ring outwards, away from the rotor. This is the state when the motor is not running... the contacts are closed, prepared to pass a pulse through to the start capacitor and on to start windings.

When the motor is powered up, the start windings fire the motor and start the rotor spinning. At that point, the metal "wings" inside the switch fly open (via centrifugal force), which pulls the little plate that rests against the contact ring in towards the rotor. This opens (disengages) the start contacts, breaks the start circuit, and the run windings take over. When you turn the motor off, the rotor spins down, the centrifugal switch recesses, and the switch plate pushes the start contact back closed. This is a photo of the centrifugal switch open, with the start contacts disengaged, which is the state while the motor is running.

Back to the reassembly. In reverse order from the disassembly, we start by working on reassembling the electrical end first. This is also the end with that troublesome blind bearing well. It's a whole lot easier to work on now. With the endbell resting on end, the start contact ring gets reattached... these were those PITA machine screws that were hard to reach while the endbell was attached before. Note that in this case, there are little washers that sit between a plastic plate and the ring plate. That makes it tough to get the assembly down into the endbell without things sliding around. I put the assembly together with one screw in place and a thin handle in the other just to keep everything aligned. Screw in one screw, pull the handle out, and screw in the other.

Next, we have to put together the center armature assembly, which you'll recall fell apart accidentally earlier. Normally, I leave this together inside the band for painting. Carefully feed the motor leads back through the opening into the junction box and slide the band into place.

Oops, forgot that one wire that we had to pull out to get the end bell off. Try again.

So now the endbell is back tethered to the armature by that wire. Gotta work with it that way from now on. I could not begin to feed the two wires that run off to the capacitor through the really tight grommet that I had already reinstalled in the endbell as seen a few photos earlier. After several futile attempts, time to give up and just get rid of the grommet. I'll wrap them in electrical tape later to provide protection.

Now to put the endbell in place. Remember those little alignment marks that were step #1 way back at the beginning? They matter now.

While we're at it, let's make sure the tie rod hole is perfectly aligned as well.

The armature is slipping around a little bit because of the little plate that fell out, so let's anchor things down by reinstalling the plate and the capacitor bracket.

The rotor shaft will fit in through the main housing from the other open end, with the bearing going all the way through the contact ring and into that blind bearing well on the far end. You can't see what's going on, but the fit is tight so it just sort of wiggles/snaps into place eventually.

The other end bell, which slips over the drive shaft, gets two flat washers and a spring washer inside the bearing well. Then it just slips onto the shaft and slides into place.

Stand the motor on end and gently tap the second endbell into place. Again, the alignment marks help make sure you get it right. This motor's pretty easy because of the feet in the endbell castings, but many motors are simply round endbells, so the marks are even more important. Note that if the painting and taping was done well, the endbells should pretty much slip into place with some gentle tapping and pressure. You should not have to use the tie rods and nuts to pull them together... if that's the case, it's generally a good idea to take it back apart and clean the intersecting surfaces further. Once all four tie rods are installed and tightened down, the motor shaft should turn freely by hand.

OK, time to deal with the capacitor. I don't know if it matters which of the two wires go to which terminal, and I forgot to mark them back when I unsoldered them. So before soldering them back into place, I do a quick test with some spare wire connectors between the leads and the cap terminals. This should also tell me whether the motor actually will work or not, before I go to the trouble of soldering in the leads.

Using my little motor tester switch that gets alligator clipped to the j-box wiring, the motor fires right up. Yippee, yahoo! Very nice.

So time to solder the cap leads and finish up.

After everything is tidied up, the cap reinstalled in place, etc., the final thing I do is clear-coat the tags. This is just a quick tape and spray with a clear acrylic like Krylon. I use an acrylic from the auto parts section at the hardware.

Fifteen minutes later it is dry to the touch, we pull off the tape, and take the final shots of the finished motor.

The wrinkle finish paint for the endbells worked absolutely great and is the perfect match for the original WT paint design. The main tag got a little deteriorated as I was cleaning it up prior to painting, but it's still in very good condition. The motor purrs like a kitten and is ready for installation once I get the drill press done.

Comments welcomed, hope you got something out of this. Thanks for following along and for all the tips. This is a major, major relief to have this thing back working again.

Know, think, choose, do -- Ender's Shadow
Motors of that vintage and type are particularly fussy to restore. That's about as good of a photo essay as one can get. You overcame a lot of existing condition problems not always found on electric motor rebuilds. Outstanding! Bookmarked it.
all i can say is wow very well done I to love restoring stuff and your pictorial is realy great that motor is as nice as any thing that ive seen
Well done and thanks for the effort in these threads!

Added to favorites.
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The more I read from you the more I am convinced you live in a vacuum of your own design and you have the patent -Bob10 to Curly

I have a feeling this one will be bumped each year.
Nice job on the rebuild, and especially on the documentation. One of the best I've ever seen.

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