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.
Bill.
