After seven years, our Sears / Kenmore Progressive vacuum cleaner gave off a horrible screech and an intense smell of electrical death, prompting me to tear it apart.
It’s easy to find the two front screws holding the top in place, although you’ll need either a bendy or offset screwdriver to remove them:
Pull up hard on the cord retraction plunger to remove it, revealing the two rear screws:
Extract the wires and motor control PCB from their niches:
Prying the latch in the middle of the rear panel (over on the right) releases the motor assembly, which you can then wiggle-n-jiggle upward and out:
Disconnect the wires, peel off various foam bits, and extract the motor from its carapace. Measure the blower diameter and cut a suitable plywood clamp for the bench vise:
I loves me some good laser cutter action, even when the plywood crate the laser came in doesn’t have much to recommend it:
I vaguely recall reading the purple tinge comes from the bromine vapor used to dis-insect the wood during manufacturing, before shipping it halfway around the planet.
One area of the commutator looks like it’s in bad shape:
Clean the commutator bars in the desperate hope it’s just random crud, even though that seems unlikely, then connect a widowmaker cord to the motor terminals:
Use a Variac to spin the motor at a (relatively) low speed while watching the brushes and commutator:
Now, that is not a nominal outcome.
The cleaned commutator again shows signs of distress:
Indeed, measuring the resistance across the line cord terminals shows a shorted winding: 0.0 Ω with the brushes aligned on the bars just antispinward of the scars.
So the motor is definitely, irretrievably dead.
Extracting the brushes shows the arcs have eroded their spinward edges:
The dark smudge on the windings seems due to internal problems, rather than just the arcs, because the wiring crossing between the commutator and the smudge remains clean:
One can buy a used motor assembly on eBay for about $40, with no assurance it doesn’t also have a shorted winding.
Dang, now I gotta make more adapters for whatever vacuum comes next …
The Smell of Molten Projects in the Morning 
I disassembled a lower cost Eureka vacuum and found that the motor housing was all finest-kind plastic. Not fiber reinforced, just clear plastic. OTOH, Eurekas tend to die with broken hoses, and dealing with the beater drivetrain is annoying.
We’re getting a few year’s* use out of our house vacuums. Switched to Bissell, but the first one of that brand broke the tab keeping the upright portion in place. It got demoted to the shop, but the replacement was as close as we could match. When I find the round-tuit, I’ll puzzle out the broken tab.
I never was fond of the auto-retract cords. Much less hassle doing it by hand…
(*) Between pumice dust and dog hair, it’s a challenge, but the Bissell is fairly easy to clean.
We’re likely to go with another canister vac, if only because the place has no carpets.
Surprisingly, despite the lingering death of Sears, one can still buy Genuine Kenmore Vacs.
In the spirit of the blog, encase the dead motor, stator and rotor and all, in resin. Then slice into neat elliptical coasters (You wouldn’t simply do a straight equatorial cut through the motor, would you?) for further talking points while consuming those hot winter drinks.
Well played, sir!
Well, that certainly does suck. As it were.
I finally bit the bullet and bought a fancy Míele vacuum. They’re nominally expensive, but I just happened to show up near closing on a slow day and they were extremely motivated to make a sale. I got a nice Solaris for $475 and it’s well designed and durable. I vacuum all sorts of things I probably shouldn’t, and I’ve clogged the hose a couple of times, but all the hose fittings easily come apart to retrieve such things. The only issue I’ve ever had with it was the cord retractor broke after a few years. They replaced it with the new stronger design and it has given no trouble since.
The Internet: How many Snow Crash references can Ed work into a blog post nominally about vacuum cleaners?
Ed: Yes.
Our Young Engineer once said she used a Snow Crash idiom in a meeting, whereupon a (much older) attendees exclaimed “You read Snow Crash?”
I was so proud of my parenting …
Makes note to pick up Snow Crash once the Kindle recovers from yesterday’s buying surge. :)
I rather liked Neuromancer when I read it mumble decades ago.
It is perhaps a satire of cyberpunk novels. One of my favorite chapter endings after a setpiece bar fight: “… after that it’s just a chase scene.”
And I’ve always wanted a can of Liquid Knuckles in my pocket, although it’d surely be illegal in most jurisdictions.