Like a Golf Ball through a Garden Hose

Since the start of our cohabitation and collusion on romantic and domestic issues, the Girly and myself have sustained a prolonged discussion of who's vacuum cleaner was better.

The challengers, as you might suspect, are both not really worth a contest... a 10 year old Kenmore Magic Blue (Model 24195) ("hers"), and a 1980-ish Electrolux Olympia-1 ("mine").

Hers has borne the brunt of the dog hair cleaning over the past few years, as mine was voted heavy and ungainly, and the hose was obviously leaking, leading to a lack of suction

The Kenmore's light construction is proving to be its downfall, however, as numerous plastic appendages have snapped off. A few weeks ago, the plug for the power nozzle finally wore free enough as to be useless. Of course, Kenmore/Sears no longer makes replacement hoses and finding the stupid little plug is an exercise in futility.

A trip to the local vacuum shop went to prove the electrolux's longevity, as I walked out with a brand new hose for it. They still make vintage electrolux parts! The new hose improved the suction quite a bit.

"It just doesn't seem powerful enough," The Jury intoned as she pushed the refurbished antique around the house.

I changed the bag. I figured the squirrel nest and 21 years of leaves I had sucked out of the ChevOldsMoBuiac were not doing it any favors. Alas, the difference was slight.

Which we found surprising. The electrolux is heavily built. I had assumed that it's lack of performance was simply due to the hose. Electrolux vacuums have a dedicated following of people who cherish their stalwart design and performance. An Electrolux is expected to be a big, strong, reliable sucker. Our expectations of new-hose based rejuvenation were built on that. That said, maybe newer engineering really was making cheaper, better vacuums. I understand that the fundamental electrolux airflow and motor design was constant from the 1950s (legendary Model G, like my mother's) until sometime in the 1980s (the Silverado...).

Here is where things get interesting

I decided to do a wee pressure test. I borrowed a vacuum gauge from a friend, plugged a small piece of hose through a square of cardboard, and measured the pressure at the end of the hose with the cardboard blocking the flow. The electrolux showed a -1 PSI pressure drop.

The Kenmore? -3 PSI. Twice the suction. From a cheap plastic vacuum.

The ultimate pressure is only one aspect of vacuum performance, the other being airflow, or how much air the vacuum can move.

That's harder to measure. I tried using a trash bag filled with air, but the vacuums were happier to inhale the bag than the gas it contained. I arranged to borrow a large-ish floating ball gas flow meter. It could easily measure the the air stream from the compressor (100 liters per minute @120 PSI), however, it the Electrolux handily overwhelmed it. Vacuum cleaners appear to have airflow rates in the range of 50-200 cubic feet per minute. Not surprising.

Unfortunately, vacuum cleaner specifications for these machines are hard to find. There are no published specifications for the Kenmore's suction and flow rate (though -3 psi is 87" of water.). The kill-a-watt reports 9.1 amps. The Electrolux is even tougher. In addition to no flow or vacuum data (-1 psi is 27" of water), I can't find information about it's current draw, but the Kill-a-Watt read 5.5 Amps.

It appeared that while the Electrolux was robust and worked, the Kenmore was eating it for lunch in terms of raw cleaning capability.

So, we used the Kenmore to clean up dog hair, and I used the Electrolux on other tasks, where every last little hair didn't matter so much.

Until I killed the Electrolux while vacuuming pollen off the porch.

I smoked the motor.

Woops.

Is that why it says "indoor use only?"

Whatever.

Lovely burnt stator

I fiddled with the idea of fixing the vacuum cleaner. Why throw something away with so much hacking potential?

I started to search for replacement motors, I noticed that they came in standard diameters, with 5.7 being the most common variety, and the Electrolux using 5.1". Further, newer motors are much more compact than the original, and an adapter was required to fit a replacement motor into the electrolux. Thus, a wee plan formed in my mind. Why not put a higher spec motor in? I contacted the sales rep at lighthouse vacuum, and deduced that their standard electrolux motor kit was a 5.1" diameter, 6.6 amp motor (LH5080 stats) and some hardware to hold the new motor and let it reach to the bag cavity. I arranged to purchase the more exciting 9.8 amp motor (LH5081 stats) with the mounting bracket, leaving the adapter as an exercise in domestic engineering.

 I was surprised at the size difference between the old an new motors... I knew from the diagrams that they would be different, but it's impressive to see in person.

Of particular interest is that the new motor is much more tightly engineered. I had some doubts that it really was a through-flowing motor (e.g. cooled by the air it sucks through the front), as the gaps in the motor itself are small, but there are no other vents. Additionally, the spacing between the fan blades and the case is much smaller than the original motor, and the density of fan blades is greater. The original motor appears to require multiple stages, while the new motor has a single stage. What a difference 35 years makes.

Another thing that impressed me is how dirty a vacuum gets over that period of time.

 In order to accommodate the gap between the motor inlet and the bag holder, I bought a rubber 3"-2" PVC pipe adapter, and trimmed the 2" collar down to the point where there was the slightest perceptible change in resistance when the motor was set in the 3" cone, pressing against the bag holder. I then applied a thick ring of silicone rubber to seal the adapter to the bag holder. I left the original bit of metal screen installed. While it probably reduces airflow a bit, in the (rare!) case of bag failure, it prevents the motor from eating anything that it can't spit out the other side.

As a further air seal check, I wet the motor side with water, and set the motor on the adapter in the vacuum. It showed that sealing was somewhat spotty, so I decided apply thick bead of silicone on the motor-adapter interface. It won't come out without a fight...

 

The new motor/electrolux combo is much more, um, peppy than the old system. It pulls -2.9 PSI, about the same as the Kenmore. The vent door must be left open, as the vent holes are not adequate for the new airflow produced by the motor. It's also very loud, you have to strain to hear if the power head is lugging on something.

It also works really well; and that's the real crux of it: The first trip around the house yielded a satisfyingly large collection of dog hair. That's why we care about this, you see.

We have got to do something about all this dog hair.

This little light of mine

I've always been slightly annoyed that the kitchens are generally designed to prevent light from reaching the work area. The counters are invariably placed under the cabinets, and the light fixture is in the center of the room, thus insuring that your fingers, the knife, and dinner are all in the shade at all times. What could possibly go wrong? The cabinetry industry and the healthcare moguls are almost certainly in collusion to reduce the number of surplus fingers in the world.

A small investment in ikea LED accent lights let me solve this problem.

Nine Fingers?

Or ten?

Obligatory Christmas Photos

A lot of work with an old hat and an unwilling model.

Two Way Street

I've recently been struck by a story of a Florida school board member who couldn't pass a 10th grade qualifying exam.
washingtonpost.com: When an adult to a standardized test
washingtonpost.com: Adult revealed

I'm torn about what to conclude from the story. A fairly successful person, with a lot of education can't pass a this low-level exam given to high school students. Without passing this exam, they get held back in school... it's life changing.

He's pretty adamant that such a test would have ruined his life, and is perhaps doing the same to students today: "It makes no sense to me that a test with the potential for shaping a student’s entire future has so little apparent relevance to adult, real-world functioning... I can’t escape the conclusion that decisions about the [state test] in particular and standardized tests in general are being made by individuals who lack perspective and aren’t really accountable."

This incident is being widely spread as evidence of the failures of outcome based education to fix our scholastic system.

I have been deeply curious about the test, fortunately, the Post placed a few example questions on their webpage. I went through the questions last night. Was the test composed of high level calculus? Discrete math? Probability? Linear algebra? Statistics? You know. The real shit.

Hardly.

The test is algebra and geometry! It's word problems, but it's all solve-for-x kinda stuff.

Word problems always throw people... speaking from years of experience grading chemistry exams.

The test isn't hard. It isn't rigged by corporate goons. The guy who took the test just isn't good at word problems.

This is not written as an advocacy of outcome based education. But there is more going on in this incident than a simple example of "evil" testing ruining lives.

What does it say about what it takes to be a successful person?

Let Jag

I'm not dead. I went to Minneapolis. Then I went to Costa Rica. Then I went to Chicago (with a cumulative 40 hours of driving). Then I went to San Fransisco.

I'm sure my dog has given up on me.

Good things he likes to make new friends.