Consumer electronics "war stories"

We've got one of those damned things. Be sure and use the "washing machine cleaner" every month or so, and use the extra rinse button. Otherwise, soap scum builds up around the shaft seal, it fails, then the drum bearing fails, and the cheap (NOT) fix is haul it to the shop and have them replace the damned drum plus bearing assembly. It ain't cheap.

My brother fixed his own, after the repairman he called said he should just replace the whole thing. Didn't even know (or want to admit) how to run the diagnostics. Chuck figured that out after he ran the guy off, and repaired accordingly.

Wife likes it, I hate the damned thing.

Pete Keillor

Very cool. Johnson Outboards made a motor for washing machines in the

1930s. And, if you have a copy of the 1952 edition of _The Boy Mechanic_ (I do), they have a plan for a flat-bottomed "sea sled" boat powered by one. It used a piece of rubber garden hose for a coupler to the prop shaft.

OMC was Johnson. (also Evinrude) and this engine was sold under all 3 names at one point. I've seen the plans. Saw one built with a twin cyl 2 stroke Maytag years ago. There wereplans to build a midget car and a scooter using the iron horse too - as well as plans for and a commercially built Maytag Midget.

The "horse" was also used on quite a few early lawn mowers and some generators and garden tractors.

They also built 2 stroke iron horse engines (used on early Lawn Boy and Jacobsen mowers)

There's a lot of charm in those old engines. I have only one of them left -- an O&R from the '60s (I think -- maybe the '50s).

It's interesting that we never feel that from electric motors. The motor that powers my bench disk sander is a 1-hp GE Century from before WWII. It's as big as a microwave oven, and all of the inertia makes for a great disk sander. But it has as much charm as a sump pump.

I've got an old universal (brushed DC- shunt wound) motor that weighs about 75 lbs - likely about 1/2 HP - built back around the first world war. A bit more charm to it than a split phase Induction motor. But not a lot.

I'd love to have a real spin dry cycle like that.

Oops.

Durned sneaky Murricans getting into the pipes, eh?

EIGHT? Wow.

Yeah, I KNEW the seals were going and the bearings were shot, but I just DIDN'T want to tear into the thing. Fear of the unknown.

Now that I've done it once, I know it really isn't that big of a deal, and I made up the pieces for the extractor/installer tool that they want to rent you for $100 a day. It takes a couple hours and costs about $70 for the kit. So, the next time it starts sounding like a 747 taking off when doing the spin cycle, i will NOT delay ordering the rebuild kit.

Jon

Life of a mechanical relay is typically only 50-100,000 operations at full rated load. Often even less for motor rated relays. That's completely specified, sometimes there is a curve showing typical life at lower than rated current, and you can easily test for that (at 2 seconds per operaton 100,000 operations takes a couple days, and you can test for 1,000,000 in a few weeks) . At only 10 operations per hour in a product, 24/7, a 100k operations relay will last less than 2 years.

Here's one that's rated for only 25,000 operations at rated current

*resistive* load.

Now as an engineer working for an appliance manufacturer, do you recommend a $5 relay (longer life or heavily derated) instead of a 50 cent one to make it last 10-20 years rather than 5 average, knowing that will increase the retail price by $50+, or do you use the cheaper part? Do you make the same decision for all the **other** parts that have a definite life span, and if so will you still have a job- or will your product be affordable enough to sell in the required quantities. It's not really evil, just an economic decision.

I've seen lots of failures of solid state relays- they almost always fail 'on' and they do so more-or-less randomly rather than mechanical relays that have a definite life. They also produce a lot of heat requiring heat sinks, are more expensive and often less reliable in the bathtub part of the life curve. They have notoriously poor tolerance for overcurrent and overvoltage. There has been little improvement over the years in SSRs or mechanical relays, though both have gotten cheaper in real terms.

It's possible to make SSRs more robust by using much larger overrated semiconductors and special I^2T fuses, but there's those pesky economic trade-offs again..

--sp

Greetings Jon, I am almost 100% sure that the motor is not shaded pole. A shaded pole motor starts because of the shorted winding "shading" a pole. This shorted winding is that heavy gauge copper loop around the laminations. They are not very effiecient and draw almost the same current when loaded or unloaded. Your motor sounds like a brushless DC motor. Eric

Or possibly a split phase? If variable speed, today, almost certainly BDC.

A friend of mine has a log cabin in the Missouri Ozarks. He has a Frigidaire (I think) washer that must have been made in 1946 or something. Seems a little too modern to have been made before most industries shut down during the great depression, so I'm taking a wild guess. You fill it with a water hose, drain it by putting the drain hose on the ground, and it has a wringer. He says it still works, but I have not actually seen him fire it up. Looks like a fair bit of trouble to use, and that wringer looks seriously dangerous.

Jon

(we're talking about the pump motors here.)

Well, it COULD be. But, it ONLY has one winding! Two wires plus safety ground. And, it seems to have (really strong) magnets in the rotor. I can't figure out how you can get a synchronous motor to run the right direction with only one winding. It REALLY looks like one of those old phonograph motors, just bigger.

Jon

The spin/agitate motor is direct drive, 3-phase brushless motor, with a rotor position sensor. It is made in the inside-out configuration, and about 9" diameter.

The two pump motors are built very much like the old phonograph motors, but appear to have a permanent magnet in the rotor. They have ONLY one winding. No capacitors, and as far as I know, the pumps are not variable speed.

Jon

I thought you were talking about the main motor. Shaded pole motors could be used for pump motors. They often are because they run just as hot when stalled as when running so if one is stalled they usually won't overheat. Though there applications where a fan is connected to the motor shaft to cool the motor and they will overheat up if stalled too long, usually a couple minutes at least. Still, with a magnetic rotor I don't understand how it would work as a shaded pole. I'm mystified and am going to try to find out just how your motors work. Though shaded pole motors have the advantage of speed control by changing the voltage, starting in the preferred direction, and resistance to overheating when stalled they still waste a lot of the power consumed as heat. And this would seem to keep them from being used in modern appliances. Do these motors have the shorted winding? A heavy, like 10 gauge maybe, bare copper loop near one of the corners of the lamination stack, opposite the coil? If so then they are indeed shaded pole motors. If there is no shorted winding then I would say they are not. Eric

Reminds me of my brother's comment of 50+ years ago regarding the sound of rubber pants going through the wringer. The Connor circa 1949 came with an optional small tub that functioned very well as a butter churn after it was restrained by a double hook formed from the rear brake actuater rod from a Model "A" Ford.

These gas powered washers usually came with a flexible length of exhaust tubing which my Grandpa often threatened to instal on Grandma!

My copy of that, after many years pumping water to the garden, went to a nephew to power his go-cart!

Junior's FiL is looking for a non-leaking gas tank for the B&S type 5 on his roto tiller.

That - sump pump with the vertical shaft and column removed - is what powers my Dunlap jigsaw.