Why can't electronics on new washers & dryers be tougher?

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brassplyer wrote:

$$$
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brassplyer wrote:

Well when you get right down to it, why does it need circuitry at all? It's a motor and a heat element. They do that to make more money. How would they make money if the damn dryer lasted 25 years like they used to?
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Steve Barker wrote:

Marketing. I saw a washing machine that was advertised as having "crystal control". Presumably, it timed its wash cycles to one part in 10^9.
Sylvia.
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Crystals aren't that good unless especially good and in temperatrure-controlled ovens. I would hope for one part in 10^6 to one part in 10^7 or so.
Meanwhile, crystal oscillator circuits are not expensive to make. Even modules of such are easily available and cost maybe a couple bucks or so, maybe closer to a buck in quantities of tens or hundreds of thousands. Cheaper crystal oscillator circuits may be had for something like 50-60 cents each in quantities of tens of thousands.
The alternative for reliably having a complete cycle's timing down to seconds out of an hour is "power line time base", costing a fraction of a buck, probably a smaller fraction, less than cheaper crystal oscillator options.
Cheaper still requires oscillators regulated by component tolerances - and oscillators tend to have at least two components affecting frequency, and finest tolerance of ones easily available at premium prices is 1%, meaning low chance of achieving timing highly reliably better than 2% in either direction unless either crystal or power line time base is used.
Mechanical timers use "synchronous motors", which gives "power line time base", good enough to make electric clocks with. Many digital electric clocks use electronic means to make use of "power line frequency time base".
- Don Klipstein ( snipped-for-privacy@misty.com)
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Don Klipstein wrote:

I'd have thought getting the cycle to within 10% would be more than adequate.
Sylvia.
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Sylvia Else wrote:

    No, because time and Tide wait for no man.
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If the washer has an automatic detergent dispenser, the Tide needn't wait.
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William Sommerwerck wrote:

I`m alergic to Tide, Daz is ok tho ;^)
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Do you mean Duz?
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William Sommerwerck wrote:

No, I meant Daz
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Plague Boy wrote:

*groan*
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Sylvia Else wrote:

It would be. Washing machines used to use synchronous motors driving a cam, which was far more accurate than necessary to do the job properly.
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wrote:

Failure of mechanical timers on appliances is VERY common, and usually results in the appliance going to the landfill.
Electronic controls, done properly, are far more reliable. Yes, there are some that are done properly!
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snipped-for-privacy@dog.com wrote:

Sure, but it was the cam/switches that would fail, not the motor.

In theory, sure.

I'm sure that there are, it's just that I haven't run into any.
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wrote:

Oh, I've seen plenty with a motor that stopped. Regardless, mechanical timers are a glaring weak spot in appliances.

Take a look at a Fisher & Paykel. When they designed it, they started with a clean sheet of paper. They didn't just slap a few blinking lights on a conventional washing machine.
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Don Klipstein wrote:

A washing machine could be out by 20% or more without causing a problem.
The traditional synchronous motor is more than accurate enough for the application.
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Sylvia Else wrote:

Jeez. I haven't run into that one in person, but it wouldn't surprise me. The current craze for insane amounts of megapixels in digicams with toy lenses is a very similar problem.
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Reminds me of DVM's with 3 1/2 digit readouts and 1% accuracy. The last digit is just noise.
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AZ Nomad wrote:

Exactly. And don't get me started on the low ohms ranges of those meters...
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LMOA.
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