That's a very good question, dutchman. I've heard tons about contrl panels failing in equipment such as washers, dishwashers and refrigerators, but I haven't heard much about what caused the failures. Users shell out the bucks, replace the control panels and move on.
I womder if tin whisker growth have anything to do with it. (See: http://www.eetimes.com/design/military-aerospace-design/4230652/Understanding-and-mitigating-tin-whiskers?cid=NL_MilAero&Ecosystem=military-aerospace-design )
Yes, Tim, there are plenty of washer stories in both the Sherlock and Monkey blogs, but most of the posts find difficulty with the control panels rather than the mechanical operation of the washer. Even with the wear and tear, washers are remarkably durable. It's the relatively new electronics that seem to create most of the problems.
We used a Maytag for about 7 years before the unit would not work. It seems the wiring to one of the pc boards was very loose so I recconnected the wires but the washer would still not wash. I replaced all of the power transistors on the motor control board to no avail. I finally purchased a combination motor and motor control board from Ebay, installed it and it has been working fine ever since. I was glad that I did not have to "junk" the entire unit causing global waste instead of repairing the washing machine. The loose wires appeared to be some kind of tachometer feedback to the motor control board. The loose wires may have taken out the motor microcontroller but I was not sure.
Washers do see a lot of force and friction during the normal operation. It is probably one of the hardest working pieces of equipment in a house. That may be the main reason that there are so many articles in Sherlock Ohms about washer failures.
This is a good example of the pitfalls of trying to validate a design solution with a test which doesn't adequately represent real-world conditions. With a small amount of water and no clothes, replacing the pressure switch appeared to work. It only became apparent that the pressure switch wasn't the problem when you tried to use the washing machine to actually wash clothes! Let those who are tasked with developing test and validation programs beware.
When my electric dryer wouldn't heat up I would have bet money it was because the heating element went bad. It took me about an hour to tear it all apart to get to where I could ohm out the element. It tested good. I took the inpection panel off from behind the controls in a matter of seconds to see the control had melted.
Truchard will be presented the award at the 2014 Golden Mousetrap Awards ceremony during the co-located events Pacific Design & Manufacturing, MD&M West, WestPack, PLASTEC West, Electronics West, ATX West, and AeroCon.
In a bid to boost the viability of lithium-based electric car batteries, a team at Lawrence Berkeley National Laboratory has developed a chemistry that could possibly double an EV’s driving range while cutting its battery cost in half.
For industrial control applications, or even a simple assembly line, that machine can go almost 24/7 without a break. But what happens when the task is a little more complex? That’s where the “smart” machine would come in. The smart machine is one that has some simple (or complex in some cases) processing capability to be able to adapt to changing conditions. Such machines are suited for a host of applications, including automotive, aerospace, defense, medical, computers and electronics, telecommunications, consumer goods, and so on. This discussion will examine what’s possible with smart machines, and what tradeoffs need to be made to implement such a solution.