OT -- switching heating elements

Well said.

I understand that if you look at the statistics on people who suffer injuries while working with (e.g.) power woodworking tools such as table saws and lathes, you find:

- A significant but moderate percentage of "newbies" who didn't read the instructions and warnings, and thus "didn't know better", and

- A rather higher percentage of people with quite a lot of experience with the equipment, who (when asked about it afterwards) say something like "Yeah, I knew better, I knew I was taking a shortcut and ignoring Precaution X". As they say, "Familiarity breeds contempt" - in this case, familiarity with the equipment or working environment tends to breed contempt for safety precautions. "I got away with that before..."

Festering? Get real. We aren't talking low temperature an a few mA.

Emergency Locator Transmitter? Extremely Large Telescope?

These are the only uses of 'ELT' I've seen in the United States. It is where I live, and so does the OP.

Sigh. Think it through. The body of the oven is grounded. If a calrod element is failing, it isn't gradual. If it shorts to the metal body the fuse blows, or the breaker trips since it is less than a full load resistance.

If the element opens inside the metal tube, it generally creates plasma which burns through the casing and opens the element permanently. Even a bad connector will self destruct at those currents. There is an exceedingly small chance for an intermittent element.

Circuit breakers don't need to be explained.

In probably less than 1/1000 of installations in any relatively modern home, there is a power plug (on a short cord) and receptacle for a kitchen range.. it's a service disconnect.

Disconnects are defined and required by codes in many places, certainly by the NEC, and just plain (un?)-common sense.

-- Cheers, WB .............

I can think of a number of reasons, the principal one being that it's easy to stick a fork in a toaster, much harder to stick one in an oven. Of course, this particular toaster used sealed elements, so it's unlikely anything within the cavity would ever be electrically hot.

The other reason for switching the neutral is that there's no guarantee the neutral is neutral -- some houses are miswired.

I had a great conversation the other day with a woman at GE's CEO headquarters, who apparently does nothing but talk to Really Unhappy customers. I admitted my carelessness, but she didn't put me down, and listened seriously. She said she would report this to The Council. ("The Kryptonian Council of Elders?" That got a big laugh out of her.) Apparently, GE has a group that pays attention to engineering issues.

You might have heard that GE is bringing major-appliance manufacturing back to Appliance Park. This is apparently due to rising wages in other countries, and GE's figuring out how to build appliances more efficiently. A guy at GE told me that the goal is return the manufacture of /all/ major appliances.

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So then why not assume that there are enough idiots out there like people who use ground busters because they have older ungrounded outlets in their homes or better yet those that file the larger prong on a plug down so that it will fit in an older outlet. If you really consider these possibilities then why not switch both the hot and neutral on every 120V appliance. Lets make them all "idiot proof" and then everyone will be safe. I mean should we assume that anyone is going to have to take responsibility for their own actions any more? When I was a kid, (back in the stone age). there was no such thing as a Calrod element, well maybe there might have been but I remember that most appliances like toasters, ovens, broilers, even space heaters were made with exposed nichrome wire. Many toasters still are. I worked on them all from the time I was a teenager. Most people, even the non technical ones realized after they had stuck a fork in the toaster once to not do that again. I'm sure that they still do. But really lets answer the bigger question. What is the goal here? Is it to build an appliance as cheaply, I'm sorry, (cost effectively), as possible or is it to keep people, even the stupid ones safe? And getting back to my other question: why did B& D obviously think that it was a good idea 15 years ago to switch both the hot and neutral on my toaster oven but now they don't? You just can't convince me that the least common denominator isn't money. Yeah maybe I am a little paranoid too, but it doesn't mean they're not out to get me.....Lenny

The GE Calrod unit goes back at least to the 50s, and probably the 30s. An electric oven using exposed nichrome wires would not be a very good idea.

If there is an answer, it's that you do certain things simply because they make sense, regardless of what you think a user might or might not do.

I have my mother's old broiler/rotisserie from the 50's down in the basement. My wife asked me to get rid of it so many times but I just can't seem to part with it. (I remember the roasts and rotisserie chickens we used to have when I was a kid). It has a coiled nichcrome wire element as they all did at that time. Early Lionel trains were connected directly to the AC line through a carbon pile or rheostat. Things were a lot different in "the old days". I finally just hid it. Maybe I'll get it out one day and cook a roast for her. Lenny

I had another question as long as we're talking about ovens. When you use the self cleaning function on these stoves, I believe that both elements are turned on for an extended period of time. We usually hold off doing this until a cold spell hits as lot of heat is generated and warms the kitchen nicely. Essentially everything in the oven is incinerated down to a fine gray powder. If you think of the bake and broil elements as "filaments" of a sort, with a finite life span, doesn't invoking this function shorten their life? Lenny

One would think so, if one were inclined to think all corporations are evil and all design engineers are stupid.

The misconception here is that the "normal" heating range on those elements is the design center. It is NOT. The "clean" cycle is the design center.

Jeff

If it does, then one has to weigh the convenience of self-cleaning against the inconvenience and higher cost of manual cleaning.

I've never used the self-cleaning feature on my oven. Yet the bottom element burned through after only about 10 years of use. Another member of this group reported the same thing for their GE.

I had a conservative, slightly paranoid friend (hi, Greg -- miss ya bad) who claimed materials science was sufficiently advanced that auto manufacturers were able to control how long a car engine lasted. I pooh-poohed this, but he was probably correct. Few products are made to last "as long as possible", because it tends to increase the price.

It's NOT some evil conspiracy.

The CONSUMER has been screaming for the past 30 years, "I don't care if it's crap, I want it now, I want it cheap and I don't care if it only last 6 months because I'll be bored with it by then anyway."

Manufacturers are supplying them with what they asked for.

Jeff

Not exactly. In the not so distant past, manufacturers produced products, set prices as best they could, and retailers did their best to sell at that price point. No more. With the demise of the small retailers, the large warehouse stores are doing it backwards. They set a price at which they know they can sell and make a profit, and then demand that their suppliers deliver at that price. If the supplier complains, then another supplier will be found. Walmart is famous for doing that. The result is that manufacturers have cheapened their products, reduced the quality, cut corners, deleted options, etc. Anything to meet the price target. If there are any subsequent quality problems, it's cheaper to deal with warranty returns, than to design in the necessary quality that prevent returns.

I see something quite different than customers that get bored in 6 months. I get complaints that it only lasts 6 months and that they want quality at any price. I deliver quite a few overkill computer systems, where a lesser machine would have been more than adequate. I see hybrid auto sales doing quite well, mostly on the basis of quality and alleged economy, where both would be difficult to innumerate and financially justify. The GUM (great unwashed masses) may have been demanding cheap junk for 30 years, but now seem to have begun to tire of the junk.

As for controlling product lifetime, it's been here for quite a while. Semiconductor life can be predicted based on the number of thermal cycles. Electrolytic capacitor life can be predicted by a combination of temperature and operating conditions. Battery lifetimes are well known and controllable. High power LED's have a predictable lifetime. I've seen products (i.e. old Sony TV's and monitors) that seem to have had components selected for a specific target lifetime. Modeling programs make such designs fairly easy.

It's a lot older than you think. Around 1980 or so, Sears wanted to sell a black and white portable TV and they could not get anyone in the US or Japan to sell them one.

They shopped around and found Samsung, which was a large company in Korea, but unheard of outside who was willing to do it. That's when the large international Korean electronics giants were born.

As for quality programs, it's not the build quality that matters as much as you think. It's the testing. Intel started it (although they may probably were not the first) when they produced RAM chips for the IBM PC and other small computers.

The only made only produced one chip speed and if the chips failed, they were tested at a slower speed, if they failed that they were tested until they failed at the slowest speed sold, or passed one of the tests.

They actually had to do it, their first chips were so bad that ECC (error correcting code) processing had to be built into the hardware of the first computer made using them. It was done at the XEROX PARC, you can read about it in "Dealers in Lightening".

Now they don't bother to test anything at the manufacturing plant, the consumer tests it for them. :-(

Geoff.

Wal*mart also (supposedly) insists that suppliers reduce their prices every year.

I know of no other "big box" store that does these things.

I've been in Wal*mart a few times, and I didn't see where their prices were categorically lower than other stores'. Regardless, I don't buy from Wal*mart.

I'm old enough to remember when discounting was uncommon. Luskin's ("Jack and Joe will save you dough.") of Baltimore was one of the first stores in the US to discount appliances, electronics, etc. It's now taken for granted that you don't pay "list price" for anything -- assuming that "list price" has any meaning.

In the case of Wal*mart, the story goes that companies are sometimes forced to send production overseas.

Again, I'm not sure. If that were so, there wouldn't be any $30 DVD players at Fry's.

Cheap merchandise -- of whatever quality -- is part of the "vicious circle" of rapid technological change and obsolesence.

Which strikes me as perverse -- why not improve the quality of those parts that were worn out? Oh, wait... cars would last longer, and there would be fewer sales, over time.

Quite true. Modern robotic manufacturing methods have the advantage of producing fairly uniform output. The 1.5% AQL QA test is somewhat of a thing of the past, as it's only necessary to test a tiny number of sample units, to predict the performance of the rest.

From my experience, in the distant past, 100% parametric (partial) testing of the product along the production line gives better results. This is where key parts of the PCB are indirectly tested during board assembly, but before final assembly. Tests such as total current drain, end to end gain, board weight, and visual (camera) inspection, do not provide a complete test, but give a fair indication if the PCB is going to work. The idea is to eliminate final test, which such methods do fairly well. The assumption is that a collection of small tests during assembly, do better than a final test. To the casual observer, it may look bad that there's no final test, but along the board assembly line, there's plenty of testing being done. Incidentally, some robotic parts stuffers test the components as they are inserted in the PCB.

Walmart offers the suppliers increased sales volume in trade for a decreased profit margin. That will work only if the supplier has an efficiency improvement program in place. It will also only work with suppliers that are large enough to have sufficient credit available to fund such programs. That eliminates all but the largest suppliers.

The dilemma for Walmart is that there are really only a few vendors qualified to sell to Walmart under such a program. There's also little to stop them from illegally organizing and fixing prices. When this happens, Walmart finds a medium size supplier, and offers to back their growth into a large supplier, in trade for profit margin concessions. How it works in Mexico:

The US gets cheap Mexican products, while Mexico gets Walmart.

My father sold lingerie to Sears during the 1960's thru mid 1980's. Sears wasn't as obnoxious and as demanding as Walmart, but such pricing policies (and others) were well established. However, Sears had a different goal. They were not after the best price. They were into growth. What they did was build up the business of their suppliers, knowing that the supplier would need to obtain expensive financing, and then abruptly cut off all orders. They could then buy what was left of their supplier for peanuts.

Most domestic companies would prefer to use domestic production facilities. It can be done, but not at the price points set by Walmart. Similarly, if the competition wants to sell anywhere near the same price point, they too have to go offshore, even if they don't sell to Walmart.

Good, fast, cheap.... pick two. The buying public has chosen fast and cheap, so the quality will suffer. Where problems start is when quality is unobtainable at any price. That's where I think we're going.

It's not just Walmart. Here's Apple demanding what appears to be regular price cuts on iPad components: Report: Apple Demands 10 Percent Price Cuts from iPad Parts Suppliers

Regardless of whether this is true or false, it's definitely has hurt Sony, which depended on its premium products to create a favorable image for everything it sold.

Sony used to be a true innovator that make a lot of Neat Stuff, but those days seem gone. Glad I got a 7M3 AIBO while they were still available.