Is Simpler Better for Fail-safe?

The manual hand crank to raise and lower automotive windows.

Having replaced electric window motors, this is one of my favorites. They will work without problems for decades.

A manual hand crank to raise and lower control rods in a nuclear power plant. Unfortunately they don't employ them. Sucks doesn't it?

Personally, I prefer something mechanical to get something done as opposed to something electronic almost every time. Not only can I look at it and understand how it works, but I can usually fix it if it breaks.

I don't know why but the first thing that came to my mind when I read that you prefer mechanical to electric, was the old brace & bit drill. Do you prefer one of those? I think I have one that my Dad had, but never used it much. My Dad had a lumber yard. I do remember in my teenage years, I would work during the summer as a carpenter's helper. One of them seemed to like to use a brace/bit for installing door knobs and keepers. And electric drills were certainly available.

Didn't mean to confuse you. I said mechanical to electronic, not electric. I was referring more to controllers, etc.............I also said, almost always.

Or take advantage of gravity--design something that holds the control rods up using power--on loss of power, have them lower automatically (I mean, by gravity) (presumably with something to keep them from simply falling and possibly damaging themselves or some part of the reactor).

I would hope by now most designs are like that, but I sort of doubt it. ;-)

One of my favorites is the 'Space Pen', developed for astronauts to use in zero gravity. Regular ink pens rely on gravity, and will not work in space. Millions of US dollars invested, just to write a note. Meanwhile, the Soviet space program solved the problem for their cosmonauts with a different tack: they used pencils.

This is an urban legend, but has some value as an illustration of too much engineering. Sometimes, simple can be better.

An interesting aside, nobody I have given this example to has ever questioned it as being factual or not... but I always come clean in the end.

Do FMEA. ( Failure Effect Mode Analysis ).

We may need to proactively think & eliminate the causes for failures.

Regards,

Sucks syntax, doesn't it?

That's what FEMA did (or not)!

One that sticks out in my mind is the modern gas stoves that have electric ignitionsand saftey interlocks on them.

Back years ago if the power went out for an extended time you could still keep your house above freezing, in most cases, by running the old gas stove as a back up heat source.

Now that doesn't work being that if the power goes out the stupid electronic igntion and saftey related circuitry goes dead and the stoves are unuseable without it.

Now that doesn't work being that if the power goes out the stupid electronic igntion and saftey related circuitry goes dead and the stoves are unuseable without it.

Gas stoves don't have a gas cutoff valve that operates in the event of a loss of power to the electric ignition (do they?), so what about a good old fashioned match?

Re: Gas stoves don't have a gas cutoff valve that operates in the event of a loss of power to the electric ignition (do they?), so what about a good old fashioned match?

I should wait for somebody else who really knows to confirm this, but I'd bet they do (modern gas stoves, at least), or maybe the inverse, the gas valves won't open without electricity. (I don't like speculating, but I do it at times... ;-)

Of course, if you have a (modern) gas stove, you can turn off the electricity and try to light a burner and find out for sure. ;-)

Mine is a newer model. The stove top burners work, I just have to light them manually. The oven won't.

Thanks!

A gorgeous view in your blog comment ..

Thanks,

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Tell that to the people making consumer products like dryers. Currently some have 3 temp senors and 2 breakers that can reset or show as good on ohm meter but not handel watts.

$800 for a dryer ? I have to repair or putting up a clothes line.