This seems to be a problem of semantics. In the case of a fuse, a "failure"
is a success - the fuse succeeded in protecting the circuit (neglecting the
cases where the fuse failed to do its job, discussed elsewhere).
I clearly recall some ads for Timken Steel in the 1960s which discussed the
successful "failure" of a mechanical "fuse", a device that would restrain
jets on the deck of an aircraft carrier until the engine thrust and
catapult force built up sufficiently for a safe launch, at which point the
device broke.
The problem is that in many cases when a metal part breaks, it is indeed a
failure. The same language gets carried across to cases where breakage is
the desired result, as in the case of the mechanical "fuse" where its
breaking is an indication things going well.
In the case of fuse operation, things are not going well. There is some
problem. The blown fuse is associated with a true failure. So perhaps there
is some guilt by association, even though the fuse is the (desired) victim
of the true failure.
I like the term "blown fuse". Though perhaps it is not as exact a
descrition as one would like, it is broadly understood, and is not
necessarily associated with failure or a "bad" fuse.
Don Borowski
Schweitzer Engineering Labs
Pullman, WA USA
owner-emc-p...@majordomo.ieee.org wrote on 05/23/2003 03:56:53 PM:
> Hello all,
>
> Recently, in my company, we've been discussing what exactly
> constitutes a good or bad fuse. In this industry we often hear that
> the trouble with a defective product was, "the fuse was bad." I
> occurred to me that the fuse is not bad, it performed exactly
> intended. In fact if the problem that caused the fuse to "operate"
> is still present, then the fuse is still good even though it is now
> an open circuit. The only time it can be a bad fuse is if it did
> not operate, resulting in shock or a fire.
>
> I have now have my ears tuned-in to this concept of a "bad fuse" and
> find it is commonly used all over the industry. In fact you can go
> to any number of websites that provide trouble shooting notes, and
> find instructions on how you can measure a bad fuse from a good fuse
> using an Ohm meter, photos included. And some of these instructions
> are from reputable manufacturers. Another term often used is
> "defective fuse", which in some way sounds more scientific, but is
> still fundamentally wrong.
>
> I recently saw a newspaper article that gave the explaination why
> electrical service was lost for over 100,000 people as a bad fuse.
> An investigation was under way to determine why the fuse went bad.
> This is a little like hearing the technologically uninitiated say
> "it must be a short somewhere", when the television set stops working.
>
> Maybe I am finicky, but this affects how companies view real product
> defects. When the "defect" is the bad fuse, then the real problem
> may be covered up. Often the answer is, increase the fuse size to
> prevent nuisance trips. The risk, of course, is that for every
> incremental increase in fuse value, you increase the risk of fire
> proportionally.
>
> Any thoughts or experiences?
>
> BTW - To all US citizens in the group, have a relaxing Memorial Day
weekend.
>
>
> -doug
>
> Douglas E. Powell
> Regulatory Compliance Engineer
> Advanced Energy Industries, Inc.
> Fort Collins, CO 80535 USA
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