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RE: High Voltage but Low Current fuses...Why ? ? ?
Original poster: "Mccauley, Daniel H by way of Terry Fritz <teslalist-at-qwest-dot-net>" <daniel.h.mccauley-at-lmco-dot-com>
May sound like a dumb question, but can you explain to me why you would
need a high voltage fuse for tesla coiling?
If your goal is to provide fusing to the output of a pole transformer or
similar, then fusing should be placed on the
input side instead on the 240VAC etc...
Trying to design a fuse (esp. a high voltage one) is a daunting task in
Contrary to most people's belief, fuses are EXTREMELY complex devices.
Not something you can just take a piece of wire and
make a simple fusible link out of.
> Apparently, there is a need for a "Tesla coiling fuse". The
> fuses and all are not right for "our stuff"...
> The key is that we do not need to break a "sustained" 4000
> amps or anything
> like that. A say 5 amp continuous AC current, 0.25 amp,
> 30,000 volt fast
> blow fuse is what we need. Not really hard to make, but none
> of the big
> guys seem to make a high voltage fuse that is designed to work with
> "little" currents...
> We make take a 4000 amp "hit" from a big impulse cap, but
> then the current
> falls to like 100mA in our case...
> I think I got a new project ;-))
> At 09:43 PM 7/15/2003 -0400, you wrote:
> >Actually, most standard fuses do fail with time, even when
> operated within
> >their specified ratings. There are microscopic cracks and
> >in the fuse bar which get locally hotter than the rest of
> the material,
> >thus further propagating the defect. Eventually, the defect
> lowers the
> >functional rating of the fuse, and the fuse blows,
> frequently with the
> >turn-on current rush, or just during normal operation.
> That's one reason
> >that critical equipment usually has a spare fuse in a holder
> right next to
> >the working one.
> >>I would think that would work here, too, only with pen springs or
> >>similar. But that's probably more complex than a simple
> weight. The
> >>weight mustn't be too large or it could promote a premature
> failure over
> >>time - copper creeps when hot.