Re: High Voltage but Low Current fuses...

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Terry Fritz" <teslalist-at-qwest-dot-net>

Hi,

Apparently, there is a need for a "Tesla coiling fuse".  The mid-voltage 
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 ;-))

Cheers,

         Terry


At 09:43 PM 7/15/2003 -0400, you wrote:
>Chris,
>Actually, most standard fuses do fail with time, even when operated within 
>their specified ratings.  There are microscopic cracks and inhomogenieties 
>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.
>Dave
>
>
>>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.
>