Re: Help Need part by 31Oct01

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

Original poster: "David Sharpe by way of Terry Fritz <twftesla-at-qwest-dot-net>" <sccr4us-at-erols-dot-com>

Matt, Terry

I like that 10kA fuse (LOL).   Only I saw the results on a motor on 460, 3ph in
an industrial plant (how about the motor terminal box and 1/3 of the casing
of a
30HP motor vaporized???)  It led to a huge investigation and edict from the
seniorVP of the division that ANY unauthorized electrical changes made on
production machinery without an Engineering Change Notice or direct
Engineering supervision was a firing offense. It only "blew" a 4kA main fuse
in the main switch gear room    ;^).  Dam.. the copper slugs survived, but the
load didn't...   :^C

All kidding aside, breaker on a variac is a good idea, you'll need some type of
"soft start" or "step-start" to prevent tripping the breaker on energizing the
variac tho...

Regards
Dave Sharpe, TCBOR
Chesterfield, VA. USA

Tesla list wrote:

> Original poster: "Terry Fritz" <twftesla-at-qwest-dot-net>
>
> Hi Matt,
>
> For a Tesla coil, and especially in a situation where a blown fuse taking
days
> to replace is painful, consider a nice resettable circuit breaker
instead.  If
> it blows you simply reset it and go on.  Fuses are nice in stable situations
> were they should never blow.  However, Tesla coils are sort of unstable
things
> and blowing fuses for a variety for reasons (like turning the power up
too high
> ;-)) is common.  A circuit breaker is far better and probably is not too
> expensive compared to your box of fuses.  Look around since breakers are very
> common as surplus.
>
> We replaced all the fuses in our variacs with breakers and I can't tell
you how
> much trouble that saves.  Copper pipe will magically fit in the old fuse
clips
> or a hammer/vice and a saw/file will make the 10,000 amp spade version ;-)
>
> BTW - Some hardware stores do sell these one at a time if you ask around but
> expect to pay a high markup (like $20 each!).  However, I imagine someone
will
> have one.  I check too if we have any of the old fuses around but I think we
> tossed them =:O
>
> Cheers,
>
>         Terry
>
> At 12:09 PM 10/25/2001 -0400, you wrote:
> >
> > Hi All Help!
> >         I found a blown fuse inside my big Variac. The fuse is a Bussmann
> > HBM50, about 1.5" long x 0.5" diam. with a forked bracket on each end. Only
> > one local supplier says minimum order 10 at $45.00 a box. I need One by
> > Halloween, maybe two in a lifetime. Anybody got one they'll part with?
> > TIA,
> > Matt D.
> > G3-1085
> > (Oldphart Hill-Geek)