[Amps] HV fuse

[Traian]

Hi Rich,

I think I wrote it wrong. The fuse was not actually destroyed (exploded)
but interrupted, so it did its job. It is quite big, seems to be made from
glassfibre+epoxy compound, hard to be destroyed.
It was the second time when it happened (first was because of a
cracked doorknob cap).
It was "repaired" before using a proper sized thin copper wire as a new
one it was impossible to find here. Even so, it still did its job.
As usual for such mistake, I did learn something new, and now was
about the HV fuses. What is interresting about that HV fuse
(labeled Buss) is that its inside is splitted in two large compartments
separated by a little wall with small hole in it (the wire is getting
through).
Later I found new 3 kV 1 amp glass HV fuses made in the former east
Germany and they have also their interior splitted but this time in three
separate compartments of different size.
Is this the "secret" of the HV fuse, can this  to be done as to prevent the
vapor arc?

73,
Traian


"R.Measures" wrote:

> On Jul 19, 2004, at 9:27 AM, Traian wrote:
>
> >
> > The Harris RF-110A uses a similar circuit for protecting the screen
> > circuit
> > from tube flash over discharge (R series resistor at the bottom of the
> > screen's
> > regulating string of zener which act a SCR; all of the tubes screens -
> > two
> > 8122 drivers and two 4CX1500B finals- are OR connected by diode at
> > the SCR anode). It saved me the entire power zener string once, when
> > I had to verify a 4CX1500B (the tube was verified ok at hi pot before,
> > but the big bang occurred anyway and destroyed the RF124's PS HV fuse).
> >
> When a fuse is destroyed during a fault, it failed to do it's job of
> interrupting current flow without creating a metal vapor arc.  Thus, a
> more capable fuse is needed.
>
> AG6K