Re: Spark gap not firing

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

Original poster: "BunnyKiller by way of Terry Fritz <twftesla-at-uswest-dot-net>" <bigfoo39-at-telocity-dot-com>

Tesla list wrote:

> Original poster: "Matus-at-snet-dot-net by way of Terry Fritz
<twftesla-at-uswest-dot-net>" <matus-at-snet-dot-net>
>
> Hello all, I am attempting to build my first coil on my own.  I have a 15kv
> neon sign transformer at 30 milliamps.

snip

> It is also wired in series with the
> capacitor.  The transformer was calculated (by wintesla) to need .0053 uf.  I
> built a foil stack capacitor composed of five aluminum flashing plates that
> were 5" x 7"  sandwiched in between them was a rubberized adhesive coating
> which I do not know the exact K value for.  The rubber adhesive was four
inches
> across and covered the length of the aluminum plate, giving a capacitor
area of
> 4" x 7". The rubber layers is about 1/64" of an inch across.

snip

Hi Michael..

I did a quick calc on your cap design and it shows that you have about
.0047 uF. If I read your
letter right, it seems that the rubber is too small of an area for the
plates. the rubber (
dielectric) should extend about an inch past the plates to prevent
flashover.  If your plates are
5 x 7 then your dielectric needs to be 7 x 9.
even tho you still hear a snap when you discharge your cap this doesnt mean
that it is working at
100%. when the NST is chargong the cap it may very well be shorting out and
causing the spark gap
not to fire.


the way I have my NST system wired is as folllows...

the hi volt leg #1 is connected to the inside of the primary and to one
side of the cap.  hi volt
leg #2 is connected to the other side of the cap and to one side of the
spark gap... the other
side of the spark gap is connected to the tapping wire to the outside area
of the primary. I also
have a safety gap that is attached across the cap

Scot D