Re: Awsome first light !! but...

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

Original poster: "Ed Phillips by way of Terry Fritz <twftesla-at-qwest-dot-net>" <evp-at-pacbell-dot-net>

Tesla list wrote:
> 
> Original poster: "The Big Giant Kevin by way of Terry Fritz
<twftesla-at-qwest-dot-net>" <neo4s-at-hotmail-dot-com>
> 
> >Original poster: "Terry Fritz" <twftesla-at-qwest-dot-net>
> >
> >Hi Kevin,
> >
> >At 12:20 AM 8/1/2001 -0500, you wrote:
> > >WOW, 8 inch streamers, at 40 volts on the variac. Help from the list was
> > >invaluable; I could not have done it without you guys, thanks to everyone.
> > >But… I couldn’t seem to get the variac over 40 or 50 volts then my
> >capacitor
> > >safety gap would start to fire. I set the cap safety gap to fire at 12 kV.
> > >Why was it so active with only 5 kV out of my NST? Tuning seemed to help
> > >reduce the safety gap firing, but not much. I didn’t spend a great deal of
> > >time tuning. I was in a small metal shed; it was 95 degrees outside, and
> >110
> > >degrees inside. Florida sucks in the summer, nothing but mosquitoes and
> > >humidity. Could tuning be my problem here? Nothing special in my setup,
> > >12/30 NST, Terry protection, static gap with fan, LTR cap, line filters.
> > >Thanks for any help, Kevin
> > >
> >
> >While your safety gap may have been set for 12kV, what was your main gap set
> >to?  It sounds like your main gap was set to something higher and allowed
> >the safety to fire.
> >
> >As a side issue, it's generally not recommended to use a safety gap alone
> >across your cap.  With no safety gap current-limiting, the discharge current
> >could potentially be bad for your cap.  Also, it's impossible for the cap
> >voltage to ever be any higher than the voltage across your main gap.
> >Whatever your main gap is set to will also limit the cap voltage, and the
> >cap-gap is redundant.
> >
> >Gary Lau
> >MA, USA
> >
> >What size primary cap do you have?  I would guess the system is resonant
> >and the main gap is having some problem where it's firing voltage is going
> >higher as it opperates.
> >
> >Please don't change the safety gaps since that should not be the problem.
> >
> >Cheers,
> >
> >       Terry
> 
> Primary cap is 9.3 nF, LTR with my 12/30 NST. So a cap safety gap is
> unnecessary? 

	A safety gap is ALWAYS necessary!  In your example, the voltage across
the transformer will probably be double the rating until the gap fires
or the transformer breaks down.

Ed