Re: Safety Gap

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

Original poster: Bart Anderson <classi6-at-classictesla-dot-com> 

Hi Luke,

Absolutely! What you basically have is a needle gap. The influence of 
electrode shape and size plays a major role defining the arc voltage for a 
given gap width. For larger electrodes and the narrow gap spacing used for 
the typical spark gap configuration, the numbers should be pretty close. 
The reason is that the electrodes appear planar. But as you start 
decreasing the electrode size where the gap width is larger than the 
electrode size, the shape and curvature come into play. And with that, if 
the gap width is "much" larger, the electrodes begin to appear like a point 
or needle gap.

Dr. Resonance last year tested flat electrodes with a 30kV supply varying 
the gap width and measuring the voltage at which the gap conducted. Javatc 
follows those actual arc voltage measurements pretty darn close throughout 
it's range. Thanks to Dr. R's measurements, I had some actual data to work 
with. However, if a needle gap such as you have set up is used, then all 
bets are off. However, what you have provided here is another good piece of 
information that can be jotted down for review regarding a needle gap setup 
with a 15/30 NST could arc across 3/4", which is certainly believable.

Take care,
Bart

Tesla list wrote:

>Original poster: "Luke" <Bluu-at-cox-dot-net>
>Yup no caps.
>Just an NST and a Spark gap.
>The spark gap in this case was nothing more than two pieces of copper
>wire cut and pointed toward eachother. So it wasn’t rounded balls or
>anything like that. Does that make a huge difference?
>
>Luke Galyan
>Bluu-at-cox-dot-net
>
>-----Original Message-----
>From: Tesla list [mailto:tesla-at-pupman-dot-com]
>Sent: Friday, February 06, 2004 6:34 PM
>To: tesla-at-pupman-dot-com
>Subject: Re: Safety Gap
>
>Original poster: Bart Anderson <classi6-at-classictesla-dot-com>
>
>Hi Luke,
>
>What are using as electrodes and what are the dimensions of the
>electrodes?
>BTW, is this test with only the NST and the sparkgap? (no cap in
>there?).
>
>Let me know.
>Thanks,
>Bart
>
>Tesla list wrote:
>
> >Original poster: "Luke" <Bluu-at-cox-dot-net>
> >I was working out how I wanted to make my safety gap and happened
>across
> >something that has me confused.
> >Using the JavaTC program with a static spark gap and a 15KV NST, if I
>set
> >the total gap spacing to anything over 0.3” I am informed that the
>voltage
> >needed to jump the gap is greater than the peak voltage of the NST.
> >
> >I was assuming that the safety gap would be set at close to this
>distance
> >as well. I started playing with a 15KV 30mA NST. I can set a gap of
>almost
> >¾” and still get an arc when I energize the NST. This seems to be close
>to
> >the cut off point since it sometimes will and sometimes will not jump
>the
> >¾” gap.
> >
> >Yes I know the peak voltage is around 21 or 22KV. And just to avoid the
>
> >questions no I am not using a variac. I just have a cord with a cord
>cap
> >on it and I plug it in, then poof an arc jumps the ¾”.
> >
> >Is JavaTC telling me something other than what I think it is? Is there
> >something I am missing? Any comments.
> >
> >Luke Galyan
> >Bluu-at-cox-dot-net
> >
> >
> >
> >
> >
>
>
>
>