RE: Safety Gap

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

Original poster: "Luke" <Bluu-at-cox-dot-net> 

The gap I used was not for use as the safety gap.  I was just trying to
get an idea as to what spacing I did need for the gap.  I knew shape had
a little to do with it but didn’t think that much.

But for the sake of getting the feel of it, let me ask this.

If I were to use
1:	standard style main static spark gap consisting of copper pipe
parallel to each other and spaced at about 0.29" as JavaTC says is about
right.

2:	Used a needle gap for a safety gap set at just over 3/4" so gap
was just large enough to prevent the NST from arcing.

Would the safety gap still perform its task?
I would assume yes but what are some thoughts on this.
I do intend to use rounded electrodes in the safety gap but what would
be the input on the above?

Luke Galyan
Bluu-at-cox-dot-net

-----Original Message-----
From: Tesla list [mailto:tesla-at-pupman-dot-com]
Sent: Saturday, February 07, 2004 3:35 PM
To: tesla-at-pupman-dot-com
Subject: Re: Safety Gap

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
 > >
 > >
 > >
 > >
 > >
 >
 >
 >
 >