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Re: victoreen spark gaps

Bob, 

I am running my TC w/ a 12/60 using the victoreen gaps.  I ended up
fastening 10 of them in a square wave type pattern and using a short
piece of 8 AWG with an alligator clip so that I could "clip in" any
number of gaps that I wanted.  For me, I start getting decent results at
7 gaps, 8 gaps is better, and 9 is bigger sparks yet.  But at 9 and 10 I
start getting arcing from the primary to the bottom of the secondary,
and I also start getting some arcing over in my EMMC, which is my fault
because I didn't leave quite enough space between the leads.  So nothing
bad happens that isn't my fault.

But......

Using Terry's method, I ended up wanting 10 in series by connecting only
them to the NST (it would just barely fire with all 10).  I set my
safety gap by connecting only it to my NST and setting it so it just
doesn't fire.  However, if I run 9 or 10 gaps in actual use, the safety
gap fires like mad, which suggests to me that the breakdown V of 9 gaps
in actual TC use is more than 12kV.  Even at 8 gaps, I had to open up
the gap a little more than its 12kV point.

So it appears to me that 7 gaps equals a series breakdown V of 12kV
under TC conditions while under non-TC conditions 10 gaps equals a
breakdown of 12kV.  At 9kV 7 gaps might be too many if you don't want
your cap to see more than 9kV.

Since my EMMC only cost about $50, I'm running closer to limit and using
as many gaps as I can even though I know my cap is probably seeing more
than 12kV.  I think if I insulated the secondary a little more and fixed
the spacing on my EMMC, I could run all 10 gaps.  

I measured all 10 of my gaps in series at .048nF.

-Stan

Tesla List wrote:
> 
> Original Poster: bob golding <yubba-at-clara-dot-net>
> 
> hi terry, all
> 
>         I have just been trying out the victoreen gaps on my coil.  I am
using 7
> of them in series with a 9 kv 60mA neon and getting breakout all over my
> toriod with a 24" arc to a grounded rod. I was wondering what the
> relationship of the series resistance/ capacitance to breakdown voltage is,
> they are rated to breakdown at 2700 volts, but this is presumably going to
> drop with more of them in series. I measured one of them for capacitance
> with my bridge at about 10 pF. Am I really getting a breakdown voltage of
> 18900 volts across 7 of them or am I missing something here? What does the
> curve look like and when should I stop adding more gaps.
> 
> cheers
> bob golding