Re: spark gap

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: Just Justin <rocketfuel@xxxxxxxxxxxxx>


Hi Tim,

My coil is similar in specs, although only 60mA instead of 120.

I found that I've had the best luck with 2 gaps out of 6 available.
The way I set them is similar to setting a safety gap: open the gap
until they stop firing and then close it back just a wee bit.  (For
the safety gap you would keep it at the just-barely-not-firing
distance).

The width of the gap will determine the voltage that the tank cap
is charged to before discharging through the spark gap.  In my
(limited) experience, a wider gap makes loud bangs that are 'hotter'
and more randomly distributed.  A narrower gap makes more of a
high pitched buzz as the breakdown frequency goes up (the tank cap
can be charged to the breakdown voltage several times in 1/2 of a
60Hz AC cycle).  Also with the narrower gap, I tend to get a streamer
that stays 'solid', and wanders around rather than the random sparks
jumping around erratically.

My gap pieces are approx 1"x6" copper pipe and they seem to stay cool
with a microwave-sourced fan blowing out the sparks.

I also found that I got much better results with a 6" minor diameter
toroid, perhaps you would as well.

happy coiling,

Justin



On Thu, Jan 19, 2006 at 11:35:13AM -0700, Tesla list wrote:
> Original poster: Timjroche@xxxxxxx
>
> I'm running:
> 12kV 120mA NST
> .03 uF 45kV maxwell tank cap
> 12 T .25" tube .25" spacing primary
> 4.343" OD 28awg 17" lng secondary
> maj. dia 17" min dia 4" toriod
>
> What is the best place to start a static gap?  I have . 5" solid Cu
> (12 pcs. 4" long), .5" tube, 7/8" tube, and 1.125" tube...is hollow
> better? bigger dia?
> What about length? my 7/8" (6 pcs. 6" long) better than .5" 3"long?
> can you have to many gaps? i.e. total gap=.5",  2 tubes?, 6 
tubes?, 12 tubes?
>
> thanxs
> Tim
>