Re: "I want bigger sparks!" (me too)

["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: "Peter Lawrence by way of Terry Fritz
<twftesla-at-qwest-dot-net>" <Peter.Lawrence-at-Sun-dot-com>
> 
> Guys,
>      I've been building 3.5"x12" TCs for years now and I've gotten to the
> same as you, about 12" sparks, in my case from 9kv-30ma NST.
> 
> The only thing I have not done is a rotary SG, I've tried all sorts of static
> gap materials (tungsten-carbide is best so far), and all sorts of primary
> caps (0.5, 1.0, 1.5, and 2.0) times "resonance" for my 9-30 NST, and all
> sorts of secondaries from 500 turns of #24 wire to 2000 turns of #36 wire.
> 
> There is a large variation in the subjective quality of the sparks with all
> these variables (my favorite is the #32 secondary with 1.0 Res cap), but the
> maximum spark length is about 12" for any of these combinations.
> 
> If anyone else does better on a coil that is only 12" high I'ld like to know
> how also!!!
> 
> It is suprising that you guys only get 12" sparks with 12 and 15 kv NSTs
> while I get that with 9kv. I've been putting off trying larger NSTs because
> I've been expecting to then have to build a long rod to remotely tune my
> SG spacing 'cause I like to do this while the TC is running.
> 
> I've seen my sparks go from ~6" on 6-30 NST, 8~9" on 7.5-30 NST, to 10~12"
> on 9-30 NST, so I expect the trend to continue, but perhaps as your
experience
> shows it might level off instead.
> 
> -Peter Lawrence.

	With a 9 kV, 60 ma transformer I get consistently 24" aparks from a
3.2" x 14" coil operating at a frequency of around 280 kHz with a 14" x
3" toroidal top load.  Using static gap of five sections, adjusted to
just fire on the transformer output when the primary circuit is
removed.  Capacitor is usually 4 3000 uufd ceramic filter capacitors,
certainly not the best.

Ed