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

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

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.

(ps, since I burned out my 7.5-30 NST I ALWAYS use a safety gap, and my spark
length measurments are based on having a safety gap set appropriately for the 
NST voltage).




>Original poster: "The Big Giant Kevin by way of Terry Fritz 
<twftesla-at-qwest-dot-net>" <neo4s-at-hotmail-dot-com>
>
>Hello List,
>    I just finished my 3.5"X12" Tesla Coil and I am getting about 8-12" 
>sparks from it. I am pleased with the output but I think it could do better. 
>Some of you get 5' arcs and more but a 12" spark really looks great. I might 
>just be saying that because I've never seen anything better. Anyways, here 
>are the specs to my coil:
>   1) Transformer is a Franceformer 15/60
>   2) Capacitors are 2 wine bottles and 2 beer bottles
>   3) Spark gap is 5 gaps spaced 1/16" apart (static gap, copper tubes)
>   4) Primary is 15 turns of #8 AWG bare copper wire, tunes at about 12.75 
>turns
>   5) Primary coupling to secondary is, well the secondary is connected to 
>the primary (see Tesla vd. Oudin thread)
>    6) Secondary is 3.5" ABS wound with 27AWG Magnet wire, 12" winding 
>length
>    7) I have a few different toploads but the one that I get the best 
>results with is a metal bowl.
>I want to know what I can do to make the sparks even longer. I think I need 
>more capacitance and a bigger gap. Any information is appreciated, thanks,
>    -Jake
>    <mailto:cybermecium2-at-home-dot-com>cybermecium2-at-home-dot-com
>    http://taradev.cjb-dot-net
>
>I also just finished my coil of similar size and type, I’m also getting 10 - 
>12 inch sparks. How can we improve coil performance? Iv widened the main gap 
>to the point where the NST safety gap is firing 50% of the time. Iv tuned to 
>1/8 turn. Should I increase MMC capacitance, its set at the optimum LTR for 
>my NST (9.33nF 12/30). The neighborhood kids would appreciate any help, 
>Kevin
>