RE: GETTING CLOSER!

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

Original poster: "Lau, Gary by way of Terry Fritz <twftesla-at-uswest-dot-net>" <Gary.Lau-at-compaq-dot-com>



>Original poster: "Nathan Morris by way of Terry Fritz
<twftesla-at-uswest-dot-net>" <themfam-at-home-dot-com>
>
>Hello all,
>This is the current status of my coil and some questions that have come up
>along the way.
>4 x 19 inch Secondary: 1600+ turns of #20 mag wire, complete with a
modified
>antique glass insulator for a torroid mount.
>Primary:  The form is complete and will be wound with close to 50 feet of
red
>insulated, stranded 10 AWG.
>Variac: 3.75 amps 145 VAC out, fused at 10amps and will be used to boost my
>tranny. (Will not be used on first light run)
>Trannys: 2 each 12kv 30ma NSTs. (Only one will be used on first light run)
>MMC:  Two rows of four oil filled porcelain caps found on ebay for a total
of
>.01uf.
>Static gap: 4 pair of contacts, each individually adjustable.
 
>Questions:
>1) What is a good distance to set my gaps at for tuning?

The gaps should be set so that WITHOUT the cap in the circuit, the gaps will
just fire at maximum NST input.  I would guess a total of 0.2" to 0.25".
Just be sure to use air blowing across the gaps.

>2) How critical is coupling and what sounds like a reasonable K for me?

All I can say is that it does matter.  Too low and you loose efficiency.
Too high and you'll destroy your secondary with the "racing sparks" running
up and down it.  The only way is to keep increasing k until you get the
racing sparks, then back off a bit.  Typical k values for a 4" coil may be
0.1 - 0.14.

>3) Who would like to sell me a spun aluminum torroid without dents?
>4) Is there any way to do a low voltage set up first? I have a function
>generator and a scope and would like to incorporate them into the tuning
>process.
>5) Does anyone know where I can find some information on the Teslathon in
Ft.
>Worth Texas?

One further comment - If you wind 19" of #20AWG wire, you'd only get about
548 turns, not 1600.  A 4" dia coil can (and should) be wound longer to
achieve a greater separation from topload to ground.  I'd recommend 23"
long.  To achieve 1600 turns in 23" you'll need to use #27AWG wire.  I'll
leave it to you to figure out what your primary needs to be to achieve
matched resonance, but you may need more turns and more than 50 feet.

Good luck, 
Gary Lau
Waltham, MA USA