Re: Do these numbers look right?

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

Original poster: "Gerry Reynolds" <gerryreynolds-at-earthlink-dot-net> 

Hi Joe,

You could recheck your numbers using JAVATC.  It is very accurate and has a
wealth of info.  You can use the auto tune feature and experiment.  If you
do use a larger Cp, you can reduce the number of turns in the primary and
get it in tune.  If you do stay at resonant Cp (or close to it), you need to
be diligent on setting the safety gap properly so you don't overvolt the
NST.  With no spark gap firing, voltages above 100KV will probably happen
(simulation shows up to 300KV)  The safety and main spark gaps are the only
things keeping this high resonant rise voltage from happening.  With 7nf Cp
(Cres=6.2nf) and the spark gap set to fire at 18KV, the BPS will be about
180 (per simulations).

50 foot Cu tubing is common and if you do need longer, it is easy to splice
another length onto the first 50 foot.  Just get some solid gauge, I think,
14 AWG wire and solder it into the core of one tube, slip the protruding
wire into the core of the extension piece and solder that together.  I used
a 150 watt iron (the kind for soldering sheet metal) to do the same and the
junction is almost seamless.  I used plumbers flux on the inside of the
tubes and on the wire and used rosin core solder to sweat the joint.  The
solder wetted very easily and made solid connection.

Gerry R.

 > Original poster: JOSEPH CACCIATORE <jocatch-at-us.ibm-dot-com>

 >
 > If anyone is willing, here are the specs I came up with:
 >
 > NST = 12,000v, 30ma, 60hz
 > Secondary = #22 wire, 20" long, 4" diameter, 765 turns-at-97%
 > Primary = flat spiral, I.D. = 6", 15 turns, .25" pipe, .25" spacing,
 > width=7.25"
 > Capacitor = .007uf
 > Toroid = Dmin= 4", Dmaj= 24"
 >
 > The spreadsheet says secondary res F = 257kh, primary res F = 221khz.
 >
 > My concern is if I use any larger cap, I can't get the prim/sec parameters
 > to match good enough. Also, I don't have any material for a toroid here
 > that I can look at so I assume 4" almunin flex hose but I don't know if
24"
 > is realistic. Lastly, the primary requires 53' of copper tubing. I am not
 > sure where to buy such a long length. I have seen only 25' at Home Depot.
 >
 > Thanks.
 >   JC
 >
 >