Re: This don't make sense.

["Tesla list" <tesla@pupman.com>]

Original poster: "by way of Terry Fritz <twftesla@uswest.net>" <Esondrmn@aol.com>

In a message dated 12/10/00 12:43:05 PM Pacific Standard Time, 
tesla@pupman.com writes:

<< Original poster: "Garry F. by way of Terry Fritz <twftesla@uswest.net>" 
<garryfre@pacbell.net>
 
 Recently, I got two 12/60 NST's (One fried immediately but they said they 
would
 replace it because they weren't sure about it) and the other I decided to try
 on this .017 uF doorknob cap I have and so I started up this tesla program on
 the internet written in java and it says I need 70+ windings on the primary 
and
 I don't believe it. I've never heard of a tesla coil that needed over 22
 windings. This compared with the program saying I needed only ~16 windings 
for
 Terry's .0061 cap with the 12/30 NST.
  
 The setup I had that worked pretty well was with a 12/30 nst and ~16 windings
 of 12 guage wire on a flat primary with four windings/inch center diameter 
6".
  
 The secondary is 3.5" * 17 3/4" wound with #28 guage wire from ESI. The 
program
 says the secondary resonant frequency is about ~255mhz. I not sure of the
 measurement unit mhz, it could be khz.
  
 I tried tuning it with the 12/60 but all I got was a lousy 1" spark compared 
to
 using Terry Fritz EMMC at .0061uf I got two foot sparks with a 12/30.
  
 I don't wanna try Terry's EMMC at 12/60 because I doubt it would take that 
kind
 of punishment and would probably be way outta tune anyway.
  
 At anyrate, can someone run these figures through thier program and tell me
 what their program comes up with for windings on the primary?
  >>
Gary,

I ran your numbers through my spreadsheet.  I had to make a few assumptions.  
The first is, I assumed you had a toroid on top of the secondary which 
provided 10 pf of capacitance.  Your secondary self resonant frequency is 376 
khz with no toroid and 244 khz with the 10 pf toroid.  Using this 244 khz 
frequency and a .017 ufd cap, the primary would tune at turn 9.6 if the 
inside diameter was 5.5" and was made from # 10 wire with .350" spacing 
between turns.  The tap point would be 9.3 with the same primary made from 
.250" diameter copper tubing.  The tap point would be turn 14 with the copper 
tubing primary and the .006 ufd cap.

Ed Sonderman