Re: [TCML] Tuning a new coil : Reality vs JAVATC

[b alex pettit jr <a_pettit_jr@xxxxxxxxx>]

Continuing with this project ....
   
  I just ran several tests measuring the F_res of this 4.5" dia x 21" 940 turn coil.
   
  I drove the primary ( without cap) via sig.gen and measured the coil's response
  on a freq.counter and scope. It was quite evident the coils F_ res was 268.98 KHz.
  Half Power points at 268.3 KHz and 269.5 KHz = a Q of 224  and well correlated 
  to  JAVATC's Q calc of 285. (The Primary and lower end of  the Secondary were tied
  to my in-ground copper stakes)
   
  With slight tweaks in ground plane and adding a turn or two to the Sec parameters,
  JAVATC calculated a F_res = 268.86 KHz ( as close as I felt needed to match 268.98 KHz).
   
  The Rest of The Story:
  That F_res via JAVATC tunes the Primary at 6.797 turns, a HalfPower point at 6.777.
  With a 45" circumference of the Primary at turn 7, this equates to +- 3/4" from resonance
  to half power point frequencies.
   
  BUT,
    I added a 'StreamerLoad " wire of 36" , it detuned the F_res by 30 ( thirty ) Hz !
   
  This changes the Primary tuning point to 7.751 turns ...a full turn !
   
  How does one actually Tune a Tesla Coil ?  
   
  I am considering a banjo type coil element equal to  1/3rd turn of the main primary to
  use for experimentation.
   
  Or, how precise IS the tuning of Pri to Sec ?
   
  I know that in lightly damped mechanical structures, the frequency of the excitation is
  extremely critical for full excitation.
   
  This is becoming a tail chasing dog senario...  am sure also changes in coupling factor
  detune the system ...
   
  good news,
  multigap spark gap is working and streamers are exceeding 24 inches...
   
  Thanks,
  Alex P
   
  ********************************************************************
  J A V A T C version 11.8 - CONSOLIDATED OUTPUT
Tuesday, May 27, 2008 2:32:20 PM
  Units = Inches
Ambient Temp = 68°F
  ----------------------------------------------------
Surrounding Inputs:
----------------------------------------------------
38 = Ground Plane Radius
100 = Wall Radius
100 = Ceiling Height
  ----------------------------------------------------
Secondary Coil Inputs:
----------------------------------------------------
Current Profile = G.PROFILE_LOADED
2.26 = Radius 1
2.26 = Radius 2
2.3 = Height 1
23.3 = Height 2
943 = Turns
24 = Wire Awg
  ----------------------------------------------------
Primary Coil Inputs:
----------------------------------------------------
4.25 = Radius 1
7.647 = Radius 2
3.3 = Height 1
3.3 = Height 2
6.793 = Turns
0.25 = Wire Diameter
0.0187 = Primary Cap (uF)
0 = Total Lead Length
0 = Lead Diameter
  ----------------------------------------------------
Top Load Inputs:
----------------------------------------------------
Toroid #1: minor=3, major=12, height=30, topload
  ----------------------------------------------------
Secondary Outputs:
----------------------------------------------------
268.86 kHz = Secondary Resonant Frequency
90 deg° = Angle of Secondary
21 inch = Length of Winding
44.9 inch = Turns Per Unit
0.00217 inch = Space Between Turns (edge to edge)
1115.9 ft = Length of Wire
4.65:1 = H/D Aspect Ratio
28.4093 Ohms = DC Resistance
30794 Ohms = Reactance at Resonance
1.36 lbs = Weight of Wire
18.229 mH = Les-Effective Series Inductance
20.096 mH = Lee-Equivalent Energy Inductance
19.905 mH = Ldc-Low Frequency Inductance
19.223 pF = Ces-Effective Shunt Capacitance
17.437 pF = Cee-Equivalent Energy Capacitance
32.248 pF = Cdc-Low Frequency Capacitance
5.61 mils = Skin Depth
11.652 pF = Topload Effective Capacitance
108.1284 Ohms = Effective AC Resistance
285 = Q

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