Re: Guide to Primaries rev 1.01

To: tesla-at-pupman-dot-com
Subject: Re: Guide to Primaries rev 1.01
From: Bert Hickman <bert.hickman-at-aquila-dot-com>
Date: Thu, 30 Jan 1997 21:28:27 -0800
Subscriber: bert.hickman-at-aquila-dot-com Thu Jan 30 23:04:55 1997
Tesla List wrote:
> 
> Subscriber: tom_mcgahee-at-sigmais-dot-com Tue Jan 28 23:15:20 1997
> Date: Tue, 28 Jan 1997 23:11:20 -0500
> From: Thomas McGahee <tom_mcgahee-at-sigmais-dot-com>
> To: tesla-at-pupman-dot-com
> Subject: Guide to Primaries rev 1.01
> 
>     [The following text is in the "ISO-8859-1" character set]
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> THE GUIDE: TESLA COIL PRIMARIES
> Rev. 1.01 January 28, 1996
> 
<MAJOR Snippola>

Tom,

Looks pretty good to me! Some fill-in formulas would also be useful for
the helical, Archimedes, and inverse conical primaries. The helical and
Archimedes forms are from Wheeler, and the inverse conical is a hybrid
closed-form that appropriately weights the vertical and horizontal
components of Helical and Archimedes inductances. 

All dimensions are in inches, and L is in microHenries. While the
Archimedes calculation is a little "hairier" than the first two, it's
relatively easy to calculate for any desired angle, especially if set up
in a spreadsheet.  

------------------------------------------------------------------------
Case 1: Archimedes Spiral:
    
          Let R = Ave Radius  
              N = Number of Turns
              w = Width of Winding            


           |   R    |      N Turns 
      o o o o o o   |   o o o o o o 
      |    W    |  


     L = R^2*N^2/(8*R+11*W)  


------------------------------------------------------------------------

Case 2: Helical Primary:
                   
                | R |
            --  o       o
            |   o       o
                o       o 
            L   o       o  N Turns
                o       o 
            |   o       o
            --  o       o

      L = R^2*N^2/(9*R+10*L)  (Vertical Helix)

------------------------------------------------------------------------

Case 3: Inverse Conical Primary:
                                    
                                   /
\                                        --  o                       
/    o
     |    o   N turns            /    o
           o                 Z  /    o
     h      o                  /    o   /
             o                /    o   /
     |        o              /    o   /  Angle = X
               o              \  o   /   
     --         o               o    ------------
                        |
        |   w   |   R   | 
                        |
            |<--  W  -->| 
                        

          Z = Coil Width (hypotenuse)
          X = Angle of Cone
          h = Z*sin(X)  Effective vertical Height
          w = Z*cos(X)  Effective horizontal Width        
          W = R + w/2   Average horizontal Radius
         

     L1 = W^2*N^2/(9*W+10*h)  (Vertical Inductance Component)
      
     L2 = W^2*N^2/(8*W+11*w)  (Horizontal Inductance Component)

      L = SQRT[(L1*Sin(X))^2 + (L2*cos(X))^2]  

------------------------------------------------------------------------

Safe coilin' to you, Tom!

-- Bert --