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Re: Formula for Inverted Cone Primarys
Subject: Re: Formula for Inverted Cone Primarys
Date: Thu, 05 Jun 1997 23:05:40 -0700
From: Bert Hickman <bert.hickman-at-aquila-dot-com>
Organization: Stoneridge Engineering
To: Tesla List <tesla-at-pupman-dot-com>
References: 1
Tesla List wrote:
>
> Subject: Formula for Inverted Cone Primarys
> Date: Thu, 5 Jun 1997 07:35:25 -0400 (EDT)
> From: tesla-at-america-dot-com (Bob Schumann)
> To: tesla-at-pupman-dot-com
>
>
> Hello,
> A while back someone posted a formula for the
> inverted cone primary to calculate inductance. It
> involved SIN and degree of angle. If anyone could
> repost this formula I would extrememly appreciative.
>
> Thanks
>
> Bob Schumann
> tesla-at-america-dot-com
> http://www.america-dot-com/~tesla
Bob,
Here's a post from back in January that should do the trick...
Subject:
Re: Guide to Primaries rev 1.01
Date:
Thu, 30 Jan 1997 21:28:27 -0800
From:
Bert Hickman <bert.hickman-at-aquila-dot-com>
To:
tesla-at-pupman-dot-com
References:
1
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]
> [Your display is set for the "US-ASCII" character set]
> [Some characters may be displayed incorrectly]
>
> 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 --