RE: New Inductance Formula

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

Original poster: "Terry Fritz" <twftesla-at-qwest-dot-net>

Hi Dave,

I have my small coil here so let's give it a try.  I just fixed things for
the pi^2 error you just mentioned...

>
>             (N * R)^2
>mH = ---------------------------
>     L * c * Cd * 16 *pi^2 *10^-4
>
>N is the number of turns
>R is the average radius
>L is the length of the wire (not length of the windings)
>c = 2.99 x 10^8
>Cd = 2.112 x 10^-4
>pi = 3.14159
>

For my coil...

N = 1175.5 turns
R = 2.125 inches (0.053975m)
L = 1316 feet (401.117m)
The winding length is 26.125 inches.

I am assuming all the dimensions should be in meters since that is how the
numbers on your site are.


             (N * R)^2
mH = ---------------------------
     L * c * Cd * 16 *pi^2 *10^-4


= (1175.5 * 0.053975)^2
  -----------------------------------------------
  401.117 x 2.99 x 10^8 x 2.112 x 10^-4 x 16 x 3.14159^2 x 10^-4

= 4025.6 / 127322.65 == 0.0100640 mH

The actual inductance is 22.1mH

So it is not working for me.  Maybe I messed up in dimensions or number
systems some where.

We can try wheeler's...

L (mH) = (N x R)^2 / (9R + 10H)

       = (1175.5 x 2.125)^2 / (9 x 2.125 + 10 x 26.125)

       = 22.254mH

So that works.

My coil is:

26.125 inches long
1175.5 turns of #24 enamel wire
4.25 inches in diameter
1316 feet of wire
inductance is 22.1mH

Maybe you can find where I messed up here.

Cheers,

	Terry



At 02:12 PM 4/28/2002 -0500, you wrote:
>Paul,
>
>Have you actually tried the formula?  What about it is nonsense or crank?
>I'm surprised.  Of all people, I thought you would be the first to try it
>and see what it does.  It wouldn't bother me at all if you could show it
>doesn't work.
>
>I'm using this formula in real Tesla coil design and it works great.  Humor
>yourself and try it please.
>
>Here it is again, hopefully in better format...
>
>             (N * R)^2
>mH = ---------------------------
>     L * c * Cd * 16 *pi *10^-4
>
>N is the number of turns
>R is the average radius
>L is the length of the wire (not length of the windings)
>c = 2.99 x 10^8
>Cd = 2.112 x 10^-4
>pi = 3.14159
>
>I have a little more detail on the formula and how Cd was derived at
>http://www.tesla-coil-builder-dot-com/inductance.htm
>
>Dave
>
>-----Original Message-----
>From: Tesla list [mailto:tesla-at-pupman-dot-com]
>Sent: Sunday, April 28, 2002 11:11 AM
>To: tesla-at-pupman-dot-com
>Subject: Re: New Inductance Formula
>
>
>Original poster: "Paul Nicholson by way of Terry Fritz <twftesla-at-qwest-dot-net>"
><paul-at-abelian.demon.co.uk>
>
>Jim wrote:
>
>> Do ANY of you guys really understand all that???
>
>Nope.  It's complete nonsense.  Best thing is to ignore crank
>postings.  See the various Tesla related yahoo groups for examples
>of the consequences of not doing so.  Those who enjoy the
>ultimately futile task of refuting pseudoscience will find
>plenty of sport.
>--
>Paul Nicholson
>--
>
>
>