[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

RE: Mutual Inductance & K Factor



Original poster: "John H. Couture by way of Terry Fritz <twftesla-at-qwest-dot-net>" <couturejh-at-mgte-dot-com>


Paul -

I apologize for my misconception of your Acmi program regarding empirical
data. I thought you had said in the past that you had to tweak (fiddle
factors) the program to make it agree with tests that had been performed on
actual coils. However, I believe a greater number and range of tests are
still required to determine how accurate any of the programs represent the
real world of Tesla coils. Thank you for bringing this error to my
attention.

Do you have any comments on the type of tests that should be performed to
find the mutual inductance and K Factor?

John Couture

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


-----Original Message-----
From: Tesla list [mailto:tesla-at-pupman-dot-com]
Sent: Sunday, March 17, 2002 4:05 PM
To: tesla-at-pupman-dot-com
Subject: Re: Mutual Inductance & K Factor


Original poster: "Paul Nicholson by way of Terry Fritz <twftesla-at-qwest-dot-net>"
<paul-at-abelian.demon.co.uk>

John H. Couture wrote:
> All the present mutual inductance and K Factor programs are
> based on empirical data.

ACMI and MandK both work by directly computing the inductance
using the Neumann integral.  This involves integrating an
elliptic integral over the coil - in MandK by direct computation
of the elliptic integral, and in acmi by table lookup.
The computation converges to an exact solution for wires which are
small compared to the turn radius.

The familiar Wheeler and Lundin equations are derived as
approximations to the elliptic integrals.

There is no reliance on empirical data.

The results of both programs should closely match low frequency
empirical data, to circa 1% for closewound solenoids, and to within
5% for open tube spirals.  Neither program contains any tunable
fiddle factors and they compute directly from the geometry.

A potential source of error may occur at high frequency, because
the inductance calculations of both programs assume a uniform
current distribution in the windings.
--
Paul Nicholson
--