Re: Small TC experiments

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

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

Ed,

Agree with your comments about Lundin's formula. For those without
access to the paper, it is:

|a = radius (metres)
|b = length (metres)
|N = number of turns
|
|PI = 3.14159
|
|MU = 4 * PI * 1.0E-7
|
|x = 4 * a * a/(b * b)
|
|f = (1 + 0.383901 * x + 0.017108 * x * x)/(1 + 0.258952 * x)
|
|L = MU * N * N * a * a * PI/b * (f - 8 * a/(3 * PI * b)) Henries.

which is certainly a lot easier to code than a double-difference
table lookup.

Referring to an air-core mutual inductance calculator program,

   http://www.abelian.demon.co.uk/acmi/

Ed Phillips <evp-at-pacbell-dot-net> wrote:
 
> Do you have a compiled version available that will run in DOS or
> Windows?

I don't run windows so I can't manage that one, but I've created
an ACMI.EXE for 16 bit DOS, which should be OK in a windows DOS
box. Use it like

|C:\ACMI>acmi < bart.in
|acmi version v0.1d, 13th December 2000
|Primary
|     radius: from 0.210 to 0.394 m
|     height: Flat at 0.035 m
|Secondary
|     radius: 0.162 m
|     height: 0.000 to 1.143 m
|     length: 1.143 m
|Primary self inductance: 108.6 uH
|Secondary self inductance: 80.3 mH
|Primary to Secondary mutual inductance: 604.1 uH
|Coupling coefficient: 0.204

where bart.in is an example text file describing the coil
geometries, made up from one of the sample input files on the web
site. I can do a version in fortran, java, or pike if anybody wants
them, but remember that this program is at the stage of being a
tentative experiment and it awaits a more thorough comparison with
measurement - released onto the web in the hope that it will collect
some empirical support.

Regards,
--
Paul Nicholson,
Manchester, UK.
--