RE: Inductance of a conical coil

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

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


Antonio -

I have tested your excellent Inca program with the JHCTES Ver 3.3 program.
The two programs gave the following results for the JHCTES default example
(spiral primary).

    Item      JHCTES       Inca

Sec Ind      35.4 mh      36.1 mh
Pri Ind      43.93 uh     44.14 uh

Mut Ind     243.3 uh      192.9 uh
Coupling      0.195         0.1528

The inductance results for both programs are close enough.
The Inca program can only accept complete pri turns. The JHCTES pri was 9.98
turns. The Inca program pri was 10 turns which would account for Inca being
slightly higher than JHCTES for the pri inductance.
The JHCTES mutual inductance and the coupling are about 26% higher than the
Inca program. The JHCTES is known to be too high and I plan to change the
program coupling data becomes available.

John Couture

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



-----Original Message-----
From: Tesla list [mailto:tesla-at-pupman-dot-com]
Sent: Saturday, February 22, 2003 10:22 PM
To: tesla-at-pupman-dot-com
Subject: Inductance of a conical coil


Original poster: "Antonio Carlos M. de Queiroz by way of Terry Fritz
<teslalist-at-qwest-dot-net>" <acmq-at-compuland-dot-com.br>

Hi:

I was reviewing the archives looking for a good approximate
formula for the inductance of a conical coil. There was a
discussion years ago, but didn't come to a conclusion. That
formula that makes an average between the Wheeler approximations
for solenoids and flat coils is very poor. The Wheeler formula
for flat coils is also poor.
What would be the best formulas now?

By the way, I have added mutual inductance calculation to my
Teslasim design/simulation program.
http://www.coe.ufrj.br/~acmq/programs

Antonio Carlos M. de Queiroz