Re: More Coupling...

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

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

Tesla list wrote:
> 
> Original poster: "Ed Phillips by way of Terry Fritz
<twftesla-at-uswest-dot-net>" <evp-at-pacbell-dot-net>

>         A friend of mine built such a high k system at TRW, in connection
with
> a million-volt (really 10^6 volts) pulse project.  It worked OK but was
> a lot of work to get set up right.  Do you know of any approximate
> method for calculating the mutual inductance for a flat primary?  I
> suppose one could do it by computing M for each of the turns and then
> summing it, but that sounds like a lot of work and have never tried it.

I have a program written by Paul Nicholson, member of this list, that
can compute inductances and coupling coefficient for concentrical coils
of all kinds of conical shapes, including solenoids and flat coils:
http://www.abelian.demon.co.uk/acmi/
 
>         I see a lot of fellows using flat primaries, and wonder how much
> coupling they actually get.

I tried with the program (acmi, version 0.1b) a transformer made of two
flat coils with minimum radius of 10 cm and maximum radius of 40 cm, 
separated by 10 cm, and got k=0.68. Humm... Good for a magnifier driver.
But then I noticed that there is a bug in the program. The calculated
coupling coefficient is always the same, no matter the distance between
the coils... Paul?

Antonio Carlos M. de Queiroz