Re: Equivalent lumped inductance and toroidal coils

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

Original poster: "Antonio Carlos M. de Queiroz" <acmdq-at-uol-dot-com.br> 

Tesla list wrote:
 >
 > Original poster: Paul Nicholson <paul-at-abelian.demon.co.uk>

 > I don't seem to be having much luck with that expression for mutual
 > coupling between filaments, either.
 >
 > You know, one of these days we'll have to figure out how to use
 > the method of partial inductances, so that we can get away from
 > circular filaments and symmetry restrictions. Then we can calculate
 > the inductance of funny shaped things. Like for example OLTC primaries?

I started to write some code for toroidal transformers, trying first
to calculate the mutual inductance between two toroidal coils with
a common central axle. It's quite simple to solve Neumann's integral
numerically for this. Self-inductances can be calculated as the
mutual inductance between two toroidal coils placed at a certain
distance, that depends on the radius of the wire (Maxwell's gmd method),
and the symmetry can be used to reduce the amount of calculation
substantially. For awhile, however, I finished only the visualization
code.
I am thinking about doing "exact" calculations using as core the
mutual inductance between two straight segments. This would allow
precise calculations for things as square toroidal coils too.
I have two old papers that derive the required formulas, but so far
they are quite difficult to interpret.

Antonio Carlos M. de Queiroz