Re: "De-coupling" coefficient?

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

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

Tesla list wrote:

 > Original poster: "Jolyon Vater Cox by way of Terry Fritz 
<teslalist-at-qwest-dot-net>" <jolyon-at-vatercox.freeserve.co.uk>
 >
 > I am interested to know how k,the coupling coefficient, affects the value of
 > the load impedance referred back to the primary across the turns ratio when
 > the transformer is not "ideal".

Use the equivalent that I posted days ago. The primary side sees the
primary inductance across the input terminals, and after it it sees
the (leakage) inductance at the output side in series with the load
impedance, both multipled by the square of the effective turns ratio
(that one that depends on k).

 > If the term k represents the fraction of the total flux which is common to
 > both windings (the coupled flux)
 > there must be another term  say, l, for the remaining fraction which
 > represents the flux which is not common to either winding (the leakage
 > flux).
 > Since k is the coupling coefficient  would it not be natural for l the be
 > termed the de-coupling coefficient?

Why not? 1-k. But this term doesn't appear anywhere in the equations.
(1-k^2) would be more useful.

 > Speaking of a mechanical analogy (perhaps not strictly accurate) is it not
 > possible to view transformers as "gearboxes" for electrical energy
 > the ideal transformer being akin to a ideal gearbox with unity coupling i.e
 > zero slippage between the gear teeth whereas  real transformers and
 > gearboxes are less than ideal exhibiting finite slippage?

A common, but not very useful or accurate analog when the transformer
is not ideal. The transformer is simple enough to be a good model for
itself.

 > And if it is permissible to speak of a de-coupling coefficient, would it not
 > be possible for the new term to be be used to derive the value of leakage
 > inductance from the values of the primary and secondary inductances.

It's simply the inductance of the side being observed multiplied
by (1-k^2).

Antonio Carlos M. de Queiroz