Re: Noncoupled Flux in Capacitive Transformers

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

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

Tesla list wrote:
> 
> Original poster: "Jolyon Vater Cox by way of Terry Fritz
<twftesla-at-qwest-dot-net>" <jolyon-at-vatercox.freeserve.co.uk>
> 
> What is the effect of non-coupled electric flux in "capacitive transformers"?
> I know that the effect of non-coupled or "leakage" flux in magnetic
> transformers is to effectively insert an inductance in series with the
primary
> of the theoretical "ideal" transformer and the resulting leakage
inductance can
> be made series-resonant with the secondary capacitance across the turns ratio
> -hence the big voltages in Tesla coils- but I amnot so sure about non-coubled
> flux in capacitive transformers:is there a comparable effect with "leakage"
> capacitance?

The concept can't be applied exactly, because a "capacitive transformer"
is not a true transformer, but just approximately behaves as one when
the 
two capacitors are part of a resonant circuit. The circuit below
resonates
at the frequency w=1/sqrt(L3*C1*C2/(C1+C2)) rads/s. 
 
       +-----+-----o
       |     |
       C2    |
       |     |
o------+     L3
       |     |
       C1    |
       |     |
o------+-----+----o

If you short-circuit the output of a step-up capacitive transformer
you see the two capacitances in parallel, C1+C2, and this capacitance 
is effectively in series with the "transformer". It can be even moved
to the output side, in series, using the "turns ratio" n=1+C1/C2,
as (C1+C2)/(1+C1/C2)^2 = C2/n. 
This would be the "leakage capacitance", but it only appears with this 
value at the resonance frequency. Not very useful, I think. At least
I didn't find a place for it in the design of the "capacitive 
transformer coil": http://www.coe.ufrj.br/~acmq/tesla/mres4ct.html

Antonio Carlos M. de Queiroz