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: "Luc by way of Terry Fritz <twftesla-at-uswest-dot-net>"
<ludev-at-videotron.ca>
> 
> Naturally I mean pancake ...ops!

An efficient magnifier requires a precise coupling, and a rather tight
one. The structure of the magnifier is justified precisely due to the
requirement of high coupling. A normal Tesla coil with k=0.6 
(energy transfer in 1 cycle) is problematic due to intense electric 
fields between primary and secondary due to their small distance, 
that I believe to be the reason of the "racing sparks" phenomenon. 
A solution is to move away the high-voltage upper section of the 
secondary, resulting in the magnifier structure. But this requires 
even higher coupling in the primary-secondary system if the result 
is to be equivalent to a Tesla coil with k=0.6. The high coupling
also adds a significant capacitance between the primary and the
secondary, and its effect must be taken into account. The result is
a required coupling coefficient between primary and secondary of
0.67. This would be obtained with a solenoidal primary with a diameter
that is about 1.3 times greater than the secondary diameter, and
the same height. A flat primary would not reach a so high coupling.

Antonio Carlos M. de Queiroz