RE: was RE: First coil built

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

Original poster: "Day, Michael" <Michael.Day-at-USPTO.GOV> 

Hi John,

A coupling coeffiecient of 0.42 appears to me to present technical
challanges.  Coupling coeffiecients of 0.2 appear to me to be more
typical for static and rotory spark gaps.  It think I read somewhere
that the dwell time of the gap is inversly related to the coupling
coeffiecient and the resonate frequency of the Tesla coil.  If this
is true, and my math is correct, there does not appear to be an
advantage to tighter coupling in a typical rotory gap.

Mike Day


-----Original Message-----
From: Tesla list [mailto:tesla-at-pupman-dot-com]
Sent: Monday, September 27, 2004 10:26 PM
To: tesla-at-pupman-dot-com
Subject: Re: was RE: First coil built


Original poster: FutureT-at-aol-dot-com

In a message dated 9/27/04 9:53:48 AM Eastern Daylight Time,
tesla-at-pupman-dot-com writes:

 >Does anyone know what the coefficient of coupling was between the primary
 >tank and the secondary in Hull's magnifier, and what kind of driver was
 >he using?


Mike,

The coupling was said to be about 0.42, but it may have been lower.
Some coupling measurement techniques give more accurate results
than others.  The overall system coupling would of course be much
lower, and would be in the range of classic coils.


 >I understand he did a lot of work with thyratron/ignitron drivers.  Are
 >they worth the trouble?


Richard did some work with the hydrogen thyratrons.  He used
one thyratron, so he was only able to let one half cycle of
energy pass from the primary to the secondary.  Ideally with
the coupling factor he used, about 3 cycles should have been
transfered.  The incomplete energy transfer made the
overall efficiency of the system somewhat low.  He had
planned to use dual crossed thyratrons, but never built
the project.  Another approach would be to use a newer
type of thyratron which can withstand some voltage reversals,
but these are very expensive.

John Freau


 >Mike Day