Re: How to rise the secondary? (fwd)

---------- Forwarded message ----------
Date: Wed, 8 Jul 1998 10:58:40 EDT
From: FutureT-at-aol-dot-com
To: tesla-at-pupman-dot-com
Subject: Re: How to rise the secondary? (fwd)

In a message dated 98-07-08 02:21:25 EDT, you write:
<< >   Do you believe your coils are critically coupled and work best when the
 > "telltale signs of overcoupling disappear"? What are the telltale signs?
        John Couture >>

John, all,

Here's the secret to the conundrum:

The terms overcoupling and undercoupling have a different definition
in Tesla coil work than they do in radio engineering work.  In radio 
engineering, they are related to the critical coupling.  In Tesla coil
work, the terms overcoupling and undercoupling have no relation to
the critical coupling.   Tesla coils do not work when critically coupled
(as defined in radio engineering terms).

A definition for overcoupling in TC work is:

   Overcoupling;  a degree of coupling that is too tight for the spark gap
   to adequately quench, and which also reduces the length of the 
   output sparks, and/or causes secondary breakdown.

A definition for undercoupling in TC work is:
   Undercoupling;  a degree of coupling such that the spark gap could
   tolerate a greater degree of coupling and still quench adequately, and
   in which tighter coupling would result in longer sparks.

In summary, the best degree of coupling for a TC is that which allows
the TC to work the best.  If loosening the coupling improves the results,
then the TC was overcoupled.  If tightening the coupling improves the
results, then the TC was undercoupled.  

The only way to know if the TC is coupled properly is to change the
coupling and see if things improve or get worse.  The proper degree
of coupling cannot be pre-determined by computer programs or
simulations because there are too many variables that cannot be
determined beforehand using today's methods.

John Freau