RE: Primary/NST case coupling effects

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

Original poster: Thomas <tom-at-pwrcom-dot-com.au> 

 > Original poster: Esondrmn-at-aol-dot-com

 > I haven't noticed any problems locating a normal metal cased
 > nst, with case
 > grounded, below the primary when the spacing is about 12" or
 > greater.  I
 > haven't tried it closer but we know any large metal objects
 > will load the
 > primary and rob power from the system if located within the
 > field produced
 > by the primary.  I would expect it to lower the self resonant
 > frequency of
 > the primary as you reduce the distance between the primary
 > inductor and the
 > transformer case.  It should induce RF currents into the
 > case, which is
 > grounded.  I doubt it would couple through the case and into the
 > windings.  I don't think it reduces coupling since that is
 > determined by
 > the physical relationship between the primary and secondary.
 > Since it robs
 > power from the primary system, you could probably then
 > increase the primary
 > / secondary coupling without causing racing sparks because
 > the amount of
 > power being coupled to the secondary is less.
 >
 > Just my thoughts, Ed Sonderman




Thanks Ed.
My NST is less than 6" below the inside of my conical primary, I will move
it and see if it makes an appreciable difference.
This is going to be a pain as the primary winding is part of the lid that
encloses the NST in a wooden box.
See: http://www.users.bigpond-dot-net.au/broken.trout/DSCF0015.jpg