Re: anyone? shortform and inner primary?

To: tesla-at-pupman-dot-com
Subject: Re: anyone? shortform and inner primary?
From: FutureT-at-aol-dot-com (by way of Terry Fritz <twftesla-at-uswest-dot-net>)
Date: Mon, 18 Oct 1999 11:43:25 -0600
Approved: twftesla-at-uswest-dot-net
Delivered-To: fixup-tesla-at-pupman-dot-com-at-fixme

In a message dated 99-10-18 05:48:25 EDT, you write:

<< 
> Dear all please consider the following:
 
> Want to build my primary inside the secondary. Believe that with a tight
> coupling much less input power is needed and a much higher q is
> achieved! Tuning the primary will be more hassle but lifting will be
> easier on the other hand.
 
> and: who has experience with very large diameter and short forms?
 
> bye arwin, the netherlands
  >>

Arwin, 

Why do you think that with tight coupling, much less input power is
needed?  I can understand a little less power, but a *lot* less?  How
much less do you mean, 10%, or more such as 50% or more?  How
will tighter coupling increase the Q of the system? (other than by 
reducing gap losses due to faster energy transfer *if* you can quench
the gap quickly....not an easy task)  Also how tight do you want the
coupling to be (what k value)?

Greg Leyh used an internal primary in his spectacular Electrum TC 
project.

In a very tight coupled arrangement, with a short secondary, and if
the primary reaches upwards a significant distance within the 
secondary, insulation issues will be difficult to deal with, especially
if there's any significant voltage/power.

Cheers,
John Freau