Re: Method of measuring self C of secondary

To: tesla-at-pupman-dot-com
Subject: Re: Method of measuring self C of secondary
From: "Malcolm Watts" <malcolm.watts-at-wnp.ac.nz> (by way of Terry Fritz <twftesla-at-uswest-dot-net>)
Date: Mon, 01 May 2000 06:32:46 -0600
Approved: twftesla-at-uswest-dot-net
Delivered-To: fixup-tesla-at-pupman-dot-com-at-fixme

Hi Robert,

> Original Poster: "Robert Jones" <alwynj48-at-earthlink-dot-net> 
> 
> Hi Terry and all,   (combined reply)
> 
> It hard to keep with Terry's prodigious output.  Thanks for the measurement
> and mods to T5 or is it T6 with an option of voltage weighted  self (vwsC or
> medC) or  self C (true or LC bridge C).  Does it  now output the self C
> (true)
> along the coil if so can I have a copy.  Should very useful.   How about a
> output for mathcad.  Does it now produce self C (true) of the topload. You
> should set the primary V to 0v because you dont know the phase relative to
> the secondary so zero will give the least error.
> 
> The measured self C (true) confirms a fiddle factor in Medhurst but Medhurst
> may be for an isolated coil.  In which case  the difference between Medhurst
> and self C (true) will be dependent on the separation from the ground plane.
> Does anybody know what Medhurst assumes and if he assumes a ground
> plain what was the separation.

He made no reference to it that I'm aware of. I've measured coils at 
ground and elevated from it and found the differences on Fr to be 
very small. The only requirement is that one end of the coil be 
grounded.

 
> The self C (true) or better the equation is required  for simulation and
> maths models.
> 
> The use of a voltage weighted C in a lumped resonance calculation or any
> calculation is totally new to me. As is the concept of a current weighted L.
> 
> The secondary can be shorted across the ends during C measurements to
> decrease L to 1/4 and hence reduce errors.

But is that how it appears electrically in use?
 
Regards,
malcolm