Re: Calculating capacitance of stacked toroids . . .

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

Original poster: "Bart Anderson" <tesla111-at-sbcglobal-dot-net> 

Hi Dan,

For what it's worth, I ran through these measurements in May of 2001 with 2 
stacked toroids. The main purpose of the measurement were comparisons of 
two different toroids on the same coil. Following those measurements, I did 
go through stacking the toroids and measured them with 3" to 14" 
separations as well as swapping toroid positions and running through the 
same measurements.

In my notes, I didn't show data for the stacked measurements but noted only 
observations. Mainly, the change in capacitance for the separation 
distances ranged from 0.6% to 3% and that the capacitance value for the 
stack measured near to 1/2 of the sum of their individual capacitances. 
Kind of wish I would have logged this data more permanently at the time. 
Toroids were similar in size.

However, this is "easily" modelled these days in Javatc, Fantc, or Inca and 
the accuracy is very good. These specific programs are particularly useful 
for stacked toroids as well as other shapes. I think Javatc will allow up 
to 10 stacked toroids.

Take care,
Bart B.

Tesla list wrote:

>Original poster: Esondrmn-at-aol-dot-com
>In a message dated 9/8/04 3:52:43 PM Pacific Daylight Time, 
>tesla-at-pupman-dot-com writes:
>
>
>>Original poster: "McCauley, Daniel H" <daniel.h.mccauley-at-lmco-dot-com>
>>
>>I know i asked this awhile ago, but the www.pupman-dot-com site where the
>>archives lie never seems to
>>work.
>>
>>Anyways, if you have two stacked toroids, what approximations can you
>>use to get a ballpark number for
>>capacitance of the toroid stack?
>>
>>Thanks
>>Dan
>
>
>
>Dan,
>
>I don't have my notes with me but I believe I have calculated in the past, 
>the effective sum is about 65% of the total of the two.  Toroid one is 40 
>pf and toroid # two is 50 pf, when stacked (and I think it depends on how 
>you stack them - ie how far apart they are) their effective capacitance 
>should be around 59 pf.
>
>Ed Sonderman