RE: Mutual Inductance & K Factor

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

Original poster: "John H. Couture by way of Terry Fritz <twftesla-at-qwest-dot-net>" <couturejh-at-mgte-dot-com>


Bart -

Thank you for the explanation regarding ETesla6. I should have realized that
this was a possibility because ETesla6 does this so well. This goes back to
the time I pointed out on the List that after the TC is built and tested the
JHCTES Ver 3.3 program can be used to find the true capacitance of the
toroid when placed on the secondary .

When the toroid is placed on the secondary the toroid capacitance is reduced
an indeterminate amount. Etesla6 estimates an operating frequency so the
toroid capacitance can be estimated very closely before the coil is built.
The actual value can be found with JHCTES Ver 3.3 or Java9.1 by reducing the
toroid capacitance value until the program operating frequency agrees with
the actual test operating frequency.

The toroid capacitance reduction has been discussed in the past on the List.
My own limited tests indicated the reduction to be about 15 to 25%. Because
the only way to find the true toroid capacitance on the secondary is by
tests all coilers will have to wait until enough tests are made. The
programs can then be updated to give more accurate outputs.

John Couture

-------------------------------

-----Original Message-----
From: Tesla list [mailto:tesla-at-pupman-dot-com]
Sent: Wednesday, March 20, 2002 7:22 PM
To: tesla-at-pupman-dot-com
Subject: Re: Mutual Inductance & K Factor


Original poster: "Barton B. Anderson by way of Terry Fritz
<twftesla-at-qwest-dot-net>" <tesla123-at-pacbell-dot-net>

Hi John -

Tesla list wrote:

> Original poster: "John H. Couture by way of Terry Fritz
<twftesla-at-qwest-dot-net>" <couturejh-at-mgte-dot-com>
>
> Bart -
>
> For some reason I keep messing up the specs on this coil. Anyhow it will
be
> interesting to find out what the tests show.
>
> I do not understand how you arrived at the 65.3 for the top terminal
> reduction. This parameter appears to affect some outputs including the
> resonant frequency but not the mutual inductance or the K Factor.
>
> John Couture

The value is derived from ETesla6. I put the secondary specs into ETesla6,
keeping the walls and
ceiling at a distance to make their effect as negligible as possible. The
toroid input is with the
toroid bottom edge even with the top secondary winding. I put the bottom of
the coil at 30" off the
ground (just an average input there). ETesla6 pumps out Fres.

I then change the top loads capacitance until JavaTC matches ETesla6 Fres
using the % Reduction input.
If I want to "reduce" the top capacitance by 10%, I put the value 10 in the
input box.

ETesla6 should actually be checked as a bare coil against programs as well
as with top load. I only
used the top load at the time. I don't know actual values of Nolan's
ceiling and walls, etc.., so it's
just an approximation to get into the ballpark.

The 65% sets uneasy with me as well, so I just ran it again and I'm getting
44.3%. I must have had an
incorrect input in ETesla6 during that particular run through (this changes
the primary tap less than
1/2 turn). Yet this is still a significant drop in effective top
capacitance which I found true in
each run through. It's an interesting coil due to it's size, small
inductance, 2.8 major/minor ratio
in the toroid. We should look at more of these geometry's. I really should
build one.

Regarding Mutual Inductance and K. Neither is made to change with
frequency. If there is significant
change with frequency that would justify pulling Fres as a factor, I've yet
to see or be informed of
that.

Take care,
Bart