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>


Malcolm -

Do you know of any computer programs that finds the toroid capacitance when
placed on the TC secondary at the design stage  other than Terry's ETesla6
program? Even Terry's program requires inputs that can be only guestimates.
Here again it is impossible to come to any conclusion about a TC program
because there is not enough test data available to verify what the program
is producing.

However, after the TC is built the actual toroid capacitance can be found by
tests and with the JHCTES or similar program. The unknowns are still
unknowns but their effects on the Tc operating frequency become known. This
frequency is then used with the program to find the true toroid capacitance.
It should be noted that this can only be done with programs that are the
automatic tuning type because several parameters are involved that must be
coordinated.

The 15 to 25% reduction is based on my limited tests. I agree that this
reduction could be much greater when the top load conditions varied from
those that existed when I made the tests.

John Couture

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


-----Original Message-----
From: Tesla list [mailto:tesla-at-pupman-dot-com]
Sent: Thursday, March 21, 2002 5:23 PM
To: tesla-at-pupman-dot-com
Subject: RE: Mutual Inductance & K Factor


Original poster: "Malcolm Watts by way of Terry Fritz <twftesla-at-qwest-dot-net>"
<m.j.watts-at-massey.ac.nz>

Hi John,

On 21 Mar 2002, at 16:38, Tesla list wrote:

> 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.

"Indeterminate amount?" I refuse to believe that a well behaved
result cannot come from some correct modelling and applied physics.
As for the 15-25% figure, that might be ballpark for a lot of systems
but as I have found, the actual figure can be almost 100% if the
terminal has a considerably smaller diameter than the coil. That is
not to say it is useful or practical to do this but it is an
illustration of the degree of variation that can be obtained.

Regards,
Malcolm