Re: Mutual inductance and K factor

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

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: "by way of Terry Fritz <twftesla-at-qwest-dot-net>"
<couturejh-at-telocity-dot-com>
>
> Bart -
>
> Thank you for bringing your list of coil parameter comparisons to my
> attention. This list must have been a lot of work. I did some research on
> this list when you first showed it but my notes are buried in boxes and not
> readily available.
>
> A quick comparison of tests of your coil and the JHCTES Ver 3.3 gave the
> following results.
>
> K Factor
> Inches       Bart      JHCTES   Difference
> 0            .173      .165       4.6%
> 1            .157      .146       7.0%
> 3            .126      .119       5.5%
>
> Mutual Inductance (uh)
> Inches       Bart      JHCTES    Difference
> 0            522       494         2.0%
> 1            473       438         7.4%
> 3            378       356         5.8%
>
> Comparisons with Weazle's tests and the JHCTES appeared to have a better
> agreement. This was a Mutual Inductance test. What did you use for the K
> Factor tests?
>
> John Couture

John, I used several items to first determine which load provides the most
consistent
(non-varying current over time/temp). However, from all the types of loads
used, I found a
hair dryer was the "most consistent current output" at greater than 10A
(with this
particular hair dryer). I even tried a 3" x 24" resistor which I have in my
possesion, but
the hair dryer still provided the "best" consistency as far as current vs.
temp change. I
spent a lot of time with this (a lot of time) to ensure exact and detailed
measurements
and ensuring measurements were not fluctuating due to heating. I know for
certain my
measurements were as perfect as possible. Terry was also performing his own
testing at the
time. Of course, this was for ACMI verification. We found (both of us) that
ACMI could
actually predict better than we could measure. Everytime I found a flaw between
measurements and ACMI, I tracked down the error to a measurement (usually
mechanical). I
re-measured over and over again, each time, refining the detail in my
measurements. Once I
knew every measurement was to the nth degree, my measurements agreed with
acmi to the nth
degree. Terry found the same thing. These were real world coil measurements
against a
program where the program probably did better than we could actually
measure to.

Of all the measurements I've made in the last 5 years, this particular one
was as accurate
as I could possibly perform (from current measurements to mechanical
measurements). I
realized empirically, if others did not perform the rigorous tasks that I
did, than there
will be flaws in empirical data to some degree. I obviously feel very
confident about my
measurements and thought I should express it.

Mechanical is just as important as current measurements when a program is
to calc the
result. Loading 10A or 50A is not as important as keeping the amps
consistent from
measurement to measurement, as well as using calibrated equipement (which I
did).

Take care,
Bart
--
Barton B. Anderson
http://www.classictesla-dot-com


>
> ----------------------------
>
> -----Original Message-----
> From: Tesla list [mailto:tesla-at-pupman-dot-com]
> Sent: Thursday, October 25, 2001 5:33 AM
> To: tesla-at-pupman-dot-com
> Subject: Re: Mutual inductance and K factor
>
> Original poster: "Barton B. Anderson by way of Terry Fritz
> <twftesla-at-qwest-dot-net>" <tesla123-at-pacbell-dot-net>
>
> Hi John, All,
>
> I remember checking ACMI a while back. I distinctly remember checking MandK
> against
> measured and ACMI outputs and they all agreed closely. I believe I checked
> JHCTES as well
> when you included this into your program.
>
> You might want to take another look at some of these measurements and
> compare them.
>
> http://www.classictesla-dot-com/temp/k.html
>
> I have a feeling there's an input that's been over-assumed in the use of
> either MandK or
> JHCTES.
>
> Bart
> --
> Barton B. Anderson
> http://www.classictesla-dot-com
>
> Tesla list wrote:
>
> > Original poster: "by way of Terry Fritz <twftesla-at-qwest-dot-net>"
> <couturejh-at-telocity-dot-com>
> >
> > Have any coilers used these programs and compared them with
> > tests of their coils for the mutual inductance and the K Factor?