Re: More Coupling...

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

Original poster: "by way of Terry Fritz <twftesla-at-uswest-dot-net>" <paul-at-abelian.demon.co.uk>

Barton B. Anderson <tesla123-at-pacbell-dot-net> wrote:

> Entering coil data into a TC modeling program (JavaTC, JHCTES,
> Ed Sonderman's spreadsheet, etc..) allows the user to make slight
> adjustments to duplicate measured inductances.

One has to resist the temptation to tune the dimensions so that the
primary inductance as computed by a standard engineering formula
(eg, as encoded in these programs) matches an inductance measurement.

> When this is peformed, these "fine tuned" dimensions can then be
> entered into acmi. Acmi then calcs almost identical Ls and Lp values
> and also becomes "sweetly" accurate.

Yes, it would do. This throws the baby out with the bathwater. Amounts
to checking acmi filament summing against an engineering formula which
will have been originally derived by a mathematical integration equiv-
alent to acmi's current summing. It tells me I got the code right, but
to gauge the limitations of current filament summing against the real
world we must stick to inputs direct from the ruler. 

Having said that, you seem to be demonstrating that if the error in
the primary inductance is 'put right' by means fair or foul, then the
calculated k converges towards the measured k - would you say that's
the case? If so then it may suggest our attention should concentrate
on sorting out the primary self inductance.

> I have found this "most important" when working with acmi:
> "Coils measured inductances must be input correctly into acmi via
> dimensions for accuracy". Since acmi uses dimensions, any coilers
> rough or even relatively precise measurements are not enough. There
> is human error in building and oversites.

Agreed. Given all the measurements I've received with dimensions like
7.5 inches, I'm amazed. If I try and wind a copper pipe into a free
standing coil say to a design of 20cm inner radius, it *never* comes
out at that! I would maybe get 20.2 or 19.7 or something. I have
to conclude that you guys must be first class constructors.

Regards,
--
Paul Nicholson,
Manchester, UK.
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