Re: RE: New Inductance Formula

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

Original poster: "Alexander Rice by way of Terry Fritz <twftesla-at-qwest-dot-net>" <alex-at-rices.myip-dot-org>

Dave,

>>For what it's worth, Acmi predicted 12.0mH 
and JavaTC predicted 11.8mH
>(Wheeler). From my inductance measurements 
and from my perspective, I am
>unable to ascertain why there's an issue.

I second this

>I came up with 8.419mH based on a calculated 
wire length of 1090.511 ft.
>How much of a pig tail is on the coil?

a straight wire has very little inductance 
when compred to a solenoid - there's no way 
that you are gonna get  4mH out of a pig tail.

>Keep in mind, my thought is that this formula 
calculates inductance for the
>coil at resonance.  Static measurements will 
necessarily be higher in a
>solenoid coil due to the impedance of the 
coil at the frequency it is being
>tested at.

whilst this is partially true the observed 
drop in inductance at resonat frequency is due 
to the inductance of the coil being shunted by 
the reactance of the self capacitance - not as 
you suggest due to any fundamental change in 
the inductance.


>  I'm not saying the full amount is
impedance, though.  It is
>quite possible that the formula may still 
need to account for something else
>such as wire gage, molecular material, or 
some other characteristic of the
>coil.

for goodness sake, inductance is not affected 
by what the current is passing through - a 
beam of electrons in a vacuum has an 
inductance the same as an equvelant straight 
wire for example, all that matters is the 
geometry. And what on earth is a 'molecular 
material' anyway.
>
>I'm just excited that it produces a close 
number AND in the correct units.

so would a whole bunch of other formula - it 
doesnt necessarily make them right though. You 
also seem to have disregarded the fact that 
Wheeler produces correct units as well - as 
someone has already explained perfectly 
clearly, in terms of the equivalent reactance 
of the capactance of a sphere.

>Thanks for your feedback.
>
>Dave

My pleasure entirely

Alex