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RE: New Inductance Formula

Original poster: "Terry Fritz" <twftesla-at-qwest-dot-net>

Just to follow up on the Les vs. Ldc thing....

Paul is running a grid simulation on my Sun computer that figures this out
for various coil geometries.  It not quite done yet BIG number crunch!!!)
But the latest results are at:


It's the second chart down.



Hi Dave,

Paul came up with the equations at:


The second box down the page shows the equations for Les.  Big equaitons
but easy for mathCad ;-)

I forget at the moment what the "pow" is in those equations...  Maybe Paul
could remind us :-)



At 03:30 PM 4/30/2002 -0500, you wrote:
>Hi Terry and Paul,
>I'm trying the grasp this too.  Does a higher H/D ratio, i.e. a taller
>skinnier coil, have an effective lower inductance rather than an effective
>lower self-capacitance?  Or is the reduction equally distributed between the
>inductance and capacitance?
>I'm interested in this because I have constructed a 48.125" x 3.5" solenoid
>coil.  The H/D ratio is greater than on the graph at Paul's site, so how do
>I calculate Les for this coil?
>-----Original Message-----
>From: Tesla list [mailto:tesla-at-pupman-dot-com]
>Sent: Tuesday, April 30, 2002 2:03 PM
>To: tesla-at-pupman-dot-com
>Subject: RE: New Inductance Formula
>Original poster: "Terry Fritz" <twftesla-at-qwest-dot-net>
>Hi Harvey,
>At 03:38 PM 4/28/2002 -0700, you wrote:
>>> I'm missing something.
>>So am I. I see others (Paul N) having a L(dc) and
>>L(es),equivalent series? but dont understand how or
>>why the inductance changes, or whether it changes at
>>resonance ect.
>L(dc) is the normal low frequency inductance of a coil where the current is
>the same throughout the entire coil.  It's what we measure with a usual
>L(es) is the inductance of something like a Tesla coil secondary where the
>current differs greatly along the coil's length.  With the current at the
>base being high and the current near the top being low, the effective
>inductance is about 80% of what one would normally think.
>Paul's work figured all this out in very high detail.  E-Tesla6 had a very
>hard time with secondary inductances until Paul derived equations to
>estimate the real operating inductance of a resonating Tesla coil.
>	Terry