Re: [TCML] Reality or Artifact

[bartb <bartb@xxxxxxxxxxxxxxxx>]

Hi Matt,

Lucky for you, I already performed that nasty daunting task ;-) . I went 
through Javatc and setup h/d ratios from 0.01 up to 1.0 in .01 
increments, found max inductance and logged data. What I was looking at 
was the difference between low and high frequency inductance (Ldc, Les) 
and how they would track.

Here's a graph of that endeavor
http://www.classictesla.com/temp/MaxL.gif

The excel file is here with the data
http://www.classictesla.com/temp/max_inductance_csv.xls

Not sure if this helps at all, but if so, great.

Best regards,
Bart

mddeming@xxxxxxx wrote:
> Hi All,
>  
> In the classic, quick and dirty formula for the calculation of solenoid inductance, 
>  
> L=(Nr)^2/(9r+10h) 
> it can be shown with a little Calculus and Algebra that the maximum inductance for a given length of wire occurs when h=0.9r. This formula was originally derived, however, for "long" solenoids but the calculation results in what may be described as a rather "short" solenoid. The maximum may be an artifact of the approximation. Does anyone know the range over which the formula is valid and if there is an actual maximum at or near this ratio (h/d = 0.45)? If not, I suppose numerous iterations of Javatc could be plotted, but there again, what is validity range of Javatc's approximations? Perhaps the next step would be for me to bring the question to the "High-Mages" of TSSP.
>
> Matt D.
>
>
>
>
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