Re: Flat-Copper-Strip Flat-Spiral-Primary Inductance Calc's?

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

Original poster: "Kurt Schraner" <k.schraner-at-datacomm.ch> 

Hi Finn,

of course i've tried Antonio's INCA for the problem. I "think" it has the 
capabilities in it, to resolve the problem. But right now, the results were 
about same as the wheeler formula. There is no input parameter about axial 
extension of the conductor in flat configurations, but perhaps, by 
implementing parallel filaments, it could be introduced?
...Or I don't see, what is already present in INCA?

I agree, measuring low inductance with an LCR-meter may not be as accurate, 
as measuring it by means of a resonance method. But in the 2 graph-links of 
my last posting, it may be noticed that the _difference_ of the 
measurements in the copper strip case is systematic, but not so in the 
wire-case. I have many other primary measurements with the LCR-meter, which 
support the reliability of the measurements, if L is not less than about 
5...10uH.

Cheers,
         Kurt

Tesla list schrieb:
>Original poster: "Finn Hammer" <f-h-at-c.dk>
>Tesla list wrote:
>
>>Original poster: "Kurt Schraner" <k.schraner-at-datacomm.ch>
>>Hi,
>>
>>anybody has handy a good method or formula for inductance calculation 
>>of  flat-strip flat-spiral primaries? I made one for my little UBTT 
>>(Uni-Bern Tesla Twin), which primary can be seen here:
>>snip
>
>I used Antonio`s INCA program to calculate the 2-turn primary of my OLTC. 
>It was the only program that got close to so small an inductance. I`m not 
>sure if this has to do with it being a flat strip primary, but it`s worth 
>a try.
>
>>The inductance measurements were done at 1000Hz, with a digital LCR-meter 
>>of the "automatic bridge type" (ESCORT ELC131D, Taiwan).
>
>I would not rely on that meter, with so small inductance, before having 
>verifyed the measurement with a capacitor across the coil, and then ring 
>it up with a sig. gen. waching it with a scope.
>My 5 oere