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

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

Original poster: Terry Fritz <teslalist-at-twfpowerelectronics-dot-com>

Hi Kurt,

You may want to check out the patent J. Reed had a hand in:

http://hot-streamer-dot-com/TeslaCoils/OtherPapers/J-Reed/us5079482.pdf

The program given may help.

Cheers,

         Terry

At 08:35 AM 8/31/2004, you wrote:
>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
>