[TCML] Secondary self frequency

[bartb]

The toroid in question would yield about 19.6pF if it was the free space 
value being looked at. But when it is coupled to this particular 
resonator, the proximity affects come into play and will bring it down 
around 19.3pF.

Regards,
Bart Anderson

Quarkster wrote:
> Jim -
>
> How did you arrive at a topload capacitance of 24.5pF?
>
> I think this is at least 20% higher than actually provided by 4.5 X 
> 18" toroid.
>
> Regards,
> Herr Zapp
> ----- Original Message ----- From: "Jim Mora" <wavetuner at gmail.com>
> To: "'Tesla Coil Mailing List'" <tesla at pupman.com>
> Sent: Friday, July 03, 2009 4:18 PM
> Subject: RE: [TCML] Secondary self frequency
>
>
>> Hi Andrew,
>>
>> First impression is with a top load that size something sure isn't 
>> right.
>> Let me run Classic TC:
>> Turns=716
>> 32.6/inch
>> Ratio 5.5 (lower yet)
>> DC ohms=12
>> XL=18763
>> K=.8472
>> Self C=8.61
>> Fo=~583Khz (coil only)
>> Top Load= 24.5pf
>> LOADED Fo= ~346Khz
>>
>> You are measuring it with the top load attached, yes? Perhaps you are
>> looking at a harmonic? It really should be near 350Khz loaded.
>>
>> Regards,
>> Jim Mora
>>
>> -----Original Message-----
>> From: tesla-bounces at pupman.com [mailto:tesla-bounces at pupman.com] On 
>> Behalf
>> Of Andrew Robinson
>> Sent: Thursday, July 02, 2009 9:45 PM
>> To: tesla at pupman.com
>> Subject: [TCML] Secondary self frequency
>>
>> Does this sound strange to anyone. A 4" OD x 22" (windings) secondary
>> using 22 gauge wire with a 4.5" x 18" spun alum toroid having a self res
>> freq of around 515kHz? I ran the tests in the lab today and thats what
>> im getting. For some reason though, I had reason to believe it was going
>> to be much lower. I'm gonna resubmit this email next Thursday when I get
>> a chance to get back in the lab and im gonna take a video of myself
>> taking the measurements. Maybe im just doing something wrong. I just
>> threw this website (http://www.teslamad.com) together just now for the
>> purpose of this email. Please go check out the pics to get a better idea
>> of whats going on. This coil isnt finished yet. You may have noticed the
>> quickie ghetto gap and, my old rotary disc from an old BIG coil on my
>> new RSG mount. In addition to my freq question above, I also have
>> another... im not getting anywhere near what I expected to, performance
>> wise with this coil. 2 - 6in max off a break out point. By the way, that
>> toroid i just got in the mail today from OW landergren... Most amazing
>> craftsmanship I have ever seen and extremely robust and heavy duty! Took
>> it to the machine shop today to center tap it and it was "over" a 1/4"
>> thick of aluminum in the center. Just google them.
>>
>> I know everyone needs numbers to even begin to help me and I figure I'll
>> resubmit a detailed report of my findings to the list like I said, next
>> thursday. Hopefully then with plenty of data, pictures, video, etc...
>> someone out there will say that catchy phrase "Well theres yer problem!"
>> Thanks everyone! Hope you all enjoyed my new coil pics... even if it
>> doesnt work hahahaha.
>>
>> Regards,
>> Andrew Robinson
>>
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>
>
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