Re: Bart's Coil

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

Original poster: "Barton B. Anderson by way of Terry Fritz <twftesla-at-qwest-dot-net>" <tesla123-at-pacbell-dot-net>

John, Malcolm - 

We are measuring LpCp via the secondary coupling (signal is on the primary).
The primary is already set to the loaded resonant frequency (68.9). The
additional mutual inductance adds to the primary and the primary frequency
drops slightly (68.493) by this additional inductance. 

I don't know anyway to find this coupled inductance except to measure. We can
mathmatically find the secondary self resonant frequency, but I don't see a
correlation between the secondary frequency and the "test" frequency. I can
only see that the "test" frequency will be slightly lower than the frequency of
LpCp due to the inductance change. 

Two different coils can have different inductances and the same frequency. It's
the inductances proximity to one another which will define the mutual
inductance. I just don't see how any frequency's at the design stage can be
used to find the test frequency(s) - - -  Fo and Fs. 

Take care, 

Bart 
-- 
Barton B. Anderson 
<http://www.classictesla-dot-com>http://www.classictesla-dot-com 
Tesla list wrote: 
>
> Original poster: "John H. Couture by way of Terry Fritz <twftesla-at-qwest-dot-net>"
> <couturejh-at-mgte-dot-com> 
>
> Malcolm - 
>
> The test frequency is not arbitrarily chosen. The bare secondary of Bart's 
> coil has three "resonant" frequencies. One is the natural resonant frequency 
> (114.56) with the coil self capacity that you can calculate or obtain using 
> one of those famous TC Design programs. There are two other frequencies 
> (68.493 and 69.444) that vary when the coupling between the secondary and 
> primary is changed. There is much more to this unsolved TC problem that is 
> not mentioned in any textbooks. 
>
> My question - At the design stage the natural resonant frequency can be 
> determined. How do you determine the other two frequencies at the design 
> stage? What is the "theoretical"? relationship between these three 
> frequencies? The secondary is unchanged for two of the frequencies, 114.56 
> and 68.493, no toroids or shorts! 
>
> If you are going to make these tests use smaller coils and tighter 
> couplings. The frequencies will be farther apart and easier to read. Refer 
> to the graph mentioned in a previous post. 
>
> John Couture 
>
> ---------------------------------- 
>
> -----Original Message----- 
> From: Tesla list [<mailto:tesla-at-pupman-dot-com>mailto:tesla-at-pupman-dot-com] 
> Sent: Wednesday, November 28, 2001 3:40 PM 
> To: tesla-at-pupman-dot-com 
> Subject: RE: Bart's Coil 
>
> Original poster: "Malcolm Watts by way of Terry Fritz <twftesla-at-qwest-dot-net>" 
> <m.j.watts-at-massey.ac.nz> 
>
> Hi John, 
>
> On 28 Nov 2001, at 10:49, Tesla list wrote: 
>
> > Original poster: "John H. Couture by way of Terry Fritz 
> <twftesla-at-qwest-dot-net>" <couturejh-at-mgte-dot-com> 
> > 
> > 
> > Malcolm - 
> > 
> > The 68.493 KHz (Fo) is with the secondary without a toroid and not 
> shorted. 
> > The 114.56 KHz (Fr) is also with the secondary without the toroid. In 
> other 
> > words the secondary coil is the same for both frequencies but the 
> > frequencies are different. 
>
> Am I right in understanding that one frequency is the test frequency 
> and the other is the natural resonant frequency of the coil? If so, 
> isn't the test frequency arbitrarily chosen? If that is true, why 
> should there be a relationship between them? Sorry for *my* 
> confusion. I obviously haven't been following this closely enough. 
>
> Regards, 
> malcolm