RE: Bart's Coil

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

Original poster: "Malcolm Watts by way of Terry Fritz <twftesla-at-qwest-dot-net>" <m.j.watts-at-massey.ac.nz>

HI JOhn,
         I've revisited the posts in question. Unless I am further 
mistaken, I understand that the 114.xxkHz frequency was measured with 
no toroid in place and the coupling frequencies (69kHz or so) were 
measured with a toroid in place. If so, the discrepancy is to be 
expected.

Regards,
malcolm

On 28 Nov 2001, at 19:47, 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]
> 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
> 
> 
> 
> 
> 
> 
>