RE: Bart's Coil

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

Original poster: "John H. Couture by way of Terry Fritz <twftesla-at-qwest-dot-net>" <couturejh-at-mgte-dot-com>


But do the artifacts give you the true coupling?

John Couture

-------------------------------


-----Original Message-----
From: Tesla list [mailto:tesla-at-pupman-dot-com]
Sent: Thursday, November 29, 2001 3:00 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 29 Nov 2001, at 11:16, Tesla list wrote:

> Original poster: "John H. Couture by way of Terry Fritz
<twftesla-at-qwest-dot-net>" <couturejh-at-mgte-dot-com>
>
>
> Malcolm -
>
> Isn't the two side frequencies test only for critical coupling when the Qs
> are related to coupling? My handbooks are not available at present so I
> cannot look this up.

Actually, no. The artifacts appear any time coupling is set beyond
critical.

Regards,
malcolm

>        Kc = 1/sqrt(QpQs)
>
> John Couture
>
> ------------------------------
>
>
> -----Original Message-----
> From: Tesla list [mailto:tesla-at-pupman-dot-com]
> Sent: Wednesday, November 28, 2001 8:44 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,
>          Now I'm a little surprised:
>
> 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.
>
> I would have expected the side-frequencies to be sitting either side
> of the 114.56kHz. They have been every time I've measured coupling
> that way. I'm not surprised there appears to be no relation between
> the side-frequencies and the 114.56kHz. I will have to revisit the
> posts on this topic to see how the tests were done. My fault for
> being lazy.
>
> > 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!
>
> I believe you already gave the formula relating k and Fo to Fhi and
> Flo. That is the only relationship I'm aware of it. It's been known
> for decades.
>
> > 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.
>
> Will do.
>
> Regards,
> Malcolm
>
>
>
>
>
>
>