Re: Fwd: That secondary harmonic voltage distribution stuff...

Hi Antonio,

	Many thanks for scanning the very interesting picture!!  The first thing
that caught my eye was the date of 1892!!  I sorta got the feeling someone
has been here before :-))

It looks like the coils have a grounded wire along the side and they are
feeding it from a TC like oscillator that they can control the frequency
of.  The pictures seem to be of the brush discharges between the coil and
the wire.  Even though this is a drawing, the artist appears to be doing a
great job at accuracy.  The first picture would tend to suggest that the Vm
x l ^ e distribution I spoke of yesterday is at work.  It does not strike
me as a sine distribution.  

The second picture is an almost exact duplication of my voltage
measurements.  The peak intensities decreasing up the coil and the top is
just a little illuminated as the yellow line in the graph below shows.


The third picture looks like the purple line in the above graph.  You say
the top of the coil is grounded?  I would suggest that it is not.  I think
someone just assumed it had to be grounded to make that pattern.  The
atrist tries very hard to show the connections and there is zero indication
of a top ground wire.

It is interesting that this experiment, done so long ago, uses completely
different measurement methods but appears to be showing the exact same
results!  Apparently, Seibt was asking the exact same questions then that
we are today.  I must wonder if he also found the answers already that were
are trying to find AGAIN now???  I wonder if Seibt was able to explain (or
even realized) that the frequencies that these patterns were appearing at
were not what they "should" be??

It is really strange to see a repeat of my test of yesterday, that seemed
so new and unusual, to be confirmed by an ancient picture from the past!!



At 08:51 PM 08/26/1999 -0700, you wrote:
>Terry Fritz wrote:
>>         I just took the measurements on my coil without top load.  Here 
>are the
>> numbers...
>Nice measurements. I made similar experiments some time ago, but
>didn't try to actually measure the fields. Note that the presence
>of even small objects close to the coil (as a probe) can shift
>the patterns substantially. Only the nodes can be accurately
>observed. In my measurements, I produced repetitive beat waveforms
>exciting a closed primary circuit with a high-impedance square wave 
>current source and made all the monitoring at the low-impedance
>primary. The system is resonant when the beats appear, and it is
>possible to map the field by just sliding a finger along the 
>secondary coil, observing at what distance the finger is from the
>coil for a degree of changes in the beat waveform. Low power 
>measurement, of course.
>The method is extremely sensitive, and I could observe as many
>modes as my primary allowed (more than 10 modes). I have to make
>this experiment again, and annotate the measurements...
>I have scanned a picture from Fleming's book, showing three
>different modes (the last with the top of the coil grounded,
>not clear how):
>The book lists the references (and a few others):
>G. Seibt, "Elektrische Drahtwellen", Elecktrotechnische Zeitschrift,
>April 10, 17, 24, May 1, 8, 1892, vol. xxiii.
>J. A. Fleming, "On the propagation of electric waves along 
>spiral wires", Phil. Mag., Oct. 1904, ser. 6, vol. 8, p. 417.
>Antonio Carlos M. de Queiroz