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Re: Jacobsladder-Oscillator, Gerry's Experiment

Original poster: "Kurt Schraner" <k.schraner@xxxxxxxxxxx>

Hi Gerry,

we carried out the experiment, and it was easier than expected, because the attraction between the rods of the JL led to a bigger displacement of its ends, than expected. Several cm-scales were copied on cardboard, which was folded to an L, in order to attach it to one of the rods, in such a way, the scales were visible and several cm behind the JL. See this picture:


Now watch the following movie (3.8MB), which is the experiment:


Andi is operating the induction coil; I'm operating the digitalcamera and commenting. As long as I'm counting 21, 22, .. the induction coil is at it's lowest output HV (say ~1kV). This was adjusted before, and allows to take notice of th inital rod distance (~7cm). When I say "now ramp up", Andi turns up the HV smoothly. It can be seen, how the rods approach very slowly, till a distance of ~6cm only, toward the end. the voltage is now about 65kV. A little more, and a spark develops at the lower end of the JL (you hear it!), and the upper end suddenly swings outwards. A moment later, the spark crosses the zoomed scene...

Because the displacement of the rods is a full 1cm (10mm), our model-assumption, the E-field (and not the magnetic field) -forces beeing the dominant mechanism, seems justified and confirmed. BTW: the capacitace of the JL was measured as 22.5pF, which also compares well with the simplified calculation of 20.7pF.

Tesla list wrote:
Original poster: "Kurt Schraner" <k.schraner@xxxxxxxxxxx>

Hi Gerry,

before talking about the experiment: I'm shure, a slow ramp up will
_not_ cause the rods to rock! It's certainly the repeated application
of a small force, in the Eigenresonant frequency of the JL, which
does the job. - Remember the children's-swing: it can be set in
appreciable movement, by pushing it with your finger's little force
only, if applying the pushs periodically, in the right moment. To
recognize the displacement of the swing, caused by one static
application of the small force, you'd need to have a very close look
at a small displacement (this corresponds to the experiment
proposed). In extending the analogy, your finger would push the swing
in a frequency of ~545Hz (like a sewing machine ;-)), which is orders
of magnitude faster than the Eigenresonance = quasi static.
I "think" we can and will try to do the experiment. It corresponds to
measuring the effect of a static force of around 0.04N (40 ponds) or
less, on the JL rods. This will lead to a very small displacement.
And the force will be applied 545 times per second (_not_ 60Hz!). I
see at least 2 problems we must overcome, in order to realize the
1.) Very slowly bringing the power resp. HV up on the JL, remembering
the HV is coming from an induction coil (not a pure DC source). This
problem is probably easy, by means of the Andiruptor, where we can
ramp up the end-charging-current easily, while not starting at zero.

2.) Mounting a displacement measuring device at the top of the JL,
which is not disturbing the field, and can be recorded without risk
for the observer. Some ideas to this are developping.

So, the experiment will not be a one moment action, but helping to
clarify the dominant mechanism, which is moving the rods of the JL.
I'll report on the outcome. If it differs from my model-ideas we have
a more interesting subject! ;-)

Thanks Gerry, for your answers and proposal.


Tesla list wrote:
Original poster: "Gerry  Reynolds" <gerryreynolds@xxxxxxxxxxxxx>

Hi Kurt,

Here's an experiment for you.  Can you very slowly bring the power up
on the JL but not to the point of starting an arc.  I'm curious how a
60 Hz field can cause an oscillation of 1 Hz.  I'm thinking the
sudden application of power is causing its natural response.  If so,
maybe a slow ramp up will not cause the rods to rock.

Gerry R.