Phenomenon observed by Tesla

[Grumpy]

"vapor"
You mean you don't think the copper was blasted into the Seventh Dimension, bypassing the enamel altogether?


Yes, that's pretty much the conclusion I came to, as well. At the time I didn't have access to a proper microscope to examine the tubular shells up close for pinholes or other penetrations. I figured the tubes might also be split lengthwise and re-curled so the split was invisible or even resealed. Of course the samples are long gone, but now I do have access to the appropriate microscopes.

"buckling"
No, never, and this was one of the things I was specifically looking for. You will note that I used (and pictured in the diagram) long loops of wire rather than a straight line between clips (although I did many straightline shots too). This would have supported the Graneau hypothesis of Ampere tension in the wire, I thought. But I wasn't able to see that effect. The only shot I made that supported Graneau's hypothesis was the single one where the wire segmented. I have heard of the effect in railguns and other high-energy pulse systems.

"creep"
No, not in my experience with this apparatus. But I wouldn't have, because most of the conductors were flexible multi-stranded cables, and I was specifically trying to explode the sample wires. But I do know, as above, that it occurs in high-energy pulse power applications, for sure.

The marks on the paper on the outside of the curve are from depolarization which can be likened to decompression.   Compression or polarization would be inside the curve and this is what smoked the wire. 

This is also "why" Tesla used a pancake coil and why the primary was outside the secondary. 

You may have mentioned that the opposite terminals have a very different effect on the wire as one is far stronger than the other.  If you do more tests like this, place a plastic board over the wire and try the wire in a steel pipe - use a blast shield or other protection in case it comes apart.  You can also try a glass tube and see if it is shattered to fine powder.

[PYRODIN123321]

http://www.peter-thomson.co.uk/tornado/Lightning.html

i wonder if some sort of cascade effect happens in the wire too...

[CARN0T]

Hello, Raui,

I don't know if this is what you are looking for--

I think the system you described is given explicity in my elementary physics textbook.  I am looking at Halliday and Resnik, Fundamentals of Physics, 2nd Edition, printed in 1986.  On page 647, a circuit is described, containing a DC source E, a resister R, and an inductor, L, in series.  At time t = 0, the circuit is closed.  Here is the equation for current:

    L di/dt + iR = E

The solution is given:

    i = E/R [1 - exp (-Rt/L) ]

If you graph this function, you see that the current starts off very slowly, then builds exponentially for a time then levels off as it reaches saturation current.  If a capacitor is added to the circuit, then oscillations can occur.

The physical explanation for why it takes time for the current to build is that moving charge produces an electromagnetic field.  This field contains energy, and it takes some time to transfer that energy from the source to the fields.

I think this answers your question, unless I just didn't understand what you were after.

Ernie Rogers

[CARN0T]

Oh, my, I was a little too quick last night.  Let's take another look at the current rise after closing the circuit.  The solution for current rise in an inductor was--

     i = E/R [1 - exp (-Rt/L) ]

The current flow for small t can be approximated using the Maclaurin series expansion for the exponential function.  Here it is---

    exp (-x)  =  1 - x + x^2 /2! - ...

So the first order approximation for small x is 1 - x.  Substituting, the current equation simplifies to---

    i = E/R [1 - (1 - Rt/L) ],

or    i = E/L t

For small t, the current rises linearly to a good approximation.  There's no "flat spot" here--no delay in the current "beginning" to rise.   But, so far, we have neglected the effect of the instrumentation.  So, let's continue.

Now, in Tesla's time, the only way you could measure current was with a galvanometer.  (I trust you know how the galvanometer is wired to measure current.)  This old-fashioned galvanometer has a needle with mass, and the response of the meter (force) is proportional to current.  Let's look at the response of the galvanometer when the cirucuit is closed--

     F = ma

     bt = m dv/dt   (b is a meter constant)

Integrating twice from t=0, v=0, and x=0 gives the needle movement as a function of time.  Here's what I got:

     x = 1/6 b t^3

Now, this function IS flat at t = 0.   So, using a mechanical meter should give a response indicating a slight delay before the needle comes up.

Now I feel better.

Ernie Rogers

[broli]

Ernie what's with all the formulas? Who asked for them? It's nice to see you have been educated but it has little to do with Tesla's phenomenon. Which is fundamentally simple...massive disruptive cap discharge.