I was just wondering if anyone has any information on the effect Tesla observed when the switch of a dc dynamo of high potential was closed. Lindemann said that the engineers of the time put it down to be some sort of 'bunching effect'. I don't want information on radiant energy rather I just want to be able to put a reliable reference in my paper I am writing about the phenomenon where when the switch is closed there is a moment where no current flows.
Thanks,
Raui
I'm afraid i can't help ya there, but when you finish your paper, would you put it up here. I would like to hear what you found.
peace
Conrad
I dunno wether this helps you;
http://www.hbci.com/~wenonah/new/tesla.htm
Start reading from Shocking Discovery.
I did some work several years ago looking at Tesla's experiences with these phenomena.
Here's one of the traces from the wire explosion work I did.
The trace is made by sandwiching the wire between 2 pieces of fine-art paper and compressing it with a weight. Then the capacitor bank is charged to a high voltage and allowed to over-volt an air gap, through an inductor, and through the wire to be exploded. I was using 0.3 microFarad charged to about 60 or 80 kilovolts. The wire was usually #40 or #42 enamel-coated copper magnet wire. If I got the parameters just right a trace like below was produced. Too much energy and you totally vaporize everything. Just right, and you can see where the globules of molten copper are ejected (always on the outside of the wire's curvature) and re-solidify some distance away. Sometimes, amazingly, the tiny hair-like tube of the enamel insulation would remain behind, seemingly intact or in only a few pieces, while the copper vanished.
I think the phenomenon of delayed current to the load happens as a result of an interaction between inductances in the lines and load, and the phase of the applied current at the moment of switch closure. The first thing that happens is that the inductance sets up the magnetic field, and only after this does current reach the load.
Very cool experiment you did there TK. Can you draw up the schematic of the circuit you had?
Quote from: broli on December 19, 2008, 08:16:58 PM
Very cool experiment you did there TK. Can you draw up the schematic of the circuit you had?
WARNING DANGER EXTREME HIGH VOLTAGE LETHAL and LOUD but fun
Thanks, here's the schematic. All conductors to the right of the capacitor should be as heavy as possible. You will be conducting tens of kiloamperes (briefly).
Be warned: I nearly killed myself doing these experiments. I severely overvolted a 60 kV Maxwell pulse capacitor and it blew up, spewing cap oil all over, and caught fire. Fortunately I was wearing a full face shield and earmuffs. I put out the fire and was safetying the remains of the exploded cap, when I accidentally brushed against its terminals. Even though it had exploded, caught fire, was put out, it still had enough charge to knock me out briefly. I was all alone and far from help. Fortunately it was only a smallish shock as these things go, and it didn't go through my chest. I was shaky for days afterwards.
Make a sturdy platform to hold the wire. Put one piece of paper down, clip in the wire segment, put the other piece of paper on top, weight heavily over the entire wire piece (or you will tear holes in the paper). I tried many different wire materials. Fine steel wire is neat, but I got the best colors from enameled copper. A thin strip of aluminum foil nearly destroyed the platform section with the violence of the explosion.
Only one time was I able to produce the classic Graneau-style segmentation from Ampere tension, with plain iron wire of about #32 size. This wire blew perfectly into a handful of very equal-length segments.
DANGER EXTREME HIGH VOLTAGE AND LETHAL ENERGY LEVELS
(EDIT to add: don't forget to make an "Allah Rod" (or "Jesus Pole" or "Jehova Stick") which is a long well-insulated handle with a conductive crossbar on the end, that you can use to short out the gaps manually to make sure the cap is discharged fully before working on the damned thing...)
Is there a reason you put a coil on the other side of the coil?
I kept thinking about this and I came up with two things.Let's assume the current rush is 5kA when the spark gap breaks down. And if we also assume the time differential of 1 ms (which is imo generous). This make dI/dt= 5 gigaA/s. And to make it more fun lets take L of the inductor to be 1 H. Then at the very first moment of the arc jumping over the coil will push back the current with a BEMF of 5.000.000.000 Volt. I first thought the high current destroyed the wire (unless I could make an experiment without the inductors and compare the destruction). But I believe the wire explodes? due to the giga high voltage that's produced (in ideal situations). Because I was also wondering about the fact the wire got completely destroyed and not only at the beginning which would have made sense. Why was the current able to go through the entire wire and then explode it. I would like to have your view on this.
TK if you don't mind can you repeat the experiment without the inductors. That is if you aren't traumatized from last experience :P.
I think you've put your finger on the reason the Capacitor exploded!!
(btw I did hundreds of these over the time of the project, only killed myself that one time...!!)
I can't do them right now, the apparatus is a long way away in storage, but we've been talking about setting up a system locally, but that won't be until after the new year, at the soonest.
Yes, depending on the inductance and the gap setting (voltage) the wire could do anything from blowing up the platen (what I called the wire and paper-holding platform assembly) and completely vaporizing the whole wire, to wire segmentation (hard to get right), to nice displays like the one I showed above, sometimes leaving the enamel tube behind, to just breaking the wire at one or the other mounting clip, to just scorching the paper where the intact wire remained.
Without any inductors, IIRC, I got mostly breaks and total vaporizations.
(I don't think the total inductance was anywhere near 1 H, though!!)
EDIT to add I cannot stress SAFETY enough here. Please please please protect yourself and your surroundings when trying this kind of stuff! It makes a sound like a pistol shot when it goes off, and I have felt the "stinging" Tesla described, so I always did this work behind a polycarbonate lab safety shield and with a face shield, apron, and ear protection, and kept one hand in pocket--most of the time-- And I STILL nearly died doing it.
EDIT again: I forgot to indicate on the diagram that the Overvolt Air Gap should be on the Positive voltage side of the Bonetti (or other) DC HV source.
Quote from: broli on December 20, 2008, 08:22:24 AM
Why was the current able to go through the entire wire and then explode it. I would like to have your view on this.
How do you view current in a wire? The way I see it, The wire is already full of the current, the voltage just pushes it through. It doesn't have to fill up first. Like a chain and cog wheel, the energy is instantly transferred. you don't have to wait for the energy to transfer to the other cog. why the wire explodes at high voltages. Is it because electrons repel each other and voltage increases that effect the instant it's applied?
Quote from: HeairBear on December 20, 2008, 09:19:02 AM
How do you view current in a wire? The way I see it, The wire is already full of the current, the voltage just pushes it through. It doesn't have to fill up first. Like a chain and cog wheel, the energy is instantly transferred. you don't have to wait for the energy to transfer to the other cog. why the wire explodes at high voltages. Is it because electrons repel each other and voltage increases that effect the instant it's applied?
Thanks for this simplistic view, it makes sense. The interesting part is that if you use the analogy of water and over pressure a tube. It would just explode somewhere randomly. In this case the wire exploded almost uniformly in the direction of the electric field around the wire. The thing to compare is try to have a steady rising current through the wire untill you reach the same peek this discharge offers and see what happens. I believe the sudden discharge has a completely different effect than just raising the current in a linear fashion. This is the main reason of Tesla's experiments.
Btw TK, you might not remember but didn't you feel some sort of shock wave or stinging just when the wire exploded?
I think HeairBear has something there. At these extreme pressures and flows, the conduction electrons in the copper are indeed somewhat like an incompressible fluid, and we know what happens when you give a sudden blow to an incompressible fluid. You get, among other things, "shock" waves (pun intended!!) that can be very physically disruptive.
Also, it is my impression that the event is a combination of EX plosion and IM plosion. The metal implodes from Lorenz pinch forces at the same time becoming superheated thru Joule heating, which vaporizes the insulation (sometimes) and the metal, which turns to plasma if the current is high enough...which explodes from overpressures and shock waves...
It's a much more complex system than it appears at first glance.
(I don't like to get into my own pet weird theories in public, but the doubled inductors in my system have to do with my ideas that, at these tensions, there does seem to me to be a positive analog to the negative electron current. That is, like Franklin, I believe there might be two electrical fluids somehow involved in an opposing circulation. Hence the inductor on each line.)
In public I will say that I am going for a somewhat underdamped ring down of the capacitor during the arc discharge and while the wire is experiencing whatever it feels. So I want the electron flux to experience an inductor between the cap and the wire sample no matter which way it's sloshing.
By far the most interesting phenomenon, to me, is when the tiny, extremely fragile tube made up of the enamel insulation coating a #36 or #40 bit of magnet wire, would REMAIN BEHIND apparently intact, or in several longish bits, even though the copper had completely vaporized or was ejected in globules like in the trace I posted above.
Explain that one, if you can!! It is much easier to replicate this effect than to get the wire segmentation effect of Graneau et al. I was able to do it a handful of times, out of the couple hundred shots I did.
Maybe the copper was in a vapor state when it went through the insulation - sort of like high pressure steam. The exit hole would be very small - possibly to small to see with your eye.
Have ever seen the "buckling" effect? - this is where the wire is bunched up by the discharge.
You can also get the wire to creep along in the direction of the discharge - it take about 1000 discharges to become noticeable and the energy must be low enough to not explode the wire.
"vapor"
You mean you don't think the copper was blasted into the Seventh Dimension, bypassing the enamel altogether?
:P
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.
TK, your contribution to this discussion is priceless. I am going to experiment with that circuit however instead of using a bonetti machine I will use the high voltage supply I have created using a fully rectified flyback transformer. When the circuit is operating I am not even going to be in the same room as it, I will be behind a brick wall outside only observing via a window which I am going to remove the glass from. One question though, how displeasant are the 'shockwaves' and from how far back can you feel them? Also does the amount of clothing you are wearing effect the strength?
Quote from: Raui on December 20, 2008, 09:33:17 PM
TK, your contribution to this discussion is priceless. I am going to experiment with that circuit however instead of using a bonetti machine I will use the high voltage supply I have created using a fully rectified flyback transformer. When the circuit is operating I am not even going to be in the same room as it, I will be behind a brick wall outside only observing via a window which I am going to remove the glass from. One question though, how displeasant are the 'shockwaves' and from how far back can you feel them? Also does the amount of clothing you are wearing effect the strength?
If you perform that experiment, get also a photographic paper enclosed in black envelope and place near the exploding wire. That way you will know if there is any radiation similar to X-Rays.
Quote from: TinselKoala on December 20, 2008, 11:54:12 AM
"vapor"
You mean you don't think the copper was blasted into the Seventh Dimension, bypassing the enamel altogether?
:P
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.
http://www.peter-thomson.co.uk/tornado/Lightning.html (http://www.peter-thomson.co.uk/tornado/Lightning.html)
i wonder if some sort of cascade effect happens in the wire too...
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
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
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.
wonder if tesla knew about this
<object width="425" height="344"><param name="movie" value="http://www.youtube.com/v/BXy_8KVZS9I&hl=en&fs=1"></param><param name="allowFullScreen" value="true"></param><param name="allowscriptaccess" value="always"></param><embed src="http://www.youtube.com/v/BXy_8KVZS9I&hl=en&fs=1" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="425" height="344"></embed></object>
http://www.youtube.com/watch?v=BXy_8KVZS9I (http://www.youtube.com/watch?v=BXy_8KVZS9I)
Any thoughts?
It almost looks like the naturally forming chem-trails which began suddenly appearing on earth.
We know they have the anti magnetic technology to go where ever they want in the solar system.
I would not be at all surprised if the "formations" originate from the same terrestrial source.
Regards...
TK here's a video you should have watched before performing that experiment of yours :D.
http://www.youtube.com/watch?v=SE0E9r9w1bo
Tee-hee. What a namby pamby little explosion. My wire explosions would have shattered his wood mount into sawdust. You couldn't do them without ear protection.
Thanks for the link! I wonder if he knows he can make traces of the explosions...