Leyden jar dangerous?

[sm0ky2]

@TK


I hate to get into semantical discussions with you
Especially since your expertise in this area
far exceeds my own.


I must state now that the Voss machine is indeed
An A/C device.


It may not appear that way because the actual freq.
Of the signal can be exponentially higher than the
Discharge rate of the machine.


I had techs at my house for over a week testing this
stuff trying to figure a way to convert it.
Which we did with, what I would call partial success.


The negative (resinous) spark is 180-degrees out of
phase to the positive ( vitreous) impulse.
These are microwave frequencies, compared to the
100-200Hz discharge of the machine.


When I speak of "frequency" with this machine I am
generally referring to the discharge rate.
But the HV carries its own freq. components
(I use the plural term because there are more than one freq.)


For you to kill someone with your jars is probably an easy task
However, for a beginner such as myself, even the largest potentials
That I can achieve would only kill a small insect.
I have breached 700kV rated insulation with my Voss
And machines not much larger than mine used to run MV X-ray
devices.


One thing I have learned about Leyden jars is that the potential
Is not the same as the capacitance
Potential has a lot to do with the physical size of the plates in the jar
Whereas capacitance is more closely related to the distance between
the plates and how well they are insulated.


My high capacitance Leyden jars take a lot longer to charge
Than my lower capacitance jars, that can reach higher potentials
And do so much more quickly.


The 10-gallon bucket caps, for example, can be deadly with the right
machine. A Voss like mine takes about 30-35 seconds to charge those
up to anything dangerous.
Generally speaking, the average person will make a capacitor out of laminent
or a small glass jar.

[sm0ky2]

Using a wooly-socked human body as a reference point
The average human capacitance is 100-200pf (some as high as 400)
And a good walk across a rug can charge you to 30-50kV


That gives the wool socked human and the silk socked human
A potential of 100kV across two 200-pf capacitors.
I socked myself and others extensively as a child, yet never
managed to kill myself or others.


Estimates put the "death zone" around 1,350 microjoules.
That is a conservative estimate for a 'weak human'.
Most people will be able to take a bigger shock than that.


You can calculate the energy of your Leyden Jar using THIs
Formula:


https://www.princeton.edu/ssp/joseph-henry-project/oscillatory-discharge/leyden-jar/


And this here:


http://nuclear.unh.edu/~maurik/Phys408_Spring2003_Holtrop/Lectures/Lecture27/ConceptQ27_sol.pdf

[TinselKoala]

Well, I tried, anyway.

Your Voss machine is DC. You have substantial inductance in your wiring. When your capacitance discharges across the spark gap, you will have AC ringing due to the capacitance and inductance making a very high frequency tank circuit. It is definitely possible that this ringing is in the "microwave" frequency range. This does not mean your machine is AC. Your machine can charge a capacitor and keep it charged until breakdown, without using a rectifier diode. This proves that it is producing DC. The "AC" ringing is only produced during the actual spark discharge and is a result of the capacitance of the machine and the inductance of the wiring.

The spacings of the parts in your Voss machine cannot possibly produce 700 kV. If your machine has breached insulation rated that high, it must have found a crack or other defect of lower resistance and poked through there. What insulation are you talking about, exactly? Don't forget that spheres of large size have the highest breakdown voltage and any other geometry (flat plates, points, corners, etc) will break down at lower voltages over a given gap distance. Or looking at it another way, the sphere gap produces the _smallest_ gap for a given high voltage, and other geometries will break down over a much greater distance at a given voltage. And 700kV will breakdown over a distance of 25-30 cm between large spheres, and over a much greater distance between electrodes of other geometries. This means that the oppositely charged areas of _any_ electrostatic or even electrodynamic machine must be _greater_ than that or the voltage will spark across. Obviously your Voss machine doesn't have its parts separated by that much. When I demonstrate a 27 cm spark between large spherical electrodes on one of my Bonetti machines, that is reaching 600 kV for sure -- and all parts of the machine carrying opposite charges are separated by more than that spacing, otherwise the spark would happen where the parts are closest and would happen at lower voltages.

Yes, Voss and other machines can reach higher voltages IF they are properly constructed and isolated for that high voltage. Yours is not. Take a look at some systems operating in the MV range to drive xray machines, you will see that they are large, that they have very smooth and large curvatures, that they are operating in pressurized gas environments for further insulation.

The capacitance of a capacitor depends on the area of the plates, the spacing between the plates, and the permittivity of the material separating the plates. The formula, in case you are interested, is
C = ε(A/d)
where A is the area and d the separation of the plates. There are many internet references available on this topic. The potential (voltage) that a capacitor can withstand, or store, is determined by the breakdown of the dielectric (presuming that leakage from edges, etc, is eliminated by proper design and isolation.) The area of the plates has nothing to do with the potential (voltage) that can be stored on a capacitor. Tiny caps can withstand very high voltage, and huge caps can breakdown at tiny voltages, all depending on the dielectric and the spacing. Do not confuse voltage (aka potential) with charge quantity; the same amount of charge can produce a high voltage if confined to a small space, or a low voltage if distributed in a large space. Voltage is charge pressure, from like charges repelling like, or charge tension, from unlike charges attracting. (same thing, different sides of the same coin.)
http://www.electronics-tutorials.ws/capacitor/cap_1.html

There is no such thing as "resinous" or "vitreous" impulse. These are ancient names for positive and negative electrical charges. In our ordinary environment we only deal with electrons (negative charges) and "lack of electrons" (positive charges, holes). We _never_ see "naked positive charges" unless we are working with protons directly. A "positively charged" thing has fewer than normal electrons, a "negatively charged" thing has excess electrons. A spark consists of a plasma produced by a stream of negative charges -- electrons -- moving from the negatively charged item to the positively charged item, and to a lesser extent, positive ions (air gas molecules stripped of one or more electrons) moving in the other direction. Yes, when you have some inductance along with capacitance, a spark will reverse polarity many times per second as the tank circuit rings down in voltage. This means the polarity of the gap electrodes alternates back and forth, positive and negative, at the ring frequency. Yes, the currents are 180 degrees out of phase then, going back and forth across the gap, possibly at GHz frequencies if capacitance and inductance are small. The energy sloshes back and forth between capacitance (electric field) and inductance (magnetic field) and a little bit dissipates at each cycle until the voltage drops to the point where it can no longer break down the gap. Yes, a spark gap also produces broadband noise in addition to its tank ringdown frequency.

Do what you like, interpret things however you like, but please don't mislead people into thinking that Leyden jars charged to hundreds of kV are going to be "safe".


Some 500+ kV sparks:

[TinselKoala]

Using a small neon (NE-2) bulb to find the polarity of an ES generator:

http://www.youtube.com/watch?v=DpoTGdbcUzE

The VDG machine polarity is determined by the materials of the belt and the top and bottom rollers, depending on their positions on the triboelectric scale. The pingpong ball itself changes polarity each time it strikes the box endplates and is repelled by the one it just struck and is attracted to the one it is about to strike. The ball in this case is actually a current-carrier! This is a "model" of some of what happens in an electrostatic spark gap when an actual spark occurs.

[Cherryman]

Tnx TK for weighing in.


Back to my power supply strubbles...   

Still something is off...


I can not get anything to rotate, even not a lightweight cup with some alufoil on it, with almost no friction.
It works when i near it with a PVC pipe , wrubbed with a cloth, it turns easaly.
But with the plasma ball power supply..  Nothing wants to move.


I tried plates, brushes, wirepoints..  al i can think off.


Could the Plasma ball be also AC HV


Here is a picture, someone capable of determine the output is DC or AC ?
(Input is 12V DC )