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Ernst · #1 07-24-2012, 01:02 AM

I have been studying Tesla's work for a few years and I would like to present my findings here.
Tesla often used mechanical analogies to describe electrical apparatus. In fact a lot of his work after roughly 1900 is not described in direct terms. Let me start with a small walkthrough of his famous article 'THE PROBLEM OF INCREASING HUMAN ENERGY' written in June 1900:

Quote:

Here, then, was an idea which, if realizable, afforded a happy solution of the problem of getting energy from the medium. But was it realizable? I convinced myself that it was so in a number of ways, of which one is the following. As regards heat, we are at a high level, which may be represented by the surface of a mountain lake considerably above the sea, the level of which may mark the absolute zero of temperature existing in the interstellar space. Heat, like water, flows from high to low level, and, consequently, just as we can let the water of the lake run down to the sea, so we are able to let heat from the earth's surface travel up into the cold region above. Heat, like water, can perform work in flowing down, and if we had any doubt as to whether we could derive energy from the medium by means of a thermopile, as before described, it would be dispelled by this analogue. But can we produce cold in a given portion of the space and cause the heat to flow in continually? To create such a "sink," or "cold hole," as we might say, in the medium, would be equivalent to producing in the lake a space either empty or filled with something much lighter than water.

Note the word 'something much lighter'. This is not necessary but he is probably thinking of ether.

Quote:

This we could do by placing in the lake a tank, and pumping all the water out of the latter. We know, then, that the water, if allowed to flow back into the tank, would, theoretically, be able to perform exactly the same amount of work which was used in pumping it out, but not a bit more. Consequently nothing could be gained in this double operation of first raising the water and then letting it fall down. This would mean that it is impossible to create such a sink in the medium.

Heat and cold represent static electricity or charge.

Quote:

But let us reflect a moment. Heat, though following certain general laws of mechanics, like a fluid, is not such; it is energy which may be converted into other forms of energy as it passes from a high to a low level. To make our mechanical analogy complete and true, we must, therefore, assume that the water, in its passage into the tank, is converted into something else, which may be taken out of it without using any, or by using very little, power. For example, if heat be represented in this analogue by the water of the lake, the oxygen and hydrogen composing the water may illustrate other forms of energy into which the heat is transformed in passing from hot to cold.

Why doesn't he boil or freeze the water to dispose of it? He is thinking about the components of electricity.

Quote:

If the process of heat transformation were absolutely perfect, no heat at all would arrive at the low level, since all of it would be converted into other forms of energy. Corresponding to this ideal case, all the water flowing into the tank would be decomposed into oxygen and hydrogen before reaching the bottom, and the result would be that water would continually flow in, and yet the tank would remain entirely empty, the gases formed escaping. We would thus produce, by expending initially a certain amount of work to create a sink for the heat or, respectively, the water to flow in, a condition enabling us to get any amount of energy without further effort. This would be an ideal way of obtaining motive power. We do not know of any such absolutely perfect process of heat-conversion, and consequently some heat will generally reach the low level, which means to say, in our mechanical analogue, that some water will arrive at the bottom of the tank, and a gradual and slow filling of the latter will take place, necessitating continuous pumping out. But evidently there will be less to pump out than flows in, or, in other words, less energy will be needed to maintain the initial condition than is developed by the fall, and this is to say that some energy will be gained from the medium. What is not converted in flowing down can just be raised up with its own energy, and what is converted is clear gain. Thus the virtue of the principle I have discovered resides wholly in the conversion of the energy on the downward flow.

Having recognized this truth, I began to devise means for carrying out my idea, and, after long thought, I finally conceived a combination of apparatus which should make possible the obtaining of power from the medium by a process of continuous cooling of atmospheric air. This apparatus, by continually transforming heat into mechanical work, tended to become colder and colder, and if it only were practicable to reach a very low temperature in this manner, then a sink for the heat could be produced, and energy could be derived from the medium. This seemed to be contrary to the statements of Carnot and Lord Kelvin before referred to, but I concluded from the theory of the process that such a result could be attained.

He describes a few methods that do not work and continues:

Quote:

But my conclusions showed that if an engine of a peculiar kind could be brought to a high degree of perfection, the plan I had conceived was realizable, and I resolved to proceed with the development of such an engine, the primary object of which was to secure the greatest economy of transformation of heat into mechanical energy.

Important key:

Quote:

A characteristic feature of the engine was that the work-performing piston was not connected with anything else, but was perfectly free to vibrate at an enormous rate.

In a mechanical sense this is close to impossible so this may indicate that he is not talking about a mechanical device. In the electrical sense it means he creates a high frequency AC (using a capacitor) but does not connect it to anything because that would remove energy from the system.

Quote:

The mechanical difficulties encountered in the construction of this engine were greater than I had anticipated, and I made slow progress. This work was continued until early in 1892, when I went to London, where I saw Professor Dewar's admirable experiments with liquefied gases. Others had liquefied gases before, and notably Ozlewski and Pictet had performed creditable early experiments in this line, but there was such a vigor about the work of Dewar that even the old appeared new. His experiments showed, though in a way different from that I had imagined, that it was possible to reach a very low temperature by transforming heat into mechanical work, and I returned, deeply impressed with what I had seen, and more than ever convinced that my plan was practicable

.
The work referred to concerns using an intermediate product to condition the start product. When cooling air; it is first cooled a bit, then this cool air is used to cool incoming air so that in the next cooling step a lower temperature can be reached. By repeating this over and over, any temperature can be reached.
Translated to electrical systems it could mean:

you send a pulse into a coil, wait until it returns and then you send a new pulse together with the echo of the first pulse so that its power increases. Thus you can obtain virtually any voltage in a coil.
A bifilar coil (patent 512340 uit 1893) which can be viewed as two coils in which one eliminates the unwanted effects of the other.

Quote:

The work temporarily interrupted was taken up anew, and soon I had in a fair state of perfection the engine which I have named "the mechanical oscillator."

A bit further in this article he describes this oscillator but this time in direct/electrical terms:

Quote:

I had arrived at the limit of rates obtainable in other ways when the happy idea presented itself to me to resort to the condenser. I arranged such an instrument so as to be charged and discharged alternately in rapid succession through a coil with a few turns of stout wire, forming the primary of a transformer or induction-coil. Each time the condenser was discharged the current would quiver in the primary wire and induce corresponding oscillations in the secondary. Thus a transformer or induction-coil on new principles was evolved, which I have called "the electrical oscillator," partaking of those unique qualities which characterize the condenser, and enabling results to be attained impossible by other means.

Let's continue...

Quote:

In this machine I succeeded in doing away with all packings, valves, and lubrication, and in producing so rapid a vibration of the piston that shafts of tough steel, fastened to the same and vibrated longitudinally, were torn asunder.

In mechanical terms this is obviously impossible, the electrical equivalent however is not only possible, it is a stroke of absolute genius.

Quote:

By combining this engine with a dynamo of special design I produced a highly efficient electrical generator, invaluable in measurements and determinations of physical quantities on account of the unvarying rate of oscillation obtainable by its means.

In the process, as I had primarily conceived it, for the utilization of the energy of the ambient medium, there were five essential elements in combination, and each of these had to be newly designed and perfected, as no such machines existed. The mechanical oscillator was the first element of this combination, and having perfected this, I turned to the next, which was an air-compressor of a design in certain respects resembling that of the mechanical oscillator. Similar difficulties in the construction were again encountered, but the work was pushed vigorously, and at the close of 1894 I had completed these two elements of the combination, and thus produced an apparatus for compressing air, virtually to any desired pressure, incomparably simpler, smaller, and more efficient than the ordinary. I was just beginning work on the third element, which together with the first two would give a refrigerating machine of exceptional efficiency and simplicity, when a misfortune befell me in the burning of my laboratory, which crippled my labors and delayed me

continued in next post...

Ernst · #2 07-24-2012, 01:03 AM

Tesla describes 3 of the 5 components that are required to generate energy from the ether. These 3 components are the key components:
1 – an oscillator that produces a constant frequency. It is well known how he used a spark gap and capacitor in combination with the primary coil to establish this.
2 – a high frequency transformer; a tuned primary and secondary coil.
3 – an extra coil, as he called it, in which through resonance any desired voltage can be achieved. Because the wire length in this coil is one quarter of the electrical wave length, one side of the coil shows a high current at 0 volts, the other end a high voltage at 0 current. This means that an excellent ground connection is essential.

Now, why would Tesla not describe components 4 and 5? The 'dynamo of special design'.
The answer is that he has already done so. Component 4 = component 3 and component 5 = component 2 but tuned at a different frequency.
So the generating part has been fully described. However, if you try to reconstruct it, you will find that there is still one more problem to be solved: how do you connect the first 3 components to the last 2? If you read on in this article you will find that he starts talking about passing electricity through the air. In the pre-hearing interview of 1916 he describes this experiment but he uses 'sectional pipes' to represent a continuous medium. This does not make sense. In combination with this article it does make sense.
Find the video on youtube where Eric Dollard demonstrates longitudinal electricity for Borderland Science at roughly 30 minutes you will see a set up that looks surprisingly much like Tesla's. Also not that Eric says he uses + because that seems to work best.
There is appearantly a difference and so a connection of this type will have a rectifying effect. This turns the 'dynamo of special design' into a giant crystal receiver oscillating at a different frequency that the system that sets it into vibration. This means that you can get power from this receiving system without consequence for the first system.
In other words: For Free.
The article continues explaining how you can distribute electrical energy without wires all over the globe. But that part has been described pretty clearly by the master himself.
Additional proof that this is the true system that Tesla designed for Wardenclyffe can be found in some documents that Leland Anderson copied from the Tesla Museum in Beograd. These circle the web under the name of 'rare notes'.

I hope this will trigger new research and new studies of Tesla's writings. The only true master of electricity!

redrichie · #3 07-24-2012, 04:58 PM

I'm not qualified to agree or disagree with your statements but the way presented damn sure makes sense. Pretty cool. hatvother resources do you have to back this claim. I live this stuff.

boguslaw · #4 07-24-2012, 07:12 PM

Ok. Here is what I think Tesla was trying to say : there is a lot of energy in radio waves but not in Hertz waves - those are rather like heliographic messages - not usable. We can catch those real radio waves and convert them into cold electricity which is normal electric current but on high frequency (this is famous "cold electricity"). Radio waves are hot but light, cold electricity is dense.
You can forget about electrons but Tesla was not against them (he knew they exist but as a wave packets in pure vacuum, else those are quantum stages or ether "density").

The most important article was about the heterodyning as a method how atoms catch radio waves. Transmit in order to receive.

We are at the edge of the REAL radio age.
I fully support explanation , seems the comprehension is just at the corner !

Universe is simple, we make complicated everything.

Important:
Look how easy everything coul be explained :
1.Ether is gaseous and all gases are a higher heat stage, must be cooled to condense into liquid
2. In gases only longitudinal waves are supported naturally but transverse are possible but highly impractical. Longitudinal are natural and are bases for two effects : pressure and sound. Two different effects like gravity and electromagnetism. This is the key to every force in nature.
Prana and Akasha you see ?

GSM · #5 07-24-2012, 09:34 PM

Quote:

Originally Posted by Ernst

There is appearantly a difference and so a connection of this type will have a rectifying effect. This turns the 'dynamo of special design' into a giant crystal receiver oscillating at a different frequency that the system that sets it into vibration. This means that you can get power from this receiving system without consequence for the first system.
In other words: [B]For Free.[B]

Hi Ernst.
Tesla was attempting to set up the generator everyone else could use -
but no matter, everyone else could still set up a generator for themselves too !

Check out Bruce Perreault's work, especially here,
does it not match very well with what you have just decoded ?

- 5x More Current Out Than In - Validation Of Proof Of Concept -

Cheers ........... Graham.

soundiceuk · #6 07-24-2012, 10:35 PM

@ GSM

I was reading Ernst's very interesting thread this morning.

"This turns the 'dynamo of special design' into a giant crystal receiver oscillating at a different frequency that the system that sets it into vibration. This means that you can get power from this receiving system without consequence for the first system."

This rang a lot of bells.

@ Ernst

Great thread! I would love to host the "rare notes" if you have them please.

Ernst · #7 07-24-2012, 11:42 PM

Thanks for the responses so far!

@ GSM
True! Tesla also mentioned that possibility but he did not support it because for the progress of human kind also inter-connection is essential.
But today that has been taken care of by the internet....
Perhaps today he would also support the idea of many small generators.

@ soundiceuk
I have them as PDF, how can I forward them to you?
... Oh I just read that purelyconstructive has a link for you. Those are indeed the ones that I was refering to.
One must keep in mind that the top-terminal of the free-system is not a metal sphere.
It is a (almost) vacuum bulb. Remember Colorado Spring Notes where he 'suddenly' starts measuring the capacity of vacuum tubes? (If you don't I can look up the date for you)

And the video of Eric Dollard...

Ernst · #8 07-25-2012, 08:24 AM

There is probably someone here with more MOSFET experience than I have. Perhaps you can help me out.

Of course I am working on a proof of concept of the above system. But as every item has to be hand made this takes a while.
Meanwhile, I thought to experiment a bit with the 'plasma bridge' and receiver coil.
The biggest coil I have (84 cm diam, 72 cm height) has a SRF of about 160 KHz.
So, to quickly have a rectified 160KHz high voltage source I was thinking about a TV/monitor fly-back transformer. I have a TC4421 MOSFET driver and a IPP60R380 MOSFET. I connect the driver directly to the MOSFET and I feed the driver directly with a TTL level signal.
Using 5 V for the FBT everything holds pretty well, though the driver does get a bit warm.
Using 12 V the driver gets a bit hot but the MOSFET (factory calls it 'cool mos'

) gets so hot in seconds, that I burned my finger on its heatsink.
All voltages, currents and frequencies are well within specs. The only thing I can think of is that the driver is a bit too rough on the FET, pushing the dV/dt too high.

Anyone? Suggestions?

mr.clean · #9 07-25-2012, 08:35 AM

Tesla would be so happy <3

Ernst · #10 07-26-2012, 12:33 AM

Actually, there are 2 reasons why I started this thread:
1- to get your opinion about what I have found
2- to trigger more/new research in Tesla's writings

As for the second reason, some extra info that may be of use:
- always remember that his main focus was on electricity. When he writes about something outside of this field, this can mean 2 things: he is actually describing an electrical system or he has an electrical system in his mind which he may or may not have written about earlier and he has found an mechanical equivalent that he thinks may be usefull as well. In either case his mechanical system has an electrical equivalent.
- he strongly believes in the existance of ether and opposes Einsteins ToR equally strongly.
- electricity he describes mostly as a fluid, capacitor as a piston, coil as something that creates a vortex, induction as cohesion/adhesion etc.
- his inventions always are highly practical. For this and other reasons you should have a look at patent 1113716, filed just before 1119732 which is commonly believed to be his magnifying transmitter. I can see no practical use and the esthetical value is questionable. I still do not understand what he has in mind here.
- some of his later work include a speedometer and ship log. I strongly believe that he is refering to ways to extract energy from the movement of earth (=ship) through space (=ether=sea).

A note on vortices (please read Prof.Dr-Ir. Konstantin Meyl's work):
When you drain a bath tub, you will see a vortex in the water. You can distinquish 2 opposing forces here. One inward force, mainly present in the water. And one outward force; centrifugal force mainly present in the centre of the vortex (air). The reason why you see this vortex is the boundary between the inside (air) vortex and the outside (water) vortex. This kind of vortex is round in 2 dimensions.
Now, if we could have a 4 dimensional vortex, that would be round in 3 dimensions (ball). It would be rotating and on its outside we would see a force towards its centre.
Does someone see a similarity here with planets?
("now I understand how the cosmos works", Tesla said when he discovered his rotating magnetic fields)
Meyl shows the relation between electricity and magnetism is also a vortex field. One is the outward force, the other the inward.

This view is very helpful when trying to understand Tesla's work.
(hope to see new threads on his work)

boguslaw · #11 07-26-2012, 06:36 AM

Quote:

Originally Posted by Ernst

There is probably someone here with more MOSFET experience than I have. Perhaps you can help me out.

Of course I am working on a proof of concept of the above system. But as every item has to be hand made this takes a while.
Meanwhile, I thought to experiment a bit with the 'plasma bridge' and receiver coil.
The biggest coil I have (84 cm diam, 72 cm height) has a SRF of about 160 KHz.
So, to quickly have a rectified 160KHz high voltage source I was thinking about a TV/monitor fly-back transformer. I have a TC4421 MOSFET driver and a IPP60R380 MOSFET. I connect the driver directly to the MOSFET and I feed the driver directly with a TTL level signal.
Using 5 V for the FBT everything holds pretty well, though the driver does get a bit warm.
Using 12 V the driver gets a bit hot but the MOSFET (factory calls it 'cool mos'

) gets so hot in seconds, that I burned my finger on its heatsink.
All voltages, currents and frequencies are well within specs. The only thing I can think of is that the driver is a bit too rough on the FET, pushing the dV/dt too high.

Anyone? Suggestions?

Yes,indeed, mosfets are not good in driving high rate dv/dt. I have the same problem. I'm trying to implement Tesla "ignition device" patent. If I would have better mechanical skills I would make a rotary interrupter

Someone has given me advice to do progress slowly by first attaching a "substitute" coil of the same inductance in series with incandescent bulb to limit current. If in such configuration MOSFET is getting hot then there is no chance to make it work; also use big sink and cooler.
I'm at the same stage, mostly everything ready but no experience with electronics makes it hard and I must be very careful to not damage any part.

I think help is very needed in such stage.

boguslaw · #12 07-26-2012, 06:57 AM

Someone on forum posted very valuable page : http://www.ovaltech.ca/tesla.html

Clearly visible that Tesla knew and fully supported ancient knowledge about Akasha and Prana.

boguslaw · #13 07-26-2012, 07:11 AM

Btw patent 1113716 is probably describing flying etheric engine like those used by very old ancient civilizations

Ernst · #14 07-27-2012, 06:24 AM

Quote:

Btw patent 1113716 is probably describing flying etheric engine like those used by very old ancient civilizations

Do you have anything to support this idea?

soundiceuk · #15 07-28-2012, 09:46 AM

Thank you all for the links.

Here is an interesting email I received this morning

Hello all,

I have replicated the power propagation via the ground. It is still the higher harmonics which will get through the ground to the receiver. Have a look at my latest video and please watch the previous videos to see the evolution to this stage for you to replicate.

https://www.youtube.com/watch?v=Rj6rY7wgM0I

gyula · #16 07-29-2012, 01:14 PM

Quote:

Originally Posted by Ernst

There is probably someone here with more MOSFET experience than I have. Perhaps you can help me out.

Of course I am working on a proof of concept of the above system. But as every item has to be hand made this takes a while.
Meanwhile, I thought to experiment a bit with the 'plasma bridge' and receiver coil.
The biggest coil I have (84 cm diam, 72 cm height) has a SRF of about 160 KHz.
So, to quickly have a rectified 160KHz high voltage source I was thinking about a TV/monitor fly-back transformer. I have a TC4421 MOSFET driver and a IPP60R380 MOSFET. I connect the driver directly to the MOSFET and I feed the driver directly with a TTL level signal.
Using 5 V for the FBT everything holds pretty well, though the driver does get a bit warm.
Using 12 V the driver gets a bit hot but the MOSFET (factory calls it 'cool mos'

) gets so hot in seconds, that I burned my finger on its heatsink.
All voltages, currents and frequencies are well within specs. The only thing I can think of is that the driver is a bit too rough on the FET, pushing the dV/dt too high.

Anyone? Suggestions?

Hi Ernst,

My first suggestion is to use plentiful decoupling capacitors very near to the supply pins of the TC4421 (1uF, 470nF, 47nF, all in directly parallel with the supply pins if you have not done so. I say this I suspect the nearfield of the
coil(s) may induce unwanted voltages in the driver circuit. Also try place a 1 kOhm or so 'terminating' resistor directly across the input pin and the neg. supply pin of the TC4421 to prevent it becoming high impedance for any moment, to be able to pick-up any nearfield induction, this will not affect the TTL drive level at all.

If these are of no help, then it may be about duty cycle, you wrote all the voltages and currents are within spec, the MOSFET dissipation simply exceeds the power level which could be allowed for free air cooling without using any amount of heat sink. At 12V supply voltage and at the same ON time for the MOSFET the self-dissipation is many times higher than at 5V, just consider the FBT's drain coil's DC + AC impedances: how much peak current can flow when the FET is ON, that current heats the FET.

What you wrote on the driver's high speed switching and due to this the flyback pulse may approach or exceed in amplitude the limit of the MOSFET drain-source max voltage rating, well this could surely increase the FET's dissipation too. An oscilloscope test on the drain peak pulse voltage is in order of course.

So maybe using a normal heat sink for the MOSFET is the solution, if the peak drain voltage is also ok, that is all, once you are satisfied with the currents and voltages. ?

rgds, Gyula

Ernst · #17 07-29-2012, 02:12 PM

Thank you, Gyula, for your suggestions!
I will surely implement all of them in the next attempt.
Unfortunately the MOSFET that I was using is no more...

But I think I still have 2 spares of this same type.

Extra information:
The duty cycle is pretty high, about 90% or so. This gives the best performance with an FBT.
I did use a small heat sink, but that was obviously not enough.
I use an old PC power supply (400W or there about).
I tried with a 7 Ohm 60W resistor between the driver and the FET in order to limit this current a bit. That is when the FET went to FET-heaven.
There is an extra diode (1KV/60A) across the drain-source to take care of the pulse that the FBT returns.

Anyway, thanks again for your help!

Ernst.

boguslaw · #18 07-29-2012, 07:07 PM

Ah, this is the question ... how to set parameters to allow mosfets pass capacitive discharge without damage :-(
I hate burning mosfets.

citfta · #19 07-29-2012, 08:47 PM

Hi Ernst,

All of gyula's suggestions are good ones. So be sure and follow them. Also you may not know what killed you FET when you added the 7 Ohm resistor. I will try to explain if you don't mind. When a transistor is turned fully on it is dissipating the least amount of power compared to being only partially turned on. When the transistor or FET is only partially turned on it is acting like a resistor so it will heat up a lot more than when it is turned fully on. As you reduced the gate voltage by putting the 7 Ohm resistor in the circuit you restricted the amount the FET could turn on and thus created even more heat in the FET. Mosfet driver chips help to overcome this problem by making sure the FET is either all the way on or all the way off so as to dissipate the least amount of power in the FET. We want our power to be dissipated in our load not our FET. Also you should be aware it is normal for power FETs to get pretty warm when running. Even with a heat sink they will feel pretty warm. They should not get hot enough to burn you though. Hope this helps.

Quote:

Originally Posted by Ernst

I tried with a 7 Ohm 60W resistor between the driver and the FET in order to limit this current a bit. That is when the FET went to FET-heaven.

Respectfully,
Carroll

Ernst · #20 07-30-2012, 12:36 AM

Thanks for explaining, Carroll!

Yes, when you put it this way, it makes perfect sense.
I have always been pretty succesfull, designing and building digital/computer circuits, but outside of the digital world, I fail where everyone else seems to succeed

Imagine my surprise when my first 3-coil Tesla transformer worked (almost) straight away.

The power supply for my new Tesla coil will be ready soon. Perhaps I should just stay with that.

Thanks again!

Ernst.

jake · #21 07-30-2012, 01:19 AM

I always thought a ZVS driver would make a good hfhv power supply. Anyone try one of these?

Ernst · #22 07-30-2012, 10:48 AM

Can a ZVS be tuned to 160 KHz?

It's not just HF-HV.
I need to be able to tune it's frequency to the SRF of the receiving coil.

gyula · #23 07-31-2012, 02:57 PM

Quote:

Originally Posted by boguslaw

Ah, this is the question ... how to set parameters to allow mosfets pass capacitive discharge without damage :-(
I hate burning mosfets.

Hi Boguslaw,

If I got your question correctly you mean you use MOSFETs as switches to discharge capacitors, right?
If yes, then you may wish to consider ALL the resistances and impedances that are included in the discharge circuit path. First thing is the capacitor itself you wish to discharge, see this link and in the Table you can see typical series resistance values for different electrolytic capacitor values and at different max working voltage ratings: Capacitance ESR typical values chart

Suppose you have a capacitor of 220uF. 250V DC rated and you have charged it up to ,say, 200V DC voltage. From the Table in the link
you can read 0.5 Ohm series resistance for a 250V rated 220uF capacitor.

Now you discharge this with a decent srewdriver, that surely has some milliOhm maximum resistance which is negligible with respect to the inner resistance of the 0.5 Ohm. What current is involved when you short this capacitor? Simply apply Ohm's law and you get 200V/0.5 Ohm = 400 Amper peak current.
And in case you happen to use a MOSFET switch that has an ON resistance under 1 Ohm (of course there are much lower values available) say you use a power FET with a 0.1 Ohm Drain-Source ON resistance, adding this to the 0.5 Ohm and using Ohm law again, you get 200V/0.6= 333.3 Amper.

Of course I do not know your actual circuit total inner resistances and impedances to figure out the actual peak current which however must have surely exceeded your MOSFET max allowed drain-source current ratings. Even if you use 20-30 Amper drain current rated MOSFETs, you may easily exceed that limit and the device fails.
So what you can do is study all the inner resistances and impedances of the components in advance which are in the path of the discharge current. Capacitors are very, very good voltage sources, due to their normally very low inner impedances, meaning huge current can flow out from them till the full discharge.
Another issue can be the drain source voltage rating of the MOSFET because in case there is an inductance in the discharge path, the switch-off spike may exceed its rating.

rgds, Gyula

boguslaw · #24 07-31-2012, 07:55 PM

Quote:

Originally Posted by gyula

Hi Boguslaw,

If I got your question correctly you mean you use MOSFETs as switches to discharge capacitors, right?
If yes, then you may wish to consider ALL the resistances and impedances that are included in the discharge circuit path. First thing is the capacitor itself you wish to discharge, see this link and in the Table you can see typical series resistance values for different electrolytic capacitor values and at different max working voltage ratings: Capacitance ESR typical values chart

Suppose you have a capacitor of 220uF. 250V DC rated and you have charged it up to ,say, 200V DC voltage. From the Table in the link
you can read 0.5 Ohm series resistance for a 250V rated 220uF capacitor.

Now you discharge this with a decent srewdriver, that surely has some milliOhm maximum resistance which is negligible with respect to the inner resistance of the 0.5 Ohm. What current is involved when you short this capacitor? Simply apply Ohm's law and you get 200V/0.5 Ohm = 400 Amper peak current.
And in case you happen to use a MOSFET switch that has an ON resistance under 1 Ohm (of course there are much lower values available) say you use a power FET with a 0.1 Ohm Drain-Source ON resistance, adding this to the 0.5 Ohm and using Ohm law again, you get 200V/0.6= 333.3 Amper.

Of course I do not know your actual circuit total inner resistances and impedances to figure out the actual peak current which however must have surely exceeded your MOSFET max allowed drain-source current ratings. Even if you use 20-30 Amper drain current rated MOSFETs, you may easily exceed that limit and the device fails.
So what you can do is study all the inner resistances and impedances of the components in advance which are in the path of the discharge current. Capacitors are very, very good voltage sources, due to their normally very low inner impedances, meaning huge current can flow out from them till the full discharge.
Another issue can be the drain source voltage rating of the MOSFET because in case there is an inductance in the discharge path, the switch-off spike may exceed its rating.

rgds, Gyula

I'm trying to discharge 8uF AC motor run capacitor to the low inductance coil like 6uH with low resistance (I have to measure it) with capacitor rated at 500V but charged to 430V max (from 290V to 430V depending on how it may charge)

gyula · #25 08-01-2012, 03:16 PM

Quote:

Originally Posted by boguslaw

I'm trying to discharge 8uF AC motor run capacitor to the low inductance coil like 6uH with low resistance (I have to measure it) with capacitor rated at 500V but charged to 430V max (from 290V to 430V depending on how it may charge)

Normally AC motor run capacitors are of much better quality than electrolytic caps so a 8uF 500V rated run cap can have a series resistance (ESR) even under 1 Ohm. Your 6uH coil's DC resistance is surely well under 1 Ohm, its inductive reactance may also be low, this depends on of course what frequency you use for discharging the 8uF cap (rate of discharge) but if it is in the some ten Hertz as the maximum (time is also needed for charging it up), then the 6uH represent just a fraction of an Ohm reactance. This may not be true when you have another coil mutually coupled to this 6uH of course (I mean transformed impedance from another coil the 6uH is coupled to) but you can figure out this for yourself knowing your own setup.
Let me assume 1 Ohm for the cap inner ESR and let me assume a worst case 1 Ohm reactance for the 6uH and let me assume a 1 Ohm drain-source ON resistance for your MOSFET switch and let me assume 290V in the capacitor, the discharge current in the moment of the switch-on is 290/(1+1+1) = 96.6 Amper, this immediately starts reducing as the stored energy in the cap is reducing of course. Question is what is the drain-source current rating for your MOSFET, is it able to cope with the near 100A peak current and if yes, then for how long time (consult data sheet, it normally includes SOA, the maximum Safe Operational Area figure for pulsed conditions too). IF your 8uF is charged up for 430V, then the discharge current in the very first moment is 430/3=143.3A!

Notice 1: my numbers above are assumptions of course but the 8uF capacitor's ESR is surely around 1 Ohm or lower, this could be known from the cap's data sheet if the type is a decent one, identifyable at all or could be measured by an ESR meter if available.

Notice 2: unfortunately, for best power MOSFETs in the 500V or higher drain-source voltage rated ranges they have at least 45-50 milliOhm ON resistance at 30 Amper drain current. See this data sheet for instance: http://www.st.com/internet/com/TECHN...CD00002391.pdf or see these here:
http://www.fairchildsemi.com/ds/FD/FDL100N50F.pdf and
http://ixapps.ixys.com/DataSheet/DS1...00N50Q3%29.pdf
(you can have them at Digikey).

Notice 3: Consider the 8uF cap as a voltage source, this has the assumed 1 Ohm inner ESR resistance, then comes in series with the ESR the assumed 1 Ohm coil impedance, then in series comes the FET 1 Ohm ON resistance, these form a voltage divider whereby the capacitor voltage is divided to 3 parts between these resistances or impedances and you may wish to use a FET with a few milliOhm ON resistance only (not the 50 milliOhm type) so that the huge current should not cause big unwanted power loss (the power loss I*I*Rds across the switch surely cannot reach the 6uH coil at all, it is a waste).

Hope this helps in some way.

rgds, Gyula

Ernst · #26 08-03-2012, 02:12 PM

Anyone interested in down scaling Wardenclyffe to something that could be used in our homes?

Let's first look at the full scale system.

What would have happened in Wardenclyffe?
- a 3 coil Tesla transformer creates a HF HV. The primairy and the shunt capacitor determine the main frequency.
- the spark gap fires at a different frequency which causes an amplitude modulation on this main frequency.
- the top load of this transformer (Tesla calls it 'the free system') consists of a vacuum bulb which has a small capacity resulting in very high voltages.
- this gives longitudinal electrical waves that can easily be picked up by another vacuum bulb
- this type of connection has a rectifying effect. Probably only a small effect but due to the very high voltages there will be a significant net result.
- because of this rectifying effect the modulated (spark gap) frequency becomes visible and can be used to bring a secondary system into resonance
- everything that happens in this secondary system has no consequence for the free system (because of the difference in frequency) so we can use this energy for free
- this energy is used to set an electrical charge in motion which is coming from the earth, going to the top of the tower and back again.
- this causes an electrical disturbance in the earths charge which can be picked up and used anywhere on earth

Extra note: There are unconfirmed (?) rumours that Tesla used a large amount of UV lights in this tower. I was thinking that if those were in some way linked to the spark gap and if they would have an effect on the amount of electricity radiated from the vacuum bulb that might strongly increase the rectifying effect.

Before we start down scaling, any comments on the full scale system as I have described it here?

Ernst.

GSM · #27 08-03-2012, 02:37 PM

Quote:

Originally Posted by Ernst

Extra note: There are unconfirmed (?) rumours that Tesla used a large amount of UV lights in this tower. I was thinking that if those were in some way linked to the spark gap and if they would have an effect on the amount of electricity radiated from the vacuum bulb that might strongly increase the rectifying effect.
Ernst.

Would the UV be from mercury arc rectifiers, or especial spark gaps.

UVC + metal (especially tin) = free electrons.

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Cheers ........ Graham.

Ernst · #28 08-04-2012, 12:27 AM

Quote:

Would the UV be from mercury arc rectifiers, or especial spark gaps.

I have been thinking about that too, but I have not found any confirmation in Tesla's own writings that he was using UV or an extra component not described in the 'rare notes'.
I would like to believe that the schematics in those notes are complete, but of course there is always a chance that while building this tower he thought up some further improvements.

Eric Dollard showed in his video that vacuum tubes (lights) radiate longitudinal electricity when subjected to RF HV. I was wondering would this effect be stronger when irradiated with UV(C)? And what if those vacuum tubes contained tin?
I would like to experiment with this a bit, but at this time I do not have the necessary equipment. Does anyone know about experiments in this area?

For our garage-Wardenclyffe however this is not a necessity because today we can use HV diodes to accomplish the same.
Yesterday I tested my magnetically quenched, pre-heated HF spark gap. Not as beautiful as some work that I have seen here, but it worked like a (bit violent

) dream.

Ernst.

dR-Green · #29 08-04-2012, 12:48 AM

May I suggest that you begin by taking on the Crystal Radio Initiative as set forth by Eric Dollard

Ernst · #30 08-04-2012, 03:36 AM

Quote:

May I suggest that you begin by taking on the Crystal Radio Initiative as set forth by Eric Dollard

You may

Thanks, dR-Green!
Do you have a link?

Ernst.

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