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Re: Is there an attraction force between two Tesla Coils?

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  • Saber
    Hi Bert Oh yeah, of course there are losses, imagine our world without losses :). But its so much easier to just calculate things first:) to get a picture.
    Message 1 of 65 , May 4 10:30 AM
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      Hi Bert


      Oh yeah, of course there are losses, imagine our world without losses :). But its so much easier to just calculate things first:) to get a picture.

      Everything discussed this far, I understood
      Ok, Everything we have said now so far is just like I understood, which unfortunately mean that I don't understand how that "little thing of the top capacitor" works in a T.C. That little question is simple but seems quiet hard to explain: As we said, the top capacitance reaches both peak- charge and -voltage twice every cycle and therefore the cap gets discharged also twice a cycle. I know that the energy get dumped from the secondary into the top capacitor. What I wonder at the end is just how can the top capacitance charge very fast, twice a cycle of 200khz with an overall original input of a small power of NST with maybe 2 kw.
      My wondering has to do with how fast you can charge a capacitor really.

      PSUpower increases with faster voltage-rate-of-change
      You know that the rate at which you can charge any capacitor depends on the input current of the power supply and that power supply must supply that current at that voltage desired to be reached by the capacitor. So for instance lets look at connecting any HF power supply with a cap first:
      if you would like to charge a 5uF 15kv cap at 60hz you need a certain current input at 15kv out of a PSU. If you want to charge a larger 10uf 15kv cap you need to have a higher current input at 15kv out of the PSU. Now, If you want to charge and discharge that 5uf 15kv cap now at faster , say 100hz rate(let alone 200khz), you are going to need a much bigger current input at 15kv (and thus input power) out of the supply to be able to charge and discharge fast enough. Do you see perhaps where I am going?


      Calculation of PSU requirement for the primary cap
      If I look at the primary capacitor we know that the capacitors size get chosen depending on the power supply´s voltage, current and frequency really... a high NST current will allow for a bigger capacitor that can charge and discharge even more charge(q) or a smaller capacitor to charge at a faster rate if the power source of course provides the rate. Let us see a common example in the primary circuit of the TCs itself, because here everything goes hand in hand and is fully understood by me because power input agrees with the power of the capacitor:
      Lets see what capacitor size we can use with a NST 20kv, 100mA, 50hz AC (2 KW)

      Z=E/I = 200000
      Capacitance=1/(6.2832xZx0.00005) = 0.016uF

      0.016mF is thus the maximum cap size you can feed at 50 cycles rate if you have an input of 100mA from that power supply. But Lets see what capacitor size you can use if you want to feed it at a higher 60hz rate but with the same total power input i.e. an identical power PSU at 20kv, 100ma but 60hz. Capacitance=1/(6.2832xZx0.00006) = 0.013uF. Clearly the higher rate of change required, the smaller a capacitor you can use for the same input power. If you want to keep the same size of cap and same frequency you need to increase power or current of PSU.

      Calculation of PSU-requirement for secondary cap.

      So this far the primary cap is fine and completely understood by me. Now lets go back to the secondary capacitor that "doesnt make sense" to me. The typical top capacitor has a capacitance of around 20pf and 400kv voltage and works at 200khz rate. Using the above equation for power needed to feed a capacitor we can solve the power for the top capacitor:

      Z=E/I
      0.00002=1/(6.2832xZx0.2)
      (1.256xZ)=50000
      Z=50000/1.256
      Z=39800
      I=E/Z =400000/39800= 10A
      Power of PSU required to charge 400kv 20pf cap at 200khz thus is = 400000x10= 4 million watts!

      It is all about power in vs power out, right?. In the primary capacitor's case everything makes sense as value of that capacitor is in good agreement with the power of the mother PSU as seen from the equation. BUT when you plug in the top-capacitor's capacitance, voltage and frequency, the equation indicates that the PSU power that is needed to do the work of the secondary capacitor is
      4 million watts! Of course something is wrong... but I am looking Where?

      You are really kind, and I really apology for being and sounding like that way I do, it is just I am looking for where I fail to understand that particular part of the circuit.

      Regards
      leviterande
      Karl
    • Saber
      Berts explanation was the closest thing to the truth I believe. How? I eliminated arcs by connecting a thin insulated wire to the dome going out around it
      Message 65 of 65 , Aug 22, 2013
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        Berts explanation was the closest thing to the truth I believe. How? I eliminated arcs by connecting a thin insulated wire to the dome going out around it while the other end is connected to a bare conductor/insulated/various shapes very close to the dome itself, I tried also two parallel conductors sitting on the top of the dome insulated and not insulated with these setups arcing is now gone and thus the attractive force is gone or almost too so this at least confirmed Bert´s explanation regarding "arcing", still though there is so many variables to find out, the two sides of the situation are:

        1-Touching conductor:is there still a force? what "direction"? what magnitude, apparently if there is any force it is very small or non existent in the case of veritably touching conductors.

        2-Isolated conductor: grounded or ungrounded arcing is very wild and attraction only happens when there is attraction. I put the whole setup arrangement in high dielectric breakdown oil, turned up the BPS to the maximum 1600bps and brought together the two 0.1mm pvc covered conductors(one connected to the dome and the other is grounded). No oil-arcs occurred so the insulation is very good. Also no attraction force at all. Oil is the only thing that can hold against the arcs from my testing.

        I will do more tests. a very strong but low dense dielectric is highly preferred I guess or otherwise any small forces wont push the thick oil.

        --- In usa-tesla@yahoogroups.com, "McGalliard, Frederick B" <frederick.b.mcgalliard@...> wrote:
        >
        > Has to do with local vs long range. The grounded plate is grounded through a long wire or some such and this has an inductance and a resonance. At 286kHz the voltage on the grounded plate is likely following (in opposite charge) the top load pretty closely. There should be an attraction because of this charge, and when the plate is in contact with the top load, the same effect observed in the ancient gold leaf electroscope should tend to push it away. That this is not easily measured is a bit surprising to me. That the spark causes a much larger attraction is also a bit surprising. I would have imagined a tube of hot air with a lot of current rushing back and forth through it (the spark itself) especially under the pressure of the pinch effects, would produce a thrust away. That you do not see a spark coming from the plate in contact with the top load does not mean that there is not a lot of ion wind holding it in place. I wonder if there are some cute experiments we could design to separate effects? You might try placing your top load and plate in a vacuum to reduce or remove the atmosphere and it's very confusing effects. Hard to design something that is all that easy to set up though. Could we put the plate inside the vacuum and not the top load? Or perhaps just connect the top load to a flat disk inside the vacuum chamber?
        >
        > From: usa-tesla@yahoogroups.com [mailto:usa-tesla@yahoogroups.com] On Behalf Of Saber
        > Sent: Tuesday, August 20, 2013 3:55 PM
        > To: usa-tesla@yahoogroups.com
        > Subject: [usa-tesla] Re: on the subject of attraction, no attraction detected?
        >
        >
        >
        > This is getting interesting
        >
        > Freddy, 286khz is the frequency used yeah compared to mhz its slow, Bert...hmm your latest post is neat. I got to read it multiple times to try and grasp it, you are not writing about any lagging problems here I assume? I tried both aluminum and insulated aluminum. Both start to attract only when there is an arc. And there was no corona on the other side of the foil. The naked aluminum sheet is perfectly absolutely stationary until a spark jumps where the aluminum gets attracted /sucked closer by the topload until space between dome and the foil ceases and arcing ceases. the isolated conductor is still attracted and is basically a part of the dome where it is like "glued" to the dome without any sparks . So the attraction phenomena seemingly exists without arcing at all as long as the conductors are touching?
        >
        > karl
        > --- In usa-tesla@yahoogroups.com<mailto:usa-tesla%40yahoogroups.com>, Bert Hickman <bert.hickman@<mailto:bert.hickman@>> wrote:
        > >
        > > Hi Karl,
        > >
        > > Hmmm... got it. The following is an educated guess for an isolated
        > > conductor that is within sparking distance of the topload:
        > >
        > > An isolated conductive object has a small isotropic capacitance (or
        > > self-capacitance - typically pF level). If placed close enough to the
        > > topload, a streamer or small spark will jump to it. The spark (or
        > > streamers) transfer a batch of charge to the object that is sufficient
        > > to quickly raise the object to the topload's potential (at that
        > > instant). However, the topload's potential is continually changing
        > > during ring-up or ring-down on a TC. As the topload potential continues
        > > to rise toward the peak value during during a given sinusoid, sparking
        > > and charge transfer can repeat many times until the peak TC output
        > > voltage peak is reached and the object also retains a similar potential.
        > >
        > > As the topload's voltage heads back towards zero, a similar process
        > > occurs, but now charge is incrementally removed (spark by spark) from
        > > the nearby object. The force between the topload and object is
        > > predominantly attractive independent of whether the topload potential is
        > > climbing or declining - the output voltage merely needs to be rapidly
        > > changing so that there is significant potential difference between the
        > > object and topload.
        > >
        > > Bert
        > >
        > > Saber wrote:
        > > > Thank you Bert!
        > > >
        > > > I suspect though that we now are not on the same train track here :)!
        > > > In my last post I was referring to charging by contact instead of
        > > > charging by induction. If I put it simply , what I strangely have
        > > > seen and tested is that grounded or ungrounded conductors become
        > > > attracted to the topload ONLY when they both arc or touch.
        > > >
        > > > So as I approach the conductor towards the topload nothing
        > > > happens(even at very close distances if I insulate the conductor)
        > > > until there is arcing. Only When it arcs, the conductor suddenly gets
        > > > strongly attracted more and more and stays attracted and attached to
        > > > the dome as long there is arcing, when the foil finally is touching
        > > > the dome itself and the arcing stops, the alu foil and the dome
        > > > become one and stay "glued"/attached/attracted to each other!. If I
        > > > had a powerful enough TC I would be able to flip the topload upside
        > > > down with and the aluminum foil would be "glued to it" My question is
        > > > just how is this mechanism working, it is quite interesting. HF AC
        > > > seemingly attracts everything in "TOUCH", unless I am doing something
        > > > horribly wrong here? ha? :)
        > > >
        > > > Really appreciating you taking your time Thanks Karl
        > > >
        > > > --- In usa-tesla@yahoogroups.com<mailto:usa-tesla%40yahoogroups.com>
        > > > <mailto:usa-tesla%40yahoogroups.com>, Bert Hickman <bert.hickman@>
        > > > wrote:
        > > >>
        > > >> Hi Karl,
        > > >>
        > > >> I suspect that the reason why grounded conductive objects become
        > > >> strongly attracted is because the E-field is quite strong at
        > > >> streamer tips (i.e., the fine, hairlike, almost invisible
        > > >> electrical discharges at the ends of unterminated air discharges).
        > > >> The E-field is typically strong enough (>26 kV/cm for RF
        > > >> discharges) to ionize the air around the _grounded_object_,
        > > >> resulting in the development of new streamers that head inward
        > > >> towards, trying to reach outgoing streamers coming from the
        > > >> topload.
        > > >>
        > > >> Once the attracted object begins moving closer to the topload, the
        > > >> local E-field (and attractive force) becomes further enhanced,
        > > >> increasing the object's velocity until a complete electrical
        > > >> discharge bridges the gap. Since the TC output waveform is
        > > >> oscillatory, streamers are extinguished on each voltage zero
        > > >> crossing, and the E-field (and attractive force) is re-established
        > > >> on the subsequent rising portion of each RF half sinusoid. The
        > > >> attractive force virtually disappears once a spark reignites the
        > > >> gap since the low impedance spark rapidly discharges the topload,
        > > >> collapsing the driving voltage and E-field in the gap.
        > > >>
        > > >> With a small ungrounded conductive object, the attractive force
        > > >> will be much less since it is stems from electrostatic induction
        > > >> (the relatively small charge differential between the side facing
        > > >> the topload and the opposite side). The force on the inward-facing
        > > >> side is almost cancelled by opposing force from counterpart charges
        > > >> on the outward-facing side.
        > > >>
        > > >> Bert -- Bert Hickman Stoneridge Engineering
        > > >> http://www.capturedlightning.com
        > > >> ***********************************************************************
        > > >
        > > >>
        > > > World's source for "Captured Lightning" Lichtenberg Figure
        > > > sculptures,
        > > >> magnetically "shrunken" coins, and scarce/out of print technical
        > > >> books
        > > >> ***********************************************************************
        > > >
        > > >>
        > > >
        > > >> Saber wrote:
        > > >>> Bert, that strong dielectics might reduce the attraction force
        > > >>> for the reasons you mentioned make sens, the attraction of NON
        > > >>> touching conductors towards a TC dome has though yet to be seen
        > > >>> by me il have perhaps to build a more powerful coil:)
        > > >>>
        > > >>> However, Bert, if the speed of light lag in the AC reversals
        > > >>> doesnt play a roll at all, how come that any object touching the
        > > >>> TC dome by conduction, arcing or streaming will indeed get
        > > >>> violently attracted. So when a piece of metal become one part of
        > > >>> a TC dome by touching it doesnt stay, it doesnt repell, it is
        > > >>> actually attracted, how?
        > > >>>
        > > >>> Regards karl --- In usa-tesla@yahoogroups.com<mailto:usa-tesla%40yahoogroups.com>
        > > > <mailto:usa-tesla%40yahoogroups.com>
        > > >>> <mailto:usa-tesla%40yahoogroups.com>, Bert Hickman
        > > >>> <bert.hickman@> wrote:
        > > >>>>
        > > >>>> Hi Karl,
        > > >>>>
        > > >>>> The changing E-field (between the topload and its
        > > >>>> surroundings) propagates at the speed of light. Electrons in
        > > >>>> within any nearby bodies "feel" this field and respond by
        > > >>>> attempting to move towards or away from the topload depending
        > > >>>> on its instantaneous electrical polarity. In objects that are
        > > >>>> good conductors, electrons accumulate at either the side facing
        > > >>>> the topload or the opposite side. This process occurs almost at
        > > >>>> the speed of light, so there will be virtually no perceptible
        > > >>>> lag in the E-field (and the resulting attractive force) between
        > > >>>> the toroid and conductive object. However, the total force will
        > > >>>> be much greater if the object is grounded.
        > > >>>>
        > > >>>> In an object that is a good electrical insulator the situation
        > > >>>> is considerably more complex since electrons are not able to
        > > >>>> freely move between the atoms/molecules of the object. However,
        > > >>>> the electrons still respond to the E-field by altering their
        > > >>>> average equilibrium positions relative to nearby nuclei
        > > >>>> (electronic polarization). Some materials also have ionic polar
        > > >>>> molecules that may stretch or rotate to become better aligned
        > > >>>> to the applied E-field (ionic and dipolar polarization
        > > >>>> effects). The resulting combination of changes within the
        > > >>>> dielectric ("polarization") counteracts the applied E-field,
        > > >>>> reducing the average electrical field inside the dielectric and
        > > >>>> altering the shape of the electrical field surrounding it.
        > > >>>>
        > > >>>> However, unlike the almost-instantaneous response to external
        > > >>>> fields in metals, some polarization processes can take a
        > > >>>> relatively long time to reach a equilibrium in respond to a
        > > >>>> changed external E-field. The overall time-repose of the
        > > >>>> dielectric to the external E-field ("dielectric dispersion") is
        > > >>>> often a complex combination of electronic, ionic, and dipolar
        > > >>>> polarizations across several time-scales. For polar materials
        > > >>>> in particular, the time lag for dipolar polarization may be
        > > >>>> significant even at Tesla Coil frequencies. This might reduce
        > > >>>> the observed attractive effect in polar dielectric materials.
        > > >>>>
        > > >>>> Bert -- Bert Hickman Stoneridge Engineering
        > > >>>> http://www.capturedlightning.com
        > > >>>>
        > > > ***********************************************************************
        > > >
        > > >
        > > >>
        > > >>>>
        > > >>> World's source for "Captured Lightning" Lichtenberg Figure
        > > >>> sculptures,
        > > >>>> magnetically "shrunken" coins, and scarce/out of print
        > > >>>> technical books
        > > >>>>
        > > > ***********************************************************************
        > > >
        > > >
        > > >>
        > > >>>>
        > > >>>
        > > >>>> Saber wrote:
        > > >>>>> Bert, I am wondering if what I have written here below could
        > > >>>>> be explanation why there is no attraction(assuming there is
        > > >>>>> truly no attraction net force at all in the first place, by
        > > >>>>> no means am I
        > > >>> right) :
        > > >>>>>
        > > >>>>> Possible Reason for no attraction There is a time lag
        > > >>>>> between when the top load gets positive and the nearby
        > > >>>>> objects get polarized. i.e. in HF AC source all nearby
        > > >>>>> objects will for sure alternately be polarized accordingly
        > > >>>>> but not
        > > >>> instantly but
        > > >>>>> actually lagging after the "mother signal charge of top
        > > >>>>> load" With this being said there would be no attraction force
        > > >>>>> since as you can see it would be almost totally cancelled
        > > >>>>> this way. This seems a logical explanation if it turns out
        > > >>>>> there is truly no attraction force. So Is this lag scenario
        > > >>>>> completely wrong and non existent? after all.. light speed is
        > > >>>>> not instant
        > > >>>>>
        > > >>>>> Thank you Kind Regards karl
        > > >>>>>
        > > >>>> <snip>
        > > >>>>
        > > >>>
        > >
        >
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