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Tesla Coil Practical Applications | Tesla FAQ No. 45 | Interesting Facts About Nikola Tesla
In operating various devices with his high-frequency power supply using only one connecting wire he realized the load can placed at some distance from the power supply and still function properly. This is what Tesla called the transmission of electrical energy through one wire without return. While a load connected to only one of the high-potential terminals does not form a closed circuit, “in the ordinary acceptance of the term” the circuit is closed in the sense that a return path is established back to the secondary by so called displacement currents. This return path is directly between the two metal plates. At greater distances the capacitive coupling to ground predominates at both the transmitter and the receiver ends of the circuit. Instead of using individual capacitor plates at the transmitting and receiving ends it is also possible to make the connection directly to ground, completing the circuit entirely through the earth. The accompanying illustration of a one-wire power transmission system is from Tesla's U.S. Patent No. 593,138 titled "Electrical Transformer," covering the Tesla coil resonance transformer.
http://www.andre-waser.ch/Publicatio...essSystems.pdf
This patent shows all characteristics of the high frequency circuits with high voltage and high currents as used by TESLA. In the following steps TESLA optimized the technology of generation and utilization of high frequency and high voltage apparatus, which he mostly applied to lighting systems with different kinds of bulbs. In the year 1897 he applied for three patents about the transmission of electrical energy. The first patent[23] he registered on March 20th about a high frequency transformer with high power capabilities. Besides a common ground connection this transmission method needs only one transmission wire.
The generator G supplies the primary of the flat coil C. This simplified diagram does not come very close to the real experimental setup[27]. Then as previously shown with the patent about the lighting system an intermediate step-up transformation with a spark gap and a high voltage transformer is necessary to achieve a resonant frequency of some million cycles per second. With some advantages it is also possible to use this step-up transformation after the flat secondary coil B. This flat coil TESLA[21] has extra patented because of its excellent performance with high voltage and high frequency signals. On one end the secondary B is connected to ground and on the other end to the transmission wire which is connected to a receiving device with a flat coil B‘ of a symmetrical form. With a step-down transformation with the coil C‘ the electrical energy is finally transmitted from the generator G to the load L with only one conducting wire.
Some months later TESLA[27] has shown that the transmission wire can be dropped completely and can be replaced by a glass tube filled with air of low pressure.
In figure 3 the arrangement of figure 2 can be found again. With this discovery of the good electrical conductivity of air of low pressure the path was free for further developments.
Then on September 1897 TESLA[24],[25] has filed two other patents for the transmission of electrical energy (figure 4). But the granting of this patent has been made dependent of the experimental success as a corresponding part in the patent shows (Pat. 645‘576, p. 3, col. 2). In this patents TESLA writes of a grounded high frequency emitter with a highly elevated ball electrode which was in resonant connection with a symmetrical, grounded resonant circuit (receiver) to enable the energy transmission through the upper atmosphere, which in great heights becomes more and more conductive for electrical currents.
The Electrical Review[24] of London published on May 1899 a summary of articles about the work of Nikola TESLA previously published by their New York colleges. Here TESLA stated that the air will have a sufficient conductivity for his experiments, if the ball electrodes are placed in a height of four miles (~6.5 km). This could probably be done by balloons, TESLA suggested.
The generator G supplies the primary of the flat coil C. This simplified diagram does not come very close to the real experimental setup[27]. Then as previously shown with the patent about the lighting system an intermediate step-up transformation with a spark gap and a high voltage transformer is necessary to achieve a resonant frequency of some million cycles per second. With some advantages it is also possible to use this step-up transformation after the flat secondary coil B. This flat coil TESLA[21] has extra patented because of its excellent performance with high voltage and high frequency signals. On one end the secondary B is connected to ground and on the other end to the transmission wire which is connected to a receiving device with a flat coil B‘ of a symmetrical form. With a step-down transformation with the coil C‘ the electrical energy is finally transmitted from the generator G to the load L with only one conducting wire.
Some months later TESLA[27] has shown that the transmission wire can be dropped completely and can be replaced by a glass tube filled with air of low pressure.
In figure 3 the arrangement of figure 2 can be found again. With this discovery of the good electrical conductivity of air of low pressure the path was free for further developments.
Then on September 1897 TESLA[24],[25] has filed two other patents for the transmission of electrical energy (figure 4). But the granting of this patent has been made dependent of the experimental success as a corresponding part in the patent shows (Pat. 645‘576, p. 3, col. 2). In this patents TESLA writes of a grounded high frequency emitter with a highly elevated ball electrode which was in resonant connection with a symmetrical, grounded resonant circuit (receiver) to enable the energy transmission through the upper atmosphere, which in great heights becomes more and more conductive for electrical currents.
The Electrical Review[24] of London published on May 1899 a summary of articles about the work of Nikola TESLA previously published by their New York colleges. Here TESLA stated that the air will have a sufficient conductivity for his experiments, if the ball electrodes are placed in a height of four miles (~6.5 km). This could probably be done by balloons, TESLA suggested.
So, Tesla first invented one-wire transmission, then he used a fluorescent as a wave-guide instead of a wire and so he concluded he could also use the upper atmosphere as a (conducting) wave guide when the spheres are lifted high up in the air using balloons.
In other words: these earlier systems he did not attempt to put the planet into resonance and basically used it as a very big capacitor. The key difference with the magnifying transmitter is that in these earlier developments, the earth connection is supposed to be "cold" and it's main function is to establish a reference point, therby forcing a voltage node (cold spot) at the earth connection of the resonating coil. And since voltage and current are out of phase, you would get a currrent antinode (hot spot) at the base of the coil, so there is some current going back/forth between the coil and the earth, both at the transmitter and the receiver coils.
Now if you would place transmitter and receiver very close to one another, you could actually use the current that normally goes trough the earth connections, if the chosen frequency and accompaning wave-length is such that along the whole path from transmitter coil trough wire and trough receiver coil you have a whole number of wavelengths.
And then you would not need the transformer of the receiver to get your hands on the power, and you wouldn't need any spheres for establishing a reference point, so you have cut these two parts out of the design and if they're no longer there, they can also no longer spray any of your precious energy into space!
And that already comes very close to what I intend to do. My idea is to go two steps further and 1. fold the whole thing into one coil and 2. replace the primary drive circuit by a circuit that drives the the coil itself directly, also with the idea of reducing components and thus "leaking/spraying" parts and reducing wave reflections and such because of wave interactions, reflections, etc. between primary/secondary.
The question remains then what the significance of a pancake coil and/or bifilar wound coils is and what the advantages are. I posted something about this earlier:
http://www.energeticforum.com/renewa...tml#post115004
http://www.energeticforum.com/renewa...tml#post115135
http://www.energeticforum.com/renewa...tml#post147380
With some editing from the latter page:
Let me also shine some light on the significance of the pancake coil. I added the following note to Eric's book on my wiki:
Tuks DrippingPedia : Theory Of Wireless Power
This refers to this document: http://www.tuks.nl/pdf/Reference_Mat...ity_Factor.pdf
This article shows that the velocity factor goes to zero when the h/d ratio goes to zero. This means that a pancake coil is the easiest coil design to drive into a higher order resonance mode because the waves propagate trough it at much lower speeds compared to when they would travel trough the air, hence you easily get long wavelengts. So, it has low resonance frequencies and is therefore easy to drive into higher order resonance, and that is most likely why Tesla liked it so much.
So far, so good.
Now in order to be able to pick up all that energy in the multiple dipoles a higher order resonance mode in a coil consists of, you have to find a way to pick up the energy of all these dipoles. In the case you choose for a transfomer, you do this trough a coupled coil, the primary. And that means first of all that is very important to match the resonance frequencies of the primaries and the secondaries in your coil. The natural resonance frequency of your primary (the outer winding) should be a multiple of the secondary one. They have to be matched to one another, IMHO, for maximum output, even though in practice that should not be too difficult, because the pancake coil as a pretty low resonance frequency.
So, the pancake coil, or better: pakcake transformer, is most suitable for picking up all the energy from in the large secondary, because all the windings as well as all the dipoles are in one plane, no matter how/where they are actually placed in 3D, even though I guess the wave pattern inside a pancake coil will look something like this:
For a long, single wound coils, things get very complicated if you want to operate it as a transformer. How do you match the primary and secondary windings such that you are able to pick up energy from all the dipoles your standing wave consists of???
However, if you just operate it as a single oscillating apparatus that you drive directly, as I intend to do, then you don't have to match primary and secondary and therefore can avoid the problems associated with that.
To sum this up: if your aim is to try and get a magnifying effect, I think pancake transformers would be most efficient in transformer mode (but are hard to "tap" and drive directly), while a single wound coil can likely be used efficiently in "direct drive" mode.
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