Tesla Coil

Next week, after waiting 69 years I am finally going to build my first Tesla Coil. I guess it is better late than never. I spent the last several years studying Tesla and personally believe that most of Tesla's inventions were so far advanced that there was very few scientists in his day could grasp the magnitude of his inventions.

Now don't get me wrong. I personally have a hard time understanding the magnitude of most if not all of his inventions, but I believe that with today's technology I will be able to duplicate his coil for my own free energy project that I have been designing. My free energy device is based on the operation of the Tesla coil.

With my limited electrical engineering knowledge, I decided to call on Wikipedia's description of the tesla coil to make sure that you the readers get all the correct information, not just my own personal theories.

Wikipedia describes the Tesla coil as follows:


"A Tesla coil is an electrical resonant transformer circuit invented by Nicola Tesla around 1891. It is used to produce high-voltage, low-current, high frequency alternating-current electricity.
Tesla coils produce higher current than the other source of high-voltage discharges, electrostatic machines. Tesla experimented with a number of different configurations and they consist of two, or sometimes three, coupled resonant electric circuits.
Tesla used these coils to conduct innovative experiments in the transmission of electrical energy with out wires. Tesla coil circuits were used commercially in spark gap radio transmitters for for wireless telegraphy until the 1920s. Today the tesla coils main use is for entertainment and educational displays.

 How does it work?

 The Tesla coil transformer employes a capacitor which, upon break-down of a short spark gap, became connected to a coil of a few turns (the primary winding), forming a resonant circuit with the frequency of oscillation, usually 20 .. 100 kHz, determined by the capacitance of the capacitor and the inductance of the coil. The capacitor was charged to the voltage necessary to rupture the air of the gap, about 10 kV by a line-powered transformer connected across the gap. The line transformer could tolerate the short circuit occurring while the gap remained ionized, or for the few millisecond until the high frequency current had died away. A more prominent secondary winding, with vastly more turns of thinner wire than the primary, was positioned to intercept some of the magnetic field of the primary.


Modern day Tesla coils

Modern high-voltage enthusiasts usually build Tesla coils that are similar to some of Tesla's "later" air core designs. These typically consist of a primary tank coil, a series LC (inductance capacitance) circuit composed of a high-voltage capacitor, spark gap and primary coil, and the secondary LC circuit, a series resonant circuit consisting of the secondary coil plus a terminal capacitance or "top load." In Tesla's more advanced design, the secondary LC circuit is composed of an air-core transformer secondary coil placed in series with a helical resonator. Most modern coils use only a single helical coil comprising both the secondary and primary resonator. The helical coil is then connected to the terminal, which forms one 'plate' of a capacitor, the other 'plate' being the Earth (or "ground"). The primary LC circuit is tuned so that it resonates at the same frequency as the secondary LC circuit. The primary and secondary coils are magnetically coupled, creating a dual-tuned resonant air-core transformer. Earlier oil insulated Tesla coils needed large and long insulators at their high-voltage terminals to prevent discharge in air. Later version Tesla coils spread their electric fields over large distances to prevent high electrical stresses in the first place, thereby allowing operation in free air.
Most modern Tesla coils use simple toroids, typically fabricated from spun metal or flexible aluminum ducting, to control the high electrical field near the top of the secondary and to direct spark outward and away from the primary and secondary windings.
More advanced Tesla coil transmitters involve a more tightly coupled air core resonance transformer network or "master oscillator" the output of which is then fed to another resonator, sometimes called the "extra coil." The principle is that energy accumulates in the extra coil and the role of transformer secondary is played by the separate master oscillator secondary; the roles are not shared by a single secondary. In some modern three-coil Magnifying transmitter systems the extra coil is placed some distance from the transformer. Direct magnetic coupling to the upper secondary is not desirable, since the third coil is designed to be driven by injecting RF current directly into the bottom end.
This particular Tesla coil configuration consists of a secondary coil in close inductive relation with a primary, and one end of which is connected to a ground-plate, while its other end is led through a separate self-induction coil (whose connection should always be made at, or near, the geometrical center of that coil's circular aspect, in order to secure a symmetrical distribution of the current), and of a metallic cylinder carrying the current to the terminal. The primary coil may be excited by any desired source of high frequency current. The important requirement is that the primary and secondary sides must be tuned to the same resonant frequency to allow efficient transfer of energy between the primary and secondary resonant circuits. The conductor of the shaft to the terminal (top load) is in the form of a cylinder with smooth surface of a radius much larger than that of the spherical metal plates, and widens out at the bottom into a hood (which is slotted to avoid loss by eddy currents). The secondary coil is wound on a drum of insulating material, with its turns close together. When the effect of the small radius of curvature of the wire itself is overcome, the lower secondary coil behaves as a conductor of large radius of curvature, corresponding to that of the drum. The top of the extra coil may be extended up to the terminal U.S. Patent 1, 119,732 and the bottom should be somewhat below the uppermost turn of the primary coil. This lessens the tendency of the charge to break out from the wire connecting both and to pass along the support."

 You can read the complete description on Wikipedia.

The above description of how the tesla coil works is more complete than anything that I could tell you, but the key to this whole tesla coil in layman's terms as I personally see it is that it is simply a high voltage air core transformer. I know I will probably get a lot of feedback over that statement.

I want it to be put on record that I am not doing this project to scare the children on Halloween. If I was to create high voltage discharges like in the photographs above I would be the one who was scared.

In future blogs I will be giving step by step instructions on how to build your own tesla coil along with some great ideas on what you could do with it when it is completed.

I am pleased to announce that the next blog will be written by Mr. Matt Orr the owner of a small Solar Energy business in Vulcan Alberta. Matt will be explaining his views on the problems that are facing Solar Energy in his area of Canada.

Stay tuned for tomorrows blog it should be exciting.