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SPECIFICATION forming part of Letters Patent No. 512,340, dated January 9, 1894.

Application filed July 7, 1893. Serial No. 479,804. (No model.)

To all whom it may concern:

Be it known that I, NIKOLA TESLA, a citizen of the United States, residing at New York, in the county and State of New York, have invented certain new and useful Improvements in Coils for Electro-Magnets and other Apparatus, of which the following is a specification, reference being had to the drawings accompanying and forming a part of the same.

In electric apparatus or systems in which alternating currents are employed the self-induction of the coils or conductors may, and, in fact, in many cases does operate disadvantageously by giving rise to false currents which often reduce what is known as the commercial efficiency of the apparatus composing the system or operate detrimentally in other respects. The effects of self-induction, above referred to, are known to be neutralized by proportioning to a proper degree the capacity of the circuit with relation to the self-induction and frequency of the currents. This has been accomplished heretofore by the use of condensers constructed and applied as separate instruments.

My present invention has for its object to avoid the employment of condensers which are expensive, cumbersome and difficult to maintain in perfect condition, and to so construct the coils themselves as to accomplish the same ultimate object.

I would here state that by the term coils I desire to include generally helices, solenoids, or, in fact, any conductor the different parts of which by the requirements of its application or use are brought into such relations with each other as to materially increase the self-induction.

I have found that in every coil there exists a certain relation between its self-induction and capacity that permits a current of given frequency and potential to pass through it with no other opposition than that of ohmic resistance, or, in other words, as though it possessed no self-induction. This is due to the mutual relations existing between the special character of the current and the self-induction and capacity of the coil, the latter quantity being just capable of neutralizing the self-induction for that frequency. It is well-known that the higher the frequency or potential difference of the current the smaller the capacity required to counteract the self-induction; hence, in any coil, however small the capacity, it may be sufficient for the purpose stated if the proper conditions in other respects be secured. In the ordinary coils the difference of potential between adjacent turns or spires is very small, so that while they are in a sense condensers, they possess but very small capacity and the relations between the two quantities, self-induction and capacity, are not such as under any ordinary conditions satisfy the requirements herein contemplated, because the capacity relatively to the self-induction is very small.

In order to attain my object and to properly increase the capacity of any given coil, I wind it in such way as to secure a greater difference of potential between its adjacent turns or convolutions, and since the energy stored in the coil—considering the latter as a condenser, is proportionate to the square of the potential difference between its adjacent convolutions, it is evident that I may in this way secure by a proper disposition of these convolutions a greatly increased capacity for a given increase in potential difference between the turns.

I have illustrated diagrammatically in the accompanying drawings the general nature of the plan which I adopt for carrying out this invention.

Figure 1 is a diagram of a coil wound in the ordinary manner. Fig. 2 is a diagram of a winding designed to secure the objects of my invention.

Let A, Fig. 1, designate any given coil the spires or convolutions of which are wound upon and insulated from each other. Let it be assumed that the terminals of this coil show a potential difference of one hundred volts, and that there are one thousand convolutions; then considering any two contiguous points on adjacent convolutions let it be assumed that there will exist between them a potential difference of one-tenth of a volt. If now, as shown in Fig. 2, a conductor B be wound parallel with the conductor A and insulated from it, and the end of A be connected with the starting point of B, the aggregate length of the two conductors being such that the assumed number of convolutions or turns is the same, viz., one thousand, then the potential difference between any two adjacent points in A and B will be fifty volts, and as the capacity effect is proportionate to the square of this difference, the energy stored in the coil as a whole will now be two hundred and fifty thousand as great. Following out this principle, I may wind any given coil either in whole or in part, not only in the specific manner herein illustrated, but in a great variety of ways, well-known in the art, so as to secure between adjacent convolutions such potential difference as will give the proper capacity to neutralize the self-induction for any given current that may be employed. Capacity secured in this particular way possesses an additional advantage in that it is evenly distributed, a consideration of the greatest importance in many cases, and the results, both as to efficiency and economy, are the more readily and easily obtained as the size of the coils, the potential difference, or frequency of the currents are increased.

Coils composed of independent strands or conductors wound side by side and connected in series are not in themselves new, and I do not regard a more detailed description of the same necessary. But heretofore, so far as I am aware, the objects in view have been essentially different from mine, and the results which I obtain even if an incident to such forms of winding have not been appreciated or taken advantage of.

In carrying out my invention it is to be observed that certain facts are well understood by those skilled in the art, viz.: the relations of capacity, self-induction, and the frequency and potential difference of the current. What capacity, therefore, in any given case it is desirable to obtain and what special winding will secure it, are readily determinable from the other factors which are known.

What I claim as my invention is—

1. A coil for electric apparatus the adjacent convolutions of which form parts of the circuit between which there exists a potential difference sufficient to secure in the coil a capacity capable of neutralizing its self-induction, as hereinbefore described.

2. A coil composed of contiguous or adjacent insulated conductors electrically connected in series and having a potential difference of such value as to give to the coil as a whole, a capacity sufficient to neutralize its self-induction, as set forth.





Comments (2)

Steven Sullivan's picture

Self-inductance acts to counter the flow of electrons within copper coils wherein each layer of a coil is inducing a voltage from the magnetic flux field of of each layer such as to oppose the flow of electrons in the other layers. The ability to eliminate this opposition an develop an adding effect can yield a negative resistance and thus creates a cooling effect. So a positive current does not create waste heat or traditional I2R losses the current flow due to the negative resistance creates a cooling effect. Thus achieving room temperature super conductivity by converting a countering effect of inductance into an adding effect.

BMan18's picture

Tesla was an Aether scientist. It is interesting to note that his patent is spun in the language of current academia, but is referring to Aetheric effects. There is no mention of magnetic effects because they are an artificial construct designed to mislead one from realizing what this means.

Properly tuned, an inductor will conduct the square of its normal current load based on the voltage of the coil. Think of capacity as the magnetic field that couples into a moving charge field, or voltage (EMF) of the conductor. This should tell you that when a solid ferromagnetic core amplifies the strength of a coil 1,000x it is simply increasing the capacity of the coil. When a transformer uses these cores to transform, it is simply conducting this amplified capacity without charge. This view should inspire new designs in transformers. Thane C. Heins recently patented a BiTT transformer that routes the returning capacity in the core away from the input coil and boostes output of a BiTT transformer up to 4x the input (lots of room for improvement on this).

According to Tesla's description, a bifilar winding tuned to the frequency of the signal would contain all the capacity of the output in the coil and not send anything back to the core. It also would be capable of capturing all 1,000 x amplification, in fact which is only a fraction of the 250,000 x amplification he calculates in his example. Is it any wonder he switched to air core transformers?

But there's more. Thane also tried to patent a motor with a bifilar winding inspired by this patent. It was denied. He found a motor under load could generate electricity and also assist in the power that drives the motor. His application was to bifilar wind an electric car motor and use the circuit that captures electricity when the motor is used to brake the car, as the car is accelerating. His winding wasn't tuned, it simply had more capacitance than inductance, which is easy since as Tesla point's out it increases with a square of the potential. One could get pretty clever with this and design windings that are self powered, or easily make motors that power generators that collectively produce more power than required to drive a motor. TC claims he can produce a self-charging car.

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