When people hear the name Nikola Tesla (1856-1943), they think of Tesla cars, Tesla coils, or electricity (assuming they have heard of him at all). Most of Tesla's inventions and patents (of which there are hundreds) are related to electricity, but several of his creations are not. In this gallery, we look at 30 of Tesla's patents. All patent images are courtesy of Tesla Universe.
This is one of the few non-electric patents by Tesla. Later in his life, he was very interested in aerial flight, especially helicopters. He went so far as to file a patent for an Apparatus for Aerial Transportation, which he termed a "helicopter-plane." In the application, he goes through all of the math on how a helicopter alights itself and attains flight and then dismisses the traditional helicopter as a waste of energy. He then proposes his device, which lifts like a helicopter and then rotates itself so the helicopter blades then become like the propeller of an airplane. During this time, the "wings" of the device (which were vertical when lifting off) become like the wings of an airplane (horizontal). His main proposition for this device was to do away with the need for runways, especially in areas where they are not as feasible.
Tesla did some very early work in Electric Circuit Controllers. In this first of two designs, he uses a rotating spindle that rapidly makes and breaks an electric circuit. He uses a liquid conductor and a solid conductor to achieve the circuit. This patent was the last in a series of patents based on this design.
Tesla's alternative design for an Electric Circuit Controller allows for the rotation of the spindle and the body of the device either in opposite directions or in the same direction at differing speeds as needed. This patent focuses on the technology behind that relative movement.
Electrical Condensers, now better known as capacitors, were another focus of Tesla's work. In this patent, Tesla uses alternating layers of conductor and insulator filled with saline to hold an electric charge.
Because electrical service to homes and business was a new idea in the late 1800s, there was a large body of work to be done on making it safe. Tesla helped by creating an Electrical Transformer, which was safer and had a higher energy potential (voltage).
Gasoline-powered engines were also very new in the late 1800s. In this patent for an Electrical Igniter for Gas Engines, Tesla proposes to use the piston of the engine as one terminal of an electric circuit and the base of the cylinder as the other. If enough charge is built up in the piston, the charge will jump to a point at the base of the cylinder causing a spark. This spark will ignite the gasoline.
Apparatus for Producing Currents of High Frequency
Most of us know that common alternating current (AC) electricity (the kind that comes into our homes and businesses) operates at a frequency of 60 Hz. Tesla's Apparatus for Producing Currents of High Frequency patent proposes one early method for converting the direct current (DC) electrical sources of the time into the now common AC.
Many gases, including ozone, are obtained by combining an ordinary gas (in this case, oxygen) with electricity. Tesla's Apparatus for Producing Ozone forces air between a pair of electrically charged plates that trigger the reaction.
In the late 1800s, many inventors were struggling to find a way to produce incandescent light. While Thomas Edison is credited with the invention of the incandescent light bulb, other inventors (including Tesla) were working on the same ideas. Tesla and others continued to work on refining the product, which led to a patent in 1894 for an Incandescent Electric Light by Tesla.
In the early 20th century, reading the frequency of an electric current of oscillation was a difficult task done with expensive and inaccurate equipment. Tesla's Frequency-Meter greatly increased the accuracy of these readings and also lowered the cost of the reading devices.
After electrical power began being delivered to homes and businesses, the electric industry needed a way to properly measure the amount of electricity that was being used. Tesla once again stepped up and created an Electrical Meter, which is composed of two carbon filaments inside of a glass vacuum tube. As an electric current passes from one filament to the other, tiny pieces of carbon also jump from one filament to the other. By measuring the resistance of each filament before and after, the amount of electricity used can be derived.
With his Lightning-Protector, Nikola Tesla attempted to improve upon the Lightning Rods originally created by Ben Franklin in the late 18th century. One fundamental flaw that he overcame was the fact that a lightning rod attracts more lightning than the building it was mounted upon. His design was to affix curved metal bars upon the vertical rod roughly in the shape of an umbrella.
Electric streetcars were a common sight in Tesla's day. One major flaw in cars' systems was the rolling or sliding contact that transferred electricity from the lines to the car. In his patent for an Electric Railway System, Tesla proposes a form of wireless power transmission that is underground. The power is conducted down a buried channel in which the streetcar's J-shaped lead passes to pick up and transfer the energy to the car.
Much earlier in his career, while he was yet a citizen of the Austria-Hungary Empire living in New York, Tesla did some work on Electro-Magnetic Motors. His invention was the ability to artificially cause a quarter-phase difference between two circuits using one motor.
Another machine that became common during Tesla's time was the Dynamo-Electric Machine. His patent for this type of device suggests alternating the poles of the surrounding magnets to reduce the need for a very long or a very large circumference cylinder or a very high speed rotation of the conductor.
A very early version of his models of transformers and inducers, this Electrical Transformer or Induction Device was primarily designed to improve the function of the motors he was creating at the time, such as those in the last two slides.
Method of Obtaining Direct from Alternating Currents
In the present day, we can convert AC power to DC power by going to the nearest store and picking up a universal adapter; in fact, most of the smaller devices we use -- from cell phones to laptops -- come with AC to DC converters. In Tesla's day, however, AC power was cheap to produce, but DC power was needed for most applications. With his Method of Obtaining Direct from Alternating Currents, Tesla proposed an efficient way of converting that power.
In an earlier patent, Tesla conceived of a method of combining multiple phases of electricity on a single transmission line. This probably led to what we commonly transmit: three-phase. In his patent for System of Electrical Power Transmission, he expands on that, creating a system of extracting those phases back out of the single transmission line and powering a multi-phase motor.