Physics School

Nikola Tesla Biography and Scientific Work

Nikola Tesla Biography

Nikola Tesla is an inventor and electrical engineer known for discovering the rotating magnetic field and inventing the alternating current (AC) induction motor and the Tesla coil.

He was named as the Father of Alternating Current. The International System of Units unit for magnetic flux density measurements, Tesla, in electromagnetism is named after his honor. Nikola Tesla is instrumental in the development of utilizing AC power in power plants and transmission lines today.

Where and when was Nikola Tesla born?

Nikola Tesla was born in Smiljan, Lika, Croatia on July 10, 1856 as the fourth child of his Serbian parents. His father, Milutin Tesla, was a Serbian Orthodox Church priest. His mother, ?uka Tesla, was Serbian Orthodox priest daughter who made home craft tools.
He first attended school in Karlovac. In 1875, he entered the Austrian Polytechnic in Graz, Austria as an electrical engineering student and studied physics and mathematics. He became interested with the idea of electric motors running on a current that is better than direct current while he was studying in Graz and this became his obsession. He also entered the University of Prague to study philosophy.

Nikola Tesla's Working Life

In 1880, Nikola Tesla worked as an electrical engineer in the American Telegraph Company in Budapest, Hungary. He was promoted to the post of chief electrician of the American Telegraph Company in 1881. He was also the engineer of Hungary's first telephone system. In the year 1882, he worked for Continental Edison Company in Paris, France as an engineer. In 1883, he worked in Strassburg to repair an electrical plant.

Nikola Tesla in America

In 1884, Nikola Tesla arrived in New York to work for Thomas Edison at the New York Branch of the Edison Company through a recommendation from a former employer of the company, Charles Batchelor.

Nikola Tesla and Thomas Edison had disagreements with AC current over DC current and this was referred to as the war of the currents. Tesla was in favor of the uses of the alternating current while Edison was an advocate of using DC current in power transmission systems. Nikola Tesla left Edison’s company and he looked for other jobs while working on his own AC polyphase system. In 1887, the Western Union Telegraph Company helped him start a business and he was able to design and produce motors, transformers, and generators.

Nikola Tesla Picture

Nikola Tesla

Nikola Tesla and the AC Induction Motor

In 1888, Nikola Tesla discovered that two coils perpendicular to each other can rotate a magnetic field if the coils are supplied with 90 degrees out of phase AC current and this discovery eventually led him to patent his polyphase system, AC induction motor and other devices. In the same year, he presented his paper entitled “A New System of Alternating Current Motors and Transformers” to the American Institute of Electrical Engineers and impressed George Westinghouse of the Westinghouse Electric Company in Pittsburgh.

His patent rights were bought by George Westinghouse who built transmission lines and power plants out of Tesla’s system and control the hydroelectric plant in Niagara Falls.

In 1891, Nikola Tesla became a United States naturalized citizen. In the same year, he invented the Tesla coil which is widely used in radio communications. In 1893, he demonstrated AC power to the World’s Columbian Exposition in Chicago. In 1913, he patented his invention of a turbine known as the Tesla turbine today.

Nikola Tesla died of heart failure on January 7, 1943 in New York City leaving the world his great inventions and works.

Scientific Work of Nikola Tesla

The AC motors used in electrical power systems are mostly induction motors. Nikola Tesla invented the AC induction motor after first discovering the principle of rotating magnetic field.

The principle of rotating magnetic field is basically shown when two coils of wire perpendicular to each other can rotate a magnetic field if the coils are supplied with 90 degrees out of phase AC current.

The  Two-phase Induction Motor

Nikola Tesla’s two-phase induction motor consists of two sets of wire coils surrounding the core of a motor. The two sets of coils are perpendicular to each other. The coils act as electromagnets when alternating current passes through them. The polarity of the coil electromagnets changes when the direction of the current flow reverses. The current that passes through the first coil creates a magnetic field around the coil and this causes the coil to turn. When the direction of the current flow that passes through the first coil reverses, a magnetic field is produced around the second coil. This process produces a rotating magnetic field. This theory of operation of a rotating magnetic field makes up the induction motor with only the rotor moving.

The Tesla Coil

The Tesla coil, which is also one of Nikola Tesla’s inventions, is instrumental in developing wireless communication especially in radio communications. The Tesla coil is a type of an air-core transformer with the primary and secondary windings set at resonance. A resonance is a condition of an electrical circuit in which the combination of the alternating currents impedance values cancel out. The Tesla coil demonstrates properties of insulators and conductors in interaction with electric fields in high frequency.

The Tesla coil consists of a primary winding, a secondary winding, a transformer, and two high-voltage capacitors. The transformer consists of an iron core in which coils of copper wire are wound around its hollow center. The iron core inside the transformer acts as an electromagnet when an alternating current is passing through the transformer and this will produce a magnetic field around the primary winding. The electrical energy stored in the capacitors is then converted to magnetic energy. When the frequency in the primary winding is high enough, a magnetic field will be produced in the secondary winding.

The Tesla Turbine

One important contribution of Nikola Tesla to the area of energy conversion is his invention of what is known today as the Tesla Turbine. The Tesla turbine is a bladeless turbine that uses the boundary layer effect to cause the rotor disk of the turbine to move in the direction of the fluid. The boundary layer effect is defined as the interaction of a fluid with a solid surface with the boundary layer as the disk surface in which the thin layer of fluid is interacting with. The adhesive property of fluids causes fluid molecules to reduce speed and stick above the metal surface of the rotor disk. These molecules will cause the fluid flow above them to slow down. The viscous property of fluids causes the fluid molecules to keep from separating. This whole process creates a pulling force that causes the rotor disk to move in the direction of the fluid.