(1856-1943) Serbian/American Experimental Physicist (Classical Electromagnetism), Electrical Engineer
Nikola Tesla was a great experimentalist and inventor whose work ushered in the age of electrical power. One of the pioneers of the use of alternating currents, he invented the alternating current induction motor and the high-frequency coil that bears his name.
He was born at midnight on July 9, 1856, in the village of Smiljan, Croatia, then part of the Austro-Hungarian Empire, to Serbian parents. Nikola was supposed to follow in the footsteps of his father, a Serbian Orthodox priest, but his natural inclinations led him along other paths. The combination of poetic imagination and scientific discipline that would characterize his amazing career manifested itself early in life. A clever child, he liked poetry (he would later write his own poetry and translate Serbian poetry into English) and scientific experimentation. At the age of five he built a small waterwheel with an unusual design that he would recall years later when designing his bladeless turbine. In secondary school he developed an interest in science and, on graduating, entered the Technical University in Graz, Austria, where he studied engineering. In 1878, after seeing a demonstration of a direct current electric dynamo and motor, he conceived the idea of improving the machine by removing the commutator and sparking brushes, which were sources of wear.
Tesla went on to the University of Prague in 1880 but was forced to leave without graduating when his father died the following year. Tesla then took a job in Budapest as an engineer for a telephone company. That year, while strolling in the park with a friend, he visualized the principle of the rotating magnetic field, which is produced by two currents running out of step with one another, or alternating. This was the principle that lay at the heart of his idea of the induction motor: an iron rotor spinning between stationary coils that were electrified by two out-of-phase alternating currents producing a rotating magnetic field. Before a working motor had been built, Tesla had conceptualized an array of practical applications for it. Years later, he would describe the manner in which an invention would come to life in his imagination:
Before I put a sketch on paper, the whole idea is worked out mentally. In my mind I change the construction, make improvements, and even operate the device. Without ever having drawn a sketch I can give the measurements of all parts to workmen, and when completed all these parts will fit, just as certainly as though I had made the actual drawings.
Tesla would not build an actual working induction motor until 1883, when he had moved to Paris and was working for the Continental Edison Company. Finding little interest in developing it in Europe, however, in 1884, he sailed to the United States. He arrived in New York with a few coins in his pocket and a letter of recommendation from a European business associate to the eminent inventor Thomas Edison at his Menlo Park, New Jersey, research laboratory. The letter said, “I know two great men and you are one of them; the other is this young man.” Edison was impressed with this and gave the young man a job, but he was a staunch supporter of direct current, which moves in one direction only, rather than alternating current, which regularly reverses its direction. After a year Tesla and Edison parted ways.
Tesla lost little time in obtaining patents for the generation, transmission, and use of alternating current electricity, which he sold, in May 1885, to George Westinghouse, head of the Westinghouse Electric Company in Pittsburgh. He received $60,000 for his patents and a contract promising him $2.50 per horsepower of electricity sold. But when Westinghouse’s company found itself in financial trouble, Tesla agreed to forgo any royalties, as a gesture of friendship and support, “so that you can develop my inventions.” His selfless act would later prevent him from realizing the financial benefits of many of his other inventions.
The Westinghouse purchase precipitated an intense power struggle between Edison’s direct current systems and the Tesla-Westinghouse alternating current approach. Because of its higher efficiency, alternating current, which can be transmitted over much longer distances than direct current, eventually won out. Westing-house demonstrated the superiority of alternating current by using his system for lighting at the 1893 World Columbian Exposition in Chicago. In 1896, Westinghouse won the contract to install the first power machinery to generate electricity, at Niagara Falls, using Tesla’s system to supply and deliver alternating current to Buffalo, 22 miles away.
Tesla himself had meanwhile become involved in a number of projects in the personal laboratory and workshop he had set up in 1887. He experimented with shadowgraphs, similar to those used by wilhelm conrad rontgen, in 1895, when he discovered X rays, as well as working on a carbon button lamp, the power of electrical resonance, and various types of lighting. To show that there was nothing to fear from alternating currents, he gave exhibitions in his laboratory in which he lighted lamps without wires by allowing electricity to flow through his body. As his fame grew, he was in demand for lectures in the U.S. and abroad.
At the time he became an American citizen, in 1891, Tesla directed his inventive powers to developing alternating currents at very high frequencies, believing they would be useful for lighting and communication. He experimented with high-frequency alternators before designing what came to be called the Tesla coil, which produces high-voltage oscillations from a low-voltage direct current source. The Tesla coil is widely used in radio and television sets and other electronic equipment. At the peak of his creative powers, during this period he also invented fluorescent lighting, the bladeless turbine, and radio.
One of his most fervid interests was radio communication. In 1898, he demonstrated remote control of two model boats before large crowds in Madison Square Garden in New York. He later extended this to remote controlled weapons, in particular, torpedoes.
During an 1899-1900 stay in Colorado Springs, Colorado, Tesla made what he viewed as his most significant discovery: terrestrial stationary waves, with which he proved that the Earth could be used as a conductor and would be as responsive as a tuning fork to electrical vibrations of a certain frequency. Using high-frequency alternating currents, he was also able to light more than 200 lamps over a distance of 25 miles without using intervening wires. Because gas-filled tubes are readily energized by these high-frequency currents, this kind of light could easily be operated within the field of a large Tesla coil. Later, he used the Tesla coil to produce artificial lightning: an electric flash 135 feet long. However, sometimes his imaginative leaps seemed excessive to his contemporaries: when he announced that he had received signals from another planet in his Colorado laboratory, he was ridiculed in scientific journals.
In 1900, with support from the financier J. Pierpont Morgan, he began building a wireless world broadcast station on Long Island, New York. His ambition was to provide worldwide communication and to furnish facilities for sending pictures, messages, weather warnings, and stock reports. When his backers found the project too expensive, he reluctantly abandoned this idea, considering it to be his greatest defeat.
Tesla created several other inventions, including electrical clocks and turbines, many of which remained on the drawing board for lack of financial backers to produce them. One of his most ambitious ideas was to transmit alternating current electricity to anywhere in the world without wires, using the Earth itself as an enormous oscillator. His scheme for detecting ships at sea was later developed into what is now known as radar.
In 1917, he received the Edison Medal, the highest honor awarded by the American Institute of Electrical Engineers. The standard international unit of magnetic flux density was named the tesla in his honor.
Eccentric and withdrawn, he lived his last years as a recluse. He was known for his loyalty to his few close friends, one of whom was Mark Twain. When he died in New York City on January 7, 1943, he owned more than 700 patents. His funeral was attended by a large crowd, and a flood of telegrams paid tribute to his genius and contributions.
It would be difficult to overstate the impact of Tesla’s inventive genius. His discovery that alternating current can be transmitted over much greater distances than direct current underlies our capability to power the machinery of the modern world.
