A Gallery of Electromagnetic Personalities 7...

Tesla, Westinghouse, Steinmetz

Nikola Tesla (1856-1943) came to the U.S. from Austria-Hungary as a young engineer. Tesla held more than 700 patents. His inventions included the principle of the rotating magnetic field machine,the induction motor, polyphase alternating-current systems, the Tesla coil transformer, wireless communication, radio, and fluorescent lights. Tesla first worked for Edison, but his enthusiasm for ac led to his leaving; he worked at odd jobs (including ditch-digging) for two years before he was hired by Westinghouse. Tesla was an eccentric with a phobia about germs, but he helped allay public fears about electricity by demonstrations in which he allowed currents to pass through his body to ignite flames. Photo: Tesla's $500M induction motor.

George Westinghouse (1846-1914) was the inventor and industrialist who fought for the adoption of ac electric power in the U. S. Westinghouse purchased transformers and an ac generator in Europe and set up an ac power system in Pittsburgh. He bought Tesla's ac motor patents and hired Tesla to adapt the motor for use in his power system. Edison and the proponents of dc power claimed that ac was a menace to human life and to support their argument they arranged for the use of a standard Westinghouse ac generator as the means of execution in New York.

Charles Proteus Steinmetz (1865-1923) arrived in the US in 1889 as a political refugee from Germany. Physically deformed (a diminutive hunchback), he was nearly denied admission to this country. His work at GE on hysteresis loss, ac circuit theory, and high power discharges provided the basis for the progress in ac circuits at the turn of thecentury.

Hertz, Marconi, Popov

Heinrich Rudolf Hertz (1847-1894) was the first to broadcast and receive radio waves. Maxwell's theory had been based on unusual mechanical ideas about the ether and had not been universally accepted. In 1884, Hertz rederived Maxwell's equations by a new method, casting them in modern form. Then, between 1885 and 1889, as a professor of physics at Karlsruhe Polytechnic, he produced electromagnetic waves in the laboratory and measured their wavelength and velocity. He showed that the nature of their reflection and refraction was the same as those of light, confirming that light waves are electromagnetic radiation obeying the Maxwell equations. Photo: Hertz's first radiator.

Guglielmo Marconi (1874-1937) was an Italian physicist who obtained a patent for a successful system of radio telegraphy (1896) at age twenty-two and remained a leader in radio technology for four decades. In 1909 he received the Nobel Prize for Physics. Marconi's great triumph was in 1901 when he succeeded in receiving signals transmitted across the Atlantic Ocean despite the general opinion that the curvature of the Earth would limit the range of communication by electromagnetic waves. This sensational achievement was the start of the vast development of radio communication and broadcasting. Listen to Marconi describing his result! (369K .wav file) Next: Photos: Marconi's transmitters.

Aleksandr Stepanovich Popov (1859-1906) is acclaimed in Russia as the inventor of radio. Popov was the son of a village priest and planned to enter the priesthood, but his interests changed to mathematics and then to electrical engineering. He became an instructor at the Russian Navy's Torpedo School. Learning of Hertz's work, in 1895 Popov constructed an apparatus that could register electrical disturbances due to lightning, and then suggested that it could be used for receiving man-made signals. In 1896, he demonstrated the transmission of radio wave signals between different parts of the University of St. Petersburg. Because there is evidence that Marconi demonstrated the transmission of intelligible signals even earlier however, Marconi's priority is usually conceded outside Russia.