Alexanderson

Patent No. 1,008,577
High Frequency Alternator

Ernst Alexanderson, Swedish-born American inventor, was the General Electric Company engineer whose high frequency alternator gave America its start in the field of radio communication.

During his 46-year career with GE, he became the company's most prolific inventor, receiving a total of 322 patents. He produced numerous inventions in such fields as railway electrification, motors and power transmissions, telephone relays and electric ship propulsion, in addition to his pioneer work in radio and television.

In 1904, Dr. Alexanderson was assigned to build a high frequency machine that would operate at high speeds and produce a continuous wave transmission. Before the invention of his alternator, radio was an affair only of dots and dashes transmitted by inefficient crashing spark machines. After two years of experimentation, Dr. Alexanderson finally constructed a two-kilowatt, 100,000-cycle machine. It was installed in the Fessenden station at Brant Rock, Massachusetts, and on Christmas Eve, 1906, it enabled that station to transmit a radio broadcast which included a voice and a violin solo.

Alexanderson's name also will be recorded in history for his pioneer efforts in television and the transmission of pictures by radio. On June 5, 1924, he transmitted the first facsimile message across the Atlantic. In 1927, he staged the first home reception of television at his own home in Schenectady, New York using high frequency neon lamps and a perforated scanning disc. He gave the first public demonstration of television on January 13, 1928.

He held patents on such devices as the inverter, by which direct current can be changed into alternating current through the mercury vapor arc, and single-phase motors for railway electrification. He also made important contributions to radiant-energy guiding systems for aircraft and the automatic steering on both air and water craft, and developed countless applications of vacuum tubes in power transmission.

He also was associated with the amplidyne--an extremely sensitive and powerful system of amplification and automatic control adapted to the firing of antiaircraft guns in World War II.

He received many honors and several honorary degrees. He was awarded, among others, the Gold Medal of the Institute of Radio Engineers in 1919 and the Edison Medal from the American Institute of Electrical Engineers in 1944.

Ernst Alexanderson died on May 14, 1975, at the age of 97.

The above information was supplied by the National Inventors Hall of Fame Foundation, Inc., Room 1D01-Crystal Plaza 3, 2021 Jefferson Davis Highway, Arlington, Virginia 22202. Videotapes and printed materials are currently available. For more information, visit the Foundation's web site at http://www.invent.org

      

         

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