Biography of Ernst Fredrik Werner Alexanderson


Ernst Frederik Werner Alexanderson was a Swedish-born American electrical engineer and television pioneer who developed a high-frequency alternator (a device that converts direct current into alternating current) capable of producing continuous radio waves and thereby revolutionizedradio communication.

He produced inventions in such fields as railway electrification, motors andpower transmissions, telephone relays, and electric ship propulsion, in addition to his pioneer work in radio and television. Ernst Fredrik Werner Alexanderson was born on January 25, 1878, in Uppsala, Sweden, son of a judge and professor of Greek. Developing an early interest in electrical engineering, he attended the Royal Institute of Technology in Stockholm and graduated in engineering in 1900.

He spent a year taking advanced studies in electrical engineering at the Technical University in Berlin, Germany. It was in Berlin that Alexanderson read “Alternating Current Phenomena” by Steinmetz. The book, by Dr. Charles Steinmetz the mathematics genius at General Electric, inspired him so much that he decided to come to the US to meet Steinmetz and seek work with him at General Electric.

He came to US and worked for a few months as a draftsman for the C&C Electric Company in New Jersey before joining the General ElectricCompany in Schenectady, NY, in 1902 at the age of 24. In 1910 Alexanderson enrolled in the famous mathematician and electrical engineer Charles Proteus Steinmetz’ Consulting Engineering Department, which afforded him still greater opportunities to concentrate on continued work with the alternator. In 1918 Alexanderson became manager of the newly established Radio Engineering Department.

From the very beginning of his employment at General Electric, Alexanderson – parallel with his regular duties in the design and testing departments – had been busy on various inventions, above all in the field of motors and generators. In 1905, this resulted in his first six approved patents. During his long period of service with General Electric, and including his years in retirement, he obtained a total of 344 patents, of which 11 private, 34 together with colleagues, and the rest as assignor for General Electric.

Each new patent was followed by a “latent patent” (a patent under development) which, when it had been processed and approved, was followed by new patents and latent patents in a long chain over the years. He left practically no aspect of electrical engineering untested. It is thus possible, from his life’s work, to sketch the development of electrical engineering from power engineering to the more and more important field of electronics. A complete list of his patents provides convincing evidence of his ability to span wide sectors of technology – not to mention the numerous designs and technical solutions he fathered, but which dit not result in any patents.

An exhaustive list includes all the patents he obtained between the years 1905 and 1973. He produced inventions in such fields as railway electrification, motors and direct-current power transmission, telephone relays, gun-control systems and electric ship propulsion, in addition to his pioneer work in radio and television. During World War II, he worked on analog computers for use with radar and developed military applications of the amplidyne.

The story of Ernst Alexanderson’s life’s work can be seen as reflecting the progress made by electricity over more than half a century. By 1902 when he commenced his employment with the General Electric Co. in Schenectady, electric power, apart from its applications in lighting, had to a large extent replaced previous sources of power in mining and metal engineering, at sawmills and at pulpmills.

A few years before the turn of the century, Marconi had succeeded with the wireless transmission of Morse signals over steadily increasing distances. Wireless telegraphy had been born, and it constituted yet another example of the advance for electricity.

As early as 1904 the young immigrant was assigned the task – regarded as impossible by all the experts – of designing for radio pioneer Reginald A. Fessenden a high-frequency generator of 100 kHz, and with the requirement of an output measured in kW.

Fessenden had been seeking to improve on the spark transmitters by building a transmitter which produced a continuous wave carrier upon which he could attach the human voice. Most alternating generators of the time were limited to about 60 Hertz. Fessenden knew he needed a much higher frequency. However, Fessenden’s own experiments failed to create the necessary machine; he was not able even to get as high as 1,000 Hertz. So, in 1904, Fessenden turned to General Electric, and set a rather impressive goal for Dr. Alexanderson: a machine which would generate a frequency of 100,000 Hertz.

Alexanderson made tests on special Swedish iron strips 1½ mils thick in strong magnetic fields at frequencies up to 200 kHz. He found the iron would operate satisfactorily at 100 kHz and therefore designed the alternator with an iron core. Fessenden rejected the design, insisting that his machine will be built with a wooden core as he was sure iron would be melted in a strong field at such a high frequency. It took two years, but in 1906, Alexanderson had constructed a 2 kW, 100 kHz alternator with a wooden core.

Fessenden installed it in his transmitter at Brant Rock, MA, and the historic Christmas Eve 1906 broadcast took place. Following a series of “CQ” transmissions in Morse code, radio operators who were monitoring that night were astonished to hear Fessenden’s voice reading the Bibleand poetry. As wireless rooms filled with the curious, a woman was heard to sing! The program concluded with a violin solo and short speech. Before the invention of his alternator, radio was an affair only of dots and dashes transmitted by inefficient crashing spark machines.

This alternator was further developed, assuming its final form at the end of the First World War. President Woodrow Wilson’s “Fourteen Points” and an exhortation to the Kaiser to abdicate were broadcast by means of the Alexanderson alternator in 1918 in the “Marconi station” in New Brunswick. Marconi who visited Schenectady in 1915 found Alexanderson’s alternator to be superior to his own equipment in the big, newly constructed station.

As a result, the Marconi equipment was torn out, and the alternator installed. Via the New Brunswick station, which had finally acquired a 200 kW alternator, and was placed during the war under the command of the US Navy, President Wilson was able to maintain wireless telephone contact with the USA throughout his voyage to the Peace Conference in Versailles, and back.

Alexanderson with his alternator at Radio Central

Marconi, who on his visit to the States in 1915 had desired to buy the exclusive right to sell the alternators on the world market, made a new offer to General Electric in 1919. President Wilson appealed to General Electric not to sell, since he feared that the English would in that event become completely dominant in the field of world communications.

Instead, an entirely new corporation was created, the Radio Corporation of America (RCA), for the purpose of marketing the alternators. Alexanderson was brought in as Chief Engineer at the new corporation, and subsequently shared his working time between GE and RCA until 1924, when he returned to working full time at GE.

The Alexanderson’s alternator at Rocky Point, New York, for 200 kW long wave transmitter at about 26 kHz.

One of his first tasks at RCA was to plan the equipment for the new Central Station that was to be constructed on Long Island for worldwideradio communications. When fully developed, it was planned that this station would have 12 multiple tuned antennas, another of Alexanderson’s numerous important inventions.

These twelve antennas were directed to different points of the compass, to cover the entire world. One antenna was intended for communications with Sweden, which had bought alternators for a station in Grimeton on the Swedish West Coast. RCA’s representative handling the sale to the Royal Board of Swedish Telegraphs was Ernst Alexanderson.

The station was officially inaugurated by the then Swedish King, Gustaf V, in 1925. In connection with the inauguration, the King sent a telegram to President Calvin Coolidge, in which he declared his conviction that the new link would greatly strengthen the cultural and commercial relations that had so long existed between Sweden and the United States with its “democratic shelter beneath which millions of Swedes have found new homes”.

Present at the inauguration were also RCA Vice President David Sarnoff, and Chief Engineer Ernst Alexanderson. The station acquired great importance for direct contacts with the USA, particularly during World War II, when the cable lines across the Atlantic were broken. Today, this station is the only remaining operable alternator station in the world.

The 1920s ushered in a period of intensive trials with shortwave radio, accompanied by experiments in wireless picture telegraphy and television. On June 5, 1924, the first wireless telegraph picture was transmitted across the Atlantic. This was a handwritten page from a letter from Ernst Alexanderson to his father Professor Alexanderson, in Sweden. Two years later, he sent the first facsimile transmission to go around the world.

Passing through successive relays, the picture was reproduced on machine in the same room as the transmitter after just two minutes. 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. On January 13, 1928, the first television play was transmitted, and the television transmissions from “Alex’s lab” at General Electric were received and shown on a screen measuring roughly 2×2 meters with the aid of Alexanderson’s new TV projector.

During the 1930s, Alexanderson began to interest himself in the transmission of high-voltage direct current with the help of mercury arc inverters, thyratrons, which had previously been developed by himself and his good friend Dr. Irving Langmuir, who was awarded the Nobel Prize in Chemistry in 1932. A test station for transmission via high voltage direct current was built between Mechanicville and Schenectady, and remained in operation until 1948.

Experiments were made with colour television, and viewings for, among others, the US National Committee for Television Systems were arranged in the basement of Alexanderson’s home in Adams Road in Schenectady in 1940. As recently as in 1955 he acquired the patents on an entirely new system of colour television reception. During World War II he designed the amplidyne, an electrodynamic amplifier. It was used among other things to generate the control voltage required to train guns, but also acquired peaceful applications in processes at steelworks etc. The thyratron motor was also developed at this time.

Dr. E.F.W. Alexanderson, who with other General Electric engineers developed the amplidyne, is shown with the device. By ingenious use of a short circuit and a coil arrangement known as a compensating field winding, the amplidyne makes possible delicate control of powerful electric machinery in war plants and on battle fronts. For example, with the help of the amplidyne, the world’s largest electric shovel, which stands 10 stories high, is now producing 100,000 more tons of coal a month.

As a result of the gradual broadening of its work to cover numerous fields, Alexanderson’s Radio Consulting Department was renamed the Consulting Engineering Department in 1928, and in 1933 it became the Consulting Engineering Laboratory. In connection with the reorganization of General Electric in 1945, this laboratory was merged with General Electric’s General Engineering Laboratory to form the General Engineering and Consulting Laboratory.

Alexanderson became consultant on the staff of the new organization, where he remained for another year after his formal retirement in 1948. He continued his inventing activities as a private person for a further 20 or so years. During that time he obtained 28 patents in a variety of fields. His last patent he acquired as recently as 1973.

His career spanned more than the first half of this century, and extended through two world wars. He served his new country as faithfully as he maintained his ties with Sweden. Many are the Swedes who experienced his hospitality on visits to the States, and obtained the assistance and good advice that he with his thorough knowledge of conditions there, was in such a good position to provide.

His broad knowledge, his outstanding personal qualities, and his close contacts with scientists and engineers booth in the USA and Europe over his long and active life make him a central figure in the many branches of electrical engineering during the first half of the 20th century.

Even during his lifetime, he received numerous tokens of appreciation. For a while he was President of the American Institute of Electrical Engineers, which awarded him its Edison Medal in 1944. In 1924 he was elected a member of the Royal Swedish Academy of Engineering Sciences, and in 1934 of the Royal Swedish Academy of Sciences.

In 1938 he was awarded an honorary doctorate by the University of Uppsala, and in 1948 an honorary doctorate by the Royal Institute of Technology, Stockholm. In 1944, he was awarded the Cedergren Medal for his outstanding technical writing in the field of electrical engineering. The medal was first awarded in 1914, to Charles Proteus Steinmetz. In 1925 he became a Knight of the Order of the Northern Star, and, also in that year, a Knight of the Polish order of Polonia Restituta. These are only a few examples of the distinctions he received over the years.

Alexanderson retired from General Electric in 1948 although he continued as a consultant to the company for several more years. His final patent was issued when he was 95. Ernst F.W. Alexanderson, the Swedish-born American inventor, died on 14 May 1975, at the age of 97.

Ernst Alexanderson was honoured posthumously in 1983, when he was elected, for his invention of the high-frequency alternator, to join the ranks of distinguished inventors in the National Inventors Hall of Fame. Several of the original Alexanderson Alternators can be found today in the museum set up in Grimeton, Sweden. In 1996, one was turned on during the 80th anniversary celebration. The station worked just it as it did in 1916, and transmitted signals back to the US.


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