Goldschmidt alternator

100 kW Goldschmidt alternator at Eilvese, Germany. The 250 HP DC electric motor (right), turned the 3 ft. diameter, 5 ton rotor (center), at 4000 RPM. The rotor had 360 poles, and the fundamental frequency of the alternator was 24 kHz. Complicated "reflector" circuits (capacitor banks against walls) forced the machine to produce alternating current at four times this frequency, 96 kHz. The transmitter was used for transatlantic radiotelegraphy traffic, exchanging Morse code messages with a similar Goldschmidt station at Tuckerton, New Jersey, USA. During World War I it was Germany's main communication channel to the outside world, and was used for diplomatic negotiations between Woodrow Wilson and Kaiser Wilhelm II leading to the Armistice.
A more powerful 200 kW Goldschmidt machine replaced the one above at Eilvese station around 1920. The rotor had 400 poles and produced a fundamental frequency of 12.5 kHz, which was multiplied by 4 to give an output frequency of 50 kHz.

The Goldschmidt alternator or reflector alternator, invented in 1908 by German engineer Rudolph Goldschmidt,[1] was a rotating machine which generated radio frequency alternating current and was used as a radio transmitter.[2] Radio alternators like the Goldschmidt were some of the first continuous wave radio transmitters. Like the similar Alexanderson alternator, it was used briefly around World War I in a few high power longwave radio stations to transmit transoceanic radiotelegraphy traffic, until the 1920s when it was made obsolete by vacuum tube transmitters.

  1. ^ Burns, Russell W. (2004). Communications: An International History of the Formative Years. Institution of Electrical Engineers. p. 365. ISBN 0863413277.
  2. ^ Graf, Rudolf F. (1999). Modern Dictionary of Electronics. Newnes. p. 323. ISBN 0750698667.