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](/Images/godic/202501/15/Eilvese_Goldschmidt_alternator4201.jpg")
![12.5 kW Goldschmidt alternator installed in 1910 at a wireless station in Eberswald, Germany. It had an output power of 12.5 kW at a frequency of 30 kHz, or 8 to 10 kW at 60 kHz. It consists of a DC electric motor (left) driving the alternator (right) through a gearbox (center) which steps up the rotation speed.](/Images/godic/202501/15/Goldschmidt_alternator4201.jpg")
![Rotor of Eilvese machine](/Images/godic/202501/15/Goldschmidt_alternator_rotor_19244201.jpg")
The Goldschmidt alternator or reflector alternator, invented in 1908 by German engineer Rudolph Goldschmidt, was a rotating machine which generated radio frequency alternating current and was used as a radio transmitter. 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.