entire family in 1906. After his return to Berlin, he continued his work at AEG and became Technical Director of the apparatus factory in 1909. On 24 October 1911, he received an honorary doctorate from the TH Darmstadt, whose Dolivo building bears his name today. During his life he obtained over 60 patents. In 1919, Dolivo-Dobrovolski died of a severe heart condition at the academic hospital in Heidelberg. He was buried at the forest cemetery of Darmstadt, where his grave (grave site: R 6a 7) - located very close to the memorial of his teacher :de:Erasmus Kittler - can still be visited today. In the city centre of Darmstadt in 1969 a street was named after Dr.-Ing. E. h. Michael Dolivo-Dobrovolsky, the Dolivostraße. Invention of the three-phase system In 1887, Director General Emil Rathenau of the Allgemeine Elektricitäts-Gesellschaft AG (AEG) in Berlin offered him a position, whereupon Dolivo-Dobrovolsky remained associated with the company until the end of his life. At the AEG, Dolivo-Dobrovolsky initially made an effort to further perfect direct current technology. After all, AEG's origins lay in an Edison subsidiary, and Edison, like Siemens, relied entirely on direct current. At that time, alternating current gradually attracted the attention of technicians, and engineers from Ganz Works in Budapest had designed the first transformer in today's sense in 1885. However, AC technology required further equipment, especially reliable and self-starting motors; AC theory was also still underdeveloped. Before Dolivo-Dobrovolsky, the Italian Galileo Ferraris drew attention to alternating current. He invented the first AC motor in 1885. After him, the German engineer Friedrich August Haselwander develops the first AC 3 phase synchronous generator in Europe which produced about 2.8 kW at 960 rev/min, corresponding to a frequency of 32 cycles per second, today known as Hertz, or Hz. The machine had a stationary, ring-shaped, three-phase armature and a rotating ‘internal-pole magnet’ with four wound salient poles, which provided the revolving field. The patent application filed in July 1887. The first AC 3 phase synchronous generator went into operation in October 1887. Regardless of these events, a forward-looking solution was found at AEG in 1888. Dolivo-Dobrovolsky worked with chained three-phase alternating current and introduced the term three-phase current. The associated asynchronous motor invented by him was the first functional solution. However, the asynchronous motor with squirrel-cage rotor had the problem of delivering only low torque at low speeds, such as when starting up.