In the first decade after the introduction of alternating current in the US (from the early 1880s to about 1893) a variety of different frequencies were used, with each electric provider setting their own, so that no single one prevailed. The most common frequency was Hz. The rotation speed of induction generators and motors, the efficiency of transformers, and flickering of carbon arc lamps all played a role in frequency setting. Around 1893 the Westinghouse Electric Company in the United States and AEG in Germany decided to standardize their generation equipment on 60 Hz and 50 Hz respectively, eventually leading to most of the world being supplied at one of these two frequencies. Today most 60 Hz systems deliver nominal 120/240 V, and most 50 Hz nominally 230 V. The significant exceptions are in Brazil, which has a synchronized 60 Hz grid with both 127 V and 220 V as standard voltages in different regions, and Japan, which has two frequencies: 50 Hz for East Japan and 60 Hz for West Japan.
In the first decade after the introduction of alternating current in the US (from the early 1880s to about 1893) a variety of different frequencies were used with each electric provider setting their own so that no single one prevailed The most common frequency was Hz The rotation speed of induction generators and motors the efficiency of transformers and flickering of carbon arc lamps all played a role in frequency setting Around 1893 the Westinghouse Electric Company in the United States and AEG in Germany decided to standardize their generation equipment on 60 Hz and 50 Hz respectively eventually leading to most of the world being supplied at one of these two frequencies Today most 60 Hz systems deliver nominal 120/240 V and most 50 Hz nominally 230 V The significant exceptions are in Brazil which has a synchronized 60 Hz grid with both 127 V and 220 V as standard voltages in different regions and Japan which has two frequencies 50 Hz for East Japan and 60 Hz for West Japan