An alternator is an electric generator that converts mechanical energy tae electrical energy in the form o alternatin current. For reasons o cost an simplicity, maist alternators uise a rotating magnetic field wi a stationary armature.[1] Occasionally, a linear alternator or a rotating armature wi a stationary magnetic field is uised. In principle, ony AC electric generator can be cried an alternator, but uisually the term refers tae smaw rotating machines driven bi automotive an ither internal combustion ingines. An alternator that uses a permanent magnet for its magnetic field is cried a magneto. Alternators in pouer stations driven bi steam turbines are cried turbo-alternators. Large 50 or 60 Hz three phase alternators in pouer plants generate maist o the warld's electric power, which is distributed bi electric power grids.

Early 20t-century alternator made bi Ganz Works in 1909 in Budapest, Hungary, in the power generating hall o the biggest hydroelectric station o the Roushie Empire (photograph bi Prokudin-Gorsky, 1911)


  1. Gordon R. Selmon, Magnetoelectric Devices, John Wiley and Sons, 1966 no ISBN pp. 391-393