
4-1
4.1 General Considerations and Constructive Characteristics
e operation of the induction motor is based on the rotating magnetic eld discovered, from the theoreti-
cal point of view by Galileo Ferraris in 1885. Nicola Tesla later developed the rst applications and the rst
induction motors as they are now known. e rotating magnetic eld is produced by a polyphase winding,
which is built-in in a xed magnetic structure in the following named the stator. is stator magnetic eld
induces a system of electromotive force (e.m.f.) and current in a polyphase winding built-in in a rotating
magnetic structure in the following named the rotor.