Abstract
It is explained why a polyphase (m > 3) induction motor supplied separately by single consecutive symmetrical components of voltage behaves as a multi-speed motor. As an example a 9-phase 4-speed motor is considered and results of computer simulations are presented. As regards the theory of polyphase machines it is shown that the so-called diagram of decomposition of polyphase induction motor into elementary machines (the graphical representation of a motor model in αβ 0 coordinates) is very convenient means for their analysis and modelling.