an induction motor comprises a stator and a rotor , which includes material essentially blocking magnetic flux at high frequencies . a difference in number of stator slots and rotor slots is chosen so that the inductance of a winding provided in a stator slot is different from the inductance of a winding provided in another stator slot . a sense means , such as stator winding or separate sense winding , is provided in at least one of the stator slots and the sense means is arranged to allow measuring of the inductance thereof . the sense means constitutes an integrated sensor , which is both inexpensive and reliable . a method of sensing the rotor position and / or speed of an induction motor is also described .