Power Electronics and Motor Drive Systems

12.4. Asynchronous or Induction Motors

Fig. 12.17 shows a typical layout of a three-phase asynchronous motor where we see the poles of the rotor as well as the three-phase stator coordinates a_s–b_s–c_s which have a phase difference corresponding to the axes a_r–b_r–c_r. Similar to the stator, the rotor consists of iron core and windings. The core of the rotor is cylindrical made of steel and constructed in such away to create grooves in the axial region where the windings are placed. In this case the electric motor is said to be motor with squirrel-cage rotor. If the electric motor is a rotor cage type, in the core grooves, bars made from copper or aluminium or any other suitable alloy material are placed with their ends short-circuited with rings ...