The rotor is composed of the following parts:
– Axle: made of steel transmits the mechanical power developed by the electric motor. It is heat treated to avoid problems such as warpage and fatigue;
– Cage (damping): The cage is made of bars and short-circuit rings, most of which are mounted at the ends of the rotor poles or together with the field windings in the case of a smooth pole rotor. Used to break the motor employing the same principles of asynchronous induction motors and can be of electrolytic copper or brass. During the nominal operating regime it also has the function of reducing sudden and transient variations in the network, helping to keep the motor in synchronism;
– Field coils: Also called field winding are formed by a set of coils fed by direct current by the excitation system;
– Core: The rotor core can be constructed of laminated sheet or solid construction in a single block of steel, there is no need for the characteristics of the plate to be the same as the stator, because on the rotor only has direct current circulation in the operation in permanent regime, which does not provide significant losses in iron.