The rotor is the component that turns on an electric machine. The same definition is valid whether the electric machine is an electric motor or an electric generator. The rotor together with its together with its fixed counterpart, the stator, form the fundamental set for the transmission of power in motors and electrical machines in general.
The rotor is formed by an axis that supports a set of coils wound on a magnetic core. This axis rotates inside a magnetic field created either by a magnet, an electromagnet or by passing through another set of coils, wound on some polar pieces. These pole pieces remain static and constitute what is called the stator of a direct current or an alternating current, depending on the type of machine involved.
In medium and high power alternating current machines, the manufacture of rotors with electric steel sheets is common. The use of this type of sheets helps to reduce the losses associated with variable magnetic fields, such as Foucault currents and those produced by the phenomenon called hysteresis.
Types of rotors
There are several types of rotors, but we highlight the following three as the most prominent electric motors rotors.
- Rotor coiled with collector.
- Squirrel cage rotor or cage rotor.
- Rotor coil with rings