The rotor of the electric motor requires a torque to start its rotation, and this torque is produced at first by magnetic forces developed between the magnetic rotor poles and those of the stator (fixed part). The attraction or repulsion forces, formed between stator and rotor, “pull” or “push” the movable rotor poles, causing torques, which cause the rotor to rotate faster and faster, until the frictions or loads attached to the axis decrease the torque resulting from the value ‘zero’. After that moment, the rotor rotates with intermittent angular velocity.
Both the rotor and the stator of the motor need to be ‘magnetic’, because these forces between poles are responsible for producing the torque needed to make the rotor rotate. The rotation of electric motors is the cornerstone of many home appliances.
This rotating movement is often obvious, as in fans or cakes, but often gets a little disguised, such as the washing machine shakers or the window “electric window” motors of certain motor vehicles. To understand the operation of the motor we need some prior knowledge about electromagnetism, such as magnets, magnetic forces between magnets, and the action of magnetic fields on currents.