Currently the servomotors are included in the category of special motors, being considered precision motors and can be applied in the most diverse activities, of which stand out the positioning systems; industrial robotics; transport lines; flexible manufacturing systems. The servomotors have a range of characteristics that distinguish them from the other engines and have a high dynamic, that is, they operate at several speeds with constant torque, they also have a strict torque control, that is, one can easily act on the torque of the servomotor to raise and lower without damaging the servomotor.
In addition to these features the servomotors have an enormous precision of their speed as well as the position of their rotor, due to the fact of their control devices. Servomotors are currently divided into the following types: Alternating Current Asynchronous Servomotor skf bearing 22222 e/c3, Alternating Current Synchronous Servomotor and Continuous Current Servomotor, Step Servomotors, Switch Reluctance Servomotors and Induction Servomotors. Prior to the increase in power electronics and magnetically hard materials, the servo motors were DC-powered having a brush-collector assembly. The torque control of this type of motors was quite simple and presented a good precision for the time.