Synchronous motors are little used in industries, because their speed is constant, but as it has a defined field armature, this causes an increase in response to the drag process created by the rotating field. It is used when stable speeds are required, such as when subjected to variable loads, when high power with constant torque is required and also to correct the power factor.
Three-phase synchronous motors are machines that transform into electrical energy into mechanical energy, which is supplied in three-phase alternating current. In this conversion there is a constant ratio between the frequency of induced electromotive forces and the speed of rotation. The three-phase synchronous motor is made as an electric machine of protruding poles. Its magnetic circuit is made by a packaging of magnetic plate, which forms a circular crown grooved on the side of the air gap. The power of this motor is directly through an electric grid, or through an electronic power converter and in any of these occurrences the study of the three-phase synchronous motor has to start by establishing an engine model. The examination of its operation allows to verify the fantastic characteristics of this type of motor, as actuator and as source of reactive energy.