Synchronous motors are often applied in industries, usually for applications requiring high nominal torque (this means applications with high power and / or low rated speed). Nowadays, with the appearance of permanent magnet technology, Gates B140 synchronous motors have been widely applied even in low power applications. Permanent magnet synchronous motors are more efficient at induction motors and are ideal for applications requiring variable speed drive where the use of frequency inverters is required.
The synchronous motor has in its rotor a magnetic field induced through field winding or through permanent magnets. This field interacts with the rotating field of the stator, being attracted by it and following at the same speed of the network. Under these conditions, synchronous motors have important advantages compared to induction motors, such as power factor control and load-invariant velocity. Due to their power factor control characteristic, these types of motors have a specific application, where they are connected to the network of some empty utilities, with the sole purpose of absorbing or supplying reactive power to the network. These machines are called “synchronous compensator”.