NIDEC Motor China Agent. 403.872 Valeo NIDEC Motor Manual

The Triple-phase asynchronous motor is a type of induction motor that is powered by a 380V three-phase AC current (with a phase difference of 120 degrees). Due to the fact that the rotor of a three-phase asynchronous motor rotates at the same direction but at a different speed compared to the rotating magnetic field of the stator, there is a slip rate, hence the name "three-phase asynchronous motor." The speed of the rotor in a three-phase asynchronous motor is lower than that of the rotating magnetic field. The rotor winding generates electromotive force and current due to the relative motion with the magnetic field, interacting with it to produce electromagnetic torque and achieve energy transformation. Compared to single-phase asynchronous motors, three-phase asynchronous motors offer better operational performance and can save various materials. Depending on the rotor structure, three-phase asynchronous motors can be categorized into squirrel-cage and wound types. The squirrel-cage asynchronous motor has a simple structure, reliable operation, light weight, and low cost, making it widely used, although its main drawback is the difficulty in speed control. The wound-type three-phase asynchronous motor also has three-phase windings in both the rotor and stator, connected to an external variable resistor via slip rings and brushes.