Asynchronous Three Phase Motors

Three-phase electric motors are motors to be connected to three phase electrical systems and are the most widely used motors in the industry. They offer better operating conditions than single-phase motors because they do not need startup aid, have higher efficiency and are found at higher power ratings. In the stator of the asynchronous electric motor of alternating current are installed three windings referring to the three phases. These three windings are mounted with a lag of 120 °.

From the stator winding, the wires to connect the motor to the mains supply can be 3, 6, 9 or 12 points. Three-phase electric motors can have two types of rotors, which are the coiled rotor, which is not closed internally short and has its coils connected to the collector, being possible to connect a rheostat, allowing regulation of the current circulating in the rotor. This will provide a smooth starting and will decrease the common current peak at motor starters. And we have the squirrel cage rotor or short circuit, of the same type used in single-phase motors.