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 120 degree lag.
From the stator winding, the wires for connecting the motor to the mains supply can be in the number of 3, 6, 9 or 12 points. Three-phase motors can have 2 types of rotors:
– Coiled rotor – it is not closed internally in short and its coils are connected to the collector, where it is possible to connect a rheostat, which guarantees and regulates the current that circulates in the rotor. This sets a soft start and reduces the common peak current in motor starters. baldor UCME759
– Squirrel cage rotor or shorted – this rotor is the same type applied in single-phase motors.
Three-phase motors are their own electrical machines to be connected to three-phase electrical systems and are the most widely used motors in the industry. They provide better operating conditions than single-phase motors because they do not need starter aid, give higher efficiency, and are found at higher power ratings.