Final answer:
The three-bladed rotor is the most common rotor used in 3-phase AC motors, favored for its efficiency and reliability in converting electrical energy to mechanical work.
Step-by-step explanation:
The most common type of rotor used in a 3-phase AC motor is the three-bladed rotor design. This design is prevalent in both industrial applications and consumer products due to its efficiency and reliability. Electric motors work by using loops of wire within a magnetic field to convert electrical energy into mechanical work, and the three-bladed rotor optimizes this process. By passing current through the wire loops, a magnetic field exerts torque on them, which rotates the shaft of the motor.