When a 3- phase supply is given to the armature of a 3 phase induction motor, it produces a rotating magnetic field. This rotating flux being linked to the rotor coils, induces voltage and produces current in the rotor. Now it follow the principle of DC motor i.e. When the current carrying rotor being placed in a magnetic field, it experiences a torque and hence begins to rotate.
When a 3- phase supply is given to the armature of a 3 phase induction motor, it produces a rotating magnetic field.It consists of cage winding which consists of parallel conductors (made up of copper or aluminium) short circuited at the ends by end rings, hence forming a closed path for current flow. Rotating flux being linked to the rotor and produce current in the rotor, which further cause rotor to rotate.