Three phase induction motors employ a simple construction made up of a stator covered with electromagnets, and a rotor made up of Induction Motor china conductors shorted at each end, arranged as a “squirrel cage”. They work on the principle of induction in which a rotating electro-magnetic field it produced by applying a three-stage current at the stators electromagnets. This in turn induces a current within the rotor’s conductors, which in turns creates rotor’s magnetic field that attempts to follow stator’s magnetic field, pulling the rotor into rotation.

Great things about AC Induction Motors are:

Induction motors are simple and rugged in construction. They are better quality and can operate in any environmental condition

Induction motors are cheaper in cost because of simple rotor construction, absence of brushes, commutators, and slide rings

They are maintenance free motors unlike dc motors due to the lack of brushes, commutators and slip rings

Induction motors can be operated in polluted and explosive conditions as they do not have brushes that may cause sparks

AC Induction motors are Asynchronous Devices meaning that the rotor will not turn at the specific same speed since the stator’s rotating magnetic field. Some difference in the rotor and stator speed is necessary in order to make the induction into the rotor. The difference between your two is called the slip. Slip must be kept within an optimal range to ensure that the motor to operate effectively. Roboteq AC Induction controllers can be configured to operate in one of three modes:

Scallar (or Volts per Hertz): an Open loop mode where a order causes a simultaneous, fixed-ratio Frequency and Voltage alter.

Controlled Slip: a Shut Loop speed where voltage and frequency are managed to keep slip within a narrow range while operating at a preferred speed.

Field Oriented Control (Vector Drive): a Closed Loop Velocity and Torque control that works by optimizing the rotating field of the stator vs. this of the induced field in the rotor.

Observe this video from Learning Engineering for a visual illustration about how AC Induction Motors are constructed and function.