Three phase induction motors have a very simple construction made up of a stator covered with electromagnets, and a rotor composed of conductors shorted at each end, arranged as a “squirrel cage”. They focus on the basic principle of induction in which a rotating electro-magnetic field it created by applying a three-phase current at the stators electromagnets. This in turn induces a current inside the rotor’s conductors, which in turns creates rotor’s magnetic field that attempts to check out stator’s magnetic field, pulling the rotor into rotation.

Great things about AC Induction Motors are:

Induction motors are simple and rugged in structure. They are more robust and can operate in any environmental condition

Induction motors are cheaper in cost due to simple rotor construction, lack of brushes, commutators, and slip rings

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

Induction motors can be operated in polluted and explosive environments as they do not have brushes which can cause sparks

AC Induction motors are Asynchronous Machines and therefore the rotor does not turn at the specific same speed since the stator’s rotating magnetic field. Some Induction Motor difference in the rotor and stator velocity is necessary to be able to develop the induction into the rotor. The difference between your two is called the slip. Slip should be kept in a optimal range in order for the motor to operate efficiently. Roboteq AC Induction controllers can be configured to operate in one of three modes:

Scallar (or Volts per Hertz): an Open loop mode in which a command 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 running at a preferred speed.

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

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