Three phase induction motors have a very simple construction made up of a Induction in Motor stator covered with electromagnets, and a rotor made up of conductors shorted at each end, arranged as a “squirrel cage”. They work on the theory of induction where a rotating electro-magnetic field it developed through the use of a three-stage current at the stators electromagnets. This in turn induces a current in the rotor’s conductors, which in turns produces rotor’s magnetic field that attempts to follow stator’s magnetic field, pulling the rotor into rotation.
Benefits of AC Induction Motors are:
Induction motors are simple and rugged in building. They are better quality and can operate in virtually any environmental condition
Induction motors are cheaper in cost due to simple rotor construction, absence of brushes, commutators, and slide rings
They are free of maintenance motors unlike dc motors due to the absence of brushes, commutators and slip rings
Induction motors could be operated in polluted and explosive environments as they do not have brushes that may cause sparks
AC Induction motors are Asynchronous Machines and therefore the rotor will not convert at the specific same speed since the stator’s rotating magnetic field. Some difference in the rotor and stator acceleration is necessary to be able to develop the induction into the rotor. The difference between your two is named the slip. Slip must be kept in a optimal range to ensure that the motor to use efficiently. Roboteq AC Induction controllers could be configured to operate in one of three modes:
Scallar (or Volts per Hertz): an Open loop mode in which a order causes a simultaneous, fixed-ratio Frequency and Voltage change.
Controlled Slip: a Shut Loop speed where voltage and frequency are managed in order to keep slip within a narrow range while working 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.