An induction engine or asynchronous motor can be an AC electric engine in which the electric current in the rotor needed to create torque is obtained by electromagnetic induction from the magnetic field of the stator winding. … An induction motor’s rotor could be either wound type or squirrel-cage type.
Benefits of AC Induction Motors are:
Induction motors are simple and rugged in structure. They are better quality and can operate in virtually any environmental condition
Induction motors are cheaper in cost because of simple rotor construction, absence of brushes, commutators, and slip rings
They are maintenance free motors unlike dc motors because of the absence of brushes, commutators and slip rings
Induction motors could be operated in polluted and explosive conditions as they do not have brushes that may cause sparks
AC Induction motors are Asynchronous Devices and therefore the rotor will not change at the precise same speed since the stator’s rotating magnetic field. Some difference in the rotor and stator speed is necessary in order to develop the induction into the rotor. The difference between your two is called the slip. Slip should be kept in a optimal range to ensure that the motor to use efficiently. Roboteq AC Induction controllers could be configured to operate in another of three modes:
Scallar (or Volts per Hertz): an Open loop mode in which a command causes a simultaneous, fixed-ratio Frequency and Voltage change.
Controlled Slip: a Closed Loop speed where voltage and frequency are controlled to keep slip inside a narrow range while running at a desired speed.
Field Oriented ac motor control (Vector Drive): a Closed Loop Velocity and Torque control that functions 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 work.