An induction electric motor or asynchronous motor can be an AC electric motor in which the electric current in the rotor had a need to generate torque is obtained by electromagnetic induction from the magnetic field of the stator winding. … An induction motor’s rotor can be either wound type or squirrel-cage type.
Benefits of AC Induction Motors are:
Induction motors are simple and rugged in structure. They are more robust and can operate in virtually any environmental condition
Induction motors are cheaper in expense 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 environments as they do not have brushes which can cause sparks
AC Induction motors are Asynchronous Devices and therefore the rotor does not switch at the specific same speed as the stator’s rotating magnetic field. Some difference in the rotor and stator swiftness is necessary in order to make the induction into the rotor. The difference between the two is called the slip. Slip must be kept in a optimal range in order for the motor to operate effectively. Roboteq AC Induction controllers can be configured to operate in another of three modes:
Scallar (or Volts per Hertz): an Open up loop mode in which a order causes a simultaneous, fixed-ratio Frequency and ac motor voltage change.
Controlled Slip: a Closed Loop speed where voltage and frequency are managed to keep slip inside a narrow range while running at a preferred speed.
Field Oriented Control (Vector Drive): a Closed Loop Rate 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 function.