Induction Motor

Three phase induction motors employ a simple Induction Motor construction composed of a 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 in which a rotating electro-magnetic field it produced by applying a three-stage current at the stators electromagnets. Therefore induces a current within the rotor’s conductors, which in turns generates rotor’s magnetic field that tries to follow stator’s magnetic field, pulling the rotor into rotation.

Great things about AC Induction Motors are:

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

Induction motors are cheaper in expense due to simple rotor construction, absence of brushes, commutators, and slide 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 environments as they don’t have brushes that may cause sparks

AC Induction motors are Asynchronous Devices and therefore the rotor will not turn at the precise same speed since the stator’s rotating magnetic field. Some difference in the rotor and stator quickness is necessary to be able to create the induction in to the rotor. The difference between the two is named the slip. Slip must be kept in a optimal range to ensure that the motor to operate efficiently. 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 control causes a simultaneous, fixed-ratio Frequency and Voltage alter.

Controlled Slip: a Closed Loop speed where voltage and frequency are managed to keep slip inside a narrow range while operating at a desired 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.

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