Induction Motor

Three phase induction motors employ a simple 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 focus on the theory of induction where a rotating electro-magnetic field it made through the use of a three-stage current at the stators electromagnets. This in turn induces a current inside the rotor’s conductors, which in turns produces rotor’s magnetic field that tries 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 any environmental condition

Induction motors are cheaper in cost due to 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 which can cause sparks

AC Induction motors are Asynchronous Devices meaning that the rotor does not switch at the specific same speed because the stator’s rotating magnetic field. Some difference in the rotor and stator rate is necessary in order to create the induction in to 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 operate efficiently. Roboteq AC Induction controllers could be configured to operate in one of three modes:

Scallar (or Volts per Hertz): an Open loop mode where a control causes a simultaneous, fixed-ratio Frequency and Voltage modify.

Controlled Slip: a Shut Loop speed where voltage and frequency are managed to keep slip inside a narrow range while Induction Motor china working at a desired speed.

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

Find this video from Learning Engineering for a visual illustration about how AC Induction Motors are constructed and work.

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