Induction Motor

Definition
                   An alternating current motor in which torque is produced by the reaction between a varying field generated in the stator and the current induced in the coils of the rotor. 
 Principle of Induction Motor  
           
                      Induction motor works on the principle of induction where electro-magnetic field is induced into the rotor when rotating magnetic field of stator cuts the stationary rotor.  
                   Types of Induction Motor
       Single Phase Induction Motor
            The single phase induction motors are made self starting by providing an additional flux by some additional means.Now depending upon the additional means the single phase induction motors are classified as.
  1. Split phase induction motor.
  2. Capacitor start induction motor.
  3. Capacitor start capacitor run induction motor.
  4. Permanent split capacitor motor.
Application of Single phase Induction motor 
             
                    These are used in low power applications and widely used in domestic applications as well as industrial.Some of these are mentioned below.
  1. Pumps.
  2. Compressors.
  3. Small Fans.
  4. Mixers.
  5. Toys.
  6. High Speed Vacuum cleaner.
  7. Drilling Machines.
  8. Electric Shavers.
Three Phase Induction Motor
                          The stator of an induction motor consist of a number of overlapping windings offset by an electrical angle of 120 degree.When the primary winding or stator is connected to a three phase alternating current supply it establishes a rotating magnetic field which rotates at a synchronous speed.
  1. Squirrel Cage Induction Motor.
  2. Slip Ring Induction Motor.
Application of Three Phase Induction Motor
                     
                          Due to the robust construction and ease of control, Three-Phase asynchronous motors are widely preferred over many other motors for the AC motor driven applications.This three-phase motor is accountable for larger load operation in several applications like goods and lift hoists, conveyors, compressors pumps,ventilation system,industrial fan controllers etc.
Advantages of Induction Motor
  1. Simple and rugged construction.
  2. Low cost and minimum maintenance.
  3. High dependability and sufficiently high proficiency.
  4. Needs no additional starting motor and necessity not be synchronized.

Disadvantages of Induction Motor 

  1. Three Phase Induction motors have poor starting torque and high in rush currents.
  2. Induction motors always operate under lagging power factor and during light load conditions they operate at very worst power factor(0.2 to 0.4 lagging).
  3. One of the main disadvantages of induction motors is that speed control of induction motors are difficult.



           
                                      
      
          

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