Single phase induction motor- single phase motor types,construction,operating principle - Electrical input

Monday, August 6, 2018

Single phase induction motor- single phase motor types,construction,operating principle


                      Single phase induction motors




Single phase induction motors are the most familiar of all of the electric motors because they are mostly used in home appliances like refrigerator,electric fans etc. These are widely used in common  appliances and for a very large number of low power drives in industry.

Different Types of Single-Phase Motors:- 
                                                
      1.    Single-phase induction motors
(a)    capacitor start type
(b)   split-phase type
(c)    shaded-pole type
(d)   capacitor start capacitor run type

       2.   Repulsion motors-->
(a)    Repulsion-induction motor
(b)   Repulsion-start induction-run motor

3     3. A.C. series motor or universal motor

       4.     Synchronous motors
(a)    Hysteresis motor
(b)   Reluctance motor
                                      
Single phase induction motor operated by two method
1.Double field revolving theory
2.cross field theory

Double revolving field theory :-

A single-phase alternating current  supplies to  the main winding which  produces a pulsating magnetic field this field could be divided into two fields, which are rotating in opposite directions.the  interaction between the fields and induced a current in the rotor bars which generates opposite torque.

cross field theory :-
in cross field theory, stator flux resolve into two factors which are mutually perpendicular. In this one act as along axis of the stator winding and other act as perpendicular.

Construction of single phase induction motor :-
    Single phase induction motor consist some parts :-
1    1.    Stator
      2.    Rotor:->
     (a). Squirrel cage rotor
     (b). wound rotor

                                    Single phase induction motor


Stator:- in the single-phase motor stator  has  laminated iron core of  two winding ordering perpendicularly. One is the  main winding  and the other is the auxiliary winding. It composed  of a steel frame , cylindrical core made up  of thin laminations of silicon steel  to prevent from  eddy current and hysteresis losses.

Rotor:-  in the rotor, mounted on a shaft, is a hollow laminated core having slots on its outer edge. The winding placed in these  are squirrel cage and wound rotor types.

A single-phase induction motor is not self starting , the starting torque of single phase induction motor is zero because because of the pulsating single-phase magnetic flux. Single phase induction motor needs initial torque to run the motor.





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