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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