Single
Phase Induction Motor
•Single
phase induction motor is
mostly used in home, office, shop and many single phase appliances like pumps, ceiling fan, washing machine etc.
•Single
phase induction motor is less
efficient than
three phase induction motor but three phase power is mostly available in large industrial places.
•Single
phase induction motor is not
self starting motor.
•Single
phase induction motor have one
main winding in the stator with
this winding by adding another winding (auxiliary or starting) and resistance or capacitor in series or parallel we can make
single phase induction motor self
starting.
•Single
phase induction motor are
Shaded
pole induction motor
Split phase
induction motor
Capacitor start induction motor
Capacitor start capacitor run induction motor
•Shaded pole induction motor
•Shaded
pole motor looks like a transformer with motor actually induction
motor is a rotating
transformer.
•An
auxiliary winding is copper
ring surround each pole added with main
winding for starting purpose.
•When
the current flows through auxiliary winding it produces flux which is unequal.
•Flux in shaded pole and in unshaded
pole opposes the main winding flux which rotates the rotor.
•Stator
have salient poles and short circuited copper turn called shading coils.
•The
rotor of shaded pole motor is squirrel
cage rotor.
•Shaded
pole motor is less
costly.
•Split phase induction motor
•Split
means break
up or divide.
•Split
phase induction motor consists of main winding and auxiliary winding or starting winding and a centrifugal switch.
•Starting
winding is placed at 90
degree electrical with
main winding.
•Centrifugal
switch is on at
starting and it splits the auxiliary field winding when
the motor start running.
•Main
winding have low
resistance and high reluctance and auxiliary winding have high resistance and low reluctance.
•Its
construction is simple.
•Capacitor start induction motor
•Capacitor
start induction motor is similar to split phase induction motor but starting
torque of split phase induction motor is less so by adding a capacitor in series with centrifugal switch
and making similar electromotive force in main and auxiliary winding.
•So it
makes capacitor start induction motor more costlier than split phase induction motor.
•The
capacitor is electrolytic capacitor whose value is about 3 to 20 micro farad.
•Capacitor
start induction motor is use where high starting torque is required.
•Capacitor
start induction motor is use for fan, pumps, compressor etc.
•Capacitor start capacitor run
induction motor
•Capacitor
start capacitor run induction motor works like three phase induction motor at some point.
•Consists
of two
capacitor one
in series with centrifugal switch (capacitor start) and one in parallel (capacitor run).
•The
capacitor run is disconnect after starting of motor but
capacitor run is still connected via auxiliary winding.
•This
gives better power factor and improves
efficiency.
•Capacitor
start capacitor run motor have smooth
torque and silent operation.
•It is
uses where silent
operation is
required.
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