Answer / benudhar sahu

1.The 3-phase motor can be made self starting like slip ring induction motor but the single phase motor can be start by connecting some extra components like high resistance,capacitor etc. which is not cost effictive.
2.The efficiency of 3ph motor is about 84% to 90% and for 1ph motor it is 80% to 85%
3.The power factor 3ph motor is about .75 to .85 and for 1ph motor it is .55 to .65

Answer / ashwin . bhange

in the three phase motor at less power& current the motor
will work with good efficiency than the single phase motor

Answer / aniruddh

In case single phase motor torque devloped is zero duto
field revolving theory so we need to auxillary wdg or
paralle capacitor to improve starting torque.
In case 3- phase motor has mmf which 120degree to each
nothing required for startig purpose.
3-phase motor connected in star conection fault occurse
in any phase motor is capable to run but lower speed.

Answer / simon

1.Self starting capacity.
2.Due to 3 phase three coils r located at 120 degree elt.
3.The Phase V of 3 phase is 440.
4.The P.f of 3 Phase is nearly 0.8 to 0.9.Which is high as compared to 1 Phase.

Answer / @vi

1.Reduction in the motor size: For the same capacity single
phase motors size is larger than 3 phase motors.
2.To deliver the same load, three phase motors draw less
current than single phase motors, Hence this will make the
reduction in the conductor size, insulation requirement and
heating effect.
3.Three phase motors are self starting where as single phase
motors require some kind of starting method.

Answer / dhivagar eee

bcoz comparing 2 single phase 3 ohase has more efficiency
&torque

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