Advantages of three phase system
•Three phase system give study output and power delivered is constant. In single phase system power delivered is pulsating.
•The output of three phase machine is greater than single phase machine of same size.
•Three phase induction motors are self starting. Single phase motor are not self starting.
•We can obtain single phase supply from three phase but three phase supply cannot be obtained from single phase.
•For transmission of three phase system conducting material required is less as compared to single phase system for given volt ampere and voltage rating.
•Efficiency of 3 phase motor is more as compared to single phase motor.
•Parallel operation of three phase alternator is simpler as compared to single phase alternator.
•Power to weight ratio of three phase alternator is high as compared to single phase alternator which reduces the cost for generating same amount of power.