Advantages of Single Phase and Three Phase:
1. The single-phase power is pulsating in nature, but the three-phase power (for a balanced 3Φ system) is a constant at any instant of time. For this reason, the single-phase motors are causing more vibration than the reference to three-phase motors.
2. For the same rating, the three-phase machines are smaller in size than the single-phase machines.
3. The three-phase machines are cheaper and less expensive than single-phase machines.
4. Single-phase motors are not self-started but three-phase motors are self-started.
5. For the same ratings, the three-phase motors have a higher power factor and are much more efficient than the single-phase motors.
6. The electrical power is transmitted by 3 phase system which is cheaper with fewer conductor materials required, has fewer line losses and has higher efficiency than the single-phase system of transmission of power for the same power and voltage to be transmitted.
7. In the 3Φ system, two different sets of voltage are available but this isn’t possible for a single-phase supply.