What are the advantages of three-phase systems over single-phase systems?

Three-phase systems deliver constant power (not pulsating like single-phase), resulting in smoother motor operation and reduced vibration. They transmit more power with less conductor material (1.5x the power with 75% of the copper), produce rotating magnetic fields directly for motor operation, and offer better voltage regulation. Three-phase is standard for industrial power distribution, motors above 5 HP, and high-power applications.