Polyphase motors are self starting and they may have a lower level of Reactive / shuttle power bouncing between the windings and the transformer.
Also, they require a lower FLA than their 1 phase counter parts.
All that stuff makes them have better overall efficiency for all areas concerned.
Other than this stuff, the HP [or wattage consumed] is equal on 1 phase motors and polyphase motors.
Oh ya, since they are self starting, they don't need the annoying aux/start circuit [or other starting means], and do not create double frequency pulsations on the shaft [or reflected back to the system in harmonic distortions].
- Require Polyphase AC Systems,
- Loss of one phase will create problems