They're used in applications with power requirements of 10 horsepower or less. AC single phase induction motors are further classified by their start and run characteristics. These characteristics are covered in more detail in this section. Three phase induction motors are widely used in industrial and commercial applications, classified either as squirrel cage or wound rotor motors. Three phase induction motors self-start and use no capacitor, start winding, centrifugal switch, or other starting device.
Power ratings range from one third to several hundred horsepower in three phase motors.
Motors of this type rated one horsepower or more cost less and can start heavier loads than their single phase counterparts. And Furthermore . . .