We utilize the single-phase power system more widely than 3 phase system for household purposes, commercial purposes plus some extent in commercial uses. Because, the single-phase system is more economical than a three-phase system and the energy speed reducer requirement in the majority of the homes, shops, offices are small, which can be easily met by an individual phase system.

The single phase AC motors are further classified as:

One phase induction motors or asynchronous motors.

Single phase synchronous motors.

Commutator motors.

The squirrel cage rotor includes aluminum, brass or copper bars. These aluminum or copper pubs are known as rotor conductors and placed in the slot machines on the periphery of the rotor. The copper or aluminium rings permanently short the rotor conductors known as the end rings.

To provide mechanical strength, these rotor conductors are braced to the end ring and hence form a complete closed circuit resembling a cage and therefore got its name as squirrel cage induction motor. As end rings permanently short the bars, the rotor electrical level of resistance is very small and it is not feasible to add external resistance as the bars get completely shorted. The absence of slip ring and brushes make the structure of single phase induction motor very simple and robust.