We utilize the single-phase power system more widely than 3 phase system for household purposes, commercial purposes and some extent in industrial uses. Because, the single-phase system is less expensive than a three-phase system and the energy requirement in the majority of the houses, shops, offices are small, which can be very easily met by a single phase system.

The single phase AC motors are further classified as:

Solitary phase induction motors or asynchronous motors.

Single phase synchronous motors.

Commutator motors.

The squirrel cage rotor includes aluminum, brass or copper bars. These light weight aluminum or copper bars are known as rotor conductors and placed in the slot machine games on the periphery of the rotor. The copper or aluminum rings permanently brief the rotor conductors called 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 hence got its name because squirrel cage induction electric motor. As end rings permanently short the bars, the rotor speed reducer electrical resistance is very small in fact it is not feasible to add external level of resistance as the bars get permanently shorted. The absence of slip ring and brushes make the building of single stage induction motor very easy and robust.