We use the single-phase power speed reducer program more widely than three phase system for household purposes, commercial purposes and some extent in commercial uses. Because, the single-phase system is less expensive than a three-phase program and the energy requirement in most of the homes, shops, offices are little, which can be easily met by an individual phase system.

The single phase AC motors are further classified as:

Single phase induction motors or asynchronous motors.

Single phase synchronous motors.

Commutator motors.

The squirrel cage rotor consists of aluminum, brass or copper bars. These aluminum or copper pubs are known as rotor conductors and placed in the slots on the periphery of the rotor. The copper or aluminum rings permanently brief the rotor conductors called the end rings.

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