There are many different types and sizes of electric motors. Electric motors can be divided into two types: Alternating Current (AC) motors and Direct Current (DC) motors. An AC electric motor requires an alternating current, while a DC motor requires direct current.

AC motors are further subdivided into single phase and three phase motors. Single phase AC electrical supply is what is typically supplied in a home. Three phase electrical power is commonly only available in a factory setting. The most common single phase AC motor is known as a universal motor because it can also run with DC current.

This type of motor is very inefficient but can be very inexpensively made. It is also used almost exclusively for small factional horse power AC motors. The other advantage that it has is that the rotational speed of the motor can be easy changed. This type of motor is commonly found in mixers, hand drills, and any other application requiring variable speed and low cost and small size.

For larger single phase AC motors, a electrical component known as a capacitor is used to create a second phase from the single phase AC current. This type of motor is known as an induction motor, and there are two basic types: a capacitor start motor and a capacitor run motor. It is the interaction between the two phases of this type of motor that causes it to turn.