An electric motor is a machine that is used to convert electrical energy into mechanical energy. It can also be used to do the reverse, i.e., convert mechanical energy into electrical energy (in which case it is known as a generator, dynamo or alternator).
An electric motor is used in a car engine starter. It can either be powered by direct current or alternating current. The motor is made up of an axle in the middle of a cylinder. The axle is covered by coils of copper wire, which are known as windings. The purpose of these windings is to create a magnetic field when a current is run through them, thereby inducing motion in the axle, resulting in rotation of the motor. The types of winding that are used are either basket windings or distributed windings.
A basket winding is a winding type with an electromagnetic coil that has successive layers of wire arranged at almost right angles to each other. It is also known as a half coil winding because it has a single layer of winding, with one coil side per slot. The sum of the active coils is half of the number of slots that are present. In this winding method, the wires crisscross each other with successive turns far apart except at the points of crossing. This design helps to reduce distributed capacitance. The wire is wound on an iron core because iron is an easily magnetized material. This type of winding is used in alternating current (AC) motors. However, the basket winding makes the motor large, which causes it to experience higher leakage inductance.
Distributed winding is the most common type of winding available. In this system, there are two layers, with two coil sides per slot. The total number of active coils is equal to half the number of slots present. The conductors in the adjacent slots are induced successively so that the voltage generated is out of phase. There are several ways of arranging the end connections of this design while giving the same electrical output. Most AC motors use the distributed winding design.
