With the advent of electrical energy distribution systems and their universal adoption throughout the world for the purpose of lightening and power the field of electric motors especially the AC type has shown a remarkable development in all prospects all over the world. As a result of the technological advancements the engineers throughout the world tried their best of best to come out with the most energy efficient and safe machines particularly, in the context of electric motors.
In this report we will confine our discussion up to electric motors, their construction, operations, applications, performance and emphasize on the Alternating Current type.
An electric motor is a device which transfers electrical energy in to mechanical energy which is either rotational or kinetic energy. There are two major classifications of electric motors on the basis of the type of electric input on which they operate obviously, AC and DC.
Basic Construction of an AC motor
Above is the basic construction of an AC motor. It consists of a couple of magnets with opposite polarities from each other. The purpose of these magnets is to create a magnetic field in between them whose direction is such that it will remain perpendicular to the coil at every point of rotation. For this purpose the poles of the magnets are made concave to concentrate the magnetic field towards the centre. A rectangular coil of soft iron core wounded with copper wire is placed freely in between the magnets which are connected with the AC terminals through a pair of slip rings known as carbon brushes to prevent wear and tear of the coil and to minimize the frictional