Write the principle of the electric motor. Explain the construction and working of the motor. Draw labeled diagram. ( CBSE 2016, 2014)

The labelled diagram of an electric motor is shown below:

The electric motor is a device which converts electrical energy to mechanical energy. When a rectangular coil is placed in a magnetic field and current is passed through it, forces acts on the coil which rotates it continuously. When the coil rotates, the shaft attached to it also rotates. In this way the electrical energy supplied to the motor is converted into the mechanical energy of rotation.

The direction of magnetic forces is towards our right side and the direction of current is clockwise as we look into the diagram.

In an electric motor the role of split rings is to reverse the direction of current flowing through the motor coil after every half rotation of the coil. Due to this reversing of current, the direction of force remains unchanged on the two sides of the coil and hence the coil continues to rotate in the same direction