Explain the construction and working of an electric motor. Draw a neat diagram and label it.

Explanation

Figure shows the construction of an electric motor. Here, a rectangular loop ABCD of copper wire with resistive coating is placed between the north pole and south pole of a strong magnet, such as a horseshoe magnet, such that the branches AB and CD are perpendicular to the direction of the magnetic field. The ends of the loop are connected to the two halves, X and Y, of split rings-X and Y have reslstive conting on their inner surfaces at are tightly itted on the axle. The outer conducting Hurfaces of X and Y are in contact with two stationary carbon brushes, E and F, respectively,
Working : (1) When the circuit is completed with a plug key or awitch, the current flows in the direction `E to A to B to C to D to F`. As the magnetie fleld is directed from the north pole to the Bouth pole, the force on AB is downward and that on CD is upward by Fleming's left hand rule. Hence, All moves downward and CD upward. These forces are equal in magnitude and opposite in direction Therefore, as observed from the side AD, the loop ABCD and the axle atart rotating in anticlockwise direction.
(2) After half a rotation, X and Y come in contact with brushes F and E respectively and the current flows in the direction EDCBAF. Hence the force on CD is downward and that on AB is upward. Therefore, the loop and the axle continue to rotate in the anticlockwise direction.
(3) After every half rotation, the current in the loop is reversed and the loop and the axle continue to rotate in anticlockwise direction. When the current is switched off, the loop stops rotating after some time.