Explain Construction and working of electric motor
Define electric motor ?
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electric motor |
Construction of electric motor :
a) Rectangular coil: A large number of turns of insulated copper wire wound on iron core in rectangular shape forms a coil ABCD as shown in figure.
b) Strong magnet: The coil is place in between two pole pieces (N and S )of a strong horse shoe magnet which provide a strong magnetic field. The side AB and CD are perpendicular to the direction of magnetic field.
c) Splits ring:It consist of two halve metallic ring (X and Y).The end of the coil is connected to this ring. The outer conducting surface of split ring X and Y are in contact with the two stationary carbon brushes( E and F).Split ring reverse the direction of the current in the coil
d) Brushes : Two carbon brushes E and F are used to press the split ring.
e) Battery: It supply current to the coil.
f) Axle : two halve of the ring have resistive coating in their inner surface and are tightly fitted on the axle . The main function of axle is to rotate with coil.
Working of electric motor:
1-When the circuit is completed , the current flows in the branch AB of the loop from A to B through the carbon brushes E .
2-the direction of the magnetic field is from north pole to south pole, according to the Fleming’s left hand rule, a force is exerted on the branch AB and pushes it down and branch CD is in the upward direction.
3-Both these forces are equal in magnitude and opposite in direction and hence the coil rotates in anticlockwise direction.
4 -Thus, the loop and the axle start rotating in an anticlockwise direction.
5-After half rotation, the two halves of the split ring X and Y come in contact with carbon brushes F and E, respectively, and the current in a loop starts flowing in the direction DCBA.
6-The current in the loop is reversed after each half rotation and the loop and the axle continue to rotate in the anticlockwise direction
7-Thus the coil rotate with the help of electrical energy.