Explain the principle,construction and working of an electric motor with the help of labeled diagram.
Answers
Principle of motor : A motor works on the principle that when a rectangular coil is placed in a magnetic field and current is passed through it. A force acts on the coil which rotates it continuously.

When electric current is passed into the rectangular coil, this current produces a magnetic field around the coil.
The magnetic field of horse shoe-type magnet then interacts with the magnetic field of the coil and causes the coil to rotate continuously.
If ABCD is in horizontal position current from battery enters the coil through brush $B _{ 1 }$, and commutator half ring C:. The current flows in the direction ABCD
and leaves via ring and brush $B _{ 2 }$
The direction of current is from A to B, the direction of current is from C to D. The force on side AB of the coil is in the downward direction. Whereas the force on the side CD of the coil is in the upward direction. ABCD rotate in anti-clockwise direction.
While rotating when the coil reaches vertical position then the brushes $B _{ 1 }$ and $B _{ 2 }$ will touch the gap between the commutator rings and current to the coil is cut off. But the coil does not stop rotating because it has already gained momentum.
The coil CD comes on the left side and AB comes to the right side. Again they come in contact with brush $B _{ 1 }$ Current direction is reversed.
The reversing of current in the coil is repeated after every half rotation due to which the coil continue to rotate as long as current from the batter is passed through it. The rotating shaft of electric motor can drive a large number of machines which are connected to it.
ANSWER:-
Electric motor is a device which converts electrical energy into mechanical energy.
Principle: electric motor is based on the principle that a current carrying conductor placed perpendicular to the magnetic field experiences a force.
Construction:
Armature coil: it consist of a rectangular coil of wire placed between the poles of a strong magnet.
Strong field magnet: Armature coil is placed between the two poles of a strong magnet. This magnet provides a strong magnetic field.
Split-ring type commutator: It consists of two halves (P and Q) of a metallic ring. The two ends of the armature coil are connected to these two halves of the ring. It reverses the direction of current in the armature coil.
Brushes: Two carbon brushes X and Y press against the commutator. These brushes acts as the contacts between the commutator and the terminals of the battery.
Battery: A battery is connected across the carbon brushes. This battery supplies the current in the armature coil.
Working:
• Initially, the current in the coil ABCD enters brush X and flows back to the battery through brush Y. Thus, the current in the arm AB flows from A to B.
• In arm CD,the current flows from C to D ,that is , opposite to the direction of current through arm AB.
• On applying Fleming’s left hand rule, we find that force acting on arm AB pushes it downwards while the force acting on arm CD pushes it upwards.
• Thus the coil and axle, rotate anti-clockwise.
• After half rotation, Q makes contact with the brush X and P with brush Y. Therefore the current in the coil gets reversed and flows along the path DCBA.
• The reversal of current also reverses the direction of force acting on the two arms AB and CD.
• Thus, now arm AB is pushed up and the arm CD is pushed down.
• Therefore the coil and the axle rotate half turn more in the same direction.
• The reversing of the current is repeated at each half rotation, giving rise to a continuous rotation of the coil and to the axle.
HOPE THAT HELPS!!!
