What is electric motor? Define its principle, its working, and its construction with the help of diagram....Dont copy from other website....If I have any doubt I will ask in comment section.
Answers
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An electric motor is a device which converts electrical energy into mechanical energy . Electric motor is used in electic fans, washing machines, refrigerators, mixers and grinder and many other appliances. These appliances have AC motor installed in them.
There are two types of electric motors:
(i) AC MOTORS
(ii) DC MOTORS
principle=>
When a coil carrying current is placed in a magnetic field, it experiences a torque.As a result of this torque, the coil begins to rotate .
i) Electric motor -
An electric motor is a rotating device that converts electrical energy to mechanical energy.
ii) Principle of electric motor -
An electric motor works on the principle of magnetic effect of current i.e., when a current carrying conductor is placed perpendicular in a magnetic field, It experiences a force as a result of which the conductor begins to move. The direction of force is determined by Felming's left hand rule.
iii) Construction of electric motor -
1) Armature coil - It consists of a single loop of an insulated copper wire in the form of a rectangle.
2) String field magnet - Armature wire is placed between 2 pole pieces of a strong magnet which provides strong magnetic field.
3) Split ring - It consists of 2 halves of a metallic ring. The two ends of armature coil are connected to these two halves of rings. Commutator reverse the direction of current in armature coil.
4) Brushes - Two carbon brushes press against the commutator. These act as contact between commutator and terminal batteries.
5) Batteries - It is connected across the carbon brush. It supplies current to the armature coil.
iv) Working of electric motor -
1) When electric current is passed into the rectangular coil, this current produces a magnetic field around the coil.
2) The magnetic field of horse shoe-type magnet then interacts with the magnetic field of the coil and causes the coil to rotate continuously.
3) 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 }
4) 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.
5) 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.
6) 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.
7) 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.
