An electric motor is an electrical machine that converts electrical energy into mechanical energy.
Principle: When a current carrying conductor is placed in a magnetic field perpendicular to it, it experiences a force.
Construction: Consider a rectangular coil ABCD placed in a magnetic field such that AB and CD are perpendicular to the direction of magnetic field. The ends of coil are connected to two halves split rings. The inner sides of split rings are insulated and attached to an axle. The external conducting edges of split rings touch two carbon brushes. The opposite sides of brushes are connected with battery and key
A device that reverses the direction of flow of current through a circuit is called a commutator. The soft iron core, on which the coil is wound, plus the coils is called an armature.
Working: The current in the coil ABCD enters from brush X. Since current carrying coil ABCD is placed in a magnetic field perpendicular to it. So by Fleming’s left hand rule, we can say that AB moves in downward and CD moves in upward direction. In next half rotation, CD comes towards north pole and AB comes towards south pole. Again by applying Fleming’s left hand rule, we see that AB moves in upward and CD moves in downward direction. This process continues and the coil starts rotating.
Uses: It is used in electric fans, refrigerator, mp3 player, washing machine etc.