DC Motor
Electric Motor
An electric motor is a rotating device used for converting electric energy into mechanical energy.
Principle:
An electric motor is based on the principle that when a rectangular coil is placed in a magnetic field and current is passed through it, two equal and opposite forces act on the coil which rotates it continuously.This force which rotates the coil is called as torque.
Construction:
It consists of a rectangular coil, say ABCD connected to a source of current and a switch. The commutators P and Q are fixed to the coil and pressed tightly against brushes X and Y. The function of commutator is to reverse the direction of current flowing through the coil every time, the coil passes the vertical position, i.e. after every half rotation in electric motor. In electric motor, split rings acts as commutator. The brushes are two flexible metal plates or the carbon rods which are so fixed that they continuously touches the revolving rings.
Working:
Electric motors involve rotating coils of wire which are driven by the magnetic force exerted by a magnetic field on an electric current. They transform electrical energy into mechanical energy.
The speed of rotation of the motor can be increases by:
1. Increasing the strength of the current in the coil.
2. Increasing the area of the coil.
An electric motor | |||
| Right Option : D | |||
| View Explanation |
Which of the following are correct : (a) An electric motor is a rotating device used for converting electric energy into mechanical energy. (b) An electric motor is used in electric fans used for cooling and ventilation. (c) An electric motor is used in water pumps. | |||
| Right Option : D | |||
| View Explanation | |||
A commutator changes the direction of current in the coil of | |||
| Right Option : A | |||
| View Explanation |
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