DC motor: Revision Notes
An electric motor is used to convert electrical energy into mechanical energy.
Main parts of electric motor-
- Power Source: A simple motor usually has a DC power source. It supplies power to the motor armature or field coils.
- Commutator: It is the rotating interface of the armature coil with a stationary circuit.
- Field Magnet: The magnetic field helps to produce a torque on the rotating armature coil by virtue of Fleming’s left-hand rule.
- Armature Core: Holds the armature coil in place and provides mechanical support.
- Armature Coil: It helps the motor to run.
- Brushes: It is a device that conducts current between stationary wires and moving parts, most commonly the rotating shaft.
working of DC motor
he working of an electric motor is based on the fact that a current-carrying conductor produces a magnetic field around it. To better understand, imagine the following situation.
Take two bar magnets and keep the poles facing each other with a small space in between. Now, take a small length of a conducting wire and make a loop. Keep this loop in between the space between the magnets such that it is still within the sphere of influence of the magnets. Now for the last bit. Connect the ends of the loop to battery terminals.
Once electricity flows through your simple circuit, you will notice that your loop “moves”. So why does this happen? The magnetic field of the magnets interferes with that produced due to electric current flowing in the conductor. Since the loop has become a magnet, one side of it will be attracted to the north pole of the magnet and the other to the south pole. This causes the loop to rotate continuously. This is the principle of electric motor.
