Question

What is the use of an electric motor? Discuss the construction, working principle and working of an electric motor with the help of a labelled diagram.

Hint:

Electric motors are integral in converting electrical energy into mechanical energy, used in everyday appliances and industrial machines.

Answer 1

Use of an Electric Motor:
An electric motor is a device that converts electrical energy into mechanical energy through the interaction of magnetic fields and electric currents. It is widely used in various appliances and machinery, such as fans, refrigerators, washing machines, and industrial machines.
Construction of an Electric Motor:
The main components of an electric motor include: 1.
Armature:
A coil of wire that rotates within the magnetic field. It is attached to a shaft that rotates to produce mechanical motion. 2.
Magnet:
The permanent magnet or electromagnet provides the magnetic field in which the armature rotates. 3.
Commutator:
A split ring that reverses the direction of the current in the armature coil at regular intervals to ensure continuous rotation. 4.
Brushes:
These are made of carbon and maintain electrical contact with the rotating armature coil. 5.
Power Source:
The external source of electrical energy that supplies the motor with current.
Working Principle:
The working of an electric motor is based on the principle that when a current-carrying conductor is placed in a magnetic field, it experiences a force (Lorentz force). The direction of the force is given by Fleming's Left-Hand Rule. The force on the armature causes it to rotate, converting electrical energy into mechanical energy.
Working of an Electric Motor:
- When current flows through the armature, it creates a magnetic field around the coil. This interacts with the external magnetic field, producing a force on the armature that causes it to rotate.
- As the armature rotates, the commutator reverses the direction of current flow in the coil at appropriate intervals to keep the armature rotating in the same direction.
- The mechanical energy produced by the rotating armature is used to drive the external machinery connected to the motor.

Conclusion:
An electric motor is essential for converting electrical energy into mechanical work in many devices. Its construction involves components like the armature, magnet, commutator, and brushes, and its working principle revolves around the interaction of magnetic fields and electric currents.