Electric Motors and Their Principles

What is the primary function of an electric motor?

Which principle does a d.c. motor operate on?

What device is used to obtain the direction of force on the conductor in a d.c. motor?

Which component of an electric motor is responsible for rotating?

What connects the ends of the armature coil to the split ring commutator?

What are the split parts of a ring in an electric motor known as?

What role do brushes play in an electric motor?

What type of source is connected to the brushes in an electric motor?

In an electric motor, what happens when the coil rotates?

What configuration does the armature coil have in a d.c. motor?

Electric Motors

Electric motors convert electrical energy into mechanical energy to drive devices like fans, washing machines, and kitchen appliances.
A DC motor operates on the principle that an electric current through a conductor in a magnetic field generates a force, causing movement.

Operating Principle

The direction of the force acting on the conductor is determined by Fleming's left-hand rule, providing guidance on force direction in electric motors.

Key Components

Armature Coil: Wound around a soft iron core; allows rotation and is mounted on an axle.
Split Ring Commutator: Consists of two split parts of a copper ring, enabling the direction of current to change.
Brushes: Usually made from carbon or copper, press against the split rings for electrical connectivity.
Horse-shoe Electromagnet: Provides a strong magnetic field essential for motor operation.
DC Source: Typically a battery that supplies electrical power to the motor.

Motor Structure & Function

The armature coil (ABCD) is positioned between the pole pieces of the horse-shoe electromagnet (N and S).
The coil rotates about its axis when current flows through it, driven by the interaction with the magnetic field.
Ends A and D of the armature coil are linked to split parts of the commutator (S1 and S2).
Brushes B1 and B2 maintain contact with the split rings, allowing current to flow and enabling rotation.
A rheostat and key manage current flow from the battery to control the speed of the motor.

This quiz covers the basics of electric motors, including how they convert electrical energy into mechanical energy. You'll explore the working principle of a d.c. motor and its applications in various electric gadgets like fans and washing machines. Test your understanding of this fundamental electrical engineering concept.