What is an Electric Motor? State its Principle.

An electric motor is a device that converts electrical energy into mechanical energy, and it operates on the principle of electromagnetic induction.

The principle of an electric motor is based on Ampere’s law and Faraday’s law of electromagnetic induction. When an electric current flows through a conductor in the presence of a magnetic field, it experiences a force, known as the Lorentz force. This force causes the conductor to move, resulting in mechanical motion. In an electric motor, this principle is utilized to generate rotational motion.

The key components of an electric motor include a coil of wire (armature), a magnetic field (usually created by permanent magnets or electromagnets), and a commutator. As the electric current flows through the coil in the magnetic field, it experiences a force that causes it to rotate. The commutator ensures that the direction of the current in the coil reverses periodically, resulting in continuous rotation.

The mathematical calculation of the motor’s rotational speed can be determined using the formula:

Rotational Speed (in RPM) = 60 × Frequency (in Hz)​ ÷ Number of Poles

Electric motors are crucial in various applications, from powering household appliances to driving industrial machinery and vehicles. They are highly efficient and versatile devices that play a fundamental role in modern technology and automation.