Question

Explain the electric generator.

Answer 1

Electric generator:

An electric generator is a device that converts mechanical energy into electrical energy.

Principle:

An emf will induce whenever there is a change in magnetic flux.

Magnetic flux is defined as,

$\varphi =BA\cos \omega t$

Here,

$\mathrm{B}$ is the field.

$\mathrm{A}$ is the area.

$\omega$ is the angular speed at which it is rotating.

According to Faraday's law. induced emf is:

$\begin{array}{c}\mathrm{\epsilon }=|-\frac{\mathrm{d\varphi }}{\mathrm{dt}}|\\ =\left|\frac{\mathrm{d}}{\mathrm{dt}}\left(\mathrm{BAcos\omega t}\right)\right|\\ \mathrm{\epsilon }=\mathrm{BA\omega sin\omega t}\end{array}$

Parts of electric generator:

A general diagram of the electric generator is shown below:

1. A magnet.
2. An armature - ABCD (A coil structure made up of copper wires which can rotate in the field).
3. A motor (petrol or diesel) - It is used to rotate the armature in the field (the axis of the armature is connected to the motor).

Here,

1. S and N are representing the south and north poles as magnets.
2. ABCD is an armature or copper wires loop.

Working:

1. A mechanical motor attached to the ABCD will rotate the loop in the magnetic field.
2. As the loop rotates, magnetic flux changes due to a change in angle.
3. This will create an induced emf.
4. If we connect the armature to an external resistor or instrument, an electric current will flow through it.

Types of electric generators:

There are two types of electric generators

1. AC - Alternating current (direction of current changes)
2. DC - Direct current (direction of current does not change)