Page 277 - Basic Electrical Engineering

We have seen earlier that when a coil rotates in a uniform magnetic field the
EMF induced in the coil is sinusoidal in nature. The wave shape of an
alternating voltage or current produced in an ac generator having uniform

flux distribution is also sinusoidal in nature. However, an alternating quantity
may be non-sinusoidal also. Any non-sinusoidal wave can be seen as

consisting of a number of sinusoidal waves of different frequencies. Such
component sine waves of a non-sinusoidal wave are called harmonic waves.

In Fig. 3.4 (a) have been shown non-sinusoidal waves. In Fig. 3.4 (b) have
been shown non-sinusoidal waves and their corresponding component sine

waves. The component sine wave having the same frequency as the original
wave is called fundamental wave and the sine waves of higher frequencies
are called harmonic waves or simply harmonics.