ABSTRACT
Harmonics is a pure tones making up a composite tone in music. A pure tone is a musical sound of single frequency, and a combination of many pure tones makes up a composite sound. Sound waves are electromagnetic waves traveling through space as a periodic function of time. Harmonic number refers to the individual frequency elements that comprise a composite waveform. A reason for using harmonic numbers is the simplification realized in performing mathematical operations involving harmonics. As their names imply, odd harmonics have odd numbers, and even harmonics have even numbers. Many of the loads installed in present-day power systems are harmonic current generators. Adjustable speed drives are generators of large harmonic currents. Fluorescent lights use less electrical energy for the same light output as incandescent lighting but produce substantial harmonic currents in the process. Harmonic currents influence the operation of protective devices. Fuses and motor thermal overload devices are prone to nuisance operation when subjected to nonlinear currents.
