What is harmonics?
Harmonics are a form of noise, produced in frequencies which are a multiple of the basic 60 cycle sine wave. They are caused by switching power supplies and in other sophisticated machines, including computers and variable frequency drivers. Harmonics can distort the basic sine wave, as well as cause high currents on the neutral and ground wires in a system.
Harmonics are defined as the sinusoidal components of a non-linear periodic waveform with a frequency that is a whole multiple of the fundamental frequency. Putting this simply; any switching operation of the mains supply sine wave will produce lots of other sine waves at higher frequencies. These are not apparent but they are harmful. Harmonics are currents or voltages with frequencies that are integer multiples of the fundamental power frequency being 50 or 60Hz (50Hz for European power and 60Hz for American power). For example, if the fundamental power frequency is 60 Hz, then the 2nd harmonic is 120 Hz, the 3rd is 180 Hz, etc. In modern test equipment today harmonics can be measured up to the 63rd harmonic. When harmonic frequencies are prevalent, electrical power panels and transformers become mechanically resonant to the magnetic fields generated by higher frequency harmonics. When this happens, the power panel or transformer vibrates and emits a buzzing sound for the different h
