Background[ edit ] With the emergence of large scale distributed electronic devices, first the radio with electronic valves, and later TV and Personal Computers, there has been a fundamental problem with mains pollution by harmonic currents. All mentioned electronic apparatus need a smoothed DC voltage as supply. A simple and cheap means of getting low ripple is to use a relatively inexpensive electrolytic capacitor with high capacitance values, direct coupled after the mains voltage rectifier. Smoothing the DC voltage can also be effected by inductors , but these are much more expensive, and have relatively large size, and large weight, but would generate much less harmonic currents. Sinusoidal voltage and non-sinusoidal current give a distortion power factor of 0. The result of mains rectifiers with connected large value smoothing capacitors is that mains current only flows in the peaks and valleys of the AC wave.
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IEC deals with the limitation of harmonic currents injected into the public supply system. It specifies limits of harmonic components of the input current which can be produced by equipment tested under specified conditions.
It is applicable to electrical and electronic equipment having a rated input current up to and including 16 A per phase, and intended to be connected to public low-voltage distribution systems. Arc welding equipment which is not professional equipment, with a rated input current up to and including 16 A per phase, is included in this document. Arc welding equipment intended for professional use, as specified in IEC , is excluded from this document and can be subject to installation restrictions as indicated in IEC The tests according to this document are type tests.
For systems with nominal voltages less than but not equal to V line-to-neutral , the limits have not yet been considered. This fifth edition cancels and replaces the fourth edition published in This edition constitutes a technical revision. Keywords: harmonic currents.
IEC System of Conformity Assessment Schemes
BS EN 61000-3-2:2014