Brief summary of IEC61000-3-2

Laplace Standards

IEC/EN61000-3-2

Limits for harmonic current emissions (Equipment input current <16 per phase).

This standard becomes a mandatory requirement on Jan 1st 2001.

This standard deals with the limitation of harmonic currents injected into the public mains supply system. It is applicable to electrical and electronic equipment having an input current up to and including 16A per phase and intended to be connected to public low-voltage distribution systems (ie supply voltages nominally 230V ac or 415V ac 3 phase.
The scope includes products such as lighting equipment, portable tools, all electronic equipment, consumer products and appliances and industrial equipment.
This standard does not cover equipment which has a nominal supply voltage less than 220V ac and no limits have been specified for professional equipment above 1kW.

Note however that there is a similar US document IEEE-std-519:1992 and the Japanese are proposing a variation for use in Japan.

Whilst the EUT is operating under specified conditions, the harmonic content of the current drawn by the EUT is measured. There are currently four sets of limits that are applied corresponding to the ‘class’ of the equipment. Classes are A, B, C or D depending on the type of EUT and, in some cases, the current ‘waveshape’.

Class A:	Balanced three phase equipment and all other equipment, except that stated in one of the following classes.
Class B:	Portable tools.
Class C:	Lighting equipment, including dimming devices.
Class D:	Equipment having an input current with a ‘special wave shape’ (defined in the standard)

The ‘Waveshape’ criteria does not apply to Class B or Class C products.

For each class, a set of harmonic limits are specified.
Class A and B limit values are specified as absolute levels and include all harmonics up to the 40th.
Class C limits are specified as a percentage of the fundamental current and are applied to the odd harmonics only (up to 39th).
Class D limits are specified in terms of rated load condition (W) with an additional absolute maximum. Again these are applied to the odd harmonics only (up to 39th).

Whilst testing the product, the input mains supply should itself be free of mains harmonics. Limits are specified for the value of allowable harmonic content in the supply. Typical mains supplies will exceed these limits thus the use of a special power source to deliver harmonic free mains is normally required.
The standard specifies in detail how the harmonics are measured, with particular attention given to fluctuating harmonics and test conditions.

The Laplace RFH kit includes all that is required for full compliance testing of products up to 1kW rating. It includes a harmonics and flicker analyser, PC software and a 1kW clean power source. For products with a rating >1kW, the harmonics analyser can be used up to 16A per phase, but the mains supply must be provided either by an appropriate power source or the public mains supply. The analyser includes a function that will measure the mains supply harmonics so that the siutability of the mains can be checked.

AC2000	Mains harmonics analyser. Fully complies with IEC61000-3-2.
AC2000-PC	PC software for display, documentation and archiving of results.
AC1000	1kW power source. Provides a ‘harmonic free’ mains supply to comply with IEC61000-3-2 requirements.

Help in the selection of the appropriate measurement techniques and automatic display of the relevant limit levels are standard features in the software provided with all Laplace EMC analysers. Note The above is for guidance only. Refer to the published standard for definitive details, exclusions and exceptions and detailed test technique.


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