Application of EN61000-3-2

[Benoit Nadeau]

Bonjour de Montreal,

Matrox is mainly build computer graphic add-on cards. Our philosophy regarding an harmonic emission testing is to ensure that, when installed in a PC that meets the actual standard, our product do not make the systems to fail. Everything was fine for a long time, and we were using an outside lab, NVLAP listed, to perform this test for us. Beginning of this year we decided to buy our own test equipment for harmonic measurements. One day we were testing one of our product in one system and we get a failing result. We then removed the card and we did get a pass situation. Looking at the measurement data we notice that there was no limit when our card was not installed because the power rating at that moment was less than 50 watts. We then returned to the standard and noticed that the appendix C was specifying testing conditions for ITE. Section C.10 states that the ITE is tested with the equipment configured to its rated current, they even specify that we have to had additional load boards to simulate the rated current conditions.

This is what we did to the PC and we got a failing result each time that we exceed 50 watts. We did that with all the platforms we had around with failing conditions for each. We then ask our outside lab to know if they were loading the power supplies of the systems they test to bring them in a rated current condition, we never got an answer... which is suspicious. We also communicated with Systems manufacturer who told us that the interpret the rated current as a typical load condition. This means as is for the proposed test configuration which should be consistent with EN 55022.

What are you views about this, should we charge up a 200 watts PC power supply only with the devices installed in the system or should we charge it up to the actual current specified on the system name plate (usually 2 amps at 240 volts).

This situation will become even more critical as the 50 watts will become mandatory in (or around) 1999.

Thank you for your lights,






--------------------------------------------------------------------------
Benoit Nadeau, ing. M.ing. (P.eng., M.eng)
Gerant du Groupe Conformite (Conformity Group Manager)
Matrox <http://www.matrox.com/>
--------------------------------------------------------------------------

1055, boul. St-Regis
Dorval (Quebec) Canada
H9P 2T4

Tel : (514) 969-6000 (x2475)
FAX : (514) 969-6275
Internet : bnad...@matrox.com, <mailto:bnad...@matrox.com>