I've been waiting for comments on this aspect of the standard since first reading it.
Firstly, for plug-in cards, I do not think that IEC1000-3-2 testing is applicable. It is for equipment that has an input current of <= 16 Amps per phase and, as such, only applies to units that are AC powered. Your plug-in cards are dc powered. The spec only applies to the host equipment, which should be tested with the system "fully loaded". Obviously the host systems you are using were not tested. As for "fully loaded"....my opinions: Most current ratings on a unit are rounded up to match the appropriate fuse sizes available and not necessarily the actual maximum TYPICAL current. For a unit which cannot take additional internal boards and has no external ports that provide power to peripherals there should be no need to load the supply to the rated current on the unit. Take, for example, a monitor with a current rating of 1 Amp at 230V. Apart from varying the video signal, refresh rates and resolutions there is no way of loading the supply above and beyond the typical usage, which may be only 800mA. It seems ridiculous to have to open up the unit to load up the power supply to the rated 1 Amp. On the other hand - for a unit that can take additional cards (e.g. PC), can provide auxiliary power to peripherals or for a power supply with a maximum output rating the device under test should be loaded as stated in the specification using resistive loads until the maximum rated current is obtained. The standard does not adequately address such issues. Combined with the confusion that implementation dates/dates of withdrawal have added this standard (and trying to work with it) is proving to be a "headache". Mark Mark Briggs [email protected]
