"Andrew Carson" <acar...@uk.xyratex.com> wrote: > > I encountered a problem with power supply a few years back. It would haply > run across a wide range of input voltages, phase to neutral or phase ot > phase, it did not really care. Apart from one little capacitor sitting in > the EMF noise filter. It was polarized and only happy if the Phase and > neutral were the correct way around. The effect of reversing the polarity > was harmonic distortions with measured current harmonics upto the 39th > order. Also the immunity to the line noise changed, changing form happily > shaking of a 3kV surge, to watching the boost caps explode at a 2kV surge. > Would run with either terminal connected to the phase, but a whole new emc > profile. The standard offering had this capacitor, the USA version did > not. Only difference on the power supply, two letters in a 20 character > part number. These little things do sometimes catch designers by surprise.
I'm not quite sure I understand. The US version had to be used to pass immunity testing when the international version couldn't pass immunity? - Doug McKean ------------------------------------------- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson: pstc_ad...@garretson.org Dave Heald davehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.rcic.com/ click on "Virtual Conference Hall,"
