With phase connected to the phase terminal and neutral connected to the neutral terminal, the international version was fine on the immunities. It was only when the PSU was connected to a phase to phase supply, or the phase and neutral reversed, that the problem became apparent. An example of, despite outward appearances, not all supplies can be reliably connected to phase to phase or any input terminal to phase and the other to neutral.
Doug McKean wrote: > "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," -- Andrew Carson - Product Safety Engineer Xyratex Engineering Laboratory Tele 023 92496855 Fax 023 92496014 ------------------------------------------- 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,"
