If the ANSI ESD standard is correct, in that "Air breakdown at a fixed distance between arcing electrodes is approximately proportional to the atmospheric pressure..... " and "Typically, air breakdown at sea level will be about 40% higher than at 3000m."
By removing it, aren't you introducing a additional undocumented source of inconsistency? Dave Spencer From: [email protected] [mailto:[email protected]] On Behalf Of Derek Walton Sent: Tuesday, April 01, 2008 12:24 PM To: Pettit, Ghery Cc: [email protected]; [email protected] Subject: Re: Looking for Barometric pressure meter More interestingly, since it seems of little significance, why not remove the requirement altogether. One less source of inconsistency... Derek Walton Pettit, Ghery wrote: > > Which brings up the question - if the tests may be performed at any > pressure for which the EUT is rated, why specify a range in the first > place? > > And, to my knowledge, this isn't under discussion for any of the > documents under SC77B at this time. SC77B "owns" the 61000-4-x > documents we're discussing here. Important enough for me to bring up > to the US national committee? > > Ghery Pettit > > > > *From:* [email protected] [mailto:[email protected]] *On Behalf Of > *[email protected] > *Sent:* Tuesday, April 01, 2008 9:08 AM > *To:* [email protected] > *Subject:* RE: Looking for Barometric pressure meter > > > In IEC61000-4-5:1995 (Line Surge Immunity), clause 8.1.1 specified a > range of barometric pressure for testing. However, IEC61000-4-5:1995 > Amd. 1 changes that to say: > "... the climatic conditions in the laboratory shall be within any > limits specified for the operation of the EUT and the test equipment > by their respective manufacturers." > In other words, you can do the test at any barometric pressure, so > long as the equipment is rated for it. > > It wouldn't surprise me if that type of change is (or will be) > incorporated into other IEC test documents. > > Pat Lawler > EMC Engineer > SL Power Electronics Corp. > > [email protected] wrote on 04/01/2008 08:34:51 AM: > > In quickly checking the 61000-4-x series that are called out in CISPR > > 24, IEC 61000-4-2 (ESD) is the only one. Section 8.1.1 calls out the > > acceptable climatic conditions for performing the tests, and the > > atmospheric pressure must be between 86 kPa and 106 kPa. That's a range > > of 25.4 inches of Hg to 31.3 inches of Hg. As standard atmosphere at > > sea level is 29.92 inches of Hg at 59 degrees F, and pressure drops > > about 1 inch per 1000 feet of altitude gain, you can see that you hit > > the minimum pressure on a standard day at 4520 feet. Denver is at 5280 > > feet (one of the steps on city hall). Not sure how you can "legally" > > perform ESD testing in EMC labs in most of Colorado. :-) > > > Ghery > > > -----Original Message----- > > From: Derek Walton [mailto:[email protected]] > > Sent: Monday, March 31, 2008 5:14 PM > > To: Pettit, Ghery > > Cc: [email protected]; Garnier, David S (GE Healthcare); > > [email protected] > > Subject: Re: Looking for Barometric pressure meter > > > Hi Ghery, > > > I'm curious as to which EMI test requires pressure, and has limits set > > for it? > > > Cheers, > > > Derek Walton > > L F Research > > > Pettit, Ghery wrote: > > > > > > The information provided by the FAA and weather guessers is pressure > > > corrected to sea level. It is not the actual pressure. I can get an > > > altimeter setting in Denver (mile high) or Olympia (206 ft MSL) and it > > > > will be in the same range, even though the actual pressure in Denver > > > is about 5 inches of mercury lower. This is one of my favorite > > > questions when auditing a lab when they have a barometer on the wall - > > > > is that absolute pressure, or corrected to sea level? And I usually > > > get blank looks. And you want to report absolute pressure. > > > > > > Ghery Pettit > > > > > > PP-ASEL > > > > > > > > > > > > > > *From:* [email protected] [mailto:[email protected]] *On Behalf Of > > > *Cortland Richmond > > > *Sent:* Saturday, March 29, 2008 2:44 PM > > > *To:* Garnier, David S (GE Healthcare); [email protected] > > > *Subject:* RE: Looking for Barometric pressure meter > > > > > > Why not get the air pressure from the nearest FAA control tower by > > > radio? Critesfield Airport in Waukesha broadcasts airfield information > > > > that includes updated barometric pressure > > > > > > http://www.critesfield.com/facilities/ > > > > > > Cortland > > > > > > KAS/6 > > > > > > ----- Original Message ----- > > > > > > *From:* Garnier, David S (GE Healthcare) > > > <mailto:[email protected]> > > > > > > *To: *[email protected] <mailto:[email protected]> > > > > > > *Sent:* 3/28/2008 10:25:25 AM > > > > > > *Subject:* Looking for Barometric pressure meter > > > > > > Hello, > > > > > > I am looking for advice or suggestions for the purchase of a > > > Barometric pressure meter for our EMC lab... > > > > > > - ---------------------------------------------------------------- > > > This message is from the IEEE Product Safety Engineering Society > > > emc-pstc discussion list. Website: http://www.ieee-pses.org/ > > > > > > To post a message to the list, send your e-mail to [email protected] > > > > > > Instructions: http://listserv.ieee.org/request/user-guide.html > > > > > > List rules: http://www.ieee-pses.org/listrules.html > > > > > > For help, send mail to the list administrators: > > > > > > Scott Douglas [email protected] Mike Cantwell [email protected] > > > > > > For policy questions, send mail to: > > > > > > Jim Bacher: [email protected] David Heald: [email protected] > > > > > > All emc-pstc postings are archived and searchable on the web at: > > > > > > http://www.ieeecommunities.org/emc-pstc - > > > ---------------------------------------------------------------- This > > > message is from the IEEE Product Safety Engineering Society emc-pstc > > > discussion list. Website: http://www.ieee-pses.org/ > > > > > > To post a message to the list, send your e-mail to [email protected] > > > > > > Instructions: http://listserv.ieee.org/request/user-guide.html > > > > > > List rules: http://www.ieee-pses.org/listrules.html > > > > > > For help, send mail to the list administrators: > > > > > > Scott Douglas [email protected] Mike Cantwell [email protected] > > > > > > For policy questions, send mail to: > > > > > > Jim Bacher: [email protected] David Heald: [email protected] > > > > > > All emc-pstc postings are archived and searchable on the web at: > > > > > > http://www.ieeecommunities.org/emc-pstc > > > > > > - > > ---------------------------------------------------------------- > > This message is from the IEEE Product Safety Engineering Society > > emc-pstc discussion list. Website: http://www.ieee-pses.org/ > > > To post a message to the list, send your e-mail to [email protected] > > > Instructions: http://listserv.ieee.org/request/user-guide.html > > > List rules: http://www.ieee-pses.org/listrules.html > > > For help, send mail to the list administrators: > > > Scott Douglas [email protected] > > Mike Cantwell [email protected] > > > > For policy questions, send mail to: > > > Jim Bacher: [email protected] > > David Heald: [email protected] > > > > All emc-pstc postings are archived and searchable on the web at: > > > http://www.ieeecommunities.org/emc-pstc - > ---------------------------------------------------------------- This > message is from the IEEE Product Safety Engineering Society emc-pstc > discussion list. Website: http://www.ieee-pses.org/ > > To post a message to the list, send your e-mail to [email protected] > > Instructions: http://listserv.ieee.org/request/user-guide.html > > List rules: http://www.ieee-pses.org/listrules.html > > For help, send mail to the list administrators: > > Scott Douglas [email protected] Mike Cantwell [email protected] > > For policy questions, send mail to: > > Jim Bacher: [email protected] David Heald: [email protected] > > All emc-pstc postings are archived and searchable on the web at: > > http://www.ieeecommunities.org/emc-pstc > > - ---------------------------------------------------------------- > This message is from the IEEE Product Safety Engineering Society > emc-pstc discussion list. Website: http://www.ieee-pses.org/ > > To post a message to the list, send your e-mail to [email protected] > > Instructions: http://listserv.ieee.org/request/user-guide.html > > List rules: http://www.ieee-pses.org/listrules.html > > For help, send mail to the list administrators: > > Scott Douglas [email protected] Mike Cantwell [email protected] > > For policy questions, send mail to: > > Jim Bacher: [email protected] David Heald: [email protected] > > All emc-pstc postings are archived and searchable on the web at: > > http://www.ieeecommunities.org/emc-pstc > - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to [email protected] Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas [email protected] Mike Cantwell [email protected] For policy questions, send mail to: Jim Bacher: [email protected] David Heald: [email protected] All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to [email protected] Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas [email protected] Mike Cantwell [email protected] For policy questions, send mail to: Jim Bacher: [email protected] David Heald: [email protected] All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
