Re: Awards for Worst EMC/PS qualities
Most of the stories are stories about EMC fixes. I've got one that is not and won't be fixed. I just live with it! It involves my '96 Honda Accord, bought new. I'm in San Diego, about 100 miles south of Los Angeles. I noticed that 50 kW Los Angeles AM stations such as KFI and KNX were really quite noisy on my car radio. So, too, are some of the local, San Diego AM stations. When I pull into my garage (in my stucco home with chicken-wire EMC shielding), the signals disappear into the noise. I chalked it up to poor AM design of the radio, or to the rear window antenna. (No whip antenna on this Honda!) One day, upon arriving at work, I turned off the ignition, but left it in the accessory position. The radio noise disappeared and the radio was clear! I repeated the same thing as I pulled into my garage. While there was some noise, most of it disappears when the ignition is turned off. The noise appears as soon as the ignition is turned on, and before the engine is started. Starting the engine has no effect on the noise. The AM radio is almost useless except for the strongest stations! Unless the iginition is off. Best regards, Rich - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, j...@gwmail.monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
RE: NRTL requirement in the NEC?
Jeff, It's a bit difficult to provide an exact answer since it's dependent on the design of your system. Is the system approved by an NRTL? What is the nature of the approval (i.e. listed, recognized, field investigated, etc.). Different AHJ's may interpret and accept different markings from some NRTLs as opposed to all markings from any NRTLs and it would have to be on your shoulders to convince him/her otherwise. I suspect the inspector is drawing upon section 90-7 of the NEC and also the definition of Listed in article 100. My 2 Cents, Kaz Gawrzyjal k...@nortelnetworks.com -Original Message- From: JENKINS, JEFF [SMTP:jeff.jenk...@aei.com] Sent: Thursday, March 11, 1999 10:48 AM To: 'emc-pstc' Subject: NRTL requirement in the NEC? Hello Group, Has anyone heard of a requirement in the National Electrical Code that power supplies which are components of larger systems be approved by an NRTL? I have an inspector telling me this, but our copy of the NEC is 20 years old, and I can't find it, anyway. In this case, the power supply is part of a rack system. It was my understanding that the supply could be evaluated as a component of the system. Is that not true? Thanks, Jeff Jenkins Senior Regulatory Compliance Engineer Advanced Energy Industries, Inc. Fort Collins, CO USA 80525 Opinions are my own and not necessarily shared by Advanced Energy Industries, Inc. or its affiliates. - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, j...@gwmail.monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators). - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, j...@gwmail.monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
Leakage Current Measurements
Dear All Safety Engineers/Technicians, I would like to make a survey of what test equipment (multimeter, scope, etc.) you or your friendly test house use to measure the voltage during the leakage current measurements in UL1950/EN 60 950. WE USE: OUR THIRD PARTY TEST HOUSE USES: PETER S. MERGUERIAN MANAGING DIRECTOR PRODUCT TESTING DIVISION I.T.L. (PRODUCT TESTING) LTD. HACHAROSHET 26, P.O.B. 211 OR YEHUDA 60251, ISRAEL TEL: 972-3-5339022 FAX: 972-3-5339019 E-MAIL: pe...@itl.co.il Visit our Website: http://www.itl.co.il - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, j...@gwmail.monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
Re: Awards for Worst EMC/PS qualities
Ed, now THAT is a good one. it should win. It's not that unusual though. It happens quite often just like you said, specially the part about the VP getting promoted. The tester gets blamed if the room fails. They dont want you to find leaks, they want you to do something and then write a report saying that it passes. It's no joke though. When that classified data leaks out and runs down the hillside it can, and occasionally DOES, get someone's kid killed. If he or she is the right age and wearing a uniform, it might be YOUR kid. Lou At 08:59 AM 3/11/99 -0800, you wrote: Subject: Awards for Worst EMC/PS qualities Author: b...@namg.us.anritsu.com (Bailin Ma) at Internet Date:03/08/1999 8:03 AM Hi Group, We have already seen awards for the most misleading ads, worst attire, worst films, . Why not awards for worst EMC and PS qualities? Barry Ma Morgan Hill, CA 95037 OK, I'll submit just one more entry, even though this will need a new category (which I'll call Stupid Construction). Many years ago, a very large defense contractor decided that a black program needed multiple shielded enclosures within their SCIF so as to keep their classified data from leaking out and running down the hillside. So, the Program Manager talked to the Facilities Engineer, and together they said We can build our own TEMPEST shielded room. We will even do it cheaper and faster than any of these dumb quotes we have. So it came to be that they ordered much chicken wire, and beryllium copper fingerstock, and lumber, and drywall panels, and oh yes, very very many 2 long drywall screws. And a three phase powerline filter. And the facilities laborers then labored mightily for what may have been months; no one really knows. But finally, it was completed. It was painted, and carpeted, and even had plywood veneer paneling on the walls. It also had fluorescent lights in each room. And telephones in each room (but alas, no telephone line filters). And the program occupied the area, setting up their computers and test equipment and their other stuff. After a while, the more troublesome technicians began to wonder why their pagers had no problem functioning within the rooms, and that workers could enjoy FM broadcast radio at their workstations. Wasn't this supposed to be an RF shielded facility? I arrived on site, with spectrum analyzer and trusty loop antenna (three turns of the extended coax center conductor formed into a loop). I'd find those leaks and plug 'em fast. The first thing I noticed was that the room doors were ordinary steel office doors, with painted frames. The fingerstock had been screwed over the painted surfaces. Many of the fingers were broken, bent or missing. And the steel door frame was mounted to the drywall. The RF shield consisted of chicken wire, a wide-mesh, twisted steel wire construction. The name should tell you what it was good for. The average chicken cannot be forced through a chicken wire barrier (at least without significant distortion). AM broadcast radio uses a wavelength long enough that the barrier yields a certain amount of shielding. But FM broadcast slips through like a mosquito. So I started to probe one of the rooms. I just tuned the SA to one of the many convenient signals around 100 MHz, and started to sweep the room. Not only did the mesh screen leak like crazy, but it also turned out that most of those many thousands of drywall screws went right through the wall without touching the mesh. So EACH of these little conductive rods acted as a path for RF in and out of the screen barrier. There were no leaky points; it was like playing laser tag in an infinite hall of mirrors. And, just to show that none of the basics of proper shielding technique had been followed, I found that the powerline filter was located about 75 feet away from the shielded rooms. The filtered power was run to the room in PVC conduit, and the filter was grounded by a six foot long #00 pigtail. After wandering the facility for about two hours, I was approached by the Program Manager, who inquired about my corrective actions. I told him something to the effect that I hadn't been able to find any shielded rooms, but that if we stripped this area clear to the concrete, we could build some right here. I went on to detail that I had seen just about every shielding mistake you could make, all concentrated in one place. This site could qualify only as a museum of inverse shielding. Bad report, bad career action. I went back to testing noisy gadgets that smelled vaguely of ozone. The customer wouldn't let them use the rooms for classified work. A year later, the PM became a VP. -- Ed Price ed.pr...@cubic.com Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA. USA 619-505-2780 Date: 03/11/1999 Time: 08:59:26 -- - This message is coming from the emc-pstc discussion list. To cancel your subscription, send
RE: Awards for Worst EMC/PS qualities
February 1999: There we were sitting in the delivery room waiting for the baby to come The TV is on in the room (to distract the wife in between contractions...it didn't work but that's a different story). Attached to my wife is an automated rather new and high tech looking blood pressure machine (manufacturer name withheld to protect the guilty). Every 10 minutes it auto inflates the cuff and takes the BP readings making a nice little table and graphs on the display screen. Every time the thing goes on, without fail, the TV picture and sound go berserk. Major static on both regardless of channel. Hm... And you thought these problems were all back in the dark days of early electronics. I would have written down the model and manufacturer, tried to find their EMC engineer if possible and sent him/her a very sarcastic note, but soon after that I was distracted for some reason. Mom and baby are doing fine, but the long term effects of broadband 50 to 800Mhz (broadcast TV freqs) will remain to be seen. ;-) Richard Cass -Original Message- From: b...@namg.us.anritsu.com (Bailin Ma) at internet Sent: Monday, March 08, 1999 2:22 PM To: emc-p...@ieee.org at INTERNET Subject: Awards for Worst EMC/PS qualities Hi Group, We have already seen awards for the most misleading ads, worst attire, worst films, . Why not awards for worst EMC and PS qualities? Barry Ma Morgan Hill, CA 95037 - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, j...@gwmail.monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators). - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, j...@gwmail.monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
re: Visible Light EMC
Allen, You are right. Transparent solids have much less loss for light waves than opaque. And mirror-like solids reflect most of light waves. B Ma - Original Text From: Allen Tudor allen_tu...@pairgain.com, on 3/11/99 1:21 PM: This question sounds goofy, but here goes anyway Why doesn't visible light travel through solid objects (plastic, wood, etc)? Unless I've totally missed the boat, visible light is electromagnetic energy beginning at about 100,000GHz. So why doesn't it behave like electromagnetic energy in the radio spectrum? My guess is that it has something to do with the wavelength vs. the thickness of the object. Allen Tudor, Compliance Engineer PairGain Technologies tel: (919)875-3382 2431-153 Spring Forest Rd. fax: (919)876-1817 Raleigh, NC 27615 email: allen_tu...@pairgain.com - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, j...@gwmail.monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators). - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, j...@gwmail.monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
Re: NRTL requirement in the NEC?
Jeff Hi! Most probably your rack system is operating in an industrial environment. Power Supplies used in such environments must either be Listed to UL508 or if Recognized (to UL1950 for example) can be accepted if loaded to 50% of its rating. I am not sure where in the NEC you can find this information, but one of my ITE power supply manufacturers just obtained Listing to UL508 because of such problems in the field. Regards, Hello Group, Has anyone heard of a requirement in the National Electrical Code that power supplies which are components of larger systems be approved by an NRTL? I have an inspector telling me this, but our copy of the NEC is 20 years old, and I can't find it, anyway. In this case, the power supply is part of a rack system. It was my understanding that the supply could be evaluated as a component of the system. Is that not true? Thanks, Jeff Jenkins Senior Regulatory Compliance Engineer Advanced Energy Industries, Inc. Fort Collins, CO USA 80525 Opinions are my own and not necessarily shared by Advanced Energy Industries, Inc. or its affiliates. - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, j...@gwmail.monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators). PETER S. MERGUERIAN MANAGING DIRECTOR PRODUCT TESTING DIVISION I.T.L. (PRODUCT TESTING) LTD. HACHAROSHET 26, P.O.B. 211 OR YEHUDA 60251, ISRAEL TEL: 972-3-5339022 FAX: 972-3-5339019 E-MAIL: pe...@itl.co.il Visit our Website: http://www.itl.co.il - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, j...@gwmail.monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
RE: Awards for Worst EMC/PS qualities
Ed, if there is a grand prize to be awarded here for the most amusing account ... you've got it hands down with this one... and your closing statement, is a gem ! george -Original Message- From: ed.pr...@cubic.com [SMTP:ed.pr...@cubic.com] Sent: Thursday, March 11, 1999 11:59 AM To: EMC-PSTC Subject: Re: Awards for Worst EMC/PS qualities Subject: Awards for Worst EMC/PS qualities Author: b...@namg.us.anritsu.com (Bailin Ma) at Internet Date:03/08/1999 8:03 AM Hi Group, We have already seen awards for the most misleading ads, worst attire, worst films, . Why not awards for worst EMC and PS qualities? Barry Ma Morgan Hill, CA 95037 OK, I'll submit just one more entry, even though this will need a new category (which I'll call Stupid Construction). Many years ago, a very large defense contractor decided that a black program needed multiple shielded enclosures within their SCIF so as to keep their classified data from leaking out and running down the hillside. So, the Program Manager talked to the Facilities Engineer, and together they said We can build our own TEMPEST shielded room. We will even do it cheaper and faster than any of these dumb quotes we have. So it came to be that they ordered much chicken wire, and beryllium copper fingerstock, and lumber, and drywall panels, and oh yes, very very many 2 long drywall screws. And a three phase powerline filter. And the facilities laborers then labored mightily for what may have been months; no one really knows. But finally, it was completed. It was painted, and carpeted, and even had plywood veneer paneling on the walls. It also had fluorescent lights in each room. And telephones in each room (but alas, no telephone line filters). And the program occupied the area, setting up their computers and test equipment and their other stuff. After a while, the more troublesome technicians began to wonder why their pagers had no problem functioning within the rooms, and that workers could enjoy FM broadcast radio at their workstations. Wasn't this supposed to be an RF shielded facility? I arrived on site, with spectrum analyzer and trusty loop antenna (three turns of the extended coax center conductor formed into a loop). I'd find those leaks and plug 'em fast. The first thing I noticed was that the room doors were ordinary steel office doors, with painted frames. The fingerstock had been screwed over the painted surfaces. Many of the fingers were broken, bent or missing. And the steel door frame was mounted to the drywall. The RF shield consisted of chicken wire, a wide-mesh, twisted steel wire construction. The name should tell you what it was good for. The average chicken cannot be forced through a chicken wire barrier (at least without significant distortion). AM broadcast radio uses a wavelength long enough that the barrier yields a certain amount of shielding. But FM broadcast slips through like a mosquito. So I started to probe one of the rooms. I just tuned the SA to one of the many convenient signals around 100 MHz, and started to sweep the room. Not only did the mesh screen leak like crazy, but it also turned out that most of those many thousands of drywall screws went right through the wall without touching the mesh. So EACH of these little conductive rods acted as a path for RF in and out of the screen barrier. There were no leaky points; it was like playing laser tag in an infinite hall of mirrors. And, just to show that none of the basics of proper shielding technique had been followed, I found that the powerline filter was located about 75 feet away from the shielded rooms. The filtered power was run to the room in PVC conduit, and the filter was grounded by a six foot long #00 pigtail. After wandering the facility for about two hours, I was approached by the Program Manager, who inquired about my corrective actions. I told him something to the effect that I hadn't been able to find any shielded rooms, but that if we stripped this area clear to the concrete, we could build some right here. I went on to detail that I had seen just about every shielding mistake you could make, all concentrated in one place. This site could qualify only as a museum of inverse shielding. Bad report, bad career action. I went back to testing noisy gadgets that smelled vaguely of ozone. The customer wouldn't let them use the rooms for classified work. A year later, the PM became a VP. -- Ed Price ed.pr...@cubic.com Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA. USA 619-505-2780 Date: 03/11/1999 Time: 08:59:26 -- - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to
RE: explanation of ESD events with coins in baggie.
I would recommend that Doug Smith of Auspex Systems answer this one as he has presented this at an ANSI C63 ESD meeting and to the FAA.(He managed to crash their computers)!! Thank you Charles Grasso Advisory Engineer StorageTek 2270Sth 88th Street Louisville CO 80027 M/S 4247. Tel:303-673-2908 Fax:303-661-7115 email:gra...@louisville.stortek.com Web Site: http://www.ewh.ieee.org/r5/denver/rockymountainemc/ -Original Message- From: Hans Mellberg [mailto:emcconsult...@yahoo.com] Sent: Thursday, March 11, 1999 12:11 PM To: emc-p...@ieee.org Subject: Re: explanation of ESD events with coins in baggie. There is an expanation for this seemingly unlikely event. Having coins in a baggie and jingeling them causes the following events to occur: The rubbing of a coin against the polymer causes triboelectric charging of both the coin and localized areas of the bag. Since there are multiple coins, each coin will charge at some voltage level but not necessarily the same as another coin. When two coins of different charged voltages come within dielectric breakdown distances, a discharge will occur from one coin to the other in order to equalize the charge distribution (q1=C1V1 and q2=C2V2. When they touch, the new q1 will be C1V3 and q2= C2V3 where V3=(q1+q2)/(C1+C2)). Since coins are electrically small with very small capacitances, the expected discharge waveform has a very fast risetime hence the radiation at the GHz region. There will also be discharges from the localized charged areas of the polymer to coins of different voltages. While separating two charged surfaces from each other, the voltage rises significantly since the capacitance is being reduced and the conservation of charge must be preserved which is the basis for tribolectric voltage generation. Hope that helps Hans Mellberg ---b...@namg.us.anritsu.com wrote: Hi Douglas, What you described is very interesting! But I cannot understand Jingling change in a ziplock bag produces very high levels of super fast transients up into the GHz range. It seems to me that jingling coins, jangling keys, and slamming metal door would certainly produce acoustic waves. How come they also produced electromagnetic waves? If do, under what conditions? What is the mechanism to produce very high level of transient EM waves? Did that company incorporate those kinds of Jingling change in a ziplock bag tests into regular ESD tests for their thereafter products? What is the lessen we all should learn from this particular example? Hopefully you don't think it's offensive to ask above questions. I am just very curious. Thank you. Best Regards, Barry Ma (408)778-2000 x 4465 - Original Text From: Douglas McKean dmck...@corp.auspex.com, on 3/10/99 2:55 PM: At 08:03 AM 3/8/99 PST, Bailin Ma wrote: Hi Group, We have already seen awards for the most misleading ads, worst attire, worst films, . Why not awards for worst EMC and PS qualities? Barry Ma Morgan Hill, CA 95037 Long ago in another company, I was completing the testing for a large rack mounted device, i.e. emissions, immunity, safety, some parts of Bellcore. We got a call from one of our customers complaining about how sensitive our equipment was and how susceptible it was to ESD events during their own testing of our equipment. This was deemed unacceptable by them. This decision of theirs jeopardized a sale of several million dollars. The finger was duly pointed by everyone right to yours truly. My head was literally in no uncertain terms put on the block. I contested producing repeatable and acceptable ESD test results that were BELOW the BER levels specified by Bellcore with ESD test levels ABOVE that specified by the test standard. I wanted as much margin as possible for our product. Well, it ended up that if you stood three to four feet in front of the rack and jingled change in your pocket or jangled a set of keys in front of it, the product would RESET. Jingling change in a ziplock bag produces very high levels of super fast transients up into the GHz range. Worse, slamming the metal door to the lab in which the equipment was setup would also reset the product. The lab door was say 20 or so feet from our equipment under test. It took six months of a redesign cycle to straighten out that one, but it was finally done. I always wanted to find out who in God's name could have come up with such an insidious ESD test by simply putting some change in a zip lock bag and jingling it in front of equipment. But, I figured he, whoever he was, was lost in time. And wouldn't you know it? ... I now work for that man. - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com,
Re: info Israel
Hans, IIf we're speaking about ITE, your product must meet IS1121 which is harmonized fully with IEC 950 A4 (except for Israel deviations; israeli plug, safety instructions and markings in Hebrew and RFI - radiated emissions only). You are required by law to meet these requirements; however, there is no regulatory body which enforces the law. Regarding ITE with telecom interfaces (faxes, PBXs, modems, tetephones, computers with telecom interfaces, etc.) one has to have an Approval by the Ministry of Communications. Our lab is accredited by the Ministry of Communications for Safety/EMC and Telephony approvals. Please visit our website for more details. Best Regards and Good Luck Does anyone on this board knows the web address of the regulatory approval body of Israel. I'm interested in finding out what kind of emc-safety regulations they have and if MRA's with this country are already in place ? Thanks You, Hans Vigne Option International - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, j...@gwmail.monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators). PETER S. MERGUERIAN MANAGING DIRECTOR PRODUCT TESTING DIVISION I.T.L. (PRODUCT TESTING) LTD. HACHAROSHET 26, P.O.B. 211 OR YEHUDA 60251, ISRAEL TEL: 972-3-5339022 FAX: 972-3-5339019 E-MAIL: pe...@itl.co.il Visit our Website: http://www.itl.co.il - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, j...@gwmail.monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
RE: Rack System Safety (UL1950/EN 60950) Questions
Richard, Adding Approved disks, tapes and similar devices and adding model designation usually involves paperwork. However, adding/changing Approved , datacom and other similar equipment usually requires a repeat of some of the tests, including but not limited to Input, Leakage and Capacitance Discharge Tests. Regards, On Wednesday, March 10, 1999 5:00 AM, WOODS, RICHARD [SMTP:wo...@sensormatic.com] wrote: As I think about this situation, there is a way of obtaining UL Listing on the rack and have other certification marks on the internal equipment. Have UL List just the rack without the equipment. Now you can mix and match the internal certified equipment as you see fit keeping in mind not to exceed the cooling and electrical capacity of the rack. This is what we use to do a decade ago at a mini-computer company. We would configure systems from Listed racks, cpus, disks, tapes, etc. RRR. So after we obtained the UL listed for rack (model ABC-001), then we configure, add recognized disks, recognized tapes ...etc. etc.. now it become new model (DEF-001). Do we have to submit this new model for certification again ???. Now to Jim's point. There is no law that requires one agency to accept the certification marks of another agency. For example, UL will not accept ETL marks on components and both are NRTLS. The only way one agency will accept the marks of another is if there is an agreement between them. The CB scheme is one good example. CSA and UL have an agreement to accept each others test data I believe, but I don't believe that they will accept each others marks. RRR. They don't accept each others mark, but would they review and accept test data??? Tac Pham HC Power -- From: Jim Eichner [SMTP:jeich...@statpower.com] Sent: Tuesday, March 09, 1999 3:23 PM To: 'EMC-PSTC - forum' Subject: RE: Rack System Safety (UL1950/EN 60950) Questions Re Richard's item 5)... 5.UL requires that all internal equipment be UL Listed or Recognized. If that is true, then the value of the CSA/NRTL mark, and conversely the cUL mark if CSA plays this way too, is highly questionable. Do you have a direct-from-UL interpretation saying that they are not accepting the CSA/NRTL mark? If so, I would expect CSA to take action to defend its mark, and UL to have no firm ground to stand on! Comments? Jim Eichner Statpower Technologies Corporation jeich...@statpower.com http://www.statpower.com Any opinions expressed are those of my invisible friend, who really exists. Honest. - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, j...@gwmail.monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators). PETER S. MERGUERIAN MANAGING DIRECTOR PRODUCT TESTING DIVISION I.T.L. (PRODUCT TESTING) LTD. HACHAROSHET 26, P.O.B. 211 OR YEHUDA 60251, ISRAEL TEL: 972-3-5339022 FAX: 972-3-5339019 E-MAIL: pe...@itl.co.il Visit our Website: http://www.itl.co.il - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, j...@gwmail.monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
RE: Awards for Worst EMC/PS qualities
Well . . . from what I read so far . . .I think Ed's experience ranks right 'up there'! (Pun intended!) Seriously though . . . I think we've got a winner there! John A. Juhasz Product Qualification Compliance Engr. Fiber Options, Inc. 80 Orville Dr. Suite 102 Bohemia, NY 11716 USA Tel: 516-567-8320 ext. 24 Fax: 516-567-8322 -Original Message- From: ed.pr...@cubic.com [mailto:ed.pr...@cubic.com] Sent: Thursday, March 11, 1999 11:22 AM To: EMC-PSTC Subject: Re: Awards for Worst EMC/PS qualities Subject: Awards for Worst EMC/PS qualities Author: b...@namg.us.anritsu.com (Bailin Ma) at Internet Date:03/08/1999 8:03 AM Hi Group, We have already seen awards for the most misleading ads, worst attire, worst films, . Why not awards for worst EMC and PS qualities? Barry Ma Morgan Hill, CA 95037 OK, I'll submit my entry for both the EMC and PS categories! Years ago, whilst working at a large defense contractor, we re-built 5 UH-1 Huey helicopters to act as test beds for a large synthetic aperture radar system. All major mechanical and electrical systems were stripped out and then replaced (at the mid-point of the job, the Hueys looked like a wire-frame model). When we got everything back together, we had to go through flight worthiness testing. After that, we installed the electronics racks and started a set of platform EMC integration tests. So, I found myself hovering for hours at about 500 feet, while we ran through various operational modes of both the electronics payload and the vehicle systems. Everything checked out fine, until we found an accidental, uhhh, feature. Suddenly, just like an elevator to heaven, we started to climb straight up. I mean wide open throttle and full positive collective pitch! Well, I don't know how fast a heavily loaded Huey can climb, but it was impressive! I don't even want to think about how far those rotors deflected. After the pilot got things stabilized, and we all started breathing again, we started to sort things out. The problem turned out to be that the pilot had his autopilot engaged (I didn't know Hueys even had one), and then decided to key the UHF radio. We found that, out of twenty thousand or so UHF channels, about a dozen would cause the Vertical Speed Indicator to deflect full negative when the radio was keyed. And that instrument told the autopilot that the Huey was going down, so the autopilot cranked in as much pitch correction as possible, and also opened to full throttle. The result was; key radio on a magic channel and you get a penthouse express. (Actually, not too bad a result, considering what the result would have been if the VSI had been deflected full POSITIVE!) After a little snooping, we found that the VSI cable harness had an improperly assembled backshell, which degraded the shielding effectiveness of that cable and allowed RF into the indicator. Ed -- Ed Price ed.pr...@cubic.com Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA. USA 619-505-2780 List-Post: emc-pstc@listserv.ieee.org Date: 03/11/1999 Time: 08:21:48 -- - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, j...@gwmail.monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators). - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, j...@gwmail.monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
worst emc problem contest
Hello members! Well, as long as we are all trading emc horror stories I might as well pitch in. I have a pretty good one. Just before the launch of Apollo 11 [the first manned moon landing] NASA discovered a big emc problem: something was causing the fuel cells of the command module to short out at random. The command module is the capsule that the astronauts rode in during launch, to the moon, back. This was bad news because you couldn't launch like that, and apollo 11 was already out on the pad, the press was arriving, and the whole world was watching. I was the youngest guy in a 5-man emc section that NASA had at the Kennedy Space Center. A bunch of big-wigs came down from Washington, DC. They told us ( i.e. my boss) to fix it. Money is no object. they said. I, who imagined myself to be a suave, sophisticated New Yorker, was stunned. My jaw just dropped open. I had absolutely no idea how to do do this. To complicate things, we were not allowed to disconnect any cables: configuration control. So my boss, who was a really smart guy, had us build a bunch of huge current probes. Some of them were about 5 ft in diameter. we built two identical pairs of each probe. We set them up around big bundles of cables, and set up a some receivers, timing receivers (clocks), and strip chart recorders. With the help of a large group of contractors (ITT Federal Electric Corp.) we monitored those probes 24 hours a day. Whenever the problem occurred, we ran to the strip charts to see if anything funny had happened in the bundle at that same time. We found time-coincident glitches. Using smaller and smaller current probes, we gradually narrowed the problem down to one cable. The problem turned out to be the following: There were a lot of mechanical relays on the umbilical tower. All of them were supposed to have arc suppression diodes on them. On one relay, someone had installed the diode using leads that were SIX FEET LONG. Needless to say, by the time the impulse hit that diode, it had already been radiated and conducted all over the place. The computer interpreted that glitch as a command to short out the fuel cells. The diode was installed correctly, the problem disappeared, and apollo 11 was launched on time. the public never found out about it. I would love to take credit for this, but it was all my boss's doing. His name was Carl L. Lennon, and I hope he's around somewhere to read this. It was 100% due to him that apollo 11 went off on time. I was just a young dude who would do whatever I was told, instantly, without stopping to ask questions or even to think. Sort of a high tech spear-carrier. Other than a tremendous amount of overtime, I dont think we spent more than $10,000 to solve this problem. I still have a couple of those makeshift current probes. Regards, Louis T. Gnecco M.S.E.E.,President TEMPEST INC. 112 ELDEN ST. HERNDON, VA 20170 (703) TEMPEST (836-7378) l...@tempest-inc.com - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, j...@gwmail.monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
RE: NRTL requirement in the NEC?
Jeff, if your rack assembly including the power supply is Listed, then the inspector has no authority to investigate the components included in that Listed assembly. On the other hand, if you added a power supply to a Listed rack, then that power supply must be Listed. -- From: JENKINS, JEFF [SMTP:jeff.jenk...@aei.com] Sent: Thursday, March 11, 1999 12:48 PM To: 'emc-pstc' Subject: NRTL requirement in the NEC? Hello Group, Has anyone heard of a requirement in the National Electrical Code that power supplies which are components of larger systems be approved by an NRTL? I have an inspector telling me this, but our copy of the NEC is 20 years old, and I can't find it, anyway. In this case, the power supply is part of a rack system. It was my understanding that the supply could be evaluated as a component of the system. Is that not true? Thanks, Jeff Jenkins Senior Regulatory Compliance Engineer Advanced Energy Industries, Inc. Fort Collins, CO USA 80525 Opinions are my own and not necessarily shared by Advanced Energy Industries, Inc. or its affiliates. - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, j...@gwmail.monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators). - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, j...@gwmail.monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
Re: Awards for worst EMC/PS qualities
While not quite as bad as the disaster Ed Price described, I once had to fix a shielded room built to the specifications of a self-described RF expert. This gentleman had convinced his management that he could build a cheap and easy facility. The intended site was an unused loft on the fourth floor of the building, a 100+ year old former hat factory. They started by removing most of the inch-thick dust and all of the dead bird carcasses. They never stopped to wonder why there were so many dead birds - more on that later. Sheet metal workers brought in a load of galvanized steel and dumped it onto the somewhat clean floor. The expert had them butt the (still oily) sheets together and screw them down over the beat up wooden floor. Then, three inch wide strips were fastened over the joints, with screws every foot or so. One of the mechanical techs was a carpentry expert, so he convinced the RF expert to hire him instead of a building contractor to install the frame for the screening. He framed the cage using two-by-fours on the flat, on four foot centers, to save on lumber. Then he ran one-by-fours horizontally to provide some support for the copper screening stapled over the whole mess. He used a cheap hollow-core door because it was easier to carry up the narrow stairs. The door, of course, was wrapped in copper screening. The screening on the outside wall was left with several horizontal seams over the windows. The first hint of trouble was that AM reception was pretty fair inside the room due to the long unsecured seams. The carpentry expert had given up by that point, so I was asked to solder the window seams by my boss, the RF expert. Anyway, to make a long story short, I eventually used several thousand sheetmetal screws, several cartons of staples, several rolls of three-inch copper tape, and over a dozen pounds of solder before the room was more or less usable. I worked on that nightmare for weeks, finally having to solder the seams between floor and walls to plug some of the worst leaks. The room was finally quiet enough to use for pre test site scans and diagnostic use. My boss demonstrated his gratitude by sulking for weeks. We soon learned to cover the equipment with plastic when it was not in use. Birds often flew into their former roost/toilet. None of the experts involved had bothered to check for access holes before starting work. There were several holes, some of them in inaccessible locations above the screen room, which was framed in such a flimsy manner that no one dared to climb onto it. It is amazing how effectively steel wool sprayed with instant foam can plug leaks when it is inserted using a long pole with a frustrated test engineer at the other end. Never, ever, again! Scott - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, j...@gwmail.monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
Re[2]: Awards for Worst EMC/PS qualities
In one of my past lives, there was a safety inspector (agency not divulged here) that adamantly defended his interpretation of the 94V marking on PWBs as a voltage rating of the PWB. He even wrote us up for this for not having a high enough voltage rating. This guy, too, is still in the safety field. BTW Monty, did that guy you were referring to have a multiple personality? :-) Best regards, Ron Pickard ron_pick...@hypercom.com __ Reply Separator _ Subject: RE: Awards for Worst EMC/PS qualities Author: Griffith Monty mgrif...@ingr.com at INTERNET List-Post: emc-pstc@listserv.ieee.org Date:3/11/99 10:39 AM I once had a Safety Engineer tell me that a class 2 transformer had opened during the overload test. He was measuring resistance primary to secondary (Duh!!!). This guy is still in the Safety Field but they don't work here thank God!!! Monty Griffith Senior Product Safety Engineer EMC Quality Manager Intergraph Compliance Services Ph. (256) 730-6017 Fx. (256) 730-6239 http://mecsrv.b29.ingr.com -Original Message- From:brian_kunde [SMTP:brian_ku...@leco.com] Sent:Thursday, March 11, 1999 9:48 AM To:emc-pstc; bma Subject:RE: Awards for Worst EMC/PS qualities In the early 1980's, I worked for a company that manufactured PCs and peripherals. I worked in a Functional Testing Lab where we ran functional tests on our new designs before allowing them to go to production. I was testing a dot matrix printer which our company purchased the electronics and incorporated it into our mechanical. The printer was setting on a printer table about six feet away from the computer which was on a computer table. I would start up the exercise program on the PC, then quickly roll my wheeled lab chair over to the printer to observe its function. When I would roll by the printer on my chair, the printer would start failing in the most destructive ways. The print head would slam back and forth against its stops, the paper would shoot out, stop, then reverse causing a major jam, the display would flash some type of hieroglyphics. Engineering could not find a test, including ESD, that could duplicate this failure. So, the problem was debugged, in our lab, (that's right) while I rolled back and forth on my lab chair. It took several days, but the problem was eventually fixed. Then I went on vacation. Brian -- From: bma b...@namg.us.anritsu.com (Bailin Ma) Sent: Monday, March 08, 1999 8:03 AM To: emc-pstc emc-p...@ieee.org Subject:Awards for Worst EMC/PS qualities Hi Group, We have already seen awards for the most misleading ads, worst attire, worst films, . Why not awards for worst EMC and PS qualities? Barry Ma Morgan Hill, CA 95037 - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, j...@gwmail.monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators). - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, j...@gwmail.monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators). - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, j...@gwmail.monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators). - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, j...@gwmail.monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
Visible Light EMC
This question sounds goofy, but here goes anyway Why doesn't visible light travel through solid objects (plastic, wood, etc)? Unless I've totally missed the boat, visible light is electromagnetic energy beginning at about 100,000GHz. So why doesn't it behave like electromagnetic energy in the radio spectrum? My guess is that it has something to do with the wavelength vs. the thickness of the object. Allen Tudor, Compliance Engineer PairGain Technologies tel: (919)875-3382 2431-153 Spring Forest Rd. fax: (919)876-1817 Raleigh, NC 27615 email: allen_tu...@pairgain.com - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, j...@gwmail.monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
Re: explanation of ESD events with coins in baggie.
There is an expanation for this seemingly unlikely event. Having coins in a baggie and jingeling them causes the following events to occur: The rubbing of a coin against the polymer causes triboelectric charging of both the coin and localized areas of the bag. Since there are multiple coins, each coin will charge at some voltage level but not necessarily the same as another coin. When two coins of different charged voltages come within dielectric breakdown distances, a discharge will occur from one coin to the other in order to equalize the charge distribution (q1=C1V1 and q2=C2V2. When they touch, the new q1 will be C1V3 and q2= C2V3 where V3=(q1+q2)/(C1+C2)). Since coins are electrically small with very small capacitances, the expected discharge waveform has a very fast risetime hence the radiation at the GHz region. There will also be discharges from the localized charged areas of the polymer to coins of different voltages. While separating two charged surfaces from each other, the voltage rises significantly since the capacitance is being reduced and the conservation of charge must be preserved which is the basis for tribolectric voltage generation. Hope that helps Hans Mellberg ---b...@namg.us.anritsu.com wrote: Hi Douglas, What you described is very interesting! But I cannot understand Jingling change in a ziplock bag produces very high levels of super fast transients up into the GHz range. It seems to me that jingling coins, jangling keys, and slamming metal door would certainly produce acoustic waves. How come they also produced electromagnetic waves? If do, under what conditions? What is the mechanism to produce very high level of transient EM waves? Did that company incorporate those kinds of Jingling change in a ziplock bag tests into regular ESD tests for their thereafter products? What is the lessen we all should learn from this particular example? Hopefully you don't think it's offensive to ask above questions. I am just very curious. Thank you. Best Regards, Barry Ma (408)778-2000 x 4465 - Original Text From: Douglas McKean dmck...@corp.auspex.com, on 3/10/99 2:55 PM: At 08:03 AM 3/8/99 PST, Bailin Ma wrote: Hi Group, We have already seen awards for the most misleading ads, worst attire, worst films, . Why not awards for worst EMC and PS qualities? Barry Ma Morgan Hill, CA 95037 Long ago in another company, I was completing the testing for a large rack mounted device, i.e. emissions, immunity, safety, some parts of Bellcore. We got a call from one of our customers complaining about how sensitive our equipment was and how susceptible it was to ESD events during their own testing of our equipment. This was deemed unacceptable by them. This decision of theirs jeopardized a sale of several million dollars. The finger was duly pointed by everyone right to yours truly. My head was literally in no uncertain terms put on the block. I contested producing repeatable and acceptable ESD test results that were BELOW the BER levels specified by Bellcore with ESD test levels ABOVE that specified by the test standard. I wanted as much margin as possible for our product. Well, it ended up that if you stood three to four feet in front of the rack and jingled change in your pocket or jangled a set of keys in front of it, the product would RESET. Jingling change in a ziplock bag produces very high levels of super fast transients up into the GHz range. Worse, slamming the metal door to the lab in which the equipment was setup would also reset the product. The lab door was say 20 or so feet from our equipment under test. It took six months of a redesign cycle to straighten out that one, but it was finally done. I always wanted to find out who in God's name could have come up with such an insidious ESD test by simply putting some change in a zip lock bag and jingling it in front of equipment. But, I figured he, whoever he was, was lost in time. And wouldn't you know it? ... I now work for that man. - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, j...@gwmail.monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators). - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, j...@gwmail.monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators). _ DO YOU YAHOO!? Get your free @yahoo.com address at http://mail.yahoo.com - This message is coming from
Component vs Listed European Style ...
To whom it may concern, Sorry, rather lengthy. I tried to cut it down. I've finally realized I don't think I fully understand European approvals and I'll discuss why with two examples. The first example will go from the *system level* down to the *sub-system level*. The second example will go from the *system level* up to a *super-system level*. In other words, I don't think I fully understand how the stateside concept of component approval versus listed gets translated over into the CE mark, or VCCI, or BCIQ for that matter ... I believe this was touched on a while back but I can't find it. System Configuration - Let's say we have product. It's *model number* is System 1. System 1 is composed of two sub-systems. Sub-systems have in turn the *model numbers* Sub-system A and Sub-system B. System 1 has a mains input of 115/230vac to a power distribution unit (PDU). The PDU inputs the 115/230vac to a power supply. The power supply outputs 48vdc to sub-systems A and B. System 1 is NOT a telco product. First - System to sub-system: System 1 has been successfully tested to the appropriate emissions, safety, and immunity requirements. It is declared that System 1 complies to have the CE mark applied. System 1 is marketed. It is shipped overseas to our friends in Europe. No problems. Now, marketing comes along and wants to sell Sub-systems A and B of System 1 on their own. In other words, the Sub-systems A and B will NOT necessarily be in configurations that will use anything from the original configuration of System 1. And they will be advertised and sold as Sub-system A and Sub-system B. Question: Is any retest of the sub-systems by themselves required? If so, why so? If not, why not? Second - System to Super-system: Marketing decides to incorporate two or more System 1's into a configuration using a product, let's call that Product A, from another company that itself has been through all required emissions, safety, and immunity requirements and is itself CE marked. And has also been marketed and sold in Europe with no problems. *** Marketing also decides to advertise and sell this super-system under a new *model number* Super-system 2. There is a high amount of confidence that this entire system Super-system 2 will never be shipped as one piece. The Bill of Lading that would come through Customs though would show Super-system 2 with parts System 1 and Product A. Question: Is any retest of Super-system 2 required? If so, why so? If not, why not? - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, j...@gwmail.monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
NRTL requirement in the NEC?
Hello Group, Has anyone heard of a requirement in the National Electrical Code that power supplies which are components of larger systems be approved by an NRTL? I have an inspector telling me this, but our copy of the NEC is 20 years old, and I can't find it, anyway. In this case, the power supply is part of a rack system. It was my understanding that the supply could be evaluated as a component of the system. Is that not true? Thanks, Jeff Jenkins Senior Regulatory Compliance Engineer Advanced Energy Industries, Inc. Fort Collins, CO USA 80525 Opinions are my own and not necessarily shared by Advanced Energy Industries, Inc. or its affiliates. - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, j...@gwmail.monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
Re: Awards for Worst EMC/PS qualities
Subject: Awards for Worst EMC/PS qualities Author: b...@namg.us.anritsu.com (Bailin Ma) at Internet Date:03/08/1999 8:03 AM Hi Group, We have already seen awards for the most misleading ads, worst attire, worst films, . Why not awards for worst EMC and PS qualities? Barry Ma Morgan Hill, CA 95037 OK, I'll submit just one more entry, even though this will need a new category (which I'll call Stupid Construction). Many years ago, a very large defense contractor decided that a black program needed multiple shielded enclosures within their SCIF so as to keep their classified data from leaking out and running down the hillside. So, the Program Manager talked to the Facilities Engineer, and together they said We can build our own TEMPEST shielded room. We will even do it cheaper and faster than any of these dumb quotes we have. So it came to be that they ordered much chicken wire, and beryllium copper fingerstock, and lumber, and drywall panels, and oh yes, very very many 2 long drywall screws. And a three phase powerline filter. And the facilities laborers then labored mightily for what may have been months; no one really knows. But finally, it was completed. It was painted, and carpeted, and even had plywood veneer paneling on the walls. It also had fluorescent lights in each room. And telephones in each room (but alas, no telephone line filters). And the program occupied the area, setting up their computers and test equipment and their other stuff. After a while, the more troublesome technicians began to wonder why their pagers had no problem functioning within the rooms, and that workers could enjoy FM broadcast radio at their workstations. Wasn't this supposed to be an RF shielded facility? I arrived on site, with spectrum analyzer and trusty loop antenna (three turns of the extended coax center conductor formed into a loop). I'd find those leaks and plug 'em fast. The first thing I noticed was that the room doors were ordinary steel office doors, with painted frames. The fingerstock had been screwed over the painted surfaces. Many of the fingers were broken, bent or missing. And the steel door frame was mounted to the drywall. The RF shield consisted of chicken wire, a wide-mesh, twisted steel wire construction. The name should tell you what it was good for. The average chicken cannot be forced through a chicken wire barrier (at least without significant distortion). AM broadcast radio uses a wavelength long enough that the barrier yields a certain amount of shielding. But FM broadcast slips through like a mosquito. So I started to probe one of the rooms. I just tuned the SA to one of the many convenient signals around 100 MHz, and started to sweep the room. Not only did the mesh screen leak like crazy, but it also turned out that most of those many thousands of drywall screws went right through the wall without touching the mesh. So EACH of these little conductive rods acted as a path for RF in and out of the screen barrier. There were no leaky points; it was like playing laser tag in an infinite hall of mirrors. And, just to show that none of the basics of proper shielding technique had been followed, I found that the powerline filter was located about 75 feet away from the shielded rooms. The filtered power was run to the room in PVC conduit, and the filter was grounded by a six foot long #00 pigtail. After wandering the facility for about two hours, I was approached by the Program Manager, who inquired about my corrective actions. I told him something to the effect that I hadn't been able to find any shielded rooms, but that if we stripped this area clear to the concrete, we could build some right here. I went on to detail that I had seen just about every shielding mistake you could make, all concentrated in one place. This site could qualify only as a museum of inverse shielding. Bad report, bad career action. I went back to testing noisy gadgets that smelled vaguely of ozone. The customer wouldn't let them use the rooms for classified work. A year later, the PM became a VP. -- Ed Price ed.pr...@cubic.com Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA. USA 619-505-2780 List-Post: emc-pstc@listserv.ieee.org Date: 03/11/1999 Time: 08:59:26 -- - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, j...@gwmail.monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
Re: Russian GOST Approval
Hi Philip, Wish I could be at that meeting. In my stead, please say my greetings to Grant, and ask him how is his stickball game these days? Mike Harris Teccom Co. tecco...@i-cafe.net 707-258-1360/fax 1361 -- From: Ling, Philip pl...@newport.com To: emc-p...@ieee.org Subject: Russian GOST Approval Date: Wednesday, March 10, 1999 9:43 AM To all Product Safety Engineers: I know many of you are looking for information regarding Russian GOST Approval . This is your golden opportunity for you to come to the meeting and find out all the information you need. Mr. Grant Schmidbauer will be the speaker on April 6, 1999, 6:00PM to 7:00PM, at Newport Corporation, 1791 Deere Avenue, Irvine, Ca. Mr. Grant Schmidbauer has been in the product safety industry for 15 years. He worked with CSA, Vancouver and TUV Product Service as a Product Safety Engineer in ITE, Telecom, Power Supply, Medical, Test Measurement, House Appliance, and Audio Video Equipment. In 1996 he jointed NEMKO, USA, San Diego ( NEMKO Compliance West ) as a General Manager over seeing both Product Safety and EMC Compliance. The topic he will speak on is Russian GOST Approval on IEC950/1010.1 Standard Equipment, including the process of getting the GOST Approval. Gosstandart of Russia accredits NEMKO, USA to perform Product Safety Approval and EMC compliance testing. For more information or direction to the meeting, please contact Philip Ling, Newport Corporation at 949-253-1762 or email pl...@newport.com. Please mark your calendar and see you in the April 6, Orange County Chapter Product Safety Meeting. Philip Ling - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, j...@gwmail.monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators). - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, j...@gwmail.monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
RE: Awards for Worst EMC/PS qualities
I once had a Safety Engineer tell me that a class 2 transformer had opened during the overload test. He was measuring resistance primary to secondary (Duh!!!). This guy is still in the Safety Field but they don't work here thank God!!! Monty Griffith Senior Product Safety Engineer EMC Quality Manager Intergraph Compliance Services Ph. (256) 730-6017 Fx. (256) 730-6239 http://mecsrv.b29.ingr.com -Original Message- From: brian_kunde [SMTP:brian_ku...@leco.com] Sent: Thursday, March 11, 1999 9:48 AM To: emc-pstc; bma Subject: RE: Awards for Worst EMC/PS qualities In the early 1980's, I worked for a company that manufactured PCs and peripherals. I worked in a Functional Testing Lab where we ran functional tests on our new designs before allowing them to go to production. I was testing a dot matrix printer which our company purchased the electronics and incorporated it into our mechanical. The printer was setting on a printer table about six feet away from the computer which was on a computer table. I would start up the exercise program on the PC, then quickly roll my wheeled lab chair over to the printer to observe its function. When I would roll by the printer on my chair, the printer would start failing in the most destructive ways. The print head would slam back and forth against its stops, the paper would shoot out, stop, then reverse causing a major jam, the display would flash some type of hieroglyphics. Engineering could not find a test, including ESD, that could duplicate this failure. So, the problem was debugged, in our lab, (that's right) while I rolled back and forth on my lab chair. It took several days, but the problem was eventually fixed. Then I went on vacation. Brian -- From: bma b...@namg.us.anritsu.com (Bailin Ma) Sent: Monday, March 08, 1999 8:03 AM To: emc-pstc emc-p...@ieee.org Subject:Awards for Worst EMC/PS qualities Hi Group, We have already seen awards for the most misleading ads, worst attire, worst films, . Why not awards for worst EMC and PS qualities? Barry Ma Morgan Hill, CA 95037 - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, j...@gwmail.monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators). - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, j...@gwmail.monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators). - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, j...@gwmail.monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
H.P. 85878A Report Generator
EMC Group: The comments I received indicate the 85878A report generator software is worth its salt and very useful for H.P.8591 series analyzers. There are some software anomalies but H.P. customer support can quide one through the pitfalls. Does anyone out there have an original 85878A software package for sale? Don Clayton ESR Engineering - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, j...@gwmail.monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
RE: Awards for Worst EMC/PS qualities
In the early 1980's, I worked for a company that manufactured PCs and peripherals. I worked in a Functional Testing Lab where we ran functional tests on our new designs before allowing them to go to production. I was testing a dot matrix printer which our company purchased the electronics and incorporated it into our mechanical. The printer was setting on a printer table about six feet away from the computer which was on a computer table. I would start up the exercise program on the PC, then quickly roll my wheeled lab chair over to the printer to observe its function. When I would roll by the printer on my chair, the printer would start failing in the most destructive ways. The print head would slam back and forth against its stops, the paper would shoot out, stop, then reverse causing a major jam, the display would flash some type of hieroglyphics. Engineering could not find a test, including ESD, that could duplicate this failure. So, the problem was debugged, in our lab, (that's right) while I rolled back and forth on my lab chair. It took several days, but the problem was eventually fixed. Then I went on vacation. Brian -- From: bma b...@namg.us.anritsu.com (Bailin Ma) Sent: Monday, March 08, 1999 8:03 AM To: emc-pstc emc-p...@ieee.org Subject:Awards for Worst EMC/PS qualities Hi Group, We have already seen awards for the most misleading ads, worst attire, worst films, . Why not awards for worst EMC and PS qualities? Barry Ma Morgan Hill, CA 95037 - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, j...@gwmail.monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators). - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, j...@gwmail.monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
Re: Awards for Worst EMC/PS qualities
Some years ago, I carted a prototype down to a Maryland area test lab for an EMI scan. What I didn't realize was that the lab technician who built the prototype crossed the power and earth lines to the power supply, resulting in a hot chassis. Well, as might be expected, there was some problem meeting the conducted emissions requirement. In fact, a plot of the spectrum was prominently displayed on the lab's shield room wall for many months afterward as an example of the worst emissions that they had ever found. It was a dubious honor, at best. Now, the guy who runs this lab is pretty sharp, and figured that something had to be wrong. Taking out his trusty Fluke DVM, he proceeded to probe around in the power supply. Why he didn't expect the chassis he was steadying his hands on to be at 120 volts is beyond me. The resulting sequence went something like this: ZAP - YIKES!!! - recoil - stab - OUCH!! - @#%$#*#@ We still joke about the two holes he poked in his brand new shirt. __ Reply Separator _ Subject: Awards for Worst EMC/PS qualities Author: b...@namg.us.anritsu.com (Bailin Ma) at Internet List-Post: emc-pstc@listserv.ieee.org Date:03/08/1999 8:03 AM Hi Group, We have already seen awards for the most misleading ads, worst attire, worst films, . Why not awards for worst EMC and PS qualities? Barry Ma Morgan Hill, CA 95037 - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, j...@gwmail.monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators). - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, j...@gwmail.monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
RE: Rack System Safety (UL1950/EN 60950) Questions
That's what I love about this mailing list. I learn something new most every day. Thanks Tania! -- From: Grant, Tania (Tania) [SMTP:tgr...@lucent.com] Sent: Wednesday, March 10, 1999 4:27 PM To: 'EMC-PSTC - forum'; 'WOODS, RICHARD' Subject: RE: Rack System Safety (UL1950/EN 60950) Questions Richard, Regarding your last statement I don't believe that they [CSA UL] will accept each others marks. Certain UL and CSA component standards have been harmonized and, I believe, this effort is continuing. If you look at Appendix P.2 [be sure it is P.2 and not P.1] of UL 1950, 3rd edition, you will find a matrix of UL and CSA component standards where meeting one or the other is considered acceptable for meeting the requirements of UL1950, 3rd edition. Additionally, if you are working with an astute UL engineer, very often they will inform you of additional components that fall under that category but have not yet been published in this Appendix. Tania Grant, Lucent Technologies, Octel Messaging Division tgr...@lucent.com -- From: WOODS, RICHARD[SMTP:wo...@sensormatic.com] Sent: Wednesday, March 10, 1999 5:00 AM To: 'EMC-PSTC - forum' Subject: RE: Rack System Safety (UL1950/EN 60950) Questions As I think about this situation, there is a way of obtaining UL Listing on the rack and have other certification marks on the internal equipment. Have UL List just the rack without the equipment. Now you can mix and match the internal certified equipment as you see fit keeping in mind not to exceed the cooling and electrical capacity of the rack. This is what we use to do a decade ago at a mini-computer company. We would configure systems from Listed racks, cpus, disks, tapes, etc. Now to Jim's point. There is no law that requires one agency to accept the certification marks of another agency. For example, UL will not accept ETL marks on components and both are NRTLS. The only way one agency will accept the marks of another is if there is an agreement between them. The CB scheme is one good example. CSA and UL have an agreement to accept each others test data I believe, but I don't believe that they will accept each others marks. -- From: Jim Eichner [SMTP:jeich...@statpower.com] Sent: Tuesday, March 09, 1999 3:23 PM To: 'EMC-PSTC - forum' Subject: RE: Rack System Safety (UL1950/EN 60950) Questions Re Richard's item 5)... 5.UL requires that all internal equipment be UL Listed or Recognized. If that is true, then the value of the CSA/NRTL mark, and conversely the cUL mark if CSA plays this way too, is highly questionable. Do you have a direct-from-UL interpretation saying that they are not accepting the CSA/NRTL mark? If so, I would expect CSA to take action to defend its mark, and UL to have no firm ground to stand on! Comments? Jim Eichner Statpower Technologies Corporation jeich...@statpower.com http://www.statpower.com Any opinions expressed are those of my invisible friend, who really exists. Honest. -Original Message- From: WOODS, RICHARD [SMTP:wo...@sensormatic.com] Sent: Tuesday, March 09, 1999 11:15 AM To: emc-p...@majordomo.ieee.org; t...@world.std.com Subject: RE: Rack System Safety (UL1950/EN 60950) Questions 1.Peter, equipment with the standard NEMA plug is considered to be Class A.. 2.Equipment using the heavy duty Industrial plugs complying with IEC are considered to be Class B. I have never seen those used inside rack mounted equipment. 3.If the power supply is UL Listed, then temperature measurements are not required. However, most power supplies are categorized as Recognized and are therefore incomplete in construction - that is, they cannot pass the safety requirements for a stand alone power supply. Temperature measurements will be required. 4.Stability is performed in a worst case situation, but reason is also taken into
Re: Awards for Worst EMC/PS qualities
Some time ago, in a far-away land, I saw a product that was on the lab bench for some initial functionality testing (1-st rev. of the device). A radio was close by, plugged to the same power circuit. The test engineer could not listen to the radio due to the interference with the noise coming from the device. He switched the radio off and, in that moment - the device reset. Neven Disclaimer: I was not involved (of course) in that design :) At 08:03 AM 3/8/99 PST, bma (Bailin Ma) wrote: Hi Group, We have already seen awards for the most misleading ads, worst attire, worst films, . Why not awards for worst EMC and PS qualities? Barry Ma Morgan Hill, CA 95037 - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, j...@gwmail.monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators). - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, j...@gwmail.monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
RE: Awards for Worst EMC/PS qualities
Along the same lines, the old VW Beatles would put out so much noise that you could pick them up on your FM receiver a hundred yards down the road. Daniel W. Mitchell Product Safety Associate Engineer EOS Corp. -- From: Hans Mellberg[SMTP:emcconsult...@yahoo.com] Sent: Wednesday, March 10, 1999 11:14 AM To: emc-p...@ieee.org Subject:Re: Awards for Worst EMC/PS qualities A certain German sports car using a certain German fuel injection system could be made to malfunction in an amuzing way (not to the sports car operator though!) such as backfire, sputter, smoke, flames from exhaust pipe, etc., by tractor-trailer operators with their CB lin-amps when keying on and off. This was a popular thing to do by truckers in the late 70's. This susceptibility problem was addressed and corrected by the sports car manufacturer. Other manufacturers may have had similar problems. At 08:03 AM 3/8/99 PST, bma (Bailin Ma) wrote: Hi Group, We have already seen awards for the most misleading ads, worst attire, worst films, . Why not awards for worst EMC and PS qualities? Barry Ma Morgan Hill, CA 95037 - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, j...@gwmail.monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators). _ DO YOU YAHOO!? Get your free @yahoo.com address at http://mail.yahoo.com - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, j...@gwmail.monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators). - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, j...@gwmail.monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
Re: Awards for Worst EMC/PS qualities
Hi Douglas, What you described is very interesting! But I cannot understand Jingling change in a ziplock bag produces very high levels of super fast transients up into the GHz range. It seems to me that jingling coins, jangling keys, and slamming metal door would certainly produce acoustic waves. How come they also produced electromagnetic waves? If do, under what conditions? What is the mechanism to produce very high level of transient EM waves? Did that company incorporate those kinds of Jingling change in a ziplock bag tests into regular ESD tests for their thereafter products? What is the lessen we all should learn from this particular example? Hopefully you don't think it's offensive to ask above questions. I am just very curious. Thank you. Best Regards, Barry Ma (408)778-2000 x 4465 - Original Text From: Douglas McKean dmck...@corp.auspex.com, on 3/10/99 2:55 PM: At 08:03 AM 3/8/99 PST, Bailin Ma wrote: Hi Group, We have already seen awards for the most misleading ads, worst attire, worst films, . Why not awards for worst EMC and PS qualities? Barry Ma Morgan Hill, CA 95037 Long ago in another company, I was completing the testing for a large rack mounted device, i.e. emissions, immunity, safety, some parts of Bellcore. We got a call from one of our customers complaining about how sensitive our equipment was and how susceptible it was to ESD events during their own testing of our equipment. This was deemed unacceptable by them. This decision of theirs jeopardized a sale of several million dollars. The finger was duly pointed by everyone right to yours truly. My head was literally in no uncertain terms put on the block. I contested producing repeatable and acceptable ESD test results that were BELOW the BER levels specified by Bellcore with ESD test levels ABOVE that specified by the test standard. I wanted as much margin as possible for our product. Well, it ended up that if you stood three to four feet in front of the rack and jingled change in your pocket or jangled a set of keys in front of it, the product would RESET. Jingling change in a ziplock bag produces very high levels of super fast transients up into the GHz range. Worse, slamming the metal door to the lab in which the equipment was setup would also reset the product. The lab door was say 20 or so feet from our equipment under test. It took six months of a redesign cycle to straighten out that one, but it was finally done. I always wanted to find out who in God's name could have come up with such an insidious ESD test by simply putting some change in a zip lock bag and jingling it in front of equipment. But, I figured he, whoever he was, was lost in time. And wouldn't you know it? ... I now work for that man. - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, j...@gwmail.monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators). - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, j...@gwmail.monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
