RE: Added paragraph
Better yet, how about the subscribers taking the additional two or three seconds it takes to do the responsible thing and delete it themselves? Peter L. Tarver Nortel ptar...@nt.com -Original Message- From: Robert Macy [SMTP:m...@california.com] Sent: Thursday, October 08, 1998 12:05 PM Is there anyway to remove the paragraph emc-pstc adds to the msgs? I archive all the msgs and it's starting to look like 30-40% of the text are those paragraphs! It's really noticeable when a quoted msg has a quoted msg with a quoted msg. Don't get me wrong. That paragraph is really handy. There must be a way to add that paragraph without it automatically transferring. I know because when I shot back some spam, the 10 pages disappeared into only the introducing paragraph (which was very innocuous). If you guys can figure out how to add the paragraph but not have it requoted when we quote the msg, I'd really appreciate it....or make it much smaller? - Robert - - 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: Shield Room Grounding
From: Scott Roleson sc...@hpsdde.sdd.hp.com Subject: Re: Shield Room Grounding Date: Thu, 8 Oct 1998 14:17:56 -0700 To: emc-p...@ieee.org Cc: sc...@hpsdde.sdd.hp.com Barry Ma forwarded to me a message from Peter Hays that said: Can someone tell me what is the best method to find out and ensure that a screen room is adequately grounded? (SNIP) There is some debate on this single-point ground approach. I know some people who think it doesn't matter, so long as the room doesn't have any gaps so that ALL potentially interfering currents stay on the outside surface of the room. This may be true, but in practice it's not always possible to have a room without any holes or gaps. -- Scott Roleson Scott: Grounding for safety is a must, since a shielded enclosure will almost always have a set of low-pass powerline filters which bring the 60Hz power into the equipment within the room. These filters usually have a few large (15uF or so) capacitors from line to filter case to bypass RF currents. Since the capacitors also have a modest Xc at 60 Hz, there will also be a 60 Hz current component to the filter case. If the room isn't grounded, a hazardous voltage potential can exist on the room wall. A person standing on the concrete floor of the parent structure can get a very serious shock just by reaching out to open the door handle or to connect a coax cable to a port. So, for almost every situation, we have to ground the room to protect the people around it. But grounding for RF shielding effectiveness isn't needed. A copper spherical Faraday cage floating in mid air (what a sight!) would make an fine RF shield. The shielding would be limited primarily by the gaps, intentional seams and accidental cracks and gaps. But... it's not very useful. Let's land that baby and now think of it as a shielded room. To be of any use, this room has to be big, say 10 feet tall. And maybe 30 feet wide. Now, let's get very simplistic. To an RF wave, propagating along happily in air, your room looks like a little old antenna. I mean, it's conductive, and it has a height above ground. An effective height. Right, it looks like a stubby, broadband vertical monopole above a ground plane. And that RF wave gives that antenna a present; it induces some RF current into the conductive structure. Now, that RF current would like to flow, along the outer surface of the conductor (skin depth effect), somewhere. By providing a single, well defined ground path, you prevent that current from flowing along paths which would create problems. What problems? Well, imagine the current flowing to ground through the outer jacket of a coax cable connected to a grounded spectrum analyzer. The noise currents would sum with the valid RF currents on the analyzer coax. Now, with all that said, let me tell you a story. At both General Dynamics and Cubic in San Diego, I needed a large shielded room (for the EUT) and a smaller shielded room or antechamber (for the program support equipment. (Support equipment is notorious for being built just barely able to work, with a rat's nest construction and no thought to EMC.) At GD, I had a solid, welded main room and a modular, 8' cube antechamber. At Cubic, I have a modular main room and a modular, screen antechamber. Both locations used the same technique to join the large and small rooms; a penetration port was located in each facing wall, and a steel tunnel was fabricated to bolt onto each room's penetration port bolt pattern. In effect, the shielded volume turned into a dumbbell shape, with the tunnel at the waist of the dumbbell. Then, a penetration port cover plate, equipped with multiple signal line filters, is bolted across the tunnel throat at one end. (This isolates the two test chambers from each other.) Each shielded room has it's own set of powerline filters (400Hz three phase, 60Hz three phase and two DC lines). The modular panel (on each room) that carries the filter sets has it's own ground well. The two powerline filter sets were over fifty feet apart in both examples. I can't remember when anybody would have recommended a design like this. I know I wouldn't. But the GD example grew from merging existing facilities, and it worked. It worked good enough that we NEVER had a trace of any ambient signals in the many emission tests that were performed there over about 15 years (using Eaton receivers and HP spectrum analyzers, often with active antennas). It was good enough to do TEMPEST testing at the facility. It worked good enough that I decided to deliberately emulate the design here at Cubic. And it's working again, good enough that my fancy HP-8571A Receiver (a re-worked 8566B), even operating with external pre-amps in some bands, doesn't see any ambient distractions. So what's the lesson in all of this? Well, I was scrupulous about seam quality and using very good powerline
RE: New CISPR22 requirement
Yea, I do. This is going to add time and cost to the test procedure in place and I don't see it fixing any problems. I might concede that it may be a more repeatable reading on cables, but that is secondary to the real issue. The real issue is this. Is the lack of this testing causing a proliferation of many non-compliant systems? I believe the answer is no.(But I certainly agree that I don't have any real data to back this statement up.). Conversely, I haven't seen a proliferation of data coming from the controlling agencies that they have identified a problem either. There are some non-compliant systems but not because of the measurement techniques are inadequate. The job of standards committees is not to invent new crap until they determine the old stuff isn't sufficient. So prove the problem first and if you can't then go away. Snort! - Gary -Original Message- From: grant.pi...@adn.alcatel.com [SMTP:grant.pi...@adn.alcatel.com] Sent: Thursday, October 08, 1998 10:38 AM To: emc-p...@majordomo.ieee.org Subject:New CISPR22 requirement The most recent issue of CISPR22 (Third edition, Nov. 1997) requires conducted emissions testing on signal cables (section 5.1). Section 9.5 provides the procedures for making such measurements. Alternative methods are suggested involving Impedance Stabilization Networks and Current Probes. All types of cables are covered (e.g. balanced/unbalanced, screened/unscreened, single pair/multiconductor, etc.). Has a CENELEC version of CISPR22-1997 been released or drafted? If not released yet, when is it expected? When would it be expected to be communicated by the Commission, and when would it become mandatory? Does it contain a requirement for conducted emissions on signal lines? Does anyone have any particular concerns regarding compliance with this standard? Thanks in advance. R. Grant Pinto Alcatel USA Ashburn, VA grant.pi...@adn.alcatel.com 1-703-724-2759 1-703-724-2132-fax - 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: Crepage/Clearance On Telecom Modem design
I believe that your experts are wrong...4.2 is a rather odd number to come up with. The most common requirement here is SUPPLEMENTARY INSULATION for a PRIMARY CIRCUIT at 250Vrms (as defined by EN 60950) between the TIP/RING (line side, or TNV-3 side) and the modem or device side. 2.5mm of surface creepage and 2.0mm of air clearance is required here. This assumes that your modem or device side already has sufficient isolation from Mains, which is almost always the case. Many countries in Europe require only BASIC INSULATION at a working voltage of 150VDC, which equates to a 1.6mm creepage spacing requirement. This also assumes that you have sufficient isolation from Mains to you modem. If you don't have sufficient isolation from Mains, your requirement will be 5.0mm. This would be consistent with the REINFORCED INSULATION requirement between Mains and the Tip/Ring side. It is possible that your consultants are correct for your particular case...however, it would be a very unusual case... They are correct about one thing...EN 60950 is the correct standard. feel free to call if you have any further questions, Mel PedersenMidcom, Inc. Homologations Engineer Phone: (605) 882-8535 mpeder...@midcom-inc.com Fax: (605) 882-8633 I disclaim anything that may be wrong. -- From: Diaco Davari[SMTP:dav...@pmc.philips.com] Sent: Thursday, October 08, 1998 2:29 PM To: emc-p...@majordomo.ieee.org Subject:Crepage/Clearance On Telecom Modem design Hello Folks, Does anyone know what the crepage distance shall be across the isolation from the line side to modem side within the DAA of Modems? Which document/standard refers to this specific spacing in detail ? I have been told by local experts on EN60950 that I need 4.2 mm spacing across the isolation. Apparently I do not need to have the spacing on the top of the board in alignment (or registration) with the spacing on the bottom of the board. Regards, Diaco - 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: Crepage/Clearance On Telecom Modem design
Hello Diaco: My reading of Clause 6 of IEC 950/EN 60950 is: between TNV circuit and primary circuit: double or reinforced insulation, including applicable creepage distance and clearance, or basic insulation and a grounded conductive barrier, including applicable creepage distance and clearance from the primary circuit to the conductive barrier. between TNV circuit and hazardous voltage secondary circuit: double or reinforced insulation, including applicable creepage distance and clearance, or basic insulation and a grounded conductive barrier, including applicable creepage distance and clearance from the hazardous voltage circuit to the conductive barrier. between TNV circuit and SELV circuit: no creepage distance or clearance requirement (but, it must pass the hi-pot test) between TNV circuit and ground: no creepage distance or clearance requirement (but, it must pass the hi-pot test) Creepage distances are measured along the shortest path between the two conductors across the surface of the insulator. There is no correspondence to traces on opposite sides of printed wiring boards (because such insulation is interposed solid insulation, and MAY be subject to insulation thickness requirements). 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: Crepage/Clearance On Telecom Modem design
In most cases, Norway, Sweden and Finland? require supplementary insulation for a primary circuit between TNV and Ground\/SELV. Assuming a primary circuit of 250VAC, I believe this works out to 2.5mm creepage and 2.0mm for clearance (I don't have my standard handy). In addition, you need 0.4mm thickness through the board, or sufficient multi layers per 2.9.4. Diaco, you didn't mention whether or not the product is intended for world wide distribution, so be careful not to disregard these additional requirements for these regions. I've heard that Sweden is considering a compromise that might remove the distance through insulation requirement, but still hold the line creepage and clearance, however, I don't know if and when this will take effect. Glenn -Original Message- From: Rich Nute [SMTP:ri...@sdd.hp.com] Sent: Thursday, October 08, 1998 8:54 PM To: dav...@pmc.philips.com Cc: emc-p...@majordomo.ieee.org Subject:Re: Crepage/Clearance On Telecom Modem design Hello Diaco: My reading of Clause 6 of IEC 950/EN 60950 is: between TNV circuit and primary circuit: double or reinforced insulation, including applicable creepage distance and clearance, or basic insulation and a grounded conductive barrier, including applicable creepage distance and clearance from the primary circuit to the conductive barrier. between TNV circuit and hazardous voltage secondary circuit: double or reinforced insulation, including applicable creepage distance and clearance, or basic insulation and a grounded conductive barrier, including applicable creepage distance and clearance from the hazardous voltage circuit to the conductive barrier. between TNV circuit and SELV circuit: no creepage distance or clearance requirement (but, it must pass the hi-pot test) between TNV circuit and ground: no creepage distance or clearance requirement (but, it must pass the hi-pot test) Creepage distances are measured along the shortest path between the two conductors across the surface of the insulator. There is no correspondence to traces on opposite sides of printed wiring boards (because such insulation is interposed solid insulation, and MAY be subject to insulation thickness requirements). 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). - 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: Crepage/Clearance On Telecom Modem design
Glen, Norway, Sweden and Finland are correct. The Finish deviation for this is somewhat hidden, it is in clause 6.2.1.4, where it states that Earth Ground is not permitted as a level of protection between Mains and TNV. Double (BASIC + SUPPLEMENTARY) or REINFORCED INSULATION between is all that can be relied upon. You can only rely on Earth Ground if your equipment has a permanent connection to Earth Ground, or if it is plugable equipment type B (Industrial). The Swedish Deviation is in clause 6.3.3.1, and the Norwegian deviation is in clause 6.2.1.2. I wonder...why couldn't they all make life a little easier and address this issue in the same location? Oh well... Mel PedersenMidcom, Inc. Homologations Engineer Phone: (605) 882-8535 mpeder...@midcom-inc.com Fax: (605) 882-8633 -- From: Lesmeister, Glenn[SMTP:glenn.lesmeis...@compaq.com] Sent: Friday, October 09, 1998 12:14 AM To: 'Rich Nute'; dav...@pmc.philips.com Cc: emc-p...@majordomo.ieee.org Subject:RE: Crepage/Clearance On Telecom Modem design In most cases, Norway, Sweden and Finland? require supplementary insulation for a primary circuit between TNV and Ground\/SELV. Assuming a primary circuit of 250VAC, I believe this works out to 2.5mm creepage and 2.0mm for clearance (I don't have my standard handy). In addition, you need 0.4mm thickness through the board, or sufficient multi layers per 2.9.4. Diaco, you didn't mention whether or not the product is intended for world wide distribution, so be careful not to disregard these additional requirements for these regions. I've heard that Sweden is considering a compromise that might remove the distance through insulation requirement, but still hold the line creepage and clearance, however, I don't know if and when this will take effect. Glenn -Original Message- From: Rich Nute [SMTP:ri...@sdd.hp.com] Sent: Thursday, October 08, 1998 8:54 PM To: dav...@pmc.philips.com Cc: emc-p...@majordomo.ieee.org Subject:Re: Crepage/Clearance On Telecom Modem design Hello Diaco: My reading of Clause 6 of IEC 950/EN 60950 is: between TNV circuit and primary circuit: double or reinforced insulation, including applicable creepage distance and clearance, or basic insulation and a grounded conductive barrier, including applicable creepage distance and clearance from the primary circuit to the conductive barrier. between TNV circuit and hazardous voltage secondary circuit: double or reinforced insulation, including applicable creepage distance and clearance, or basic insulation and a grounded conductive barrier, including applicable creepage distance and clearance from the hazardous voltage circuit to the conductive barrier. between TNV circuit and SELV circuit: no creepage distance or clearance requirement (but, it must pass the hi-pot test) between TNV circuit and ground: no creepage distance or clearance requirement (but, it must pass the hi-pot test) Creepage distances are measured along the shortest path between the two conductors across the surface of the insulator. There is no correspondence to traces on opposite sides of printed wiring boards (because such insulation is interposed solid insulation, and MAY be subject to insulation thickness requirements). 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). - 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).
Feeding 2 phases into one telco rack
Members, Can anyone enlighten me whether reugulations exist in EU countries ( Excepting the UK) which advise against or prohibit the practice of feeding duplicated powere supplies from different 230 V phases into the same shelf or rack of telco TDM ( or any) equipment. The UK regs say no. Any guidance whether by proprietary standards or ETSI work would be welcome. Jerry Roberton EMEA Homologation NET Europe - 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).
SLIM
I have an electronic (WORD) copy of the SLIM document. REPORT OF THE SLIM III TEAM ON THE ELECTROMAGNETIC COMPATIBILITY DIRECTIVE (89/336/EEC as amended) Please email me if you would like a copy. Keith L. Nicholas Manager, Electrical Controls AMP Incorporated, Automachine Systems Group Mail Stop: 161-39 * (717) 810-2601 * (717) 810-2443 * keith.nicho...@amp.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: Lab qualification
ISO/DIS is available at: http://web.ansi.org/reports/master.asp?room=22 http://web.ansi.org/reports/master.asp?room=22 -Original Message- From: Matejic, Mirko [SMTP:mmate...@foxboro.com] Sent: Wednesday, October 07, 1998 7:07 AM To: 'emc-pstc' Subject:RE: Lab qualification ISO/DIS 17025 is DRAFT industry standard which has been produced as the result of extensive experience of the implementation of ISO/IEC Guide 25: 1990 and EN 4500l :1989 both of which it will replace. It contains all of the requirements that testing and calibration laboratories have to meet if they wish to demonstrate that they operate a quality system, are technically competent, and are able to generate technically valid results. It is likely that it would be adopted with some modifications. Voting on this document terminates on 1998-12-09. If you have suggestions or comments on this document, please let me know. File will be posted soon on http://www.rcic.com http://www.rcic.com IEC standards. My suggestions are along the line of already posted responses. Consider only test laboratories accredited by NVLAP, A2LA or any other accreditor having MRA with either of them. Let them assess test laboratories for you. Personal visit to the laboratory could be valuable. Regards, Mirko Matejic - 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: Room grounding
'Single point ground' in this situation is used for the same purpose as we would in electronics design. When using a shielded room for making low frequency measurements (particularly MIL-STD), multiple ground connections can make significant power frequency and harmonic noise. Generally this is not so much of a problem for commercial operations because emission measurements are not as restrictive (either in frequency or in limit). Because,as Jon says, the conduit, etc. is not always reliable (particularly at the higher frequencies which filters are designed to shunt) an effort is made to provide ground through an independent means. I have used enclosures where great care has been taken (multiple 12' ground rods in close proximity, with Cu Sulfate 'salting') to provide a very 'robust' ground. This is then connected to both the enclosure and the building ground. In some cases, you have to convince the electrician and/or the inspector that your room provides at least as good a ground as the conduit in order to be able to take advantage of the isolation provided by the PVC. It goes against their grain to connect a metal box without using metal conduit. Bob Martin Sr. Technical Manager Intertek Testing Services (978)263-2662 fax(978)263-7086 r...@itsqs.com The opinions expressed are my own and not necessarily those of my employer. -Original Message- From: Jon D. Curtis [SMTP:j...@curtis-straus.com] Sent: Thursday, October 08, 1998 11:52 AM To: lfresea...@aol.com Cc: mhopk...@keytek.com; emc-p...@ieee.org Subject:Re: Room grounding As I understand it, Lingren connects the shielded rooms they build back to the main building ground point by a separate ground wire. The conduit is disconnected by use of a plastic sleave. I assume they do this because the AC filters incorporated in the shielded room include LARGE capacitors to the shielded room walls. Effectively the leakage through these capacitors turns the ENTIRE room surface into an AC electrode with respect to building ground. This leakage current is potentially leathal unless returned back to the source where the neutrals of the building are tied to ground at the circuit panel. Not grounding the room (if it incorporates standard room filters) should not be considered acceptable. If there is an regular outlet on an adjacent building wall, then a lethal hazard will exist between a metal test instrument pluged into that outlet and the room surface. I would hazard a bet that most room installations are not well enough controlled to insure that building ground and a separate room ground are NEVER allowed to meet. Consider that no sparks will fly if it happens, but hearts may stop. People automatically consider dead metal as ground. I would also caution against those in this thread who rely on conduit. Conduit breaks, is removed, etc. For high leakage threats only a dedicated ground wire of suitable gage to carry the total fault current of the supply should be employed. This is not about a single fault problem. You have a hazardous condition with NO fault because of filter leakage if you do not ground the room to the building ground at the circuit panel. Watch out for LISNs Also. The design of all lisns incorporate LARGE capacitors to ground for filtering. Without a ground connection on the LISN case, high leakage threats exist. Most use LISNs bonded to the ground plane which addresses this threat as long as the ground plane is connected to the building ground. The debate on reduction of noise and effects on EMC results should continue, BUT personel safety comes FIRST and should not be compromised. lfresea...@aol.com wrote: Mike, sorry you disagree. Inside the room, all equipment is referenced to the room itself, there is no new safety risk introduced by the room being grounded differently. Outside the room, again, all equipment is referenced tightly to the room, so the operator does not see any differential. Should lightning strike the building, then true, the building earth potential may lift, but the operator is protected because he is referenced to the room which will not move much because the energy has been dissipated by the building earthing system. I state again this is for performance reasons, and is accepted practice. In a true Faraday shielded room, earthing the room is not even neccessary. Mind you, since these don't exist off the shelf, I'll stick to grounding using my original guidlines. NEC inspectors, when the rationale is explained to them have little problem. However, I have come across situations were the two unique earths were tied by a very heavy inductor Best regards, Derek N. Walton - 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: Ozone...
Can somebody confirm information I picked on the radio that each Shuttle launch causes a major damage in the Ozone layer? Mirko Matejic - 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: SLIM
You should post it in the contributed document section of the RCIC. Monty Griffith Senior Product Safety Engineer Intergraph Computer System Huntsville, AL 35894-0001 PH: (256) 730-6017 FX: (256) 730-6239 http://mecsrv.b29.ingr.com -Original Message- From: Nicholas, Keith L [SMTP:keith.nicho...@amp.com] Sent: Friday, October 09, 1998 6:56 AM To: 'emc-p...@majordomo.ieee.org' Subject: SLIM I have an electronic (WORD) copy of the SLIM document. REPORT OF THE SLIM III TEAM ON THE ELECTROMAGNETIC COMPATIBILITY DIRECTIVE (89/336/EEC as amended) Please email me if you would like a copy. Keith L. Nicholas Manager, Electrical Controls AMP Incorporated, Automachine Systems Group Mail Stop: 161-39 * (717) 810-2601 * (717) 810-2443 * keith.nicho...@amp.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).
ThanX from The Safety Link (A Milestone!)
Hello PSTCers, Last night the 100,000th visitor entered the Safety Link (the web's most comprehensive collection of electrical product safety and standards resources.) Our counter was started towards the end of 1995. 40,000+ have visited in the past year and the rate continues to climb. ThanX to all who have visited (from 50+ Countries), contributed the location of useful sites (now in excess of 400) or provided indications that a link no longer functions (fortunately, a limited occurrance). AND, THANX to our corporate sponsors, (who provide financial support). 100,000 Product Safety Professionals can't be wrong. If you are not familiar with our offerings, please visit www.safetylink.com With appreciation, Art Michael, Webmaster - the Safety Link Int'l Product Safety News A.E. Michael, Editor P.O. Box 1561 INT Middletown CT 06457-8061 U.S.A. Phone : (860) 344-1651 Fax: (860) 346-9066 Email : i...@connix.com Website: http://www.safetylink.com ISSN : 1040-7529 - 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).
IEC 1000-X-X vs EN 61000-X-X
Hello group, I currently have a number of the IEC 1000-X-X standards and test in accordance with them, EN 50082-1:1997 references the EN 61000-X-X standards. Can I safely continue to use my IEC 1000-X-X set or do I have to buy the EN 61000 series. any comments appreciated Thanks Jeff Bailey SST - 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: Shield Room Grounding
Hi Ed, I appreciate your kindness to share your experience with us about constructing equivalent load: I constructed a load bank consisting of 16 surface mount light bulb sockets, all wired in parallel. I just screw in an array of 25/60/75/100 Watt rated lamps until I get the necessary current. Sure, there's some unknown slight lead inductance and capacitance. But all I want to do is draw a few amps DC I have two questions: (1)What is the impedance of your bulb array at 30 MHz? i.e., Zb=? @30 MHz. (2)What is the impedance of EUT at 30 MHz? i.e., Ze=? @30 MHz If we are not sure Zb=Ze @30 MHz, I am afraid, it's hard to say the spectrum analyzer would receive the same RF emission at 30 MHz from noise sources other than EUT, although the bulb array draws the same current at 60 Hz as EUT does. In other words, Zb=Ze @60 Hz is one thing, and Zb=Ze @30 MHz would be another. Let's see an example, assuming Ze=Re+jXe, where Xe=Omega*Le, and Omega=2*Pi*F. Re=20 Ohm, Xe=0.1 Ohm @60 Hz, Ze=20+j*0.1=20 Ohm Be=20 Ohm, Xe=5 Ohm @30 MHz,Ze=j*5 Ohm Conclusion: As far as the equivalent load is concerned, we can only pay attention to the equivalence of resistance part of Zb and Ze @60 Hz. At 30 MHz, however, we should pay more attention to the equivalence of reactance part of Ze and Zb instead. Suggestion: We might need to check the equivalence of Zb and Ze @30 MHz by using an Impedance Analyzer, e. g., HP4191A(?). Thank you. Please correct me. Best Regards, Barry Ma - 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: Crepage/Clearance On Telecom Modem design
Hello Diaco, As you can see from all the responses to your question, you have received many contradictory answers! As the Israeli member of the IEC 950 WG7 Committe, I would like to provide you with the correct answer. However, I would first need you to provide me with details of what a DAA modem is. Best Regards, Date sent: Thu, 08 Oct 1998 12:29:28 -0700 To: emc-p...@majordomo.ieee.org From: Diaco Davari dav...@pmc.philips.com Subject:Crepage/Clearance On Telecom Modem design Send reply to: Diaco Davari dav...@pmc.philips.com Hello Folks, Does anyone know what the crepage distance shall be across the isolation from the line side to modem side within the DAA of Modems? Which document/standard refers to this specific spacing in detail ? I have been told by local experts on EN60950 that I need 4.2 mm spacing across the isolation. Apparently I do not need to have the spacing on the top of the board in alignment (or registration) with the spacing on the bottom of the board. Regards, Diaco - 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).
Two diverse questions
To my knowledge, Germany is the only country that has an acoustics law that affects routine ITE. The German Workplace Law sets limits in the 60+dBA? range for workplaces. OSHA also sets limits, but they begin (as I recall) around 85dBA, and well above routine ITE noise. Where acoustic levels are claimed they are usually measured in accord with ISO 7779 and reported in accord with ISO 9296. George Alspaugh Lexmark International -- Forwarded by George Alspaugh/Lex/Lexmark on 10/09/98 03:34 PM --- Gary McInturff gmcinturff%packetengines@interlock.lexmark.com on 10/09/98 02:05:11 PM Please respond to Gary McInturff gmcinturff%packetengines@interlock.lexmark.com To: 'emc-pstc list server' emc-pstc%ieee@interlock.lexmark.com cc:(bcc: George Alspaugh/Lex/Lexmark) bcc: George Alspaugh/Lex/Lexmark Subject: Two diverse questions *Sound pressure measurements - What standard drives those requirements? *TNV3 connectors are BNC types - are their connectors that can provide higher density connections than 1? - given the nature of coax this seems counter-intuitive but I am passing the request for information. - 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).
Two diverse questions
[Correction to prior note below. German limits are for imission as opposed to emission. It is the total sound pressure as measured at the worker's location. Therefore, it is the employer who is held accountable to provide equipment, drapes, carpet, or whatever that helps meet the limits.] To my knowledge, Germany is the only country that has an acoustics law that affects routine ITE. The German Workplace Law sets limits in the 60+dBA? range for workplaces. OSHA also sets limits, but they begin (as I recall) around 85dBA, and well above routine ITE noise. Where acoustic levels are claimed they are usually measured in accord with ISO 7779 and reported in accord with ISO 9296. George Alspaugh Lexmark International -- Forwarded by George Alspaugh/Lex/Lexmark on 10/09/98 03:34 PM --- Gary McInturff gmcinturff%packetengines@interlock.lexmark.com on 10/09/98 02:05:11 PM Please respond to Gary McInturff gmcinturff%packetengines@interlock.lexmark.com To: 'emc-pstc list server' emc-pstc%ieee@interlock.lexmark.com cc:(bcc: George Alspaugh/Lex/Lexmark) bcc: George Alspaugh/Lex/Lexmark Subject: Two diverse questions *Sound pressure measurements - What standard drives those requirements? *TNV3 connectors are BNC types - are their connectors that can provide higher density connections than 1? - given the nature of coax this seems counter-intuitive but I am passing the request for information. - 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: IEC 1000-X-X vs EN 61000-X-X
The IEC is simply renumbering the 1-x-X series to become the 61000-x-x series. Any new standard in that series will be numbered 61000-x-x. Existing standards are not going to be re-issued just to change the number, but when they are re-issued for whatever reason, the numbers will be changed. Hope this helps. Mike Hopkins mhopk...@keytek.com -Original Message- From: Bailey, Jeff [SMTP:jbai...@sstech.on.ca] Sent: Friday, October 09, 1998 12:53 PM To: 'EMC-PSTC' Subject: IEC 1000-X-X vs EN 61000-X-X Hello group, I currently have a number of the IEC 1000-X-X standards and test in accordance with them, EN 50082-1:1997 references the EN 61000-X-X standards. Can I safely continue to use my IEC 1000-X-X set or do I have to buy the EN 61000 series. any comments appreciated Thanks Jeff Bailey SST - 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: Shield Room Grounding
Hi Barry et al, I'm I missing something here? Is this exercise worth the trouble? If one doesn't have a clear margin to any commercial limit line with any kind of resistive dummy load attached to your LISN shouldn't you examine the your system setup? Accurate determination of your measurement system noise floor with a known impedance through the frequency range is really only of academic use in this case, isn't it? This should have no bearing on pass/fail of an EUT as the measurement system noise floor and the limit line should be well separated for conducted emissions in a shielded room. Regards, Kevin Harris -Original Message- From: b...@namg.us.anritsu.com [SMTP:b...@namg.us.anritsu.com] Sent: Friday, October 09, 1998 1:33 PM To: emc-p...@ieee.org Subject: Re: Shield Room Grounding Hi Ed, I appreciate your kindness to share your experience with us about constructing equivalent load: I constructed a load bank consisting of 16 surface mount light bulb sockets, all wired in parallel. I just screw in an array of 25/60/75/100 Watt rated lamps until I get the necessary current. Sure, there's some unknown slight lead inductance and capacitance. But all I want to do is draw a few amps DC I have two questions: (1)What is the impedance of your bulb array at 30 MHz? i.e., Zb=? @30 MHz. (2)What is the impedance of EUT at 30 MHz? i.e., Ze=? @30 MHz If we are not sure Zb=Ze @30 MHz, I am afraid, it's hard to say the spectrum analyzer would receive the same RF emission at 30 MHz from noise sources other than EUT, although the bulb array draws the same current at 60 Hz as EUT does. In other words, Zb=Ze @60 Hz is one thing, and Zb=Ze @30 MHz would be another. Let's see an example, assuming Ze=Re+jXe, where Xe=Omega*Le, and Omega=2*Pi*F. Re=20 Ohm, Xe=0.1 Ohm @60 Hz, Ze=20+j*0.1=20 Ohm Be=20 Ohm, Xe=5 Ohm @30 MHz,Ze=j*5 Ohm Conclusion: As far as the equivalent load is concerned, we can only pay attention to the equivalence of resistance part of Zb and Ze @60 Hz. At 30 MHz, however, we should pay more attention to the equivalence of reactance part of Ze and Zb instead. Suggestion: We might need to check the equivalence of Zb and Ze @30 MHz by using an Impedance Analyzer, e. g., HP4191A(?). Thank you. Please correct me. Best Regards, Barry Ma - 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: Ozone...
All I found was the following from 1996 ... http://www.ssnewslink.com/html/governme.html At 09:44 AM 10/9/98 -0400, Matejic, Mirko wrote: Can somebody confirm information I picked on the radio that each Shuttle launch causes a major damage in the Ozone layer? Mirko Matejic - 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: Two diverse questions
From: Gary McInturff gmcintu...@packetengines.com Subject: Two diverse questions Date: Fri, 9 Oct 1998 11:05:11 -0700 To: 'emc-pstc list server' emc-p...@ieee.org * TNV3 connectors are BNC types - are their connectors that can provide higher density connections than 1? - given the nature of coax Gary: Not sure what I'm answering, but higher density could be defined by a triaxial connector or a twin-ax connector. Twin-ax is seen in a BNC type connector, while I think I have only ever seen triax in a TNC body. 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: 10/09/1998 Time: 13:19:19 -- - 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: Added paragraph
Unfortunately, my Email system does not allow me to edit any Email I am replying. For example, Peter, I am not able to change anything of you message.--Barry Ma - Original Text From: Peter Tarver peter.tarver.ptar...@nt.com, on 10/8/98 2:57 PM: Better yet, how about the subscribers taking the additional two or three seconds it takes to do the responsible thing and delete it themselves? Peter L. Tarver Nortel ptar...@nt.com -Original Message- From: Robert Macy [SMTP:m...@california.com] Sent: Thursday, October 08, 1998 12:05 PM Is there anyway to remove the paragraph emc-pstc adds to the msgs? I archive all the msgs and it's starting to look like 30-40% of the text are those paragraphs! It's really noticeable when a quoted msg has a quoted msg with a quoted msg. Don't get me wrong. That paragraph is really handy. There must be a way to add that paragraph without it automatically transferring. I know because when I shot back some spam, the 10 pages disappeared into only the introducing paragraph (which was very innocuous). If you guys can figure out how to add the paragraph but not have it requoted when we quote the msg, I'd really appreciate it....or make it much smaller? - Robert - - 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).
UL1950 vs UL508 for Switching Power Supplies
Dear PSTC Members, Assuming a manufacturer had UL1950 Third Edition Recognized Component Class I (earthed) ITE Power Supplies and they wanted to have a Listing (as an open-end device) to the Standard for Industrial Control Equipment, UL508. 1) What additional requirements must be met? I am already aware that the input/output terminal blocks must be suitable for field wiring. 2) What about spacings? 3) What about if the input terminal block design is such that the earth goes directly to the PCB trace? Under UL1950 Recognition this was OK since the manufacturer decided to add a Condition of Acceptability (instead of meeting a 1000 Amp short-circuit test) that states that the power supply earthing terminal is not the protective earthing terminal and that this terminal should be reliably bonded to the end-product protective earthing terminal. Since manufacturer intends to also List his power supplies to UL508, this Condition of Acceptability must be removed and I wonder if the UL508 standard has a similar 1000A test as applied to to ITE equipment where the trace is relied upon for protective earthing! 3) Any other considerations for Listing to UL508? Thank you all, - 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).
Capacitors Between TNV and SELV for ITE Equipment
Dear Fellow Members, Per UL1950 and EN60950: 1) Can you tell me what type of capacitors will be suitable to bridge basic insulation between TNV-3 circuits and SELV circuits? 2) Assuming that the body of above TNV-3 to SELV capacitors can touch SELV components, can the body be considered suitable for basic insulation or should there be an additional sleeving or tubing over the capacitor that meets the requirements for basic insulation? Thanks and Best Regards, - 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).
(Fwd) UL1950/CSA C22.2 950 Third Edition; Telco Overvoltage Te
Forwarded message: From: Self Single-user mode To: pstc-...@ieee.org Subject: UL1950/CSA C22.2 950 Third Edition; Telco Overvoltage Tests List-Post: emc-pstc@listserv.ieee.org Date: Fri, 9 Oct 1998 23:50:09 +0200 Dear Fellow members, After the application of the Overvoltage Tests to telecom interfaces subjected to exposed plant, one of criteria for passing to the above specified standards is the application of a Dielectric Voltage Withstand Test or the Leakage Current Test. As such, if the manufacturer failed the Dielectric Voltage Withstand Test, manufacturer can choose to comply with the Leakage Current Test. As the standard is written today, it is not necessary to apply a 600 V to the telephone interface (to simulate a power line coming across the telephone interface) when conducting the Leakage Current Test. Application of the 600 V to the telephone interface when measuring Leakage per the Standards for Telephone Equipment UL1459 and CSA C22.2 225 was a common practice and makes sense. I believe there was a big mistake in overlooking this point when the UL1950/CSA C22.2 950 standard was developed. I know one manufacturer with a piece of equipment which was submitted to one NRTL and received Listing (because after failing Dielectric Strength Test, they passed the Leakage Current Test- obviously he passed since 600 V was not applied to the telco interface). When OEM submitted the same piece of equipment to another NRTL, they couldn't get Listing since engineer evaluating product applied 600 V to the telco interface when measuring Leakage (even though standard does not require it) and the product failed the test. Any comments, especially from pstc members who are also in the North American Standardization Committe for UL1950/CSA C22.2 950? - 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).
RATED VOLTAGE UL1950
Dear group, I have a question on defining the RATED VOLTAGE that should be applied to TNV in UL1950 Clause 6.3.3.1 Additional Test for separation between telecommunication network and earth (Figure 17) for a Class III device that operates from an external nominal 12VDC (SELV) Listed Class II Level 3 adapter. I know by definition RATED VOLTAGE 1.2.1.1 is the primary voltage as declared by the manufacturer. I see that this is obviously the case if the power supply is physically part of the equipment and directly mains powered. In this case it is a seperate module. Should I use as the the RATED VOLTAGE for this test the upper limit of the mains voltage to the adapter (125VAC) or can the test be done at the rated voltage of the EUT (e.g. 16VDC)? If it's the mains voltage to the adapter, then in reality its seems we are re-testing an already Listed and proven adapter where there should be no more than 0.25ma leakage. Your responses are greatly appreciated. --- Larry Barnette Compliance Engineer GAI-Tronics Corp. Memphis Facility Instrument Associates Division 2455 Harbor Ave. Memphis, Tenn. USA 38113 larry_barne...@instrumentassociates.com Phone: 901-947-4000 Ext. 176Fax: 901-948-0471
