Re: Lightning Surge Characterization/Standards
Anil, Remember, some of those tests you mention assume a Primary Protector is also in place. In the U.S. maybe you can assume this is true, but can you worldwide? Also, for some of those tests, the criteria for failing are fragmentation/fire, obviously the product would not continue to work then - but you may still hold a passing test report. In short, meeting those requirements assures a very limited degree of safety presented to the user and quality of the product, not a thoroughly robust lightning proof design. Best regards, Stephen At 12:37 PM 8/5/2003, Anil Allamaneni wrote: Greetings folks, We have products that meet all the Surge requirements of NEBS GR-1089, FCC-68 and EMC 4-5. But, the same products are continuously failing in the field due to real-world lightning strikes. I have spoken to four other manufacturers who make similiar interfaces (DSL) and they all have the same problem : they meet the standards, but fail in the real world. I have two questions for the esteemed people here : 1) Were these standards written based on somebody doing some field evaluations? Has IEEE/Bellcore done any research into what the waveforms really are for actual *real-world* lightning strikes? How do they do that? 2) Is somebody working on re-charaterization of lightning strikes throughout US (eg, the surges seem to be more lethal in TN as opposed to CA)? Would you have the contact details of Working Groups? Thanks a...@occamnetworks.com __ Do you Yahoo!? Yahoo! SiteBuilder - Free, easy-to-use web site design software http://sitebuilder.yahoo.com http://sitebuilder.yahoo.com/
Re: OFF is zero
I think I missed the beginning of this thread, so please forgive me if I rehash old ground. The 'vertical line' and 'circle' you refer to, are actually a 1 (One) and 0 (Zero); as in digital logic on/off respectively. Best regards, Stephen At 11:53 AM 10/21/2002, Rich Nute wrote: Hi Neil: The origin may be true, but IEC60417 is quite clear. ON is a vertical line (symbol 5007) and OFF is a circle (symbol 5008). Agreed. And thank you for the clarification. Best regards, Rich --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Re: Use of pre-plated steel.
John, Sharp edges of pre-plate can be a real problem. And deburring can cause the pre-plate to rust. I'm told you can't run a deburring process on pre-plate - for that reason. I've also been told that a sharp tool will leave less sharp edges on the finished piece, and I'm not only skeptical of that - but even if it is true, concerned also of how long the tool will remain as sharp as it is then dependent upon. Some years ago I bought a sharp edge tester, because all of our bandaged fingers and bloody prototype chassis' were not enough to convince a particular mechanical engineer on that first pre-plate project of the problem at hand. I do admit that we have in some instances allowed the use of pre-plate since - because in those instances it met our criteria - I'm not certain I recall what they changed to achieve that, but I do keep an eye on it. Best regards, Stephen At 11:33 AM 10/2/2002, Crabb, John wrote: Has anyone encountered problems in the use of pre-plated sheet steel in IT equipment metalwork ? Typically such material is cheaper to use than having to plate parts after they have been produced, but there may be issues with sharp edges produced when the material is punched out, and with rust on the edges which are not protected. Regards, John Crabb, Development Excellence (Product Safety) , NCR Financial Solutions Group Ltd., Discovery Centre, 3 Fulton Road, Dundee, Scotland, DD2 4SW E-Mail :john.cr...@scotland.ncr.com Tel: +44 (0)1382-592289 (direct ). Fax +44 (0)1382-622243. --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
RE: creepage v breakdown voltage
Time certainly couldn't account for wide ranging humidity or altitude, but perhaps lessor humidity and air pressure changes. The time may have more to do with settling capacitive effects first. Stephen At 10:38 AM 3/15/2002, MCA Compliance wrote: These factors are certainly all relevant, but I was under the impression (maybe incorrectly so?) that the requirement to apply the test voltage for 60 seconds during the type test was to account for all these degradating factors. Brian -Original Message- From: Stephen Phillips [mailto:step...@cisco.com] Sent: 15 March 2002 15:17 To: Roman, Dan Cc: 'MCA Compliance'; Emc-Pstc Post Subject: RE: creepage v breakdown voltage Try this. For flat electrodes, at sea level, and normal temperatures; eliminating such factors as humidity, dust, illumination, and the electrode materials; the molecules of the gases that compose common air, get ionized in the presence of an electric field of about 30KV/cm. So, since - electrode shape, barometric pressure, temperature, humidity, dust, presence of photons, and composition of the materials and shape of the electrodes, as well as the composition of the 'air' (gases), and also any other local (competing) electromagnetic fields - can all affect the definitive voltage that will jump a given gap - is it any wonder that the standard includes what otherwise appears to be a lot of slop. Stephen At 09:28 AM 3/15/2002, Roman, Dan wrote: I was looking into this a few weeks ago also and found similar results experimentally as other posters have mentioned. The only voltage per inch spec I was able to come up with was in the IPC specs but they were way out of whack! 0.12 mils per volt or more meaning that 2121 Vdc distance that the safety standards say should be 2.5 mm the IPC spec is saying you need 5 mm While the safety standards may be conservative to allow for temperature, grease, dirt, etc. over time the IPC specs are ultra-conservative. The dielectric tables for hermetically sealed material group III is probably closer to the actual breakdown but I never did find a spec I could use to predict the ACTUAL breakdown voltage of a gap between traces. If anyone finds a rule of thumb or equation I'd like to have it also. Dan -Original Message- From: MCA Compliance [mailto:bally...@iolfree.ie] Sent: Friday, March 15, 2002 4:54 AM To: Emc-Pstc Post Subject: creepage v breakdown voltage does data exist which correlates creepage distance on a pcb with hi-potential test voltage it should withstand ? for example, I know 60950 sugests a test voltage of 1500Vrms for 1 minute and a creepage of 2.5mm (material group III) for basic insulation. How did they arrive at 2.5 mm ??? Brian email: i...@mcac.ie --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Re: creepage v breakdown voltage
Regarding Paschen's Law: http://home.earthlink.net/~jimlux/hv/hvmain.htm http://home.earthlink.net/~jimlux/hv/paschen.htm Stephen At 12:51 PM 3/15/2002, Doug McKean wrote: I've done my own testing and researched the thing as well. I think we've had some serious discussions here about this subject in the past. If the archives are available, it would be beneficial to go through them. Also, get a little hipot tester from any of the hipot mfrs for your own bench testing. That's highly educational as well as nipping problems in the bud. You'll first have to jump into Paschen's Law and all that involves with pressure/humidity/geometry of the probe tips used, etc ... Basically, I start with 1Mv/meter STP and work down from there. Therefore, 1mm means 1Kv. Now, throw in a x2 safety factor and you get 2mm spacing. Now increase to 1.5Kv and you end up with 2.5mm? Well, okay. Surface contamination sets in over time? Well, okay again. Obviously, I've been doing some extreme fudging, but it ends up darn close most of the time. Follow the standards when in any doubt. I'm not really sure, but I was told many years ago that wire mfrs use as much as a x7 safety factor for their insulation or used to. - Doug McKean --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
RE: creepage v breakdown voltage
Try this. For flat electrodes, at sea level, and normal temperatures; eliminating such factors as humidity, dust, illumination, and the electrode materials; the molecules of the gases that compose common air, get ionized in the presence of an electric field of about 30KV/cm. So, since - electrode shape, barometric pressure, temperature, humidity, dust, presence of photons, and composition of the materials and shape of the electrodes, as well as the composition of the 'air' (gases), and also any other local (competing) electromagnetic fields - can all affect the definitive voltage that will jump a given gap - is it any wonder that the standard includes what otherwise appears to be a lot of slop. Stephen At 09:28 AM 3/15/2002, Roman, Dan wrote: I was looking into this a few weeks ago also and found similar results experimentally as other posters have mentioned. The only voltage per inch spec I was able to come up with was in the IPC specs but they were way out of whack! 0.12 mils per volt or more meaning that 2121 Vdc distance that the safety standards say should be 2.5 mm the IPC spec is saying you need 5 mm While the safety standards may be conservative to allow for temperature, grease, dirt, etc. over time the IPC specs are ultra-conservative. The dielectric tables for hermetically sealed material group III is probably closer to the actual breakdown but I never did find a spec I could use to predict the ACTUAL breakdown voltage of a gap between traces. If anyone finds a rule of thumb or equation I'd like to have it also. Dan -Original Message- From: MCA Compliance [mailto:bally...@iolfree.ie] Sent: Friday, March 15, 2002 4:54 AM To: Emc-Pstc Post Subject: creepage v breakdown voltage does data exist which correlates creepage distance on a pcb with hi-potential test voltage it should withstand ? for example, I know 60950 sugests a test voltage of 1500Vrms for 1 minute and a creepage of 2.5mm (material group III) for basic insulation. How did they arrive at 2.5 mm ??? Brian email: i...@mcac.ie --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
RE: creepage v breakdown voltage
Humidity matters. Some years back, when doing some experiments around this subject - I too was surprised at just how much voltage different gaps could bear, such that the standard seemed gross overkill. But in a less than purely scientific way, I decided to breath (just breath, not blow) in the vicinity of the withstand, and got different results. It was winter (dry air), and my merely breathing normally - within about a foot of the gap under test - caused a 400V(DC) lower breakdown. I know the standard doesn't hold us to tight humidity spec's, only pollution degree, but maybe the committee that came up with this added enough margin to be sure to always cover such issues. The geometry of the surface across which the potential is laid matters too (curves, points, parallel planes), doesn't it. Again, maybe the committee just added guaranteed slop. There is no such thing as too safe. Stephen At 07:39 AM 3/15/2002, MCA Compliance wrote: Peter I agreee with your comment, but, I have seen lots of boards (material group III) pass high pot tests at 1.5kV with only 2 mm creepage on the boards. yet, 950 specifies 2.5mm for basic insulation. This is why I am after some independent experimental test data correlating creepage and dielectric strength, with different board material properties taken into account. I suppose to flip it around, if a board passes the hi-pot for 1 minute with 2 mm creepage (and the fact that it passes the hi-pot, means the clearance must also have been adequate?), why does 60950 look for 2.5mm creepage ??? rgds Brian -Original Message- From: Peter Merguerian [mailto:pmerguer...@itl.co.il] Sent: 15 March 2002 12:00 To: 'MCA Compliance'; Emc-Pstc Post Subject: RE: creepage v breakdown voltage Brian, Your PCB manufacturer should be able to tell you what spacings to keep in order to withstand the test voltages. It all depends on the base material used for the PCB which all have different dielectric strength properties. Remember, the standards reference a minimum creepage distance AND you must still pass the electric strength tests. This e-mail message may contain privileged or confidential information. If you are not the intended recipient, you may not disclose, use, disseminate, distribute, copy or rely upon this message or attachment in any way. If you received this e-mail message in error, please return by forwarding the message and its attachments to the sender. PETER S. MERGUERIAN Technical Director I.T.L. (Product Testing) Ltd. 26 Hacharoshet St., POB 211 Or Yehuda 60251, Israel Tel: + 972-(0)3-5339022 Fax: + 972-(0)3-5339019 Mobile: + 972-(0)54-838175 http://www.itl.co.il http://www.i-spec.com -Original Message- From: MCA Compliance [mailto:bally...@iolfree.ie] Sent: Friday, March 15, 2002 11:54 AM To: Emc-Pstc Post Subject: creepage v breakdown voltage does data exist which correlates creepage distance on a pcb with hi-potential test voltage it should withstand ? for example, I know 60950 sugests a test voltage of 1500Vrms for 1 minute and a creepage of 2.5mm (material group III) for basic insulation. How did they arrive at 2.5 mm ??? Brian email: i...@mcac.ie --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Re: EMC and Safety PCB Reviews
Alex, Not really a thorough checklist per se, but for Safety - roughly this: Throughout this process, I prefer to make notes on paper doc's, and then sit with the CAD engineer to go over the review on his computer screen and make any changes right then. - Schematic review (identify and mark up areas such as exceeding SELV and TNV, identify critical nets). - Provide Creepage Clearance guidelines to PCB CAD engineer (who inputs into the CAD system, based on properties assigned to the nets via the schematic). - Placement Review (using marked up silk-screen or assy. dwg based on previously marked up schematics), and also layer stack-up review at this time. - Layout review, layer by layer routing, and adjacent layer to layer. - Layout review with mechanical dwg superimposed (since sheet metal could violate CC to the PCB). - Thieving review (since thieving could violate CC). - Photo Artwork review (especially planes). - Also make sure the drawings tell the PCB fab. vendor not to put their logo smack in that nice clearing which is your CC! Obviously I left out a lot of the detail as to what we design for and what we specifically look for, but these are the higher granularity steps I routinely take. EMC would take more or less the same steps, just with different criteria. I hope this helps, Stephen At 09:46 AM 3/6/2002, you wrote: Hi Guys, I am being asked to review PCB's for EMC (and Safety) acceptance. I was going to try and collate a check list then I thought of this wonderful forum!! Does any kind person have such a thing as an EMC PCB Design Check list? Does any kind person have such a thing as an Safety PCB Design Check list? Kind Regards Alex McNeil Principal Engineer Tel: +44 (0)131 479 8375 Fax: +44 (0)131 479 8321 email: alex.mcn...@ingenicofortronic.com
Re: Pencil erasers for pre-EMI cleaning?
I'm not trying to be antagonistic, but unless you plan to perform this procedure on all production devices - neither should you do so to the test sample(s). My 2 cents worth. Regards, Stephen At 02:43 PM 2/28/2002, you wrote: All, I'm preparing for an emissions test and I had started cleaning some of my chassis mating surfaces with a pen/pencil eraser then alcohol to ensure the surface to surface contact was good. A friend then told me that using an eraser would also remove the anti-corrosive coating that was on the metal (Thanks Paul!). So I would end up with a very short term benefit, then rust. What I am trying to determine is if maybe light rubbing with a pencil eraser might only remove surface contaminants and leave the metal and coatings intact. (the pencil eraser is much less abrasive than the pen side) So the real question is... Does anyone have direct good or bad experience with the aftereffects of using a pencil eraser to clean mating edges (card faceplates in a telco box for example)? I have both steel and aluminum surfaces to worry about so info for either type is welcome. (and don't worry the different metal types are not adjacent). Any feedback would be greatly appreciated as the system is really dirty right now.
Re: Sometimes product safety just isn't enough
I hope you didn't let him watch the news either...
he could become a murderer, drunk driver, rapist,
embezzler, adulterer, car thief, or politician... or one
of those guys who goes surfing in a hurricane. Or -
learn by what he saw, not by what he didn't see.
With all due respect,
Moe Howard
Obviously, personal opinions - not those of my
employer (as far as I know anyway).
At 12:56 PM 12/14/2001, Tania Grant wrote:
Gert,
You may be technically correct, but I also believe that we should bring up
citizens to be prudently knowledgeable about electrical hazards. These
are not intuitively obvious. The manufacturer has a responsibility for
designing a safe product. The user has a responsibility for using it
prudently. The manufacturer also has a responsibility for warning
against possible (conceivable) misuse. It is here that the gray area waffles.
Would you countenance your daughter, clad in a bikini and barefoot,
repeating the same actions as in the picture, while you complacently view
this scene from the comforts of a beach chair, beer in hand?
By the way; I found the picture very humorous. However, slapstick humor
and hazards, especially electrical, do not mix. I would not want to
defend this pictorial from any safety perspective. This is a prime
candidate for What's wrong with this picture? to be analyzed by safety
professionals only.
PS: Ages ago the neighbors complained that my pre-kindergarten angel son
was hitting other kids on their heads with his fist. Those who were
brought up on the Three Stooges thought these antics were
humorous;-- since I was not brought up like that, I thought they were
just gross. I put a stop immediately to my son watching Three Stooges
re-runs on the TV, a harmless show from many perspectives. He is now a
very civilized adult and does not hit people over the head with his fists.
mailto:taniagr...@msn.comtaniagr...@msn.com
- Original Message -
From: CE-TEST
Sent: Thursday, December 13, 2001 11:57 PM
To: Robert Johnson; emc-p...@majordomo.ieee.org
Subject: RE: Sometimes product safety just isn't enough
{ Please read this email with more then average sense of humour , and then
: THINK !)
So, What's Wrong With That,
The guy on the picture (see link below) is protected by 2 layers of safety:
1/ Basic Insulation, rated for the mains voltage PLUS transient levels
2/ Grounding , for in case the basic insulation wears out or fails for
whatever reason (drops in the pool ?)
Many of us on this list are in some way responsible for the safety of their
employers products, or even test houses (like me) !
Do we have that much confidence in our work ?
Are we somewhere concerned the safety regulations are not strict enough ?
Do we, when working with electricity , count for extra layers of safety,
such as not
standing bare foot on an aluminium ladder, in a swimming pool ?
Are we concerned that the safety measures won't suffice for the lifetime
of the equipment ?
This man is doing what we expect our customers to do: have confidence that
products
sold comply with essential safety regulations.
Regards,
Gert Gremmen
ce-test, qualified testing
-Original Message-
From: owner-emc-p...@majordomo.ieee.org
[mailto:owner-emc-p...@majordomo.ieee.org]On Behalf Of Robert Johnson
Sent: woensdag 12 december 2001 19:28
To: emc-p...@majordomo.ieee.org
Subject: Sometimes product safety just isn't enough
I couldnât help passing on this reference to a bit of unforeseeable
misuse.?xml:namespace prefix = o ns =
urn:schemas-microsoft-com:office:office /
http://electrical-contractor.net/ubb/Forum4/HTML/48.htmlhttp://electrical-contractor.net/ubb/Forum4/HTML/48.html
Bob Johnson
Re: German Translation
I don't carry my various language conversion dictionaries in my briefcase anymore, since spec's have come in English for many years now. But I think it might mean (in some form) Danger; spelled differently though (die Gefaehrdung: danger, hazard, peril, accident risk). Try: http://dictionaries.travlang.com/GermanEnglish/ Best regards, Stephen At 08:32 AM 11/30/2001, richwo...@tycoint.com wrote: Can someone please tell me what the word Gefäedungen means in English? Richard Woods Sensormatic Electronics Tyco International --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
Re: LED Color Assignments
Joe, Get a copy of EN 60073 - 1993, (IEC 73 - 1991) - it is a good reference. BSI publishes it as BS EN 60073. I doubt it is adhered to entirely by most manufacturers these days, but some of us still do. Like most everything in the Compliance world, it is at least open to dogged interpretation discussions, and perhaps individual concessions. UL/EN60950 reference this, so check there for more supporting verbiage (Colours; clause 1.7.8.2). Best regards, Stephen At 05:35 PM 10/2/2001, Joe Finlayson wrote: Would anyone know of an equivalent (ETSI) requirement for the EU, and possibly rest of world, for the Telcordia requirements in GR-474 for LED color assignments? The EU requirements are most important although any additional information would be helpful. I would appreciate it if your answers could be accompanied by a document number, section, etc. The following is from GR-474: 2.2.3.2 NE Display - Visual Assignments and Meanings R2-36 [36] The colors red, yellow or amber, green, and white, indicating the severity of the trouble, shall be used on the NE's physical control/status display panel to visually represent various alarm levels and status conditions at the NE's equipment location and the OC. (See Section 2.7, Maintenance Person - NE Interface.) R2-37 [37] Color assignments for physical panels shall be as follows: ... a. Red shall indicate a critical or major failure, error, or danger. ... b. Yellow or amber shall indicate a minor failure, caution, warning, or temporary malfunction, or state for which the craftsperson should use caution. ... c. Green shall indicate satisfactory operation, active condition, or completion of a process or procedure. ... d. White shall indicate a neutral condition that implies nothing about the success or failure of system operations. Thx, Joe *** Joe Finlayson Manager, Compliance Engineering Telica, Inc. 734 Forest Street, Bldg. G, Suite 100 Marlboro, MA 01752 Tel: (508) 804-8212 Fax: (508) 480-0922 Email: jfinlay...@telica.com --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
Re: Steel ball for impact tests
I think they let that slide. If they didn't, then you'd have to respond to the manufacturers who use denser materials for their products. Since all objects (anything, having mass) gravitationally attract each other, the impact to a product of greater density is going to be relatively greater (no matter how difficult to quantify) than that to a product of lesser density. Maybe we should recalibrate the ball based on a reading of relative spacetime curvature per product. Stephen At 11:53 PM 9/24/2001, Jacob Schanker wrote: The mention of traceable calibration for a steel ball makes me wonder (tongue partially in cheek) about verification of the gravitational constant involved in the testing. Are adjustments to be made for local gravitational anomalies, altitude above sea level at the place of measurement, and the mass of the item tested (gravitational attraction being a function of mass)? :) Jack Jacob Z. Schanker, P.E. 65 Crandon Way Rochester, NY 14618 Phone: 716 442 3909 Fax: 716 442 2182 j.schan...@ieee.org --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
Re: Copper Thieving
Copper applied to the outer PCB layers, in a pattern, to even out the copper placement so the board is less likely to warp through soldering. Obviously, it would be put where there is not etch, large open areas, to somewhat offset where you might have planes of copper elsewhere on the layer. Beware of Creepage and Clearance violations (if applicable). Some PCB fab. houses have carte-blanche to add this, we don't allow that - and control it as part of our own PCB CAD instead. Best regards, Stephen At 09:15 AM 1/18/01 Thursday , rehel...@mmm.com wrote: Please excuse my lack of knowledge..what is copper thieving? --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
Re: Got a beef with an NRTL ...
Doug, You don't say for certain, but can we assume that the fact that the NTRL even knew of the internal fuse's limitations - that you and the ps company used the very same NRTL, including the same office? Or is this a case of one NRTL not accepting the 'interpretation' of another? Also, are you sure there are no CofA's on this supply? I require a copy of the UL and CB reports for every power supply, in an effort to avoid issues approaching this. It sounds very scary. I'd be pretty darn mad too! I'd direct some of that energy at the ps manufacturer as well as the NRTL. Best regards, Stephen At 12:42 PM 10/19/00 Thursday , Doug wrote: I'm just about ready to escalate this issue. Issue: Major NRTL has recognized a DC-DC power supply. Said ps is being used within the confines of it's stated purpose, input power, output power, temps, etc ... Said product is submitted to NRTL for what appeared to be a walk through. Oh no, Mr. McKean. You can't use THAT power supply as intended. Input fuse of power supply (that is the fuse INSIDE the power that is out of our hands) is an AC fuse. It should be a DC fuse. (From the documentation from the ps mfr, the approval was done with the aC rated fuse.) You have to either: 1. have the ps mfr change the input fuse. or 2. drop an in-line fuse between the power inlet of the product and the input of the ps. EXCUSE ME!?! How the heck can a power supply mfr get NRTL approval on one hand and, yet, when that power supply is used within it's intended and stated purpose, get rejected? Even bringing this to the attention of the test engineer (who has approx over 10 years experience as a test eng) it defaults to - well, that's just because the OTHER test engineer interpreted it that way ... I can understand and have been in those areas of interpretation with NRTLs, but this one really ... er ... surprises me. Yours truly and totally confused, Doug --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
Re: Sharp edge point
Bob, I agree with your statement about using it to settle arguments. That is why we bought it. The bloody fingers of several engineers were not convincing enough, so we had to resort to a tool of less subjectivity. It succeeded it getting the then prototype sheet metal in question run through a deburring process as a production function. Downplaying its' own inherent degree of subjectivity, for my money - it works as well as a gauge as it does as an argument ender, and I like having it in my tool arsenal. Stephen At 05:28 PM 10/16/00 Monday , Robert Johnson wrote: It's also available directly from UL. It is not very sensitive. It takes a very sharp edge to fail. It is not for testing points, only edges. I find it mainly of use to settle arguments. It also seems it would be rather variable if it came from several different manufacturers. After some experience, I would prefer to stick with the wording in the standards and leave it up to interpretation and judgement. Bob Stephen Phillips wrote: Raymond, We use a device from Technical Engineering Service, in NY, that has replaceable cylinders with the tape, indicator, and foam backing pre- applied - and we bought a virtual lifetime supply with the finger (40-50). It's a pre-loaded spring device, and each cylinder can be used many times. Let me know if you want their address and phone number. Best regards, Stephen At 04:10 PM 10/16/00 Monday , Jim Bacher wrote: forwarding for: raymond...@omnisourceasia.com.hk Reply Separator Subject:Sharp edge point Author: Raymond Li raymond...@omnisourceasia.com.hk Date: 10/17/00 1:05 AM In EN60065 EN60335 standards, there are no specific methods to determine sharp edge and point. Should we adapt EN71 toys standard as reference for type evaluation? It requires adhesive test tape. Can anyone advise me where I can find the test tape. Thanks and regards, Raymond Li Omni Source Asia Ltd. --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
RE: Sharp edge point
Raymond, Here you go. Sharp Edge Tester, Model Set - 50 Technical Engineering Service 140 Rumford Road Kings Park, NY, 11754 516-265-4290 Stephen At 09:11 PM 10/16/00 Monday , Raymond Li wrote: Stephen, I would be grateful if you could provide me with their email address, telephone number and fax number. Thanks, Raymond -Original Message- From: Stephen Phillips [mailto:step...@cisco.com] Sent: Tuesday, 17 October, 2000 03:42a To:jim_bac...@mail.monarch.com; raymond...@omnisourceasia.com.hk; emc-p...@majordomo.ieee.org Subject: Re:Sharp edge point File: att1.htm Raymond, We use a device from Technical Engineering Service, in NY, that has replaceable cylinders with the tape, indicator, and foam backing pre- applied - and we bought a virtual lifetime supply with the finger (40-50). It's a pre-loaded spring device, and each cylinder can be used many times. Let me know if you want their address and phone number. Best regards, Stephen At 04:10 PM 10/16/00 Monday , Jim Bacher wrote: forwarding for: raymond...@omnisourceasia.com.hk Reply Separator Subject:Sharp edge point Author: Raymond Li raymond...@omnisourceasia.com.hk Date: 10/17/00 1:05 AM In EN60065 EN60335 standards, there are no specific methods to determine sharp edge and point. Should we adapt EN71 toys standard as reference for type evaluation? It requires adhesive test tape. Can anyone advise me where I can find the test tape. Thanks and regards, Raymond Li Omni Source Asia Ltd. --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org - att1.htm
Re:Sharp edge point
Raymond, We use a device from Technical Engineering Service, in NY, that has replaceable cylinders with the tape, indicator, and foam backing pre- applied - and we bought a virtual lifetime supply with the finger (40-50). It's a pre-loaded spring device, and each cylinder can be used many times. Let me know if you want their address and phone number. Best regards, Stephen At 04:10 PM 10/16/00 Monday , Jim Bacher wrote: forwarding for: raymond...@omnisourceasia.com.hk Reply Separator Subject:Sharp edge point Author: Raymond Li raymond...@omnisourceasia.com.hk Date: 10/17/00 1:05 AM In EN60065 EN60335 standards, there are no specific methods to determine sharp edge and point. Should we adapt EN71 toys standard as reference for type evaluation? It requires adhesive test tape. Can anyone advise me where I can find the test tape. Thanks and regards, Raymond Li Omni Source Asia Ltd. --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
Beware Of Virus: Jokes text
FYI. From: Tom Donnelly tdonne...@lucent.com Subject: Jokes text Date: Mon, 19 Jun 2000 12:41:27 -0400 Sender: owner-emc-p...@ieee.org Virus Warning Message Found virus SHS_STAGES.A in file LIFE_STAGES.TXT.SHS
Re: Buying a VCR
More likely an impedance mismatch problem, isn't it? I'm not an RF person, but it would seem that even if: When a VCR is turned off, the RF signal from your cable is switched directly to the output RF cable that goes to your TV cable input. Therefore as long as the coax cables are OK, that this switching, and routing, introduces an opportunity for impedance mismatch, which would clearly degrade the signal to the receiver. Who knows how much care the manufacturer does or does not take to avoid this. Although, using top grade cable on both ends may limit this to that switching - as opposed to adding to it. Stephen At 03:04 PM 1/10/00 , Tony J. O'Hara wrote: Regarding your new VCR problems! The one thing you said that makes the least technical sense is that This was, of course, true even when the VCR was turned off. When a VCR is turned off, the RF signal from your cable is switched directly to the output RF cable that goes to your TV cable input. Therefore as long as the coax cables are OK, you should see the same results, regarding picture quality etc., that you had before you installed the new VCR. I would bet that you had/have a bad cable/connector problem. I can't imagine any modern VCR being that susceptible to emissions from what-your TV? What did a tape playback from the VCR look like? If Ok, then the cable to TV is OK and the TV VCR output are on the same channel! In a previous life I worked on TV VCR systems so if you still need help, call or e-mail me! Regards Tony Colorado 303-948-2577 - 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, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
Re: BEAB
Mel, Wow, a long - long - LONG time ago... I might recall that it was British (British Electrotechnical Approvals Board), and may have had something to do with spec's or approvals of (at least) primary power components (ie: line cords, xfmrs, switches, fuses, etc.)?? Try, the only number I have handy: 44-932-24-44-01. Best regards, Stephen C. Phillips === Direct: 508-244-8116 Fax: 508-244-8039 | |Cisco Systems, Inc. ||| ||| Core Business Unit | | 250 Apollo Drive | |Chelmsford, MA 01824 | U.S.A. E-mail: step...@cisco.com === All opinions expressed are my own, not necessarily those of Cisco Systems. - Begin Included Message - From owner-emc-p...@mail.ieee.org Thu Sep 12 16:47:13 1996 From: Mel Pedersen mpeder...@sun1.anza.com To: 'emc-pstc' emc-p...@mail.ieee.org Subject: BEAB Dear emc-pstc'ers: Has anyone heard of an approvals body called BEAB? If so, any information on them would be helpful. Thanks a lot Mel PedersenMidcom, Inc. Homologations Engineer Phone: (605) 882-8535 e-mail: mpeder...@midcom.anza.com Fax:(605) 886-6752 - End Included Message -
Re: TUV Product Service ?
Bob, You don't say what state (or country) you're in; I have a number in MA: 508-777-7999 (I think). Best regards, Stephen C. Phillips Cisco Systems, Inc. All opinions expressed herein are my own, and not necessarily those of Cisco Systems Inc. - Begin Included Message - From owner-emc-p...@mail.ieee.org Mon Aug 26 16:35:54 1996 Subject: TUV Product Service ? To: emc-p...@ieee.org Hello, I am currently shopping for testing services in order to meet the Low Voltage Directive. One of the companies that I thought might be helpful is TUV Product Service. I have sent email to i...@tuvps.com (last week) and called the 1-800-TUV-0123 (answering machine). So far there has been no response at all. If there is anyone on this list that knows how to contact a living, breathing person at TUV, I would be most grateful for the help. Thanks in advance, Bob Sykes bob_sy...@gilbarco.com - End Included Message -
Re: Survey: Experiences with EMI Consultants
Max, It sounds as though you don't have any expertise in-house, so I would recommend getting a consultant into the design phase - as early as possible. Alot will depend upon the product though. The higher the frequency - the tougher the problems, pcb routing is critical. Do you have to meet Class A or Class B? Is the enclosure metal, is it already designed, I would suggest that the consultant work directly with the design engineers during schematic review, a mechanical review, and largely during pcb layout. The more you do then, the less you have do worry about later, you may find that you don't even need the consultant through the testing and certification phase. But if you wait UNTIL then, you may wind up losing alot of sleep. You don't say where you're located, so I can't recommend anyone specific, but in my experience - yes - there are excellent consultants available - worldwide (but also, buyer beware). I hope this helps some. Best regards, Stephen C. Phillips Telecom Engineer === Direct: 508-244-8116 Fax: 508-244-8039 | |Cisco Systems, Inc. ||| ||| Core Business Unit | | 250 Apollo Drive | |Chelmsford, MA 01824 | U.S.A. E-mail: step...@cisco.com === All opinions expressed are my own, not necessarily those of Cisco Systems. - Begin Included Message - From owner-emc-p...@mail.ieee.org Fri Jul 12 16:52:15 1996 To: emc-p...@ieee.org Subject: Survey: Experiences with EMI Consultants From: Max mkel...@chekov.corp.es.com I am wondering if anyone has had experience with hiring EMI/EMC consultants to solve their problems and what sort of results they have obtained. I would be very interested in any details that anyone might be able to provide. For example, did you use a consultant after the system was prototyped or early on, during the design process. Was the consultant most useful at providing board-level, design suggestions or was he most helpful at providing after-the-fact type fixes that pertain to cabinet design and I/O cable filtering and grounding techniques, etc. Also, did the consultant, deal directly with design engineers or interface with just one person within your company, etc.? Does anyone have the names of any good consultants? Max Kelson mkel...@es.com - End Included Message -
EN60825 TEST HOUSES?
Dear TREG EMC-PSTC Compliance Colleagues, I am investigating Other test houses that can perform EN60825 (IEC 825-1, IEC 825-2) testing for Fiber-Optic (LASER) transmission systems. I have used some organizations for this in the past, but would prefer more choices. Any suggestions, and value added comments, for such service providers would be greatly appreciated. Oh, also - similarly for FDA/CDRH 21-CFR-1040, 1041 testing. Thanks alot! Best regards, Stephen C. Phillips = Stephen C. Phillips E-mail: step...@cisco.com Hardware Engineer Direct Phone: 508-262-1116 | | ATM Business Unit ||| |||Cisco Systems, Inc. | | 1100 Technology Park Drive ..:|||:...:|||:.. Billerica, MA 01821 U.S.A. Cisco Systems, Inc. FAX: 508-262-1039 = All opinions are my own, not necessarily those of Cisco Systems, Inc.
