Any restriction in Europe over the band of 90KHz to 250KHz?
Intentional radiator that is narrow band but rather energetic. Is there any frequency I can set this transmitter at in this low frequency range and not accidentally step on a restriction. Vaguely remember some military bands down there that forbid *any* transmitters down there, but can't find any documentation supporting that memory. Robert - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list.Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald:emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Information on operation in the 6.78 MHz ISM Band
Does anyone have experience in this band? Or, have URLs to find limits and required characteristics to operate in this band? Robert - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list.Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald:emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Re: Germanium ITO Window shielding effectiveness
Andrew, My firm has the technology to make optically transparent magnetic shield. Optical transparency is better than 65%. Costs relate to the requirement of how much field of view reduction of field Please contact me directly, off the group. - Robert - Robert A. Macy, PE. . m...@california.com 408 286 3985. . . . . . . fx 408 297 9121 AJM International Electronics Consultants 101 E San Fernando, Suite 402 San Jose, CA 95112 On Thu, 16 Sep 2004 08:21:12 +0100 Price, Andrew P (UK Basildon) andrew.p.pr...@baesystems.com wrote: Hello group. Can anyone help with finding information on shielding effectiveness of Germanium and ITO coated windows against magnetic fields? Regards Andy Andrew Price Principal Development Engineer (EMC Specialist) BAE SYSTEMS Avionics A125 Christopher Martin Road Basildon, Essex SS14 3EL tel: +44 (0) 1268 883308 email: andrew.p.pr...@baesystems.com This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list.Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/listserv/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: emc_p...@symbol.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://www.ieeecommunities.org/emc-pstc
Re: Difference between the HP 8566A and the HP 8566B
Alas, all my vintage reference books are in storage. As I recall, B refers to lower frequency capability and/or finer BW resolution, like from 30Hz BW down to 10Hz BW Simply has extended lower ranges. - Robert - On Tue, 25 Nov 2003 08:38:30 -0800 Pettit, Ghery ghery.pet...@intel.com wrote: Not true. The 8566 (A or B) goes to 22 GHz. The 8568 (A or B) goes to 1.5 GHz. Ghery Pettit -Original Message- From: owner-emc-p...@majordomo.ieee.org [mailto:owner-emc-p...@majordomo.ieee.org] On Behalf Of Gaby F. Abboud Sent: Tuesday, November 25, 2003 6:37 AM To: lfresea...@aol.com; emc-p...@ieee.org Subject: Re: Difference between the HP 8566A and the HP 8566B 8566A can be used up to 1GHz 8566B can be used up to 22GHz I hope this helped. Gaby, From: lfresea...@aol.com Date: 2003/11/24 Mon PM 11:23:10 EST To: emc-p...@ieee.org Subject: Difference between the HP 8566A and the HP 8566B Hi there, can anyone tell me the difference between the two spectrum analysers? Thanks, Derek N. Walton Owner, L F Research EMI Design and Test Facility Poplar Grove, IL 61065 --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ieee-pses.org/ 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: emc_p...@symbol.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://www.ieeecommunities.org/emc-pstc --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ieee-pses.org/ 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: emc_p...@symbol.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://www.ieeecommunities.org/emc-pstc This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ieee-pses.org/ 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: emc_p...@symbol.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://www.ieeecommunities.org/emc-pstc
Re: RFID tags
My vote.. Passive means to modify the field, this includes harmonic content. Active means use the field to generate new frequencies, as though a battery were attached. - Robert - Robert A. Macy, PE .. m...@california.com 408 286 3985 . . . .. . . fx 408 297 9121 AJM International Electronics Consultants 101 E San Fernando, Suite 402 San Jose, CA 95112 On Thu, 20 Nov 2003 14:38:05 -0500 djumbdenst...@tycoint.com wrote: I have heard the term passive used 2 ways, as indicated below or as a device that actually transponds an independent code from that which it received from the interrogator, powered off the interrogator's field. Thus in the latter it is a function of with or without a battery, with = active, without = passive. What is the consensus of the Forum for passive regarding RFID tags? Don Umbdenstock Sensormatic 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: emc_p...@symbol.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Re: Leakage at Enclosure Seams
From vague memory... there was some work done by Don White (?) that shows tables of this type of improvement. Full of practical data and information. - Robert - On Mon, 17 Nov 2003 15:21:54 - Jeff Chambers j.chamb...@ndirect.co.uk wrote: I have been asked to comment on what improvement might be expected in changing the design of an equipment lid from: A flat lid sat on the edges of the box, where the gaps between fasteners can be modelled as a simple aperture, where the attenuation decreases linearly with log(f) to zero at a half wavelength. To: A stepped lid, with the lid sat on the edges, and with the projection extending below the inner edge of the box.This removes the 'line of sight' gap into the enclosure. Does this improve the attenuation? Intuitively it should, but if the leakage occurs because of the interruption in shielding conductivity and hence current flow at the seam, it won't. Does anybody have any references to analyses of the above, or comments, please? (No emi gaskets are used btw). Thanks, Jeff Chambers Dr Jeff Chambers Westbay Technology Ltd Main St Baycliff Ulverston Cumbria LA12 9RN England Tel: 01229 869 108 Fax: 01229 869 108 http://www.westbay.ndirect.co.uk --- 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: emc_p...@symbol.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc 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: emc_p...@symbol.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Re: System test PCs - Are we cops?
Isn't it fraud to sell an item that does not meet spec? As in, the vendor says the product is compliant when it is not. Don't all the customers then have a legal recourse to return any/all product? Doesn't policing the policy of compliance then become a non-governmental function? As far as competition, it would not be out of line for the marketing representative of a compliant company to disuade potential customers from buying noncompliant products by pointing out that fraud between the other vendor and this customer sets a bad tone of a business relationship. One could stretch this to the point of mentioning complicity. g - Robert - Robert A. Macy, PE .. m...@california.com 408 286 3985 . . . .. . . fx 408 297 9121 AJM International Electronics Consultants 101 E San Fernando, Suite 402 San Jose, CA 95112 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: emc_p...@symbol.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Re: Effective length of half wave dipole
From Dave Cuthbert's comments to me regarding a 1/4 wavelength dipole; he said that the current moves down the rod as the rod becomes thicker, which implies that the current distribution absolutely determines the effective length. Was that effective length or tuned length? hmm However, the whole thing may start with the conductivity of real life materials... Interesting to see the others' comments. - Robert - Robert A. Macy, PE .. m...@california.com 408 286 3985 . . . .. . . fx 408 297 9121 AJM International Electronics Consultants 101 E San Fernando, Suite 402 San Jose, CA 95112 On Wed, 29 Oct 2003 16:59:20 +0800 kcc...@hkpc.org wrote: Dear all I got confused with the effective length of a half wave dipole. 1) It is due to non-constant current distribution, or 2) It is due to the wave velocity in materials different from that in vacuum. What do you think which one is correct? Regards KC Chan 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: emc_p...@symbol.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Re: Help finding Company
David, Just did a search in Rich's Northern California Directory for both air and modem which showed many companies, but no results. Also searched through Reference USA for *any* firm with modem in their name, again many companies, but no results. If a company has been around for a while and is fairly large, these lists usually have it. If new, or small, or privately owned; a company can get missed. If serious about search; make certain of the name, check the registry of corporations in Sacramento. Are they looking for Air-Space, an ISM band wireless modem company made up of the people previously at Metricom (Ricochet product line)? - Robert - Robert A. Macy, PE .. m...@california.com 408 286 3985 . . . .. . . fx 408 297 9121 AJM International Electronics Consultants 101 E San Fernando, Suite 402 San Jose, CA 95112 On Mon, 13 Oct 2003 19:39:19 -0400 David Seabury d.seab...@worldnet.att.net wrote: A friend in Europe is trying to obtain contact info on a company called Air-Modem Inc. He thinks they are in Northern California. Does anyone know where there might be located? He has a contact name, Ashwin Mody?? Thanks, David Seabury 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: emc_p...@symbol.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Re: Corrosion tests - NEBS or Milspec acceleration factors?
Gary, These were stainless steel wires inside protective polymer sheathing, extra thick multiple coatings. The wires were mounted on a fence and then placed under tension to make their resonance from wind, etc fairly high frequency - like the e string on a bass guitar. Seems the tension put so much internal stress into the wires and encouraged so much corrosion that the wires would only last a year, even 2 miles from an ocean. - Robert - On Fri, 10 Oct 2003 14:56:39 -0700 GARY MCINTURFF mcinturff3...@msn.com wrote: Robert, Thanks for the info. Do you mean stress from normal nut/bolt torque or from a press-fit application. Here is another small tidbit you might consider - a trick I got from an aircraft mechanic. Even if the part is stainless steel if you are working around it with non-stainless tools you can compromise the stainless part with the tool. It is the tool material that could be starting the corrosion. In the particular instance I was discussing it was stainless steel panels that were being sheared, and the shear didn't have stainless shoes or whatever the actually shearing components are. These shoes smeared onto the stainless parts and viola corrosion. When they put stainless shoes on the shear the problem disappeared. This was a Boeing 747 crew chief so he certainly has the experience to make him believable. Might want to check your manufacturing plant just for grins. Gary - Original Message - From: robert Macy To: GARY MCINTURFF ; emc-p...@ieee.org Sent: Friday, October 10, 2003 12:01 PM Subject: Re: Corrosion tests - NEBS or Milspec acceleration factors? Gary, From experience with security systems only close to the seashore (approx 2 miles away) it is best to *NEVER* have any of the metal parts under stress/tension, else the corrosion rates are incredibly accelerated. The particular stainless steel part had been tested real time in worse environments with absolutely no degradation detectable. Yet, in the actual application under mounting stress the stainless steel part repeatably failed within 1 year even that far away from the ocean. - Robert - Robert A. Macy, PE .. m...@california.com 408 286 3985 . . . .. . . fx 408 297 9121 AJM International Electronics Consultants 101 E San Fernando, Suite 402 San Jose, CA 95112 On Fri, 10 Oct 2003 09:47:40 -0700 GARY MCINTURFF mcinturff3...@msn.com wrote: Ernie, I know you received Naftali's email so I will just clarify a little more. We test and pass the GR-487 outdoor enclosure requirements for the telecommunications industry but I have a client who is non-telecom. Telecommunciations customers seem to accept the test, because past experience has shown in meets the equipment and time needs (20 years). Non-Telecommunications customers not familiar with the tests kind of expect some sort of acceleration factor for the hours under test to demonstrate how long the equipment will work, rather than a more or less pass fail salt fog test. He wants to how long the equipment can withstand the elements at his coastal location. Is there any sort of acceleration model used in the salt fog test, or the mixed gasses and hygroscopic tests? He is a little unhappy with my current response (understandably) that experience shows the test satisfies the screening requirements or else they would have been changed long ago to something that did meet the equipment and time requirements. Can you give me a little insight? Thanks Gary McInturff 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: emc_p...@symbol.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Re: Corrosion tests - NEBS or Milspec acceleration factors?
Gary, From experience with security systems only close to the seashore (approx 2 miles away) it is best to *NEVER* have any of the metal parts under stress/tension, else the corrosion rates are incredibly accelerated. The particular stainless steel part had been tested real time in worse environments with absolutely no degradation detectable. Yet, in the actual application under mounting stress the stainless steel part repeatably failed within 1 year even that far away from the ocean. - Robert - Robert A. Macy, PE .. m...@california.com 408 286 3985 . . . .. . . fx 408 297 9121 AJM International Electronics Consultants 101 E San Fernando, Suite 402 San Jose, CA 95112 On Fri, 10 Oct 2003 09:47:40 -0700 GARY MCINTURFF mcinturff3...@msn.com wrote: Ernie, I know you received Naftali's email so I will just clarify a little more. We test and pass the GR-487 outdoor enclosure requirements for the telecommunications industry but I have a client who is non-telecom. Telecommunciations customers seem to accept the test, because past experience has shown in meets the equipment and time needs (20 years). Non-Telecommunications customers not familiar with the tests kind of expect some sort of acceleration factor for the hours under test to demonstrate how long the equipment will work, rather than a more or less pass fail salt fog test. He wants to how long the equipment can withstand the elements at his coastal location. Is there any sort of acceleration model used in the salt fog test, or the mixed gasses and hygroscopic tests? He is a little unhappy with my current response (understandably) that experience shows the test satisfies the screening requirements or else they would have been changed long ago to something that did meet the equipment and time requirements. Can you give me a little insight? Thanks Gary McInturff 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: emc_p...@symbol.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
PSpice model for 1/4 wavelength antenna
Does someone out there have a PSpice model for a 1/4 wavelength antenna? 433.92MHz Something that I can change to reflect diameter of the rod, detuning, etc. Or, do you know someone who has such a model? Need it fast, please. - Robert - Robert A. Macy, PE .. m...@california.com 408 286 3985 . . . .. . . fx 408 297 9121 AJM International Electronics Consultants 101 E San Fernando, Suite 402 San Jose, CA 95112 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: emc_p...@symbol.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Re: GFI Question
Scott, How much wire is buried in the wall between the GFI and the outlet that doesn't cause the problem? Does the addition of an extension cord between the present outlet and the shredder calm it down? Do you have metal conduit? If so, you have a small filter through your AC mains to the other outlet. Around 7 to 10 uH common mode choke and some capacitance. Don't know, but probably in the order of 50 to 100pF. Might be just enough filter components to solve the touchiness. Let us know if a 9-12 foot extension cord solves the problem. - Robert - Robert A. Macy, PE .. m...@california.com 408 286 3985 . . . .. . . fx 408 297 9121 AJM International Electronics Consultants 101 E San Fernando, Suite 402 San Jose, CA 95112 From: Scott Douglas sdoug...@ptcnh.net To: EMC-PSTC List emc-p...@majordomo.ieee.org Sent: Thursday, September 11, 2003 12:09 PM Subject: GFI Question Fellow Listees, It's been bugging me for a long time. So now I have to ask you all for some wisdom. Here is the setup: table top shredder, rated 120V, 60 Hz, 2.0 A. UL/CUL Listed, made in China. It has a 60 inch 3 wire power cord with 3 prong plug (presumably 3rd wire is PE). The problem: The shredder is plugged into the GFI outlet in the laundry room (nothing else active on circuit). This GFI is the protector for 3 outlets in the laundry 1/2 bath as well as for a 4th outlet in the upstairs bath. From time to time the GFI trips while shredding envelope addresses. Not always, just sometimes, it may be a length of run time related thing but have not been able to verify that as yet and it is not consistent. There is another outlet 60 inches away (down the counter) protected by this GFI outlet. If I plug this same shredder into the distant outlet, the GFI never trips. Never. Note the shredder sits immediately in front of the GFI outlet on the counter. Even if I leave it in the same place and just stretch the cord to plug into the other outlet I get the same results. That makes me wonder. GFI. Is this some kind of leakage from the shredder motor? Is this leakage reduced when you connect to the distant outlet? Are GFI outlets susceptible to EMI of any kind? And most important, is there an easy fix while leaving the shredder where it is and plugged into the GFI outlet? I suppose a GFI circuit breaker in the panel in the basement would do it, but that could be a costly item. Last up, and to the point of this forum, would this problem be exhibited in any kind of safety or EMC testing that would be required on this type of product? Looking forward to your comments, on- or off-line. Regards, Scott Douglas Email: sdoug...@ptcnh.net 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: emc_p...@symbol.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Re: Conformal Coatings
Michael, Back when I used to design coin operated games we had a problem with intentional ESD doing damage to the electronics. Turns out, that ESD would, every now and then, give a free game. Being rewarded with free games, they quickly learned a damaging ritual - the kids would link arms, up to six of them, scuff their feet around the carpeting and then discharge to the machine through a quarter to really blast the machine. More than likely they killed the machine, but what did they care? First thing I did was make the electronics extremely robust for ESD, *THEN* I modified the software so the slightest (interpret that to mean so low level that it wasn't damaging) ESD event simply reset the game, even erased accumulated games. They lost their money. Never had problems after that. The next time we watched a field installation, you couldn't believe how the kids protected those machines from even the most accidental of discharges. Like yelling at another kid to keep away while he's playing the game. Anyway, it was one way to get the customer to help protect your electronics. It's all in the reward/punishment system. - Robert - Robert A. Macy, PE .. m...@california.com 408 286 3985 . . . .. . . fx 408 297 9121 AJM International Electronics Consultants 101 E San Fernando, Suite 402 San Jose, CA 95112 On Wed, 3 Sep 2003 10:31:58 -0500 Sosnoski, Michael gl...@wmsgaming.com wrote: Ladies Gentlemen, I am wondering if you have ever heard or know of any printed circuit board conformal coatings that are better than others for protecting against ESD? Are some just better than others for anything? Not that we don't use proper grounding, shielding board layout techniques, but this industry is concerned with deliberate, and intentional stimuli to the equipment, and the more robust I can make the boards, connectors, etc,.. the better. Also, as in any commercial industry--the accountants Thanks, Mike --- 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: emc_p...@symbol.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc 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: emc_p...@symbol.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Re: ESD from wiring
Sounds like you just described the triboelectric(sp?) effect and teflon insulation has one of the highest electron work functions you will find. Mechanical motion causes a separation of the insulation from and along the conductor. That mechanical separation causes a GUARRANTEED charge separation. Generates a voltage. This effect is the bane of cable makers, that is why the insulation is so tightly wrapped and stuck to the conductor. If not, 1000 feet of cable and the slightest slippage and you have voltage. This principle is used in the security industry to make buried cables that detect any motion for the cable. Cables in walls detect drilling and digging through them. Cables buried in the ground detect footsteps of people walking around above ground. Yes, it is that sensitive. An example of such a cable is a coax made with teflon insulation, very loosely wrapped around the center conductor. So loose that if you grab the center conductor with pliers and pull, you can pull the whole 20 feet of center conductor right out of the coax. I thought we were talking millivolts when I first heard of such a cable. So to check signal level, used a scope on the cable and with a light tap produced over 8 volts! The scope is a high impedance load and the cable is a high impedance source, but still very energetic. It is my understanding that this is one of forms of deterioration for aging cables. Alas, the solution is to not let a cable move. - Robert - Robert A. Macy, PE .. m...@california.com 408 286 3985 . . . .. . . fx 408 297 9121 AJM International Electronics Consultants 101 E San Fernando, Suite 402 San Jose, CA 95112 On Sun, 31 Aug 2003 15:49:43 EDT lfresea...@aol.com wrote: Hi all, well, I have found myself involved with an interesing problem. I'm testing an aircraft system, that only has a few wires... 8 or so, that interface with the outside world. 28 volt dc power, an programming loop, a manually operated switch and an indicator. Well, evey time the push button is pressed, I see a 10 to 50 nS pulse, very consistant. The problem first was noticed during RE testing, and I found it easier to hook my scope to the antenna rather than use the SA. I have eliminated the EUT operating, since I have disabled the trigger by removing the component that allows it to trigger. I did leave in place the 2 resistors that terminate the push button wire. I have a predictable set up. I remove either of the two reminating components, and the signal drops, it almost goes away. Anyway, after I'd removed the circuit board to make a change, I pushed the wire harness and saw a very similar transient! So I jiggled the harness and saw many... Cursing a loose connection, I checked, they were all sound. Not sure what was going on, I disconnected power, I could still got them. So I stripped down to my cotton shorts.. still got them. One section of the harness is sleeved with heatshrink sleeving, it holds the wires tighly. Jiggling that produced no events. So, I can only conclude, that the wire is generating a charge during the movement/jiggling, that when it discharges any one of a number of places causes my event. The parasitics of the harness set the ringing frequency. When I press my push botton, I believe I also kick the wiring with the impulse, again it rings very close to the frequency when I jiggle the cables. My questions are, am I off base with the charging supposition? The cable appears to be a teflon type insulation. If so, how can I get around it. I can't really blame the EUT for it. Opinions very welcome Thanks, Derek Walton 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: emc_p...@symbol.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Re: 94V-0 question
Kapton comes to mind. - Robert - On Tue, 12 Aug 2003 11:55:25 -0600 drcuthb...@micron.com wrote: I need a sheet of plastic that goes between a PCB and a metal enclosure. This is to make a creepage spec. What plastics are good for this? Will polycarbonate be suitable and have a 94V-0 rating? Thanks. Dave Cuthbert Micron Technology --- 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: emc_p...@symbol.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc 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: emc_p...@symbol.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Re: Thanks to EMC-PSTC List!!
Muriel, Congratulations! Is your thesis in English? If so, is there a location to make it available for download? I'm sure many would be interested in it. - Robert - On Mon, 11 Aug 2003 16:19:58 -0300 Muriel Bittencourt de Liz mur...@eel.ufsc.br wrote: Hello List-members, I'm sending this e-mail this e-mail to thank you. Last friday, august, 8, I've got my doctor degree in electrical enegineering, with a thesis about reduction of EMI in switched mode power supplies. This thesis would not be the same without the contribution of the members from this invaluable list. A lot of topics that were not clear to me at the beggining became clear with your help, through the list or private e-mails answering my basic questions. Be sure that your comments were all referred in my bibliographic references chapter. I'd like to put some names that help me most, but I think that I could forget someone! ;-) and it would no be just... Once again, I'd like to emphasize the importance and relevance of this list to my work and another works of research world-wide. Best Regards, Muriel Bittencourt de Liz August, 11, 2003 Florianópolis, Santa Catarina, Brazil Electrical Engineering Department Federal University at Santa Catarina (UFSC) --- 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: emc_p...@symbol.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc 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: emc_p...@symbol.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Re: Clayton Pauls - Intro to EMC - an error or two? for those that have the text
Simple eqn to remember (2 skin depth = sqrt ( -- ) ( w * u * sigma w is radians per sec; or 2 pi f, with f in Hz u is permeability . or . u rel * u free space u free space is 4 pi 10-7 sigma is conductivity in S/m all MKS units so skin depth in meters One important point to remember is that this formula calculates skin depth, like attenuation versus depth, for a *PLANAR WAVE* If the impinging wave has curvature, like from a close by radiator; that wave really punches through and there is not as much attenuation. How much? Depends on curvature, but for close sources the effective thickness can be reduced to less than half. Conclusion:. Use thicker material than you think you need. - Robert - Robert A. Macy, PE .. m...@california.com 408 286 3985 . . . .. . . fx 408 297 9121 AJM International Electronics Consultants 101 E San Fernando, Suite 402 San Jose, CA 95112 On Fri, 8 Aug 2003 13:33:24 EDT garymcintu...@aol.com wrote: My anal-retentive self is having some trouble with an occasional example in the text and I need either a confirmation or a slap in the forehead. I was just fiddling around with the text and reviewing some of the examples and in section 6.4 he presents a table of skin depth for copper, but then in question 6.2 he asks for the skin depth of steel - and the numbers for the skin depth are the same. My calculations say otherwise and makes sense to me since the permeability is different between the materials. copper = 1 and steel is 1000, that and the conductivity is different between the two. If you have the text and little or nothing else to do could you give me the number you come up with? ( in mm's or mils) When I'm trying to learn or relearn stuff and I'm at odds with the various references it just drives me wild and I don't have anyone else to confer with up here. One is torn between the I'm right response and the author's obvious authority on the subject. Thanks Befuddled (Gary) 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: emc_p...@symbol.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Re: Carton box dimension and gross weight to EU
Paul, Forgot to mention, one company years ago added their own maximum width dimension of less than 30 inches so the boxes could be put on a two wheel truck and easily wheeled through a standard door! - Robert - On Tue, 29 Jul 2003 15:41:54 +0800 Paul Chan ncc...@tuvps.com.hk wrote: Dear all, I have been asked for the max. dimension and weight of the carton box [loaded with product]. Do you know any requirements/guidelines? Thanks in advance Paul Chan 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: emc_p...@symbol.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Re: Carton box dimension and gross weight to EU
Paul, Sample shippers: http://www.ups.com At UPS website could not find any numbers, only definitions. http://www.fedex.com At the FedEx website could not find any weight restrictions, but did find Maximum length plus girth* per piece is 300 inches . where *Girth = 2(Width + Height) Maximum height per piece 70 inches Maximum length per piece 119 inches There was a footnote that said anything different could still be discussed. I remember a maximum from old days as either 60, or 70 pounds, essentially what a man could carry. But I believe that maximum restriction has been removed. Hope that helps - Robert - Robert A. Macy, PE .. m...@california.com 408 286 3985 . . . .. . . fx 408 297 9121 AJM International Electronics Consultants 101 E San Fernando, Suite 402 San Jose, CA 95112 On Tue, 29 Jul 2003 15:41:54 +0800 Paul Chan ncc...@tuvps.com.hk wrote: Dear all, I have been asked for the max. dimension and weight of the carton box [loaded with product]. Do you know any requirements/guidelines? Thanks in advance Paul Chan 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: emc_p...@symbol.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Re: self blinking LEDs as EMI sources WAS: LED lamps
Interesting observation. You said hum gets louder. Implying hum is already there. What kind of phone? Is it only that one telephone instrument? Only occurs when LEDs are near the instrument, not near the phone lines with the phone in another location? Is the effect more pronounced at less than 3m? Are the LEDs turned on/off while appear to be on? In other words, LEDs are OFF then come ON OFF ON OFF ON OFF at some high rate, perhaps near the 50Hz frequency? Do the LED ckts affect an AM/FM radio held close by? - Robert - Robert A. Macy, PE .. m...@california.com 408 286 3985 . . . .. . . fx 408 297 9121 AJM International Electronics Consultants 101 E San Fernando, Suite 402 San Jose, CA 95112 On Sat, 26 Jul 2003 11:36:37 +0800 Wan Juang Foo f...@np.edu.sg wrote: Dear All, I observe recently that some self blinking (and color changing) LEDs 'are' what seem to be a substantial emitters of radiated emission/interference. These LEDs are rigged up by hobbyists as decorative illuminators and acts more or less like the blinking lights for Christmas trees. I observe that each of theses circuits can be made to hung like Christmas tree ornaments. I came across a situation where the telephone lines were 'substantially noisier' :-) when several sets of battery operated circuits was about 3 m away from the telephone. It is not a very scientific method but I did a quick check and found by the method of elimination ;-) or what some would call systematic trials to find the source of the problem. It took me by surprise that the LEDs had a substantial role to play in the interference. LED circuits gets connected (on), hum gets louder. LEDs circuits gets disconnected, hums gets quieter and so on and so forth... These are very simple circuits with a single resistor and the LED in series. The 2 AA sized NiCad battery with holder, single resistor and LED including wire, total length about 5, tip to tip. These circuits were found to (well at any rate, seems to) emit interference that cause a telephone to pick up (50Hz) hum! It looks like the mains hum was pick up and modulated by the 'device' and reradiated or broadcasted... I can see that the blinking action at about 1 Hz have a duty cycle and that may generate a lot of ringing but what is surprising is the interference finding its way into the a telephone handset! I find it hard to believe that how the 'carrier' of the mains hum can eventually gets demodulated a puzzle. One wonders what can be observed if I get the circuits to a OATS? There again, how do I recreate the 50 Hz environment to couple the mains into these LED circuit? I had the Helmholtz coil in mind but can that be 'treated' as part of a test setup? Did anyone here have similar observation? One wonders if there any 'product specific standards' for such battery operated device that uses LEDs as decorative illuminators. :-) One wonders what will happen if there are such gadgets line up to 'hit' the market this Christmas... Looks like there will be a lot of testing work coming for EMC engineers! Tim Foo --- 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: emc_p...@symbol.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc 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: emc_p...@symbol.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Re: MRI-safe test lab
In case you have difficulty finding a strong enough field, there is a company in St. Louis that makes a medical device that creates 3D fields strong enough to rip a piece of metal around inside the brain under computer control for Parkinson surgery. Their fields are in excess of 1 to 3 tesla, I believe. Anyway the fields are generated using helium cooled superconducting coils. Just in case you have difficulty getting the field strength you need, you might be able to use their equipment. - Robert - Robert A. Macy, PE .. m...@california.com 408 286 3985 . . . .. . . fx 408 297 9121 AJM International Electronics Consultants 101 E San Fernando, Suite 402 San Jose, CA 95112 On Mon, 21 Jul 2003 10:36:58 -0700 Knudsen, Patricia J. pknud...@alarismed.com wrote: I am looking to test to ASTM F 2052, Standard test method for measurement of magnetically induced displacement force on medical devices in the Magnetic Resonance environment. It involves applying a large magnetic force to the EUT to see if it will get pulled inside an MRI machine during a scan. Patty -Original Message- From: Peter L. Tarver [mailto:peter.tar...@sanmina-sci.com] Sent: Monday, July 21, 2003 10:33 AM To: emc-p...@majordomo.ieee.org Cc: Knudsen, Patricia J. Subject: RE: MRI-safe test lab Patricia - Can you be more specific as to what standards are applicable and what aspect of such testing you are looking for (EMC, safety, operational, other) Regards, Peter L. Tarver, PE Product Safety Manager Sanmina-SCI Homologation Services San Jose, CA peter.tar...@sanmina-sci.com -Original Message- From: Knudsen, Patricia J. Sent: Monday, July 21, 2003 7:33 AM I am looking for a lab that can test medical products for use within an MRI room. Does anyone know of a test house that can do this, preferrably in the U.S. on the west coast? Patty Patricia Knudsen Sr. Certification Engineer Alaris Medical Systems Ph: (858) 458-7280 Fax: (858) 458-7095 pknud...@alarismed.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: Ron Pickard: emc-p...@hypercom.com Dave Heald: emc_p...@symbol.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc 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: emc_p...@symbol.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Re: Instrument Controller Software
John, If you buy a GPIB card for your laptop *and* your analyzer has the GPIB interface *and* you get your analyzer's software manual, you can learn and write all the software you need for your project in less than 2 hours. Ok, ok, more like 6 hours, but still - Robert - Robert A. Macy, PEm...@california.com 408 286 3985 fx 408 297 9121 AJM International Electronics Consultants 101 E San Fernando, Suite 402 San Jose, CA 95112 On Tue, 08 Jul 2003 18:29:04 + John Cronin croni...@hotmail.com wrote: 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: emc_p...@symbol.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Re: Source of noise
Derek, Most of the PS manufacturers I've dealt with use passive dummy loads or quiet active loads. These very handy quiet active loads provide programmable loading, BUT IN NO WAY SIMULATE THE SUPPLY'S ACTUAL USE. In other words, how many quiet loads do you power? Almost every load is a micro or some digital electronics. I've been training my clients to inject heavy noise at their load outputs [common mode and differential mode] to make certain that their supplies are not transparent to those variable loads. Most now test some time during development with active digital loads to make certain their supplies don't pass the noise right back through the supply. Above 30MHz does not require a lot of bulk for filtering. Most of the bulk is there for the near 150KHz noise. You'll find that part selection and layout are more critical for filtering above 20MHz. I always encourage end-users to include operating specs in their PS purchase agreements to put the burden for proper design back onto the PS manufacturers. - Robert - Robert A. Macy, PEm...@california.com 408 286 3985 fx 408 297 9121 AJM International Electronics Consultants 101 E San Fernando, Suite 402 San Jose, CA 95112 On Wed, 2 Jul 2003 15:16:22 EDT lfresea...@aol.com wrote: Hi All, Thanks for the great replies! looks like the PCI bus is the problem.. But here's the quandry.. Now we are adding the cards back in, they should add little to the profile, correct? After all, they all have the CE mark on them, and some have the FCC sticker too. This is not happening, in fact some emissions are quire strong.. I've also noticed that the Power supply is letting the PC noise out. I opened the power supply ( bang goes the warrenty ), and there is the minimal of filters.. Are the power supplies tested individually to carry the agency sticker?, with a real PC? or just load resistors? Are they designed to suppress the PC noise? Cheers, Derek N. Walton Owner L F Research EMC Design and Test Facility Poplar Grove, Illinois, USA www.lfresearch.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: Ron Pickard: emc-p...@hypercom.com Dave Heald: emc_p...@symbol.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Re: Crest Factor
I use 3, with 10 as worst case. - Robert - Robert A. Macy, PEm...@california.com 408 286 3985 fx 408 297 9121 AJM International Electronics Consultants 101 E San Fernando, Suite 402 San Jose, CA 95112 - Original Message - From: rehel...@mmm.com To: emc-p...@majordomo.ieee.org Sent: Friday, June 13, 2003 3:57 AM Subject: Crest Factor I'm trying to spec a power supply. Can someone provide me with a typical crest factor that a typical power supply should be able to source without distortion.? Thanks, Bob Heller 3M EMC Laboratory, 76-1-01 St. Paul, MN 55107-1208 Tel: 651- 778-6336 Fax: 651-778-6252 === --- 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: emc_p...@symbol.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc 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: emc_p...@symbol.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Re: Graphing Software
Doesn't Excel work for this? If not, I use a simple one called Grafdemo.exe which is best for plots up to 150 data points *and* has curve fitting SW for smooth displays and approx formulas. Or, Computer Calculus 4.0 CC4 which plots 2D and surface plots CC4 has good presentation of 2D with maxima *plus* you can rotate all the axes around for best view. Both have a good price - free. - Robert - Robert A. Macy, PEm...@california.com 408 286 3985 fx 408 297 9121 AJM International Electronics Consultants 101 E San Fernando, Suite 402 San Jose, CA 95112 On Fri, 16 May 2003 12:44:49 EDT lfresea...@aol.com wrote: Hi All, I'm looking at plotting the response of devices on a polar plot, either 2D or 3D. In this cases it's the response of a field probe. Several plots will be used for different frequencies. Does anyone have suggestions of what package to use? I know or Origin, but it's very expensive. Cheers, Derek N. Walton Owner L F Research EMC Design and Test Facility Poplar Grove, Illinois, USA www.lfresearch.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: 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 Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Re: ESD gun verification
Most spectrum analyzers don't do very well with a single event. The repetitive waveform needs to be there to be operated upon. - Robert - Robert A. Macy, PEm...@california.com 408 286 3985 fx 408 297 9121 AJM International Electronics Consultants 101 E San Fernando, Suite 402 San Jose, CA 95112 On Fri, 9 May 2003 08:28:11 -0400 Chris Maxwell chris.maxw...@nettest.com wrote: One question that struck me is: Why isn't a spectrum analyzer used to verify the waveform? Most labs don't have a 4Ghz oscilloscope; but they almost all have a 10Ghz spectrum analyzer. It seems that the spectrum of the waveform should be just as traceable and repeatable as the waveform itself. From my own experience, I use this method to quickly verify our EFT generator in our own lab (although I'm just a manufacturer, not a third party lab). We have the EFT generator calibrated yearly; and whenever I use it, I turn on the spectrum analyzer and read the spectrum just to make sure that it's working. Chris Maxwell | Design Engineer - Optical Division email chris.maxw...@nettest.com | dir +1 315 266 5128 | fax +1 315 797 8024 NetTest | 6 Rhoads Drive, Utica, NY 13502 | USA web www.nettest.com | tel +1 315 797 4449 | 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 Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Re: FCC Limits
Interference from an adjacent/inband radiating source is likely to cause the receiver's AGC circuitry to limit the incoming RF signal to the point where the signal you're trying to receive gets buried in the system's noise. Or, the interfering signal is of sufficient magnitude so as to simply confuse the receiving electronics. Ghery, are you Insturment Rated, yet? - Robert - Robert A. Macy, PEm...@california.com 408 286 3985 fx 408 297 9121 AJM International Electronics Consultants 101 E San Fernando, Suite 402 San Jose, CA 95112 On Tue, 29 Apr 2003 10:32:20 -0700 Pettit, Ghery ghery.pet...@intel.com wrote: Ken, The FCC made the change for several reasons, international harmonization being foremost. We do have users of the RF spectrum below 450 kHz in the US. The ADF receivers in the airplanes I fly tune in non-directional beacons below that frequency. I'd really rather home in on one of those as opposed to your PC (although there is a rather large difference in the signals, but...). The only significant opposition in the Rule Making came from some interests who wanted even lower limits to lower frequencies. They were not successful. Manufacturers of ITE with international markets supported the change as they were already testing to the CISPR 22 limits and this was a non-issue to them. Ghery Pettit Intel Corporation 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 Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Re: Low signal switching
Don, It is my understanding that physical switch contacts are cleaned with current - and use. It is probably ok at the lower signal levels since from time to time you're running the higher levels through the switches. Is there someway you can switch and then verify contact? - Robert - Robert A. Macy, PEm...@california.com 408 286 3985 fx 408 297 9121 AJM International Electronics Consultants 101 E San Fernando, Suite 402 San Jose, CA 95112 On Mon, 21 Apr 2003 13:27:38 -0400 djumbdenst...@tycoint.com wrote: Hello Friends, I have an application in which I would like to switch system signals on coax cables. One system is 80 to 1000 MHz, the other is 1-2 GHz. I have found coax switches by Narda, DB Products and Dow Key. Dow Key indicates that the signals should be above -20 dBm to ensure that contact resistance doesn't cause a problem. The others do not spec or address low signal issues. My branches operate at -35 dBm, 0 dBm and 50 dBm. The 2 higher values are not a problem, just the -35 dBm. Are there other companies that you are aware of that make 50 ohm coax switches that are specified to operate at low signal levels? Other ideas? Best regards, Don Umbdenstock Sensormatic 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 Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Re: high immunity
If GW, wouldn't that voltage be more like 600KV/m, or at least 30KV/m? - Robert - Robert A. Macy, PEm...@california.com 408 286 3985 fx 408 297 9121 AJM International Electronics Consultants 101 E San Fernando, Suite 402 San Jose, CA 95112 On Wed, 26 Mar 2003 17:30:14 -0700 drcuthbert drcuthb...@micron.com wrote: With the advent of E-weapons we might need some new immunity specs. I read that they can output several GW. Testing for equipment survival at over 5000 V/m should be fun (and profitable to some). Dave Cuthbert Micron Technology 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 Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Re: Help wanted with succinct subject description for non-special ists
To me, all this regulation can be synopsized: Electronics shall not put out stuff - conducted or radiated Electronics shall not be upset when stuff comes in - susceptibility to conducted or radiated. Difference in attitude between US and elsewhere: It is my understanding that in the US the FCC thought not to complicate the manufacturing process by adding susceptibility tests to product testing, but rather have the consumer simply modify their behaviour. If a product does not work well because it is easily upset by stuff coming in, the consumer will buy a different product and/or complain to the manufacturer, thus automatic control without FCC intervention. But in the EC and elsewhere, they thought to add tests ahead of time in order to establish a minimum quality standard of performance for the consumer, like prescreen for the consumer. Which is better control? Arguments go both ways. - Robert - Robert A. Macy, PEm...@california.com 408 286 3985 fx 408 297 9121 AJM International Electronics Consultants 101 E San Fernando, Suite 402 San Jose, CA 95112 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 Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Re: HP 6034L Power supply schematics / repair (was Agilent 6842A)
Being a past employee of HP and having met David Packard and Bill Hewlett (just as the HP-35 calculator was coming out), it was with great sadness I watched as the management team headed by Carly F effectively dismantled everything they had built and stood for despite and in front of Bill's son. For manual's, I've seen them for printing fee available on the news group: sci.electronics.repair If you can find the threads there, you'll find at least two sources I remember seeing offering them. - Robert - Robert A. Macy, PEm...@california.com 408 286 3985 fx 408 297 9121 AJM International Electronics Consultants 101 E San Fernando, Suite 402 San Jose, CA 95112 From: Kurt M. Marden To: emc-p...@majordomo.ieee.org Cc: Michael Taylor ; 'emcp...@aol.com' Sent: Wednesday, February 05, 2003 8:40 AM Subject: HP 6034L Power supply schematics / repair (was Agilent 6842A) On that note of (lack of) support, Agilent has no or will not release documentation on the old 6034L power supply. I recently acquired one which powers up but has no output and the front panel display shows 0 volts / amps. Agilent will be happy to charge me $140 just to look at it. Best effort is all they can guarantee on a repair (which would be over and above the $140). Sheesh! Anybody have a owners manual or repair guide / schematics for this model? Thanks, Kurt Michael Taylor wrote: If you think Carley and the rest of HP / Agilent upper management are really more concerned about your thoughts - over short term profits, there are several of us that would like to interest you in some swamp land in Florida and a bridge in New Jersey. Seriously, I have had several instances lately with Agilent that convince me that the old HP is gone and the NEW - lean-mean Agilent machine no longer values customer loyalty the way the old HP did. In my case, the way I was treated on several issues would have never occurred under the old HP. The net result is I now consider purchasing test equipment from others - something I would have never done in the past. Welcome to the brave new world of bean counting business. Michael Taylor (loyal HP test equipment fan) Frozen in Colorado From: emcp...@aol.com [mailto:emcp...@aol.com] Sent: Tuesday, February 04, 2003 11:00 AM To: emc-p...@majordomo.ieee.org Subject: Agilent 6842A I think all of the people that own the Agilent 6842A Harmonic and Flicker Test System should get together and request Agilent to update their software for the new standards. As a loyal HP/Agilent customer, I would expect them to take care of this issue. This is why we buy certain brands of test equipment, and not others. I feel that we got ripped on this deal since the 6842A is not a cheap piece of test equipment. Tim Pierce -- Kurt M. Marden Environmental Simulation Manager Curtis-Straus LLC kmar...@curtis-straus.com Laboratory for EMC,Safety Environmental Simulation Lab NEBS,SEMI-S2 and Telecom168 Ayer Rd. 527 Great Road Littleton, MA 01460 Littleton, MA 01460 voice (978) 486-8880 http://www.curtis-straus.comfax (978) 486-0806 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 Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Re: CALIBRATION AND CONSTRUCTION OF HELMHOLTZ COILS
Ian, Contact me off line and I will share with you the SW tools (free on the internet) that I use to do these calculations. The first is an antiquated tool that runs on DOS called Computer Calculus 4.0, or CC4 I like it because it's powerful but easy to learn and retain. The second is a 2D finite element analysis program called femm that is located at http://femm.berlios.de/ When you use the SW in asymmetric analysis you get true 3D values, so it's very powerful. You can use the program for plotting the B field over whatever effective area of interest you're after. - Robert - Robert A. Macy, PEm...@california.com 408 286 3985 fx 408 297 9121 AJM International Electronics Consultants 101 E San Fernando, Suite 402 San Jose, CA 95112 From: Gordon,Ian ian.gor...@edwards.boc.com To: 'IEEE EMC-PSTC GROUP' emc-p...@majordomo.ieee.org Sent: Thursday, January 23, 2003 7:15 AM Subject: CALIBRATION AND CONSTRUCTION OF HELMHOLTZ COILS All I would like to construct a Helmholtz coil to perform magnetic field immunity testing at DC frequencies and thus simulate the effect of a permanent magnet. There are some details on construction in EN61000-4-8 which details power frequency magnetic field immunity testing within the scope of the EMC directive. However the fields referred to are measured in A/m, whereas I need a field of, for example, 5mTesla. Can anybody advise me as to how to construct such a coil with a test volume of 0.5 x 0.5 x 0.5m and a field of 5mTesla? Thanks Ian Gordon 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: Measuring AC Line Impedance
Do you have the liberty to share your report - or details and results with the group? - Robert - Robert A. Macy, PEm...@california.com 408 286 3985 fx 408 297 9121 AJM International Electronics Consultants 101 E San Fernando, Suite 402 San Jose, CA 95112 - Original Message - From: Spencer, David H david.spen...@usa.xerox.com To: emc-p...@majordomo.ieee.org Sent: Wednesday, October 30, 2002 8:57 AM Subject: RE: Measuring AC Line Impedance Follow up Having just completed an ton of work on this using input I got around here (thanks to Don Borowski, Patrick Lawler, Joe Randolph and John Woodgate). I believe we have characterized the AC mains of our facility. As a sanity check/ technical check can any one comment on process. Part one 1)Open circuit voltage measured. 2)Resistive load placed in circuit. 3) Voltage drop and current measured. 4) Voltage drop divided by current provides resistance component of AC mains. Part 2 1) Open circuit voltage measured. 2)Reactive load placed in circuit (approximately 120uF!) 3) Voltage change (increase really) and current measured (phase angle was recorded to back check math vectorialy). 4) Voltage change divided by current provides reactive component of AC mains. As a side note, I also connected an isolation transformer as the reactive load, the reactive numbers were very very close. The resistive number + reactive number then make up the AC line impedance for this site: Ztest if you will. My two remaining questions: Is this method of characterizing the AC line impedance valid (is there something I'm missing)? Based on my knowledge of these values, and their ratio to the reference impedance(s) specified in EN61000-3-3 and EN61000-3-11, I should be able to calculate and correlate the measured Dmax, Pst, et. al...to the limits specified in those standards. (REFERENCE section 6.1.3 of EN61000-3-11), using our existing AC mains. Any comments or input would be welcome. Thanks Regards David Spencer Xerox Corp. -Original Message- From: John Woodgate [mailto:j...@jmwa.demon.co.uk] Sent: Thursday, September 19, 2002 11:56 AM To: emc-p...@majordomo.ieee.org Subject: Re: Measuring AC Line Impedance I read in !emc-pstc that Spencer, David H david.spen...@usa.xerox.com wrote (in 052106A55179D611B34300096BB02E3F8B1D@USAMCMS4) about 'Measuring AC Line Impedance' on Thu, 19 Sep 2002: Is anyone familiar with a method to measure and calculate those values. The generic values I have for short circuit condition (which include 4 wires in a magnetic conduit) come out higher than my measured values, and those do not include the motor generator source. Put a large capacitor (mains voltage rated) across the mains and measure the voltage change; it may actually increase. You need about 50 uF to get a decent change on 120 V 60 Hz mains. With that result and the one with the resistive load, you can calculate the source impedance as an R and L in series. I'd be interested to learn the result. -- Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk Interested in professional sound reinforcement and distribution? Then go to http://www.isce.org.uk PLEASE do NOT copy news posts to me by E-MAIL! --- 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 --- 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 ---
Need services of Professional (PE) Mechanical Engineer registered in California
Dear group, A fabricator of shell and tube heat exchangers located in Stafford, Texas has a requirement for a California PE to perform a structural design check on supports on two vessels that will be erected at the Shell Oil Plant in Martinez, California. Could you recommend a California PE? - Robert - Robert A. Macy, PEm...@california.com 408 286 3985 fx 408 297 9121 AJM International Electronics Consultants 619 North First St, San Jose, CA 95112 --- 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: Need Drivers Programming Guide for HP8592B
Andy, About 4 years ago I bought a book called something like Programming Guide for the ... from HP which cost around $20. Not sure if it was for this model or not, but watch out. Their system had the wrong part number and I got some unrelated book and it took another 10 days to get the right one. - Robert - Robert A. Macy, PEm...@california.com 408 286 3985 fx 408 297 9121 AJM International Electronics Consultants 619 North First St, San Jose, CA 95112 - Original Message - From: andrew.p.pr...@baesystems.com To: emc-p...@majordomo.ieee.org Sent: Tuesday, August 13, 2002 4:33 AM Subject: Need Drivers Programming Guide for HP8592B Is there anyone who can help? I require information on HP8592B Commands and Programming for GPIB interface. Regards Andy Andrew Price Principal Development Engineer (EMC Specialist) BAE SYSTEMS Avionics A125 Christopher Martin Road Basildon, Essex SS14 3EL tel: +44 (0) 1268 883308 email: andrew.p.pr...@baesystems.com This email and any attachments are confidential to the intended recipient and may also be privileged. If you are not the intended recipient please delete it from your system and notify the sender. You should not copy it or use it for any purpose nor disclose or distribute its contents to any other person. --- 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: Need copies of specs addressing ISM bands in Europe
Bill, Rich, Just couldn't find out all of what I wanted there. Did find individual country's allocation for ISM bands and that was encouraging. What am I doing wrong? At this site I at least found some numbers: http://europa.eu.int/comm/enterprise/newapproach/standardization/harmstds/re flist/radiotte.html ETSI EN 300 328-2 V1.1.1 (07-2000) Electromagnetic compatibility and Radio Spectrum Matters (ERM); Wideband Transmission systems; Data transmission equipment operating in the 2,4 GHz ISM band and using spread spectrum modulation techniques; Part 2: Harmonized EN covering essential requirements under article 3.2 of the RTTE Directive. ETS 300 328/A1:1997 Date expired (30.04.2001) Art.3.2 ETSI EN 300 328-2 V1.2.1 (11-2001) Electromagnetic compatibility and Radio Spectrum Matters (ERM); Wideband Transmission systems; Data transmission equipment operating in the 2,4 GHz ISM band and using spread spectrum modulation techniques; Part 2: Harmonized EN covering essential requirements under article 3.2 of the RTTE Directive EN 300 But no documents. My question is still, What is the equivalent European requirement that matches FCC Part 15.247 regarding ISM bands? - Robert - Robert A. Macy, PEm...@california.com 408 286 3985 fx 408 297 9121 AJM International Electronics Consultants 619 North First St, San Jose, CA 95112 - Original Message - From: Bill Morse bill...@verifone.com To: 'Robert Macy' m...@california.com; emc-p...@ieee.org Sent: Monday, August 12, 2002 12:52 PM Subject: RE: Need copies of specs addressing ISM bands in Europe Try the following URL. http://www.ero.dk/ Technical Staff Senior EMC Engineer William Morse NCE Phone 916.630.2540 FAX916.630.2501 EMAILbill...@verifone.com -Original Message- From: Robert Macy [mailto:m...@california.com] Sent: Monday, August 12, 2002 10:07 AM To: emc-p...@ieee.org Subject: Need copies of specs addressing ISM bands in Europe Apologize if duplication of question here. Is there a website to get a copy of the European Community's rules regarding ISM bands similar to FCC Part 15.245-9? - Robert - Robert A. Macy, PEm...@california.com 408 286 3985 fx 408 297 9121 AJM International Electronics Consultants 619 North First St, San Jose, CA 95112 --- 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
Need copies of specs addressing ISM bands in Europe
Apologize if duplication of question here. Is there a website to get a copy of the European Community's rules regarding ISM bands similar to FCC Part 15.245-9? - Robert - Robert A. Macy, PEm...@california.com 408 286 3985 fx 408 297 9121 AJM International Electronics Consultants 619 North First St, San Jose, CA 95112 --- 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: NEBS compliance for 100baseT / 1000base T
The people who supply these inbedded filter connectors, Regal Electronics, can answer this and more. - Robert - Robert A. Macy, PEm...@california.com 408 286 3985 fx 408 297 9121 AJM International Electronics Consultants 619 North First St, San Jose, CA 95112 -Original Message- From: Muhammad Sagarwala msa...@force10networks.com To: emc-p...@majordomo.ieee.org emc-p...@majordomo.ieee.org Date: Monday, July 22, 2002 3:32 PM Subject: NEBS compliance for 100baseT / 1000base T Hello Gurus, I am new to this list so pardon me if my questions sound naive. The question I had was, for nebs compliance we need to pass power cross and lightening tests. For boards with copper ports (100baseT and 100base T), is it possible to use rj45 connectors with integrated magnetics and still get pass these tests. Has anybody done that - if yes, is it possible to share the method. I believe there are components (e.g. sedactors) one can use, but those are capacitve and might impact the signal integrity. Also, mostly that kind of stuff is used on the line side of the transformer. I am just a little bit hesistant to put in on the secondary side... Any input would be highly appreciated... Thanks Muhammad --- 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: case of units
Still use KHz For me it's a logical carrier over from small letter = small value capital letter = large value mOhm means milli Ohm NOT mega Ohm mHz is milliHertz KHz is kilo Hertz (note magnifier is larger than one) MHz is megaHertz and so on - Robert - Robert A. Macy, PEm...@california.com 408 286 3985 fx 408 297 9121 AJM International Electronics Consultants 619 North First St, San Jose, CA 95112 -Original Message- From: Price, Ed ed.pr...@cubic.com To: emc-p...@majordomo.ieee.org emc-p...@majordomo.ieee.org List-Post: emc-pstc@listserv.ieee.org Date: Monday, June 24, 2002 8:24 AM Subject: RE: case of units -Original Message- From: Brent DeWitt [mailto:bdew...@ix.netcom.com] Sent: Sunday, June 23, 2002 7:04 PM To: emc-p...@majordomo.ieee.org Subject: case of units I've always found it interesting that the small k is the only lower case letter used for multipliers greater than unity. I presume it is because the temperature folks got there first with Lord Kelvin's initial. Too bad really since kilo has a linguistic meaning for numbers and Kelvin is just a name. Also rather interesting that we have no trouble using G for both Giga and Gauss. Just Sunday evening thoughts. Brent DeWitt Brent: For years, I had always written kiloHertz as KHz. Then, as a hirling, I bumped up against the Information Technology Group at General Dynamics Electronics Division. I noticed that all my text came back using kHz. After a few cycles of this, I decided to follow up on the cause. I found that they worked to a bureaucratic style manual, which dictated the style for abbreviations and technical terms. I had the temerity to ask who wrote the style manual, and why KHz was rendered as kHz. They finally produced a Mil-Std, which had a list of acronyms and special terms. And, there on the list, was kHz! No explanation, just kHz. So I asked them if maybe the Mil-Std was just a typo error, and that shouldn't we allow logic to prevail? No, because if they did that, someone might think the abbreviation actually meant degrees Kelvin Hertz. They won. Lately, after many more years of continuing to personally use KHz (and having re-educated my MS Word about my preference), I find that I am wearying of the explanations, and have started to use kHz. Yup, they won. Ed Ed Price ed.pr...@cubic.com Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military Avionics EMC Services Is Our Specialty Shake-Bake-Shock - Metrology - Reliability Analysis --- 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 --- 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: Lightning Protection for PA System
Scott, Not knowing how your system is exactly built makes it difficult to second guess the lightning. However, here is one way to protect your amplifiers: Move the protection interface out to the edge of your building. Use rod located there with all referenced to ground. At this same location use a 10A AC mains line filter between the amplifier and the speakers (cheap filtering which should be able to pass the audio) with AC line towards amp and load towards speakers. Between filter and speakers place fusing in series (won't do much for truly high voltage which will jump, but will take care of a lot of nuisance discharges) place gas discharge tubes there. [ If you can get a surplus telephone entry block, the type with the carbon shorts, they work great here, too. ] Back side of filter place tranzorbs, then back at amp place more tranzorbs. You prevent lightning damage by designing a filtering system which limits the maximum amplitude that can get into your electronics. And the most effective rejection filter is always high impedance in series, low impedance to ground, high impedance in series and low impedance to ground, ad nauseum. Just make multiple paths that do this and you can even sustain a direct hit. Speakers and wires will probably fry though. - Robert - Robert A. Macy, PEm...@california.com 408 286 3985 fx 408 297 9121 AJM International Electronics Consultants 619 North First St, San Jose, CA 95112 -Original Message- From: Scott Lacey sco...@world.std.com To: emc-p...@majordomo.ieee.org emc-p...@majordomo.ieee.org List-Post: emc-pstc@listserv.ieee.org Date: Saturday, June 15, 2002 9:19 AM Subject: Lightning Protection for PA System To the group, I am seeking advice as to the best methods of protecting a Public Address system against recurring lightning damage. The system uses several commercial PA amplifiers, each driving several speakers at indoor and outdoor locations. There are also several locations where microphones can be plugged in. The longest speaker wires may be up to 250 yards long. It is believed that the charge is being coupled to the speaker wires where it then returns to ground at the amplifier location within the building, destroying the solid state devices within the amplifier. A technician has added fuses to all external microphone inputs and speaker outputs. While these have blown several times during storms without obvious damage to the amplifiers it is my belief that fuses are generally too slow to protect semiconductor devices. I am seeking advice as to surge suppression devices. System particulars are as follows: 1) The PA amplifiers have 70 volt outputs. All speakers are transformer coupled. 2) All microphones use standard XLR connectors. They plug into metallic conduit mounted jacks at locations inside and outside the building. The outside microphones are unplugged during storms. 3) The amplifiers are located on the second floor of the building. Each amplifier is dedicated to a set of speakers at one location. The amplifier driving the longest wires is the one which most often has to be replaced. 4) The building is in a location known to be susceptible to lightning activity. Electrical appliances have been destroyed on at least two occasions. 5) All protective grounding efforts to date have been made to the conduit. I am recommending that this be supplemented by driven rods. It is pretty easy to buy commercial surge suppression devices for the ac lines. I feel I need advice as to the best methods to protect the audio inputs and outputs. For the 70 volt outputs I am thinking of using gas tubes to earth where the wires enter the building supplemented by MOV, Tranzorb, or other devices near the amplifier location. I welcome suggestions as to device types. For the microphone inputs I am thinking of using semiconductor transient voltage suppressors near the amplifier. Again, any suggestions are welcome. Thanks in advance for any advice and guidance. Scott Lacey sco...@world.std.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: 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: Side Issue: Proximity Cards in Wallets ...
No - Robert - Robert A. Macy, PEm...@california.com 408 286 3985 fx 408 297 9121 AJM International Electronics Consultants 619 North First St, San Jose, CA 95112 -Original Message- From: Doug McKean dmck...@corp.auspex.com To: EMC-PSTC Discussion Group emc-p...@majordomo.ieee.org List-Post: emc-pstc@listserv.ieee.org Date: Thursday, June 13, 2002 11:07 AM Subject: Side Issue: Proximity Cards in Wallets ... A proximity card reading security system is used in a company, possibly based on the Wiegand Effect. Some of the employees put their security cards in their wallets to have them all the time. When needing access to an area that requires a card, users simply pull out their wallets, swipe the wallet in front of the reader and thus gain access. For those people with cards in their wallets, they do not pull the security card out of the wallet and then swipe the reader. They all swipe the reader with the wallet. A question was posed to me that involved the swamping of the card with a magnetic field to identify the card. The electronics in the card generates a series of pulses from the pulsed magnetic field that when received by the card reader validate or invalidate the card. Is this field strong enough to wipe any magnetic strips on any credit or bank or any of the other types of cards using magnetic strips that may also be in the wallet? Regards, 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...@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: ferrite transient voltage/current response
Then why would a 10 A surge change their characteristics? Unless it cracks it? - Robert - -Original Message- From: Robert Wilson robert_wil...@tirsys.com To: Robert Macy m...@california.com; emc-p...@majordomo.ieee.org emc-p...@majordomo.ieee.org List-Post: emc-pstc@listserv.ieee.org Date: Thursday, June 06, 2002 8:51 AM Subject: RE: ferrite transient voltage/current response Soft Ferrites cannot be permanently magnetized. This is precisely why they are used as beads and cores. Bob Wilson TIR Systems Ltd. Vancouver. -Original Message- From: Robert Macy [mailto:m...@california.com] Sent: June 5, 2002 11:20 PM To: don_borow...@selinc.com; emc-p...@majordomo.ieee.org Cc: shbe...@rockwellcollins.com Subject: Re: ferrite transient voltage/current response He may have magnetized it. Degaussing with one of those Radio Shack thingies would probably brought it back. Can he try it again? - Robert - Robert A. Macy, PEm...@california.com 408 286 3985 fx 408 297 9121 AJM International Electronics Consultants 619 North First St, San Jose, CA 95112 -Original Message- From: don_borow...@selinc.com don_borow...@selinc.com To: emc-p...@majordomo.ieee.org emc-p...@majordomo.ieee.org Cc: shbe...@rockwellcollins.com shbe...@rockwellcollins.com List-Post: emc-pstc@listserv.ieee.org Date: Wednesday, June 05, 2002 2:52 PM Subject: RE: ferrite transient voltage/current response While I was at Agilent in Spokane, one of the engineers or technicians claimed that he had changed the RF characteristics of a 6-hole ferrite bead (wound with 2 1/2 turns) used on a power supply trace to a noisy assembly. The normal current was about 1 amp, but he accidently shorted the power supply voltage after the inductor. This caused a current spike as the power supply filter capacitor discharged (and then the supply current limited at about 10 amps). After this, there was a problem with RF leakage from the assembly. Replacing the inductor fixed the problem. Apparently the effect was repeatable. I didn't observe this personally, so I can't guarantee it. Don Borowski Schweitzer Engineering Labs Sorry that I wasn't clear; I typically try to keep my questions general so not to get too detailed about the specific application. And thanks to Bob, Chris and Mike who have responded ... putting it into Chris's words ... I was just trying to find out if ferrites had ratings to prevent them from j ust plain blowing the ferrite to smithereens. Also, I was looking for a shortcut if someone else had faced this question rather than reading through all of the vendor web sites. I understand and have used ferrites quite often for typical EMI suppression; the ferrites typically being rated for the application currents, voltages, etc. In this case, the program is trying to protect a power supply input from the DO-160 waveform 5B pin injected lightning pulse of 300 volts open circuit 300A short circuit. If the Gas Discharge Tube is located past (closer to the supply which was done for packaging limitations) than the T EMI filter, a question was raised as to whether the ferrite properties would be altered by the lightning pulse. Most of the standard literature on the use of ferrites does not address these types of transients. Susan Beard Robert Wilson robert_wil...@tirsys.com@majordomo.ieee.org on 06/04/2002 02:16:48 PM Please respond to Robert Wilson robert_wil...@tirsys.com Sent by:owner-emc-p...@majordomo.ieee.org To:shbe...@rockwellcollins.com, emc-p...@ieee.org cc: Subject:RE: ferrite transient voltage/current response Your question is not all that clear. It appears to imply that transients have an affect on the ferrite beads, but it is the other way around (maybe that is what you meant). But in general, small ferrite beads have little effect, except at very high frequencies (hundreds of MHz), unless they are no longer beads (i.e. they are very large). Have a look at the various magnetics vendors data sheets and app notes. Magnetics Inc: www.mag-inc.com Fair-Rite Inc: www.fair-rite.com (whoever came up with THAT name should be shot! Steward Inc: www.steward.com Ferroxcube: www.ferroxcube.com Epcos (was Siemens): www.epcos.com Bob Wilson TIR Systems Ltd. Vancouver. -Original Message- From: shbe...@rockwellcollins.com [mailto:shbe...@rockwellcollins.com] Sent: June 4, 2002 8:57 AM To: emc-p...@ieee.org Subject: ferrite transient voltage/current response Could someone point me to some good App Note information on the response of and affect on ferrite beads to transient voltage current waveforms? The waveforms are based on the indirect lightning pulses specified in Section 22 of DO-160. Thanks in advance, Susan Beard This e-mail may contain SEL confidential information. The opinions expressed are not necessarily those of SEL. Any unauthorized
Re: ferrite transient voltage/current response
He may have magnetized it. Degaussing with one of those Radio Shack thingies would probably brought it back. Can he try it again? - Robert - Robert A. Macy, PEm...@california.com 408 286 3985 fx 408 297 9121 AJM International Electronics Consultants 619 North First St, San Jose, CA 95112 -Original Message- From: don_borow...@selinc.com don_borow...@selinc.com To: emc-p...@majordomo.ieee.org emc-p...@majordomo.ieee.org Cc: shbe...@rockwellcollins.com shbe...@rockwellcollins.com List-Post: emc-pstc@listserv.ieee.org Date: Wednesday, June 05, 2002 2:52 PM Subject: RE: ferrite transient voltage/current response While I was at Agilent in Spokane, one of the engineers or technicians claimed that he had changed the RF characteristics of a 6-hole ferrite bead (wound with 2 1/2 turns) used on a power supply trace to a noisy assembly. The normal current was about 1 amp, but he accidently shorted the power supply voltage after the inductor. This caused a current spike as the power supply filter capacitor discharged (and then the supply current limited at about 10 amps). After this, there was a problem with RF leakage from the assembly. Replacing the inductor fixed the problem. Apparently the effect was repeatable. I didn't observe this personally, so I can't guarantee it. Don Borowski Schweitzer Engineering Labs Sorry that I wasn't clear; I typically try to keep my questions general so not to get too detailed about the specific application. And thanks to Bob, Chris and Mike who have responded ... putting it into Chris's words ... I was just trying to find out if ferrites had ratings to prevent them from j ust plain blowing the ferrite to smithereens. Also, I was looking for a shortcut if someone else had faced this question rather than reading through all of the vendor web sites. I understand and have used ferrites quite often for typical EMI suppression; the ferrites typically being rated for the application currents, voltages, etc. In this case, the program is trying to protect a power supply input from the DO-160 waveform 5B pin injected lightning pulse of 300 volts open circuit 300A short circuit. If the Gas Discharge Tube is located past (closer to the supply which was done for packaging limitations) than the T EMI filter, a question was raised as to whether the ferrite properties would be altered by the lightning pulse. Most of the standard literature on the use of ferrites does not address these types of transients. Susan Beard Robert Wilson robert_wil...@tirsys.com@majordomo.ieee.org on 06/04/2002 02:16:48 PM Please respond to Robert Wilson robert_wil...@tirsys.com Sent by:owner-emc-p...@majordomo.ieee.org To:shbe...@rockwellcollins.com, emc-p...@ieee.org cc: Subject:RE: ferrite transient voltage/current response Your question is not all that clear. It appears to imply that transients have an affect on the ferrite beads, but it is the other way around (maybe that is what you meant). But in general, small ferrite beads have little effect, except at very high frequencies (hundreds of MHz), unless they are no longer beads (i.e. they are very large). Have a look at the various magnetics vendors data sheets and app notes. Magnetics Inc: www.mag-inc.com Fair-Rite Inc: www.fair-rite.com (whoever came up with THAT name should be shot! Steward Inc: www.steward.com Ferroxcube: www.ferroxcube.com Epcos (was Siemens): www.epcos.com Bob Wilson TIR Systems Ltd. Vancouver. -Original Message- From: shbe...@rockwellcollins.com [mailto:shbe...@rockwellcollins.com] Sent: June 4, 2002 8:57 AM To: emc-p...@ieee.org Subject: ferrite transient voltage/current response Could someone point me to some good App Note information on the response of and affect on ferrite beads to transient voltage current waveforms? The waveforms are based on the indirect lightning pulses specified in Section 22 of DO-160. Thanks in advance, Susan Beard This e-mail may contain SEL confidential information. The opinions expressed are not necessarily those of SEL. Any unauthorized disclosure, distribution or other use is prohibited. If you received this e-mail in error, please notify the sender, permanently delete it, and destroy any printout. Thank you. --- 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
Re: Constant for Change of Resistance formula.
Bill, Big oops. Measuring the resistance to determine the temperature is not productive *unless* the resistance dominates the resistance measurement. Picture three equal valued resistances in a row. The middle one gets very hot (more than 100C rise) and increases over 40%, the two on the edges are heat sinked and barely increase in temperature. The resulting change in resistance is 13% which implies the temperature in there has only gone up around 33C. Measuring the resistance doesn't tell you much. At least with transformers the dominant resistance is pretty much the bulk resistance. - Robert - -Original Message- From: Bill Ellingford bill.ellingf...@motion-media.com To: 'Robert Macy' m...@global.california.com; emc-p...@majordomo.ieee.org emc-p...@majordomo.ieee.org List-Post: emc-pstc@listserv.ieee.org Date: Monday, May 13, 2002 1:56 PM Subject: RE: Constant for Change of Resistance formula. Hi Robert / group OK, Not the best choice of website to demo the answer. The differing figures are because the formula has been transposed to give Temp from change of R from the original formula which gives R from change of T. To do this, another constant (The 234.5 constant) is required. This is the implied point of zero resistance for copper on the Celsius scale. The formula we use is: Rfinal - Rorig x (234.5 + Tamb start) -(Tamb finsh - Tamb start) Rorig The Tamb start and finish are the changes (if any) in Room ambient. If the room remains at 20c then 234.5 + 20 is the multiplier. -Original Message- From: Robert Macy [mailto:m...@california.com] Sent: 13 May 2002 14:54 To: Bill Ellingford; emc-p...@majordomo.ieee.org Subject: Re: Constant for Change of Resistance formula. Bill, Thanks for the site. Went there and found the same formula and constant I use. For copper, Temp Coeff = 3.9 x 10-3 Then I clicked on table of coeff and there was a very long list of materials, but the temp coeff of copper there was 6.8 x 10-3 ???!!! Any ideas for this disparity? - Robert - Robert A. Macy, PEm...@california.com 408 286 3985 fx 408 297 9121 AJM International Electronics Consultants 619 North First St, San Jose, CA 95112 -Original Message- From: Bill Ellingford bill.ellingf...@motion-media.com To: 'Colgan, Chris' chris.col...@tagmclaren.com; emc-p...@majordomo.ieee.org emc-p...@majordomo.ieee.org Date: Monday, May 13, 2002 5:38 AM Subject: RE: Constant for Change of Resistance formula. Hi Folks Further to the answer given, here is a little more data. The constant used is for the change of resistance with temperature. metals and alloys (conductors) all exhibit a different constant. This can be used for calculating temperature rise or resistance change. i.e. find the temp rise from a start and finish test measurement on a winding (for example) at the begining and end of a on load heat run or, find R for a given temp: using a table or the formula, resistance at various temperatures can be pre-determined from a measurement made at one particular temperature. A website with the formulae can be found at http://hyperphysics.phy-astr.gsu.edu/hbase/electric/restmp.html Where you have a transition from one metal type to another, you must measure each metal part individually. If you have only two metals in contact, you may be able to apply a combination of the temp coefficient methods and transposition of the measurement of change of junction voltage formulae i.e. Thermocouple laws. Hope this adds some value: Bill Ellingford -Original Message- From: Colgan, Chris [mailto:chris.col...@tagmclaren.com] Sent: 13 May 2002 10:28 To: emc-p...@majordomo.ieee.org Subject: RE: Constant for Change of Resistance formula. Ned is referring to the constant used in the temperature rise calculated by change in resistance formula ie ... Where dt is the temperature rise, R1 is start resistance, R2 is end resistance, T1 is start ambient and T2 is end ambient. 234.5 is the formula constant for copper. This formula is used extensively when heat testing transformers and coils. I'm afraid I don't know the constant for brass but I believe the figure may be related to the inferred absolute zero of a material. Try asking a metallurgist? Regards Chris Colgan Compliance Engineer TAG McLaren Audio Ltd The Summit, Latham Road Huntingdon, Cambs, PE29 6ZU *Tel: +44 (0)1480 415 627 *Fax: +44 (0)1480 52159 * Mailto:chris.col...@tagmclaren.com * http://www.tagmclaren.com -Original Message- From: Robert Wilson [SMTP:robert_wil...@tirsys.com] Sent: Friday, May 10, 2002 7:00 PM To: emc-p...@majordomo.ieee.org; Ned Devine Subject: RE: Constant for Change of Resistance formula. What are the units? 234.5 ...what?? Looking at what the units are, will basically tell you exactly what the property is related to. Nonetheless, you cannot
Re: Constant for Change of Resistance formula.
Bill/group Let's check all these numbers. Room temp of 20C? 68F (br). More like 25C, 77F. Most people assume room temp is 297K (or is that 298?) which is more like 23.82C, ~75F (seems more reasonable), putting that into the linear equation gives 234.5 + 23.82 = 0.00387 error less than 0.7% compared to 0.0039 However the formula is very clear that this is a short range linearity When you extrapolate to 100C, or 75C rise above ambient, the linear formula predicts 1.295 times the room temp resistance, but the actual value climbs more like: (1+0.0039)^75 = 1.339 (for 1 degree steps) error is now more than 3% My conclusion is to just measure it. Run current through the contacts, measure the resistance, then stick the whole thing in a temp chamber and increase temp 'til you read the same resistance. Or, lower the temp from ambient, until you read the SAME resistance. Then that temperature difference is your rise above ambient. I know, I know. The first method does not take into account thermal gradients that cool parts of the conductors and would suggest less rise than actually occurs - which could be a large error, say measure 25C rise, but actually have 35C rise in the hotspots. The second method is moving into the nonlinear range, but for a temp change of 25C is only 0.4% error. Therefore, to more closely approximate the actual conditions, I'd recommend you cool the connector and reproduce the resistance measurement made at room temp. Any idea why their chart (at that website) showed temp coefficient of 0.0068 for copper? - Robert - Robert A. Macy, PEm...@california.com 408 286 3985 fx 408 297 9121 AJM International Electronics Consultants 619 North First St, San Jose, CA 95112 -Original Message- From: Bill Ellingford bill.ellingf...@motion-media.com To: 'Robert Macy' m...@global.california.com; emc-p...@majordomo.ieee.org emc-p...@majordomo.ieee.org List-Post: emc-pstc@listserv.ieee.org Date: Monday, May 13, 2002 8:15 AM Subject: RE: Constant for Change of Resistance formula. Hi Robert / group OK, Not the best choice of website to demo the answer. The differing figures are because the formula has been transposed to give Temp from change of R from the original formula which gives R from change of T. To do this, another constant (The 234.5 constant) is required. This is the implied point of zero resistance for copper on the Celsius scale. The formula we use is: Rfinal - Rorig x (234.5 + Tamb start) -(Tamb finsh - Tamb start) Rorig The Tamb start and finish are the changes (if any) in Room ambient. If the room remains at 20c then 234.5 + 20 is the multiplier. -Original Message- From: Robert Macy [mailto:m...@california.com] Sent: 13 May 2002 14:54 To: Bill Ellingford; emc-p...@majordomo.ieee.org Subject: Re: Constant for Change of Resistance formula. Bill, Thanks for the site. Went there and found the same formula and constant I use. For copper, Temp Coeff = 3.9 x 10-3 Then I clicked on table of coeff and there was a very long list of materials, but the temp coeff of copper there was 6.8 x 10-3 ???!!! Any ideas for this disparity? - Robert - Robert A. Macy, PEm...@california.com 408 286 3985 fx 408 297 9121 AJM International Electronics Consultants 619 North First St, San Jose, CA 95112 -Original Message- From: Bill Ellingford bill.ellingf...@motion-media.com To: 'Colgan, Chris' chris.col...@tagmclaren.com; emc-p...@majordomo.ieee.org emc-p...@majordomo.ieee.org Date: Monday, May 13, 2002 5:38 AM Subject: RE: Constant for Change of Resistance formula. Hi Folks Further to the answer given, here is a little more data. The constant used is for the change of resistance with temperature. metals and alloys (conductors) all exhibit a different constant. This can be used for calculating temperature rise or resistance change. i.e. find the temp rise from a start and finish test measurement on a winding (for example) at the begining and end of a on load heat run or, find R for a given temp: using a table or the formula, resistance at various temperatures can be pre-determined from a measurement made at one particular temperature. A website with the formulae can be found at http://hyperphysics.phy-astr.gsu.edu/hbase/electric/restmp.html Where you have a transition from one metal type to another, you must measure each metal part individually. If you have only two metals in contact, you may be able to apply a combination of the temp coefficient methods and transposition of the measurement of change of junction voltage formulae i.e. Thermocouple laws. Hope this adds some value: Bill Ellingford
Re: Constant for Change of Resistance formula.
Bill, Thanks for the site. Went there and found the same formula and constant I use. For copper, Temp Coeff = 3.9 x 10-3 Then I clicked on table of coeff and there was a very long list of materials, but the temp coeff of copper there was 6.8 x 10-3 ???!!! Any ideas for this disparity? - Robert - Robert A. Macy, PEm...@california.com 408 286 3985 fx 408 297 9121 AJM International Electronics Consultants 619 North First St, San Jose, CA 95112 -Original Message- From: Bill Ellingford bill.ellingf...@motion-media.com To: 'Colgan, Chris' chris.col...@tagmclaren.com; emc-p...@majordomo.ieee.org emc-p...@majordomo.ieee.org List-Post: emc-pstc@listserv.ieee.org Date: Monday, May 13, 2002 5:38 AM Subject: RE: Constant for Change of Resistance formula. Hi Folks Further to the answer given, here is a little more data. The constant used is for the change of resistance with temperature. metals and alloys (conductors) all exhibit a different constant. This can be used for calculating temperature rise or resistance change. i.e. find the temp rise from a start and finish test measurement on a winding (for example) at the begining and end of a on load heat run or, find R for a given temp: using a table or the formula, resistance at various temperatures can be pre-determined from a measurement made at one particular temperature. A website with the formulae can be found at http://hyperphysics.phy-astr.gsu.edu/hbase/electric/restmp.html Where you have a transition from one metal type to another, you must measure each metal part individually. If you have only two metals in contact, you may be able to apply a combination of the temp coefficient methods and transposition of the measurement of change of junction voltage formulae i.e. Thermocouple laws. Hope this adds some value: Bill Ellingford -Original Message- From: Colgan, Chris [mailto:chris.col...@tagmclaren.com] Sent: 13 May 2002 10:28 To: emc-p...@majordomo.ieee.org Subject: RE: Constant for Change of Resistance formula. Ned is referring to the constant used in the temperature rise calculated by change in resistance formula ie ... Where dt is the temperature rise, R1 is start resistance, R2 is end resistance, T1 is start ambient and T2 is end ambient. 234.5 is the formula constant for copper. This formula is used extensively when heat testing transformers and coils. I'm afraid I don't know the constant for brass but I believe the figure may be related to the inferred absolute zero of a material. Try asking a metallurgist? Regards Chris Colgan Compliance Engineer TAG McLaren Audio Ltd The Summit, Latham Road Huntingdon, Cambs, PE29 6ZU *Tel: +44 (0)1480 415 627 *Fax: +44 (0)1480 52159 * Mailto:chris.col...@tagmclaren.com * http://www.tagmclaren.com -Original Message- From: Robert Wilson [SMTP:robert_wil...@tirsys.com] Sent: Friday, May 10, 2002 7:00 PM To: emc-p...@majordomo.ieee.org; Ned Devine Subject: RE: Constant for Change of Resistance formula. What are the units? 234.5 ...what?? Looking at what the units are, will basically tell you exactly what the property is related to. Nonetheless, you cannot possibly directly determine what the temperature change of something as physically and geometrically complex as a connector, merely by factoring in what its resistance change is. Among other things, the solution is extremely non-linear and iterative. Changing resistance will generate more heat, which will increase temperature, which will generate even more heat and on and on! Add this to the fact the resistance coefficient with temperature is itself non-linear, and you can see how this complicates things further. The final temperature that the system stabilizes at, is reached when the logarithmically increasing (i.e. also very non-linear) heat transfer to the environment caused by increasing temperature, balances increased heat being generated. To reach a solution, you need to iterate your calculations, where the results of one calculation are plugged as variables into the next iteration. Typically a thermal analysis program will require several hundred iteration before a converged solution results. Bob Wilson TIR Systems Ltd. Vancouver. -Original Message- From: Ned Devine [mailto:ndev...@entela.com] Sent: May 10, 2002 8:29 AM To: emc-p...@majordomo.ieee.org Subject: Constant for Change of Resistance formula. Hi, Does any one know how the constant for CoR formula was determined? I know the K is 234.5 for copper and 226 for aluminum, but what property is this related to? I am trying to determine the change in temperature of a connector, based on the change of resistance. The connector contacts are made of brass. Thanks Ned Ned Devine Program Manager Entela, Inc. 3033 Madison Ave. SE Grand Rapids, MI 49548 1 616 248 9671 Phone 1 616 574 9752 Fax
Re: Constant for Change of Resistance formula.
Ned, Not familiar with this K term. For straight resitance changes in transformers, we always used 0.0039 per C. Does K somehow include contact resistance, not just bulk resistance? This is definitely the time to measure it. Environmental chamber at -50, 0, 50, 100, and 150. Make your own curves. - Robert - Robert A. Macy, PEm...@california.com 408 286 3985 fx 408 297 9121 AJM International Electronics Consultants 619 North First St, San Jose, CA 95112 -Original Message- From: Ned Devine ndev...@entela.com To: emc-p...@majordomo.ieee.org emc-p...@majordomo.ieee.org Date: Friday, May 10, 2002 8:45 AM Subject: Constant for Change of Resistance formula. Hi, Does any one know how the constant for CoR formula was determined? I know the K is 234.5 for copper and 226 for aluminum, but what property is this related to? I am trying to determine the change in temperature of a connector, based on the change of resistance. The connector contacts are made of brass. Thanks Ned Ned Devine Program Manager Entela, Inc. 3033 Madison Ave. SE Grand Rapids, MI 49548 1 616 248 9671 Phone 1 616 574 9752 Fax ndev...@entela.com e-mail Entela, Inc. A Certified Woman Owned Business www.entela.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: 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: ESD
Slight adjustments Part I http://www.pcdmag.com/mag/archives/OEG20010928S0122.html Part II http://www.pcdmag.com/online/redux_0701_esd.html - Robert - Robert A. Macy, PEm...@california.com 408 286 3985 fx 408 297 9121 AJM International Electronics Consultants 619 North First St, San Jose, CA 95112 -Original Message- From: John Barnes jrbar...@iglou.com To: Richard Jones gw0...@ntlworld.com; emc-p...@majordomo.ieee.org emc-p...@majordomo.ieee.org List-Post: emc-pstc@listserv.ieee.org Date: Tuesday, April 23, 2002 7:10 AM Subject: Re: ESD Richard, I invite you to read my article Designing Electronic Equipment for ESD Immunity. Part I was published in the July 2001 Printed Circuit Design magazine (vol. 18 no. 7, pp. 18-26). Part II was published on the magazine's web site in November 2001. You can download the entire article from the Internet: * Part I-- http://www.pcdmag.com/story/OEG20010928S0122 * Part II-- http://www.pcdmag.com/redux/0701_esd.html I also have a (partially-) annotated bibliography for the article at http://www.r-e-d-inc.com/esd-anno.htm which covers close to 1400 source documents on the subject. Enjoy! John Barnes Consultant, Robust Electronic Design, Inc. President, dBi Corporation --- 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: Marking - Made in XXX
Amund, I believe it's a law in the US that all products be labeled with their country of origin. - Robert - Robert A. Macy, PEm...@california.com 408 286 3985 fx 408 297 9121 AJM International Electronics Consultants 619 North First St, San Jose, CA 95112 -Original Message- From: am...@westin-emission.no am...@westin-emission.no To: emc-p...@majordomo.ieee.org emc-p...@majordomo.ieee.org List-Post: emc-pstc@listserv.ieee.org Date: Saturday, April 20, 2002 3:08 PM Subject: Marking - Made in XXX Is it necessary to describe where a product is manufactured, as in Made in XXX. I have see this statement/label on many products, but is it only voluntary ? Best regards Amund Westin, Oslo/Norway --- 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 --- 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: Decoupling - capacitor values
Years ago in ultrasonic echocardiography instrumentation (the ultrasonics analog is a wide band receiver listening in the 1-10MHz region down to less than 10uV, so the digital had better be quiet!) which used a bit slice architecture system containing Schottky logic with a clock of 20MHz for controlling and manipulating images in real time. We're talking 4 PCBs using 10 amps each board, so you can see the opportunity for generating horrific noise that would be injected into the analog section. We found that power distributed using a tree type of distribution where traces were thick then thinner out at the extremities *and* +5 was over top of GND made for the quietest distribution. The tree technique worked much quieter than the recommended grid structure where +5 distribution on bottom layer goes one direction with GND distribution on the top going the other. This structure made little tiny loop antennas that radiated energy all around inside the box and was awful! But easier for the layout people. - Robert - Robert A. Macy, PEm...@california.com 408 286 3985 fx 408 297 9121 AJM International Electronics Consultants 619 North First St, San Jose, CA 95112 -Original Message- From: am...@westin-emission.no am...@westin-emission.no To: ieee pstc list emc-p...@ieee.org List-Post: emc-pstc@listserv.ieee.org Date: Thursday, April 18, 2002 12:49 AM Subject: SV: Decoupling - capacitor values Correct, the picture is complex. The PCB is 2-layer with signal, 5V-power and 0V-ref lines routed on both sides. There is no ground layer/plane. There must be a large number of RF current loops because the 0V-lines are routed up and down and around. Beside trying to achieve a good decoupling I assume that reducing loop area is the most important. Amund -Opprinnelig melding- Fra: Cortland Richmond [mailto:72146@compuserve.com] Sendt: 18. april 2002 00:54 Til: am...@westin-emission.no; ieee pstc list Emne: Re: Decoupling - capacitor values Yes, it makes sense. But the goal here is preventing or reducing Vcc drop during the time the microprocessor is switching. You need not only low reactance, but *also* enough capacitance to supply the current needed _while it is switching_. You have not given enough information here to tell if 820pF is sufficient. Regards, Cortland Richmond Amund Westin wrote: Insert a SMD ceramic capacitor of value 820pF in parallel with the existing 100nF. The reason for the low value 820pF is because the capacitor self-resonance frequency is approximate 180MHz, and I believe it is important to choose a Cap value with a resonance frequency higher than the frequency we would like to decouple. Does it make sense? --- 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: Faying
Ed, Thank you. Especially the part blaming Woodgate. My grandfather's name was Fay (son of Irish immigrant) and I always wondered at the origin of that name. - Robert - Robert A. Macy, PEm...@california.com 408 286 3985 fx 408 297 9121 AJM International Electronics Consultants 619 North First St, San Jose, CA 95112 -Original Message- From: Price, Ed ed.pr...@cubic.com To: 'EMC-PSTC List' emc-p...@majordomo.ieee.org List-Post: emc-pstc@listserv.ieee.org Date: Monday, April 01, 2002 7:13 AM Subject: Faying A couple of weeks ago, there was a thread discussing bonding techniques for ground studs. I suggested that MIL-B-5087 had some nice drawings showing typical accepted military practices. Of course, MIL-B-5087 has been superseded by MIL-STD-464, but you can still find electronic copies of MIL-B-5087. Jacob Shanker read through all of the 464 sections on Bonding, and then asked me if I knew what the term faying meant. It seems that MIL-STD-464 uses that term without any definition, as if it's a very common American English word. IMHO, I consider myself to possess a rather decent vocabulary. But faying left me puzzled, even after closely reading the context of the several citings in MIL-STD-464. It's certainly not in any common usage in my part of the world. I certainly wouldn't want to call something faying at any typical US military base. So, off to the dictionary web sites. 1. Britannica says: not found. 2. Merriam Webster says: Main Entry: fay // Pronunciation: 'fA // Function: verb Etymology: Middle English feien, from Old English fEgan; akin to Old High German fuogen to fit, Latin pangere to fasten Date: before 12th century : to fit or join closely or tightly 3. Harcourt's Metallurgy Engineering Dictionary says: faying surface // Metallurgy: the interface between two metallic parts that are to be joined. 4. Finally, turning to Google in desperation for a simple explanation, I find pictures at: http://www.offroaders.com/info/tech-corner/reading/bolt-tension/bolt_tensio n .htm So after all this searching, I find that MIL-STD-464 faying is just a 12th Century Old English way to say facing or mating surfaces. I'm not sure how he did it, but I suspect John Woodgate is to blame for this. Regards, Ed Ed Price ed.pr...@cubic.com Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military Avionics EMC Services Is Our Specialty Shake-Bake-Shock - Metrology - Reliability Analysis --- 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: Relative merits of various logic families in not generating RFI
Thank you for the prompt reply. Yes, faster rise time would lend the signal and its generation to create energetic RFI, but just in case there were some internal states that blew power out, or high impedance return paths through the substrate that caused all the outputs to dance in common mode horror would be examples of the gotchas I was looking for. - Robert - -Original Message- From: peter.pou...@invensys.com peter.pou...@invensys.com To: Robert Macy m...@california.com List-Post: emc-pstc@listserv.ieee.org Date: Tuesday, March 19, 2002 8:23 PM Subject: Re: Relative merits of various logic families in not generating RFI Robert, I suggest you have a look at the logic selection guides and application notes from the major semiconductor logic manufacturers. As a starting point, check out page 13 to 15 of http://www.fairchildsemi.com/ms/MS/MS-520.pdf for a rule-of-thumb guide on how to assess EMI generation from the manufacturer's specs for the logic. Generally the slower the rise fall time, the lower the emissions. Robert Macy m...@california.com To: emc-p...@ieee.org Sent by: cc: owner-emc-pstc@majordomFax to: o.ieee.org Subject: Relative merits of various logic families in not generating RFI 20/03/02 08:49 Please respond to Robert Macy Group, What are the relative merits of the various logic families HCT, HC, AC, ACT with regard to generating RFI? I remember one time we replaced an HCT which made more noise than Schottky TTL due to an internal overlap in the switching causing a power rail shorting spike. I'm sure by now that most IC vendors have addressed the EMC problems associated with poorly designed chips, but what's the status on these now? What's the order of preference? Which one's best? - Robert - Robert A. Macy, PEm...@california.com 408 286 3985 fx 408 297 9121 AJM International Electronics Consultants 619 North First St, San Jose, CA 95112 --- 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
Relative merits of various logic families in not generating RFI
Group, What are the relative merits of the various logic families HCT, HC, AC, ACT with regard to generating RFI? I remember one time we replaced an HCT which made more noise than Schottky TTL due to an internal overlap in the switching causing a power rail shorting spike. I'm sure by now that most IC vendors have addressed the EMC problems associated with poorly designed chips, but what's the status on these now? What's the order of preference? Which one's best? - Robert - Robert A. Macy, PEm...@california.com 408 286 3985 fx 408 297 9121 AJM International Electronics Consultants 619 North First St, San Jose, CA 95112 --- 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
Doing high voltage power supplies we found we always got in trouble using 20,000 V/in and things worked well when we kept below 10,000 V/in. Metric that's 790 V/mm and 390 V/mm This was free air and not some kind of pointy structure. - Robert - Robert A. Macy, PEm...@california.com 408 286 3985 fx 408 297 9121 AJM International Electronics Consultants 619 North First St, San Jose, CA 95112 -Original Message- From: Roman, Dan dan.ro...@intel.com To: 'MCA Compliance' bally...@iolfree.ie; Emc-Pstc Post emc-p...@majordomo.ieee.org List-Post: emc-pstc@listserv.ieee.org Date: Friday, March 15, 2002 6:49 AM Subject: RE: creepage v breakdown voltage 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: Don'r Get Caught Running a Red Traffic Light!
Did you take a look at the people who make traffic light controllers? , and the magnetic sensor people? If you can't find something, I'll see what's in archives around here. Know nothing related to your needs, just some of the players' names. Also, you'd be amazed the information you can get from the city engineers regarding this stuff - well at least here in San Jose. - Robert - Robert A. Macy, PEm...@california.com 408 286 3985 fx 408 297 9121 AJM International Electronics Consultants 619 North First St, San Jose, CA 95112 -Original Message- From: Peter Merguerian pmerguer...@itl.co.il To: EMC-PSTC (E-mail) emc-p...@majordomo.ieee.org List-Post: emc-pstc@listserv.ieee.org Date: Wednesday, March 06, 2002 9:18 AM Subject: Don'r Get Caught Running a Red Traffic Light! Dear All, For an outdoor pole-mounted computerized camera taking pictures of your car and its license plates when you run over a red light, does anyone have an objection to the following safety standards for ITE? Is it ok to assume that the mains transient voltage for outddor equipment is limited to 2500V? UL60950:2000] EN60950:2000 IEC60950:2000 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 --- 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: CCFL light output
Recommend you get a copy of Westinghouse Lighting Handbook In one table they show lumens output for various fluorescent lamps with current and volts input required. for the Preheated des.len curr. vol. *pwr lumens *lumens/watt 4W 6 0.132 32 4.32 115 26.6 6W 9 0.147 47 6.91 250 36.2 8W 12 0.170 56 9.56 420 43.9 20W 24 0.380 56 21.321220 57.2 30W 36 0.355 98 34.8 2100 60.3 84W 60 1.530 63 96.4 6250 64.8 for the High Output len*pwr lumens *lumens/watt 24 32.8160048.8 48 60 400053.5 72 90.4645071.3 961328 900068.2 for the Super-Hi, Outdoor, and Low temp-jacketed len*pwr lumens *lumens/watt 48 129 6900 53.5 72 19211100 62.5 96 25815500 60.1 *calculated values Appears to be a nonlinear relationship. Also, Slimline which come in smaller/different diameters have different lumens per watt for the same length. There is another curve rating efficiency (lumens per watt) which ranges from 52 lumens per watt for a natural color lamp to 80 lumens per watt for warm white lamps. But it doesn't say which basic tube is used as a reference. Probably 72inch Is this enough for you to do your modeling? - Robert - Robert A. Macy, PEm...@california.com 408 286 3985 fx 408 297 9121 AJM International Electronics Consultants 619 North First St, San Jose, CA 95112 -Original Message- From: Wani, Vijay (V) vw...@dow.com To: 'emc-p...@majordomo.ieee.org' emc-p...@majordomo.ieee.org List-Post: emc-pstc@listserv.ieee.org Date: Wednesday, February 27, 2002 8:27 AM Subject: CCFL light output Group: I am trying to build a thermal model a cold cathode fluorescent lamp (CCFL) for cooling analysis. CCFL manufacturer showing a chart of light output in Lumens as a function of lamp length and diameter. I need to convert lumens to watts for input into Icepak. I would appreciate any help you can provide. thank you in advance. Vijay Wani --- 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: Use of PCB Traces as Fuse and Voltage suppressor
Jim, You touch on an important issue concerning a fuse - just how does it blow? Years ago I discovered by accident that fuses were designed with some remarkable properties, when we had to make our own transient generator to verify some telcom equipment's compliance to a BABT power supply transient spec. The BABT spec required that you simulate some very husky power transients. It was like a short occurs in adjacent electronics followed by the inductive kick. The -48 voltage would clamp to around 10 volts then pop up to over 300 volts capable of supplying 500A for something like more than 50mS. If you didn't design your protection properly you would have a lot of unintentional PCB trace fuses. [ Actually heard that the spec originated because a workman had dropped his wrench across the 1 inch diameter rods which supply the -48 to the telco building from the battery building. After the wrench evaporated, they found the whole room of equipment was blown, thus the spec. Somebody verify that? ] The simulator used 4 deep discharge current vehicle batteries supplying the telcom equipment through 50uH of inductance (that was cable on a spool). Parallel to that you used a starter solenoid to short out a fuse with a dead short. Amazingly the larger fuses never produced much kick back. They were designed to blow gently away. Tried all kinds. Most of the 8AG didn't do much, other types, nothing, even the 100 amp cartridge types, nothing, The absolute best was a 1A 8AG type. When that went, you'd get a flash of light, 300 volts trying to drive 500 amps into everything, and even the coil would jump up off the floor. Talk about PCB traces acting like fuses. Anyway, I learned a respect for people who design fuses to make them go away so gently when there is an incredible potential for some extremely high voltage transients. - Robert - Robert A. Macy, PEm...@california.com 408 286 3985 fx 408 297 9121 AJM International Electronics Consultants 619 North First St, San Jose, CA 95112 -Original Message- From: Jim Bacher jim.bac...@paxar.com To: 'Cortland Richmond' 72146@compuserve.com; Chris Maxwell chris.maxw...@nettest.com; ieee pstc list emc-p...@ieee.org List-Post: emc-pstc@listserv.ieee.org Date: Monday, February 25, 2002 3:04 PM Subject: RE: Use of PCB Traces as Fuse and Voltage suppressor Long time ago we found that the traces worked well as fuses when the batteries were fully charged. However, when the batteries were mostly discharged, the PC Board traces did not work well as fuses. At lower battery charge levels, the traces became very hot and ignited the PC Board rather than opening the traces up. I therefore would recommend against using PC Board traces as fuses. Jim Jim Bacher, Senior Engineer Paxar Corp. e-mail: jim.bac...@paxar.com or j.bac...@ieee.org voice: 1-937-865-2020 fax: 1-937-865-2048 -Original Message- From: Cortland Richmond [mailto:72146@compuserve.com] Sent: Thursday, February 21, 2002 12:53 AM To: Chris Maxwell; ieee pstc list Subject: RE: Use of PCB Traces as Fuse and Voltage suppressor When do you need a fuse? Level II is the only time you are allowed to lose functionality, and the requirement for THAT is, it can't catch fire or explode. I've seen trace fuses tried. The problem comes after the trace blows. You are at the mercy of your board shop, and if you use a number of them, results might not be all that repeatable. AS i said earlier, I've had a board catch fire in my hand (though not as a result of stress, but a solder splash). It is instructive. Cortland --- 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:
Re: Need Help on Inner PCB plane for RF shielding in isolated circuit
Chris, Using a PCB layer as an RF shield. Don't forget you probably have that PCB layer cut into swiss cheese with vias, unless you used blind vias. Background: A microstrip trace will radiate off the board a certain amount - makes sense since part of its field is out in free space. A stripline should not radiate anything because it is between two ground layers, right? Wrong. A stripline in a practical PCB layout will only drop the emission around 14dB, due to all the swiss cheese that got cut into the PCB. My point is, knowing the above practical information are you sure that an RF shield made by a swiss cheese PCB layer will give you that much shielding? - Robert - Robert A. Macy, PEm...@california.com 408 286 3985 fx 408 297 9121 AJM International Electronics Consultants 619 North First St, San Jose, CA 95112 -Original Message- From: Chris Wells cdwe...@stargate.net To: EMC-PSTC Discussion Group emc-p...@majordomo.ieee.org Date: Thursday, February 21, 2002 5:45 AM Subject: Need Help on Inner PCB plane for RF shielding in isolated circuit Hi - I'm looking for some practical advise on using an inner Printed Circuit Board PCB plane tied at the corner mounting holes of the chassis as a shield from RF exposure coming in on an isolated field circuit relative to another digital logic board. Questions: a.. Must my shield layer be the bottom most inner plane to be effective? Note that the 2 board solder sides face each other. Layout wise it is very difficult to do without going to a 6 layer board - I am trying to stay with 4 if possible. b.. Would I get some capacitive bypass protection if the grounded shield plane where the top inner layer of the field circuit and the isolated field circuit common was the bottom inner plane exposed to the adjacent board? I know the field would not be blocked but the capacitive bypass to the chassis should reduce the RF intensity. c.. Would the placing of the grounded plane between the top PCB components and the Isolated common plane disturb the performance of the field circuitry? What would this do to the field circuit return path loop area? d.. Would a ground pour on the solder side of the adjacent PCB hurt or help? It would increase the capacitance between the two boards but it would reduce the loop area of the traces on the solder side of the adjacent board too. e.. PCB clearance issues within a PCB - What are the clearance/voltage rating issues within a PCB? What voltages can I support from: a.. Surface trace to inner grounded plane - Can 240VAC be supported. b.. Electrically hot via passing through the grounded plane - What inner pad clearance would one use on a 240VAC circuit? f.. What do the safety standards say? - I see that UL3111 version of IEC 61010-1 can treat the PCB as a molded void free material and so the clearance issues are not addressed. I understand that IPC has a spec on voltage ratings versus construction - I am looking for it now. Details: The circuit worked fine at 10V/M but I am now being asked to take this to 35V/M and that is somewhat of a challenge. Testing to ANSI C37.90.2 1995 25-1000 MHz. My problem area is 400-500 Mhz. I am trying to keep RF energy on field circuit from coupling over to an adjacent board and corrupting the bus of some microprocessor based logic. The two boards are only .200 apart. I have experimented with an insulated grounded shield plane placed in-between the two boards and it works great. I can withstand 50V/M WITH 80% modulation!!! Unfortunately the shield is very difficult to make for production and the cost is an issue. I am trying to put the shield into the 4 layer PCB in the area around the field circuit. The solder sides of the two boards face each other. The field circuitry has lots of through hole PCB type components and so there are leads and trace pads that are exposed on the bottom of the field PCB. I have trimmed the leads and this helps some. Even with a 6 layer board and the bottom inner layer as a grounded shield I would have the leads sticking through the shield like holes in cheese. The field circuit construction is: a.. top +5V pour plus a couple traces b.. top inner layer presently free - this is where I would like to put the grounded shield plane. c.. second inner layer (solder side) is the isolated field circuit common, d.. Bottom solder side are a number of field circuit traces. Unfortunately the free plane is not the bottom inner plane but the second from the top component side. The two boards have DC:DC and opto signal isolation on the field board relative to the adjacent logic board. The two boards and are connected at one edge of the board with a
Re: Use of PCB Traces as Fuse and Voltage suppressor
Our experience with gas discharge tubes was that they worked according to spec in the lab. fired perfectly around 400V like they're supposed to, but down inside of the PVC oil tank holding the 150KV isolation transformer they liked to fire at 600V+ Guess they needed photon energy to make the gas trigger or something. - Robert - Robert A. Macy, PEm...@california.com 408 286 3985 fx 408 297 9121 AJM International Electronics Consultants 619 North First St, San Jose, CA 95112 -Original Message- From: Chris Maxwell chris.maxw...@nettest.com To: bogda...@pacbell.net bogda...@pacbell.net Cc: EMC-PSTC Internet Forum emc-p...@majordomo.ieee.org List-Post: emc-pstc@listserv.ieee.org Date: Wednesday, February 20, 2002 2:15 PM Subject: RE: Use of PCB Traces as Fuse and Voltage suppressor Hi Bogdan, I'm sorry if you thought that my previous message was an endorsement for using necked down PCB traces as a fuse. I understand and share the sentiment that it is an unpredictable and probably not even cost effective solution. I was wondering why anyone would shape a PCB trace in such a way (two triangles pointing at each other with a thin trace between the points). A fuse is probably not the likely intention. A reasonable explanation may be a cut jumper. The triangles make the trace visible; while the thin trace provides an easy spot for the trace to be cut with an exacto knife which permanently removes the jumper.Another reason (suggested by a colleage) are alignment marks used by the PCB fab house to help align layers. Just to be sure... I'm not suggesting the above as design ideas. I'm just trying to figure out why anyone would do such a thing. One solution to the original problem that I haven't seen suggested is the good old air discharge tube, gas-discharge tube, gas tube ...whatever you want to call them. Of course, they aren't free (about $1 each). They are more predictable than open air terminals, they are UL/CSA recognized and they can handle some massive breakdown currents. They are available from Bourns and Sankosha USA... probably some other manufacturers as well. Chris -Original Message- From: bogdan matoga [SMTP:bogda...@pacbell.net] Sent: Wednesday, February 20, 2002 4:19 PM To: gab...@simex.ca; Chris Maxwell; emc-p...@mahordomo.ieee.org Subject: Use of PCB Traces as Fuse and Voltage suppressor Gabi: I believe that there is a basic rule which is not published anywhere: when you design something, then do it right. When transient suppressors are needed, then use the correct component, which will not depend on Paschen's Law and give predictable performance. Same for necked down fuses. When you want performance, then do it right. The above original suggestions are perfect for Mickey-Mouse-engineering. Bogdan. --- 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: CM Choke simulation
Derek, Yes, do it all the time. As long as you don't get into saturating any cores, you can pretty much use lumped models and none of the nonlinearities associated with core material. Don't forget to include your AC mains cable. It's a trifilar wound transformer. A Belden AC cord looks like a 3 winding transformer with 7uH core. You can also model the LISN and the parasitic capacitance in your test setup. Very educational. Why do you ask? - Robert - -Original Message- From: lfresea...@aol.com lfresea...@aol.com To: emc-p...@majordomo.ieee.org emc-p...@majordomo.ieee.org Date: Friday, February 15, 2002 1:42 PM Subject: CM Choke simulation Hi all, I'm trying to model a common mode choke in Micro-sim. Has anyone tried this? Failing that, any suggestion on how to model one in Spice, possibly using magnetic models? Thanks in advance. Derek. --- 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: Clean class B test bed
Tony, When we had to test a 100MHz video two board system, weaknesses in grounding structures of the PC's became extremely evident. Two stood out as the best (best internal motherboard grounding) Gateway (best) and Dell (very close 2nd best). No other PC's yielded a compliant system. [ Even had to fuss with the grounding plates on the back.] Sorry, don't know model numbers, but they were large with the proportions of the old rack mount types. - Robert - Robert A. Macy, PEm...@california.com 408 286 3985 fx 408 297 9121 AJM International Electronics Consultants 619 North First St, San Jose, CA 95112 -Original Message- From: Tony raym...@bellsouth.net To: emc-p...@ieee.org emc-p...@ieee.org Date: Friday, February 08, 2002 11:42 AM Subject: Clean class B test bed Hello, I am looking to find a clean Class B test bed (PC) for radiated emission testing. If anyone knows of such a thing please post the manufacturer, model number, any other information I would need to acquire one for use here. Thanks for the help. Tony Rayman
Re: Teslars???
That's Tesla, which is a weber per sq meter. It is a measure of the B field, flux per area. If you're English, 1 tesla is 10,000 gauss. I don't believe those numbers. We have light rail train go by here which is powered by 600Vac (I believe it's 600 Vac) I haven't seen the fields from the motors, only the fields from the disturbance to the earth's field (approx 50uT) as it is being deflected by the large metal vehicles. Much more an effect than from the power source. If those specs you quoted go down to 50 Hz or 60Hz, than they relate, otherwise doubt if you'lll easily relate them. It would be susceptibility to AC mains magnetic fields. Might also look at the Swedish MPR II, or is that III now? The limit for a monitor radiating is 200nT in this bandwidth. Underneath high tension wires I've seen fields around 100mG, which translates to 10uT! and those fields are considered big. Again, I question those specs. Maybe they meant 0.6 to 1.7 microtesla. - Robert - Robert A. Macy, PEm...@california.com 408 286 3985 fx 408 297 9121 AJM International Electronics Consultants 619 North First St, San Jose, CA 95112 -Original Message- From: marti...@appliedbiosystems.com marti...@appliedbiosystems.com To: emc-p...@majordomo.ieee.org emc-p...@majordomo.ieee.org List-Post: emc-pstc@listserv.ieee.org Date: Thursday, February 07, 2002 3:15 PM Subject: Teslars??? We have a customer that is concerned about how our product, laboratory equipment, will respond to electromagnetic disturbances from a high speed train that runs close to their lab. The customer states that the disturbance will be around 0.7-1.2 m Teslar. Can someone please explain what the unit Teslar is and how that unit relates, or if it relates, to the immunity tests of EN 61000-4-3 Radiated immunity, or any other immunity test. Has anyone ever had a similar concern from a customer dealing with this type of disturbance? Your responses are appreciated. Regards Joe Martin EMC/Product Safety Engineer Applied Biosystems marti...@appliedbiosystems.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: 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: Safety Link Offers Classifed Ads to EMC-PSTC members (no-charge)
Agree, worthwhile. All the newspaper articles in the Career section of the newspapers say that after being laid off to take off a few weeks, gain bearings, then look for your new position. I totally disagree. I say take 20 minutes, shake your head, and go for new places as agressively and thoroughly as if looking for a position were the new job. Usually, there are severance packages that allow for the following gap in income. Any reduction in that gap is free money. Also, you maintain the mental advantage of not needing the new position so you'll just have a different attitude while you're looking, one of more power. Years ago when I was hiring people, I always was more impressed with the person who hits the pavement the next day, even better, the same day. That makes them look like a self starter, agressive, *and* someone who actually likes to work, wants to be back at work. Just my two cents here. - Robert - Robert A. Macy, PEm...@california.com 408 286 3985 fx 408 297 9121 AJM International Electronics Consultants 619 North First St, San Jose, CA 95112 -Original Message- From: Cortland Richmond 72146@compuserve.com To: Art Michael amich...@connix.com; ieee pstc list emc-p...@ieee.org List-Post: emc-pstc@listserv.ieee.org Date: Tuesday, February 05, 2002 10:52 AM Subject: Re: Safety Link Offers Classifed Ads to EMC-PSTC members (no-charge) Art, What a nice thing to do! I am just getting ready to pick up my stuff from the office, and then ... Why wait for the outplacement firm? Forward momentum! Cortland (I cannot speak for Alcatel They cannot speak for me; OF all that we might choose to say, The other now is free!) --- 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: Harmonics measurement instrumentation
Hmmm...measured with a current meter, then measured with a wattmeter and got different answersHarmonics out of phase? contain no power? - Robert - Robert A. Macy, PEm...@california.com 408 286 3985 fx 408 297 9121 AJM International Electronics Consultants 619 North First St, San Jose, CA 95112 -Original Message- From: gunter_j_ma...@embraco.com.br gunter_j_ma...@embraco.com.br To: emc-p...@majordomo.ieee.org emc-p...@majordomo.ieee.org List-Post: emc-pstc@listserv.ieee.org Date: Tuesday, January 22, 2002 11:56 AM Subject: Harmonics measurement instrumentation List I would like your precious opinion about a situation regarding harmonic current measurement (61000-3-2). First case: Using a sinusoidal AC power source, with a controlled output voltage (almost perfect sine, voltage THD lower than the needed, even with load), I measured the current harmonics using the internal instrument of the power source. The 13th and 15th harmonics were right above the limits (Class A limits). Second case: I add a digital wattimeter to measure the harmonics. The harmonic content became 30% lower than the first case (good enough to pass). And I got this results with the two instruments (the one inside the power source, and the wattimeter). My first thought was the increased impedance due to the wattimeter (Zm). But I got 50mV of drop voltage in this instrument (peak voltage), that is lower than the specified in 61000-3-2, Annex B (0,15Vpeak maximum). And the impedance of its current shunt is only 0,008 ohms (data from its manual). This put my first guess down ! Theoretically, the wattimeter couldn't attenuate so much the harmonics ! Any idea of what could be happening ? Thank you again. Günter J. Maass Researcher - Power Electronics Development EMBRACO S.A. --- 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. --- 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: radar
I'm going to say British pass on the left because the jousting pole is usually held by right handers. Sailors pass on the right, yet don't know the origin of that. Maybe the sailing tradition started a propensity to pass on the right for colonists. Automobiles in the US are made so the driver can easily use his right hand to operate a stick shift, which was mounted down the center of the automobile on the transmission system. - Robert - -Original Message- From: Andrew Wood andrew.w...@landinst.com To: 'douglas_beckw...@mitel.com' douglas_beckw...@mitel.com Cc: 'emc-pstc' emc-p...@ieee.org List-Post: emc-pstc@listserv.ieee.org Date: Friday, January 11, 2002 1:38 AM Subject: RE: radar I don't know whether it is true or not, but I recall hearing this some time ago The convention of passing to the left on a road dates back to the days of riding horse back and was related to the normal position for wearing a sword or pistol. The first motor carriages had the driver sat centrally but kept to the same convention. What I don't recall is the final piece of the story ie why most of the non British Commonwealth nations decided to go the other way. Andy. From: Douglas Beckwith@MITEL on 01/10/2002 11:17 AM Aha, a man after my own heart. Now you are talking about real cars. As an ex South African living in Canada, I still can't get used to the idea of driving on the the wrong side of the road. Doug Beckwith Veit, Andy andy.v...@mts.com on 01/10/2002 08:29:14 AM Please respond to Veit, Andy andy.v...@mts.com To: emc-p...@majordomo.ieee.org cc:(bcc: Douglas Beckwith/Kan/Mitel) Subject: RE: radar Why would someone want to take a car out of UK with the steering wheel on the wrong side? I can think of at least one good reason to take a RHD car out of the UK - its called the Lotus Super 7. There, its out in the open now. I am a British car nut. :) Rerards, Andrew Veit Systems Design Engineer MTS Systems Corp 1001 Sheldon Drive Cary, NC 27513 -Original Message- From: John Woodgate [mailto:j...@jmwa.demon.co.uk] Sent: Wednesday, January 09, 2002 3:35 PM To: emc-p...@majordomo.ieee.org Subject: Re: radar I read in !emc-pstc that John Shinn john.sh...@sanmina.com wrote (in 001f01c1992f$09f5c960$0b3d1...@hadco.comsanmina.com) about 'radar', on Wed, 9 Jan 2002: Why would someone want to take a car out of UK with the steering wheel on the wrong side? There are actually more *countries* where you drive on the left. Not more RHD cars, though. (No, I don't have the list of RHD countries, but it's on the web somewhere - everything is!) Besides, it is *undeniable* that a British car has the steering wheel on the right side. -- Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk After swimming across the Hellespont, I felt like a Hero. --- 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. --- 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. This e-mail and its contents may be confidential, privileged and protected by law. Access is only authorised by the intended recipient. The contents of this e-mail may not be disclosed to, or used by, anyone other than the intended recipient, or stored or copied in any medium. If you are not the intended recipient, please advise the sender immediately. --- This message is from the IEEE EMC Society
Re: Magnetic measurement per CISPR 15
It is my understanding that the conversion factor converts the voltage reading on a 50 ohm receiver to the amperage reading directly. In other words, 1dbuV *is* 1dBuA and already takes into account the 50 ohm input impedance. Sadly, all this was written before advancements in electronics occured. For example, I designed and built a small portable magnetic preamp I use for measuring magnetic fields. It has a 4 inch diameter air core coil, produces 1 V per microTesla over the frequency range of 5 Hz to 1 MHz with a noise floor of around 5 nT (the noise coefficient is dropping as a function of frequency and integrates over the bandwidth) so most of the noise energy is around the 5 to 100 Hz range. It was originally designed to address the Swedish MPRII rules. - Robert - Robert A. Macy, PEm...@california.com 408 286 3985 fx 408 297 9121 AJM International Electronics Consultants 619 North First St, San Jose, CA 95112 -Original Message- From: KC CHAN [PDD] kcc...@hkpc.org To: emc-p...@majordomo.ieee.org emc-p...@majordomo.ieee.org List-Post: emc-pstc@listserv.ieee.org Date: Friday, January 04, 2002 8:57 PM Subject: Magnetic measurement per CISPR 15 Hi all I got a question about the magnetic measurement per CISPR 15, it says that the sensitivity of the current probe is 1V/A. My interpretation is that X dBuV measurement you got from the EMI receiver, corresponding to XdBuA, which is then compared to the limit, say 88dBuA at 50 kHz for 2-m 3-loop system. The manual I have says the same thing. Is it correct? My question is 1) Do we need to covert the voltage to current taking consideration of the 50 Ohm impedance of the receiver? If that is the case, we need to minus 34 dB from my voltage measurement to get the current measurement . 2) In what ways the whole system has considered the impedance variation of the current probe impedance. I have checked the impedance of the current probe, the impedance is ranging from 40+ Ohm at 10kHz to 150+ Ohm at around 150K and decreases to around 75 Ohm at 1 MHZ. Thank you KC Chan --- 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: EMC-related safety issues
Perhaps, it merely interfered with the sensor electronics, not the true magnetic field that was being sensed. - Robert - Robert A. Macy, PEm...@california.com 408 286 3985 fx 408 297 9121 AJM International Electronics Consultants 619 North First St, San Jose, CA 95112 -Original Message- From: Pettit, Ghery ghery.pet...@intel.com To: 'James Collum' james.col...@usa.alcatel.com; emc-p...@majordomo.ieee.org emc-p...@majordomo.ieee.org Date: Thursday, January 03, 2002 11:46 AM Subject: RE: EMC-related safety issues I still have a hard time believing it was a compass that was affected by a laptop computer. ADF indication, could be. VOR, maybe. Magnetic compass? I wouldn't want a magnetic source that strong in my lap! My belt buckle would be stuck to it. There is quite a distance between a magnetic compass in the cockpit of an airliner and anything a passenger is carrying. Not so in a Cessna 172, but in a DC-10? Ghery Pettit -Original Message- From: James Collum [mailto:james.col...@usa.alcatel.com] Sent: Thursday, January 03, 2002 10:47 AM To: emc-p...@majordomo.ieee.org Subject: Re: EMC-related safety issues * A routine flight over Dallas-Fort Worth was disrupted when one of the compasses suddenly shifted 10 degrees to the right. The pilot asked if any passenger was operating an electronic device, and finding that a laptop computer had just been turned on requested that it be turned off, whereupon the compass returned to normal. Following RTCA guidelines the pilot requested that the laptop be turned on again 10 minutes later, when the compass error returned. Ref: Compliance Engineering (European edition) Nov/Dec 1996 p12 * I am fascinated by this amazing story (which must surely be an urban myth) and went in search of more info on the internet. I had never heard of the RTCA ( a private corporation) before, but noticed via their web site that you have to be a member company (i.e. pay) to receive the wisdom that it contains. Aviation is merely a hobby of mine but I'm interested in reading a copy of the RTCA's DO-233/214 and 196 documents without shelling out hundreds for the privilege, can anyone advise? Also does anyone know what recommendations have they made to modifying FAR 91.21 (as per their web site). In reading this again, I'm curious as to how the pilot would have known about a private companies convoluted guideline for fault finding on errant radio direction equipment involving locating industrious passengers and commandeering their computers at 10 minute intervals. Surely he would have done what any professional engineer would do, beat or kick the 10 degree error out of the RDF equipment? Or maybe just wonder to him/herself about how strange things happen in the Dallas Fort Worth area? Tounge in cheek, my comments and not those of my employer etc. Jim --- 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: EMC-related safety issues
Great, Now we have to start adding information on the sales brochure, like As the purchaser of this product places this product into service said purchase is forming a licensed arrangement with the vendor to not hold said vendor culpable for all uses and potential misuses of this product You get the drift, just copy the MS licensing language on all software. - Robert - Robert A. Macy, PEm...@california.com 408 286 3985 fx 408 297 9121 AJM International Electronics Consultants 619 North First St, San Jose, CA 95112 -Original Message- From: Gary McInturff gary.mcintu...@worldwidepackets.com To: Ken Javor ken.ja...@emccompliance.com; cherryclo...@aol.com cherryclo...@aol.com; emc-p...@majordomo.ieee.org emc-p...@majordomo.ieee.org Date: Wednesday, January 02, 2002 2:38 PM Subject: RE: EMC-related safety issues Did the camera have proximal cause to the event that befell the child, well not unless it fell of of the ceiling or the tripod fell over and hit the infant, or the camera overheated and started a fire. Other than that the Lawyers need to dig their heads out - juries as well. They are just trying to chase the money. Cameras don't cause disease likes SIDS. They don't cause buildings to collapse, or burglaries or whatever else might befall the baby They are just a convenience. If they an additional input path to the parents may stop, but the actual monitoring (or the failure of monitoring) neither helped or hindered the health of the child. The camera manufacturer, even if this is sold as a baby monitor, I can't see how holding the camera manufacturer responsible can even be considered, except that it gives the lawyers somebody to sue with some money. I suppose it might give the parents a misplaced sense of (and I hate this word) closure because they can blame some body, rather than just life, fate, or whatever. I don't doubt your statement that somebody is trying to hold the manufacturer responsible, I just point out that it is asinine and in my opinion inexcusable to do so. Recorded history doesn't show a huge plethora of infant deaths because parents weren't able to have a video camera in the room. Gary -Original Message- From: Ken Javor [mailto:ken.ja...@emccompliance.com] Sent: Wednesday, January 02, 2002 11:22 AM To: cherryclo...@aol.com; emc-p...@majordomo.ieee.org Subject: Re: EMC-related safety issues I have read a part of the IEE guide mentioned below. What I have read on a paragraph by paragraph basis is fine, but I find the overall philosophy deeply troubling. The tone of the document is that the manufacturer is responsible for all uses or misuse of the equipment he sells in concert with every other type of equipment made or that might be made at some time in the future. This document is a trial lawyer's dream. It takes us from a society in which a sale was deemed a transaction of mutual benefit between equals to a society in which an Omniscient Producer must cater to the needs of an ignorant, childlike Consumer, and in direct corollary, any misuse of any product by any consumer is deemed proof that the Omniscient Producer was profiting by taking advantage of a helpless victim. I realize this document merely reflects this prevalent view, but the idea that an Industry group would provide such a smoking gun for some trial lawyer to use in defense of some poor misled swindled consumer is, to say the least, troubling. To say that Industry standards don't go far enough, that it is the responsibility of the Producer to be able to determine all possible environments and failure modes that might ever occur is placing an impossible burden and any rationale entity, upon reading this document will immediately cease production of anything that could conceivably ever malfunction in anyway whatsoever. Case in point: A friend of mine bought one of these 2.4 GHz remote miniature video cameras with integral IREDs and is able to monitor his infant twins from his own bedroom, even in the middle of the night with no lights on in the twins' bedroom. Suppose that 2.4 GHz link is disturbed in some way and he misses something important happening in that bedroom. Is the manufacturer of that video system responsible for any ill that then befalls my friend's twins? I think not. But this safety guide says yes, and places the manufacturer at risk. -- From: cherryclo...@aol.com To: emc-p...@majordomo.ieee.org Subject: Re: EMC-related safety issues Date: Wed, Jan 2, 2002, 9:49 AM Once again, John, you seem to be trying to give a negative impression about the IEE's guide on EMC and Functional Safety (which you now admit you haven't
Fw: question on emc and networks
I offered to forward this to the emc group for help. Please answer directly. - Robert - Robert A. Macy, PEm...@california.com 408 286 3985 fx 408 297 9121 AJM International Electronics Consultants 619 North First St, San Jose, CA 95112 -Original Message- From: Dieguito diegu...@gmx.net List-Post: emc-pstc@listserv.ieee.org Date: Saturday, December 29, 2001 8:04 AM Subject: question on emc and networks Hi there, I've got this assignment to make for school and I realy don't know where to begin: I have to find what standards a network has to be compliant with, concerning emc levels. So is there anyone who knows what stardards I need and where I can find them, because on iso.org, they ask a lot of money (if just for a silly assignment). And is there someone who knows where to find emc specs on networkcables, hubs, etc.? All concerning emc of course. Or does someone knows a better newsgroup to ask for this? (please let me also know the server, I'm now on pandora (belgium)). Thanks a lot and a happy newyear to all. Dieguito --- 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: Field Strength - Substitution Method
Hear, hear. It may have been hand waving but I always assumed that test sites never correlated very well (although their calibration curves do) because the actual radiators one is measuring are strange and not well controlled impedances like an antenna. The sources can be low or high impedance and each act completely differently than one expects. With that in mind, I don't see how it is possible to substitute a controlled antenna, measure the power going to it, and predict anything to the original - within plus or minus 12 dB. Just opinion here and experience fighting battles at test sites. - Robert - Robert A. Macy, PEm...@california.com 408 286 3985 fx 408 297 9121 AJM International Electronics Consultants 619 North First St, San Jose, CA 95112 -Original Message- From: Cortland Richmond 72146@compuserve.com To: Sam Wismer swis...@bellsouth.net; ieee pstc list emc-p...@ieee.org List-Post: emc-pstc@listserv.ieee.org Date: Thursday, December 27, 2001 10:12 AM Subject: Re: Field Strength - Substitution Method Sam, I think you did it right with one AF and one gain. There's a problem with that method. You need more information needed to make the _results_ right. Given a certain power at the antenna terminal, and a known gain and efficiency, you can calculate the free-space field strength at some distance due to RF applied to that antenna. Then you add loss or gain due to reflection from the ground plane. This gets you down to some fairly reliable way to estimate what field strength will be created over a ground plane at some distance from an antenna. What you don't have -- and what, I think, is most difficult -- is a model that reliably correlates a substitution antenna as a source with the equipment under test. A rack seven feet tall and two feet on a side -- with wires overhead and off to its sides -- will NOT radiate the same as a dipole. And it will differ more from an antenna as its dimensions become larger than the antenna. I would expect differences to become more pronounced, in other words, at higher frequencies. This is what you saw. Cortland (my own opinion and not that of my employers) --- 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: Non-compliant product put into EU marked
Wow! I've been telling clients that even a Beta test is allowed, as long as absolutely no revenue is derived from it. Can't sell it. Can't rent it. With no revenue, it is an exhibition, a test. Is this wrong? - Robert - Robert A. Macy, PEm...@california.com 408 286 3985 fx 408 297 9121 AJM International Electronics Consultants 619 North First St, San Jose, CA 95112 -Original Message- From: Massey, Doug C. masse...@ems-t.com To: IEEE - PSTC FORUM (E-mail) emc-p...@majordomo.ieee.org List-Post: emc-pstc@listserv.ieee.org Date: Thursday, December 27, 2001 6:20 AM Subject: RE: Non-compliant product put into EU marked Article 8.2 of the RTTED (1999/5/EC) allows exemptions for .. trade fairs, exhibitions, demonstrations, etc.. It also requires that a visible sign clearly indicates that such apparatus may not be marketed or put into service until it has been made to comply. Beta testing at a customer site does not fall under the Art. 8.2 exemptions. A sales team demonstrating the product to a customer could be exempt for the period of their demonstration. However, you can't call a large scale Beta test a demonstration - the Beta test is 'putting into service'. IMHO, it's in clear violation of the RTTED. Doug Massey Lead Regulatory Engineer LXE, Inc. -Original Message- From: am...@westin-emission.no [mailto:am...@westin-emission.no] Sent: Monday, December 17, 2001 5:05 PM To: emc-p...@majordomo.ieee.org Subject: SV: Non-compliant product put into EU marked As far as I know the product shall be produced in a large scale. The reason for putting it on the marked for a time limiting period is (again as far as I know) to run the product ( beta version) in a test installation and thereafter will it go through the entire test program (EMC, LVD, etc). It seems that they did not manage to do the testing before the 1 month test period on the field. Again, I feel they are not doing things in the consecutive order and I also think they are no allowed to put in on the marked, even the short period. Amund -Opprinnelig melding- Fra: Tania Grant [mailto:taniagr...@msn.com] Sendt: 17. desember 2001 19:33 Til: am...@westin-emission.no; emc-p...@majordomo.ieee.org Emne: Re: Non-compliant product put into EU marked Is the manufacturer serious, or completely ignorant? If serious, I would disassociate from them as much as possible. If merely ignorant, and you have some sort of association with them, I would recommend that you educate them fully. Another thought, -- is this product slated for mass distribution, even for only a month, or is it going to another location or a particular customer for some special in-house use or application? What does this customer think? Are they aware, and do they agree to this? The Directives do have special provisions for certain special applications where non-compliant (or is it merely untested !) product can be shipped to Europe, but I believe that under those circumstances, the name of the manufacturer and product model name or designation has to be published broadly in the EU. I don't remember the details. If anyone can shed more light, that would be very nice. taniagr...@msn.com - Original Message - From: am...@westin-emission.no To: emc-p...@majordomo.ieee.org Sent: Sunday, December 16, 2001 2:06 PM Subject: Non-compliant product put into EU marked Hi all, You place a radio product into the EU marked with the following status: - Not been EMC, radio or safety tested (the previous model was tested and compliant, major modifications have later been implemented) - The product will only be in the marked for a time limiting period ( 1 month) - During the time limiting period it will be operating as in a normal condition - No CE mark on the product and no DoC I mean that you can't do this. You have to confirm that you fulfil the EMC, radio and safety requirements, DoC in place, even that the product just will be in the marked for 1 month and thereafter withdrawal. Any other comments from the list members ? Best regards Amund Westin, Oslo/Norway --- 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: noise figure
NoiseFigure new
= sqrt ( ( NF1^2 - 1 ) + ( NF2^2 - 1 ) + ( NF3^2 - 1 ) + ... + 1 )
where all noise figures are ratios and referenced to a
single location.
A few points:
1 Definition:
Noise Figure is the ratio of increased noise in a system above the expected
level of Johnson noise. For our 50 ohm system that will give a voltage of
sqrt(4KTRBw) where K is Boltzmann's constant, T is temperature in absolute
Kelvin, R is the resistance of the system (for our case 25 ohms {50 ohms in
parallel with 50 ohms}), and Bw is the bandwidth of interest in Hertz. For
a Bw of 1 MHz that yields a noise floor of around 0.641uV, or -3.9dBuV
2 Relate noise figure to some place in your system.
For simplicity (and ease of using specs) relate to the front end Noise
figure specs relate to the front end of a system block. The noise is
amplified, or attenuated, along with the signal and therefore track
together. As you go from the output to the input of each system block, gain
subtracts from the NF and attenuation adds to the NF. Modify the Noise
Figure by each block you must go through to get to the input. For example,
through cable loss, add the few dB. For gain, subtract the gain.
3 Make up a list (Use Excell spread sheets) You will end up with
contributions from every block now referenced to the front end. then...
4 Remember that uncorrelated noise does not add, but adds as the square
root of the sum of squares. However! you must only take into consideration
the noise contribution from each additional noise source. You cannot keep
adding in the contribution from the 50 ohm source impedance. Therefore,
each Noise Figure ratio must be squared and then have 1 subtracted from it.
After combining all the contributions, you will add the 1 back. Simply take
the square root of that total sum and find the 20log value and you will have
your total system's new NoiseFigure.
For example, let's find the noise figure for a receiving system that
attaches to an antenna consisting of long cable, amp, cable, and spectrum
analyzer (SA).
Passive devices have 0 dB noise figure (they do not add any noise)
Antenna is passive, but converts volts per meter into volts in a 50 ohm
system. Since it does not add any noise, there is no difference between
minimizing the NF at the antenna port or at the field that it measures.
So let's find out the NF of our system at 200MHz
long cable 3dB attenuation
amp24dB 6 dB NF
cable -
SA 32dB
Note: You could have a perfect receiver that contributes no noise located
after the long cable and you would still have a 3 dB NF That's why
amplifiers are placed near the signal source.
Check your particular SA. It can have a Noise Figure from 26dB to 36dB
depending on its design. That means for a 1 MHz bandwidth you can only see
down to around -80dBm.
So let's move the amplifier out to the antenna and change the order of the
list:
cable -
amp gain 24dB with NF = 6 dB
long cable atten 3dB
SA with NF = 32dB
The list would show 6 dB NF at the input and (32-24+3=11) 11dB from the SA.
That is a ratio of 2 and a ratio of 3.55.
New Noise Figure is sqrt( (2^2-1) + (3.55^2-1) + 1 ) = 4 or 12dB
See how the SA still dominates?
To rewrite the equation:
NoiseFigure new
= sqrt ( ( NF1^2 - 1 ) + ( NF2^2 - 1 ) + ( NF3^2 - 1 ) + ... +
1 )
where all noise figures are ratios and referenced to a
single location.
- Robert -
Robert A. Macy, PEm...@california.com
408 286 3985 fx 408 297 9121
AJM International Electronics Consultants
619 North First St, San Jose, CA 95112
-Original Message-
From: KC CHAN [PDD] kcc...@hkpc.org
To: emc-p...@majordomo.ieee.org emc-p...@majordomo.ieee.org
List-Post: emc-pstc@listserv.ieee.org
Date: Friday, December 21, 2001 5:46 PM
Subject: noise figure
Hi all
It may not be purely EMC question, actually it is RF related, but I am sure
the experts here can answer my questions.
We all know that we need to have a pre-amp. that is as lower noise figure
as possible, but how low it is enough or how it is related to the noise
floor viewed by a receiver or spectrum analyzer.
Thank you
KC Chan
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Re: High Frequency Pre-amp
Just a reminderalways make certain that no signal gets in to saturate, or even start to overdrive, your amplifier at frequencies you're not looking at. - Robert - Robert A. Macy, PEm...@california.com 408 286 3985 fx 408 297 9121 AJM International Electronics Consultants 619 North First St, San Jose, CA 95112 -Original Message- From: Ken Javor ken.ja...@emccompliance.com To: rehel...@mmm.com rehel...@mmm.com; emc-p...@majordomo.ieee.org emc-p...@majordomo.ieee.org List-Post: emc-pstc@listserv.ieee.org Date: Friday, December 21, 2001 11:42 AM Subject: Re: High Frequency Pre-amp MITEQ and Mini-Circuits come to mind for octave and multi-octave band amps. HP (Agilent) makes the the 8348A covering 1 - 26.5 GHz around $14 K. The HP model has a 10 dB noise figure and 25 dB gain below 20 GHz. With MITEQ you can pick your noise figure and gain from a large variety of models. Mini-Circuits is the low price leader, I saw amps up to 8 GHz but you would need several models and the price will still likely be less than with the others. If you are using an HP8566 or similar model which uses harmonic mixing above 2 GHz then you need enough gain to push the signal above the degraded noise floor. -- From: rehel...@mmm.com To: emc-p...@majordomo.ieee.org Subject: High Frequency Pre-amp Date: Fri, Dec 21, 2001, 10:16 AM This question may have recently posted but I'm not able to search the archives so I'll ask again. We have an immediate need for a pre-amp above 1000 MHz. Would you be so kind as to let me know what brands/models and frequency range you are using. Any pro/con insights would be welcome as well. Please contact me on or off-line. Thanks, Bob Heller 3M Product Safety, 76-1-01 St. Paul, MN 55107-1208 Tel: 651- 778-6336 Fax: 651-778-6252 --- 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. --- 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: power supply to GOST 30429-96
Low frequency conducted noise is usually generated by the periodic demand on the energy storage cap (greatly, greatly affected by esr). This noise is differential and no y-cap (unless it's so large it becomes a killer size, and then not really) will stomp on it. Your first problem (conducted emissions) is trying to get rid of the fundamental of the power supply which can be a bit challenging. You see, the y-caps are low impedance *AND* your noise source is low impedance, so adding y-caps is not going to short out that noise source. The best way to solve your problem is is to use minimum esr caps and, of course, very judicious layout inside the supply. There are external things you can do, but they can get bulky. How much power does this supply take? Do you have control over the manufacturing process at all? Once you've tackled the conducted emissions, we can move on to the radiated emissions. - Robert - Robert A. Macy, PEm...@california.com 408 286 3985 fx 408 297 9121 AJM International Electronics Consultants 619 North First St, San Jose, CA 95112 -Original Message- From: Lou Guerin lgue...@littlefeet-inc.com To: emc-p...@majordomo.ieee.org emc-p...@majordomo.ieee.org List-Post: emc-pstc@listserv.ieee.org Date: Friday, December 21, 2001 10:49 AM Subject: power supply to GOST 30429-96 Dear Fellow EMC workers, I am trying to get a SMPS to pass this GOST standard and am having a devil of a time getting it done. After 3 days of mitigation testing at our local lab we are still out at the low frequency range 10-60kHz and at 15-50MHz. We pass the Class A limits for CISPR 22 but these GOST limits are far more stringent. The power supply is convection cooled in a IP66 box that is powering a repeater. We have been able to determine that the noise is being generated by the power supply and thus far we are not able to suppress all the low frequency and high frequency conducted noise. I have copied the limit requirements below for your review. Has anyone run into this standard before? Is there something we may be overlooking? We are not using a custom supply, this is an off the shelf supply that we are packaging into a IP66 box. The usual fixes didn't seem to work, X and/or Y caps, ferrite beads, inductor. These were applied liberally during the past 3 days. The requirements for EMC of radio equipment in Russia (as well as in several other CIS countries) are set by the standard GOST 30429-96 (Electromagnetic Compatibility of technical equipment. Man-made noise from equipment and apparatus used t6ogether with service receiver systems of civil application. Limits and test methods), according to this standard the following measurement must be done. 1. Conducted Emissions Frequency range Limits, dB(uV) 0.009 MHz - 0.15 MHz U = 90 - 28.9lg(f/0,01) (Quasi-peak) 0.15 MHz - 0.5 MHz U = 66 - 22.7lg(f/0,15) (Quasi-peak) 0.5 MHz - 6 MHz U = 54 - 12.97lg(f/0,5) (Quasi-peak) 6 MHz - 30 MHzU = 40 (Quasi-peak) 30 MHz - 100 MHzU = 48 (Quasi-peak) 40 (Average) This test is done looking at the emissions from the 220 V power cables, using a LISN 2. Radiated Emissions Frequency range Limits, dB(uV/m) 0.01 MHz - 0.15 MHzE = 60 - 20.4lg(f/0.01) 0.15 MHz - 30 MHz E = 37 - 7.39lg(f/0.15) 30 MHz - 100 MHzE = 36 - 21.0lg(f/0.30) 100 MHz - 1000 MHzE = 25 + 20.0lg(f/100) According to GOST 30429-96 this test is done at 3 meters in frequency range 0.01MHz - 30 MHz and at 1 meter in frequency range 30 MHz - 1000 MHz in the screen room. Any help will be eagerly accepted. Best regards and happy holidays, Lou Guerin Agency Approvals Manager Littlefeet, Inc. lgue...@littlefeet-inc.com mailto:lgue...@littlefeet-inc.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: RE:RJ45 filtered connector
Did you see Regal Electronics? They make filtered RJ45 connectors If not, try Regal Electronics 408 988 2288 4251 Burton Dr Santa Clara, CA 95054 might have a website around www.regalusa.com A technical contact is Bill Kunz - Robert - Robert A. Macy, PEm...@california.com 408 286 3985 fx 408 297 9121 AJM International Electronics Consultants 619 North First St, San Jose, CA 95112 -Original Message- From: Reginald Henry rhe...@vicon-cctv.com To: emc-p...@majordomo.ieee.org emc-p...@majordomo.ieee.org List-Post: emc-pstc@listserv.ieee.org Date: Thursday, December 20, 2001 11:25 AM Subject: RE:RJ45 filtered connector To All, Can anyone out there tell me where I would be able to purchase a fully shielded and filter RJ45 connector that is Bulkhead mountable. The RJ45 must be able to handle data rates from 10Base T to 100Base T I will be performing CE testing in the chamber so it must be bulkhead mountable ! Thanks and Happy Holidays to YOU ALL ! Reg --- 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: Power station equipment
Nick, Contact this man, he has a lot of experience in the technical aspects of the power distribution business. Don Kelly d...@home.com - Robert - Robert A. Macy, PEm...@california.com 408 286 3985 fx 408 297 9121 AJM International Electronics Consultants 619 North First St, San Jose, CA 95112 -Original Message- From: Nick Williams nick.willi...@conformance.co.uk To: emc-p...@majordomo.ieee.org emc-p...@majordomo.ieee.org List-Post: emc-pstc@listserv.ieee.org Date: Wednesday, December 19, 2001 5:12 AM Subject: Power station equipment Can anyone tell me what the likely certification requirements for equipment intended for use in the power generation/distribution industry in Califiornia will be? I think I'm reasonably up to speed with what the NEC and OSHA have to say, but some practical guidance based on experience would be rather welcome. I'm not at liberty to divulge much detail about the product in an open forum, but the equipment I am concerned with is heavy current generation equipment, not instrumentation. Regards Nick. --- 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: Sometimes product safety just isn't enough
AR!! I went there, read down through much, before it soaked in. - Robert - -Original Message- From: Pettit, Ghery ghery.pet...@intel.com To: 'Robert Macy' m...@california.com; James Collum james.col...@usa.alcatel.com; emc-p...@majordomo.ieee.org emc-p...@majordomo.ieee.org List-Post: emc-pstc@listserv.ieee.org Date: Friday, December 14, 2001 4:15 PM Subject: RE: Sometimes product safety just isn't enough Now, you do need to worry about some of these obscure chemicals. There is an entire web page devoted to the hazards of DHMO, di-Hydrogen Monoxide. www.dhmo.org Check this out. It could save someone you love. Ghery Pettit Intel -Original Message- From: Robert Macy [mailto:m...@california.com] Sent: Friday, December 14, 2001 1:39 PM To: James Collum; emc-p...@majordomo.ieee.org Subject: Re: Sometimes product safety just isn't enough In deference to the warning label on the peanuts bag. Some people have life threatening allergies to peanuts and take warnings such as that and warnings on cookies, etc very seriously. But then again, you'd think with the main label Peanuts would be sufficient. Perhaps, someone is making peanuts out of soy beans already. - Robert - Robert A. Macy, PEm...@california.com 408 286 3985 fx 408 297 9121 AJM International Electronics Consultants 619 North First St, San Jose, CA 95112 -Original Message- From: James Collum james.col...@usa.alcatel.com To: emc-p...@majordomo.ieee.org emc-p...@majordomo.ieee.org List-Post: emc-pstc@listserv.ieee.org Date: Friday, December 14, 2001 1:57 PM Subject: Re: Sometimes product safety just isn't enough Following a recent airline flight, I was given a bag of peanuts, marked Peanuts which contained a health warning contains peanuts. I was thinking that in a similar style that maybe electrical products could have an added warning may contain electricity. The may would elude to the connection of a mains cable for mains powered equipment, or even batteries in battery powered equipment. I think the IEC should be prompt to act in this vital area. Following this illogical train of thought, the swimming pool should have a warning contains water and the ladder could have a warning may alter altitude. But on a slightly more serious note (but not much) If I am ever present when someone is about to do something interesting with electricity I always advise that the person about to do the deed make sure to note who present will provide the kiss of life when it all goes pear shaped. It tends to work (although I don't know why, as I think I'm very kissable). Jim -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 couldnââ'¬â¢t 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.html Bob Johnson . --- 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: Sometimes product safety just isn't enough
In deference to the warning label on the peanuts bag. Some people have life threatening allergies to peanuts and take warnings such as that and warnings on cookies, etc very seriously. But then again, you'd think with the main label Peanuts would be sufficient. Perhaps, someone is making peanuts out of soy beans already. - Robert - Robert A. Macy, PEm...@california.com 408 286 3985 fx 408 297 9121 AJM International Electronics Consultants 619 North First St, San Jose, CA 95112 -Original Message- From: James Collum james.col...@usa.alcatel.com To: emc-p...@majordomo.ieee.org emc-p...@majordomo.ieee.org List-Post: emc-pstc@listserv.ieee.org Date: Friday, December 14, 2001 1:57 PM Subject: Re: Sometimes product safety just isn't enough Following a recent airline flight, I was given a bag of peanuts, marked Peanuts which contained a health warning contains peanuts. I was thinking that in a similar style that maybe electrical products could have an added warning may contain electricity. The may would elude to the connection of a mains cable for mains powered equipment, or even batteries in battery powered equipment. I think the IEC should be prompt to act in this vital area. Following this illogical train of thought, the swimming pool should have a warning contains water and the ladder could have a warning may alter altitude. But on a slightly more serious note (but not much) If I am ever present when someone is about to do something interesting with electricity I always advise that the person about to do the deed make sure to note who present will provide the kiss of life when it all goes pear shaped. It tends to work (although I don't know why, as I think I'm very kissable). Jim -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 couldnââ¬â¢t 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.html Bob Johnson --- 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: IATA
It is also interesting that 2mG limit closely approximates the emotional one established through epidemiological studies. Here in the Bay Area the field is around 50uT( 500mG ) It is my understanding that the magnetic field has been steadily declining. From the time of Christ until now it has dropped in half. And is evidently on a decline towards zero (reversing poles) The significance? I was told that every ice age was accompanied by a pole reversal (but not every pole reversal is accompanied by an ice age) - Robert - Robert A. Macy, PEm...@california.com 408 286 3985 fx 408 297 9121 AJM International Electronics Consultants 619 North First St, San Jose, CA 95112 -Original Message- From: Andrew Carson acar...@uk.xyratex.com To: WELLMAN,RON (A-PaloAlto,ex1) ron_well...@agilent.com Cc: 'richwo...@tycoint.com' richwo...@tycoint.com; emc-p...@majordomo.ieee.org emc-p...@majordomo.ieee.org List-Post: emc-pstc@listserv.ieee.org Date: Tuesday, December 04, 2001 1:39 AM Subject: Re: IATA You want Packing Instruction 902, within the section on Dangerous Goods. To summaries the limits are, 2mG at measurement distance of 2.1m - Non Magnetic Material 2mG at a measurement distance of 2.1m - Hazardous Magnetic Material, must be marked accordingly 5.25mG at a measurement distance of 4.6m - Can not be transported by aircraft. Not much when you think the Earths magnetic field is 450 to 550mG --- 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: physics behind EMI powerline filter
Muriel, Good thinking. The answer is, depends..Keep in mind that at 30MHz the 1/4 wavelength is still over 8 feet, so we're not really talking much about waveguides and volumetric resonators. Two areas to consider: First, at the low frequencies most of the energy is simply not used *and* from the lesser energy source which is simply shorted out only slightly increases the energy consumed. The bulk of the energy is in a sense reflected back, but a better concept may be just not used. There are two main sources for only switching power supply noise, one is from the high voltage that the FET switches which is transferred around using parasitic capacitance (high impedance) and is usually a common mode signal, the other comes from the curent demands placed upon the storage capacitor across its own esr and appears as differential noise (low impedance) These two sources merely present themselves to the AC mains and are allowed to supply energy down the wires. However the EMI filter stops this from happening. It shorts out the high impedance source using the y-caps so the noise doesn't go down the AC wires and then blocks the residual signal with the large valued common mode choke. The low impedance source is first converted to a higher impedance as it tries to go through the little differential inductors, then the signal is shorted with the huge line to line cap.For the high impedance source it is shorted to ground thus increasing the losses, while for the low impedance noise source it is blocked with a high impedance and just left as an open. Second, at higher frequency where almost all the noise has become common mode (and caused more by the load), the filter still acts like an open due to those two differential coils. So one could say the energy is simply blocked from escaping. Now what happens with the combination? Depends. One could argue that the energy stayed inside, but then again one could argue that that energy would never have been created in the first place had it not been allowed an egress. It's a small percentage of power floating around in the box anyway. - Robert - Robert A. Macy, PEm...@california.com 408 286 3985 fx 408 297 9121 AJM International Electronics Consultants 619 North First St, San Jose, CA 95112 -Original Message- From: Muriel Bittencourt de Liz mur...@eel.ufsc.br To: EMC-PSTC List emc-p...@ieee.org List-Post: emc-pstc@listserv.ieee.org Date: Monday, December 03, 2001 12:35 PM Subject: physics behind EMI powerline filter Hello Group, I have a long-time question, concerning the energy issues in a EMI powerline filter. I'll put a case, and ask the question after. This is the case: - When trying to minimize the conducted emissions from a electrical equipment / circuit, one of the things to do is to put a EMI filter at the power entrance. This filter can be from a manufacturer (ready filter) or you can make one (with common mode inductors, capacitors, inductors). This are the questions (they arearelated, i.e., complete each other): - What, physically speaking, happens to the EMI energy that leaves the equipment when I add a filter??? When there is no filter, I understand that the energy goes to the mains?? Does the filter reflect the EMI energy, keeping it arrested inside the equipment? - Thinking under the light of the principle of energy conservation, what happens to the EMI energy when I add a filter?? It cannot be lost... - ... And, supposing that the energy keeps arrested inside the equipment, isn't it worse for radiated emissions?? i.e., it can increase the level of radiated emissions?? Thanks in advance for your attention. Regards, Muriel Bittencourt de Liz Ph.D. Student Interest Areas: EMC for power electronics, RF measures, EM interference Federal University at Santa Catarina State Florianópolis, Santa Catarina, Brazil --- 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: [Fwd: User Warning Signal Words]
Perhaps, it's time to utilize Alert instead of Warning for Class A compliance information. - Robert - Robert A. Macy, PEm...@california.com 408 286 3985 fx 408 297 9121 AJM International Electronics Consultants 619 North First St, San Jose, CA 95112 -Original Message- From: douglas_beckw...@mitel.com douglas_beckw...@mitel.com To: David Heald davehe...@mediaone.net Cc: emc-p...@majordomo.ieee.org emc-p...@majordomo.ieee.org; ni...@tsd.serco.com ni...@tsd.serco.com List-Post: emc-pstc@listserv.ieee.org Date: Wednesday, November 07, 2001 5:43 PM Subject: Re: [Fwd: User Warning Signal Words] From: Douglas Beckwith@MITEL on 11/07/2001 04:27 PM Hi All, If I may submit my two Canadian pesos worth. There is a US miltary handbook on technical writing that discusses the defintion of these words and how they should be used. Can't remember what it is off hand, but I will look it up and post it. These are the definitions that we use in our documentation. Here is a brief summary. CAUTION - Potential damage to the equipment, e.g. ESD or static WARNING - Potential minor injury or harm to the the user/maintainer. e.g sharp edges, corners etc DANGER - Potential major injury or death of the user/maintainer, e.g. exposed High voltage terminals. That being said, I have seen so many misuses and applications of these terms that deviate from the definitions, for example in the UK you are required to put an EMC Class A warning note in the documentation. In that case, I don't think that Class A emissions from an unintentional radiator are harmful, but that is another debate. Regards Doug Beckwith Mitel Networks --- 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: EMC test table construction plans
John, Your point is well taken with regard to testing a unit while closely matching the testing environment to the environment it will be used in. However, we don't sell a lot of equipment to people who have 40 meters of ground plane, either. It is my understanding a reasonable false environment is an attempt to control the testing environment and obtain repeatable results. Controlling the table material so it does not appreciably affect the outcome of the test seems to be consistent with that goal. - Robert - Robert A. Macy, PEm...@california.com 408 286 3985 fx 408 297 9121 AJM International Electronics Consultants 619 North First St, San Jose, CA 95112 -Original Message- From: John Woodgate j...@jmwa.demon.co.uk To: emc-p...@majordomo.ieee.org emc-p...@majordomo.ieee.org List-Post: emc-pstc@listserv.ieee.org Date: Friday, November 02, 2001 2:30 AM Subject: Re: EMC test table construction plans I read in !emc-pstc that Pommerenke, David davi...@ece.umr.edu wrote (in 9da8d24b915bd1118911006094516eaf0ba31...@umr-mail02.cc.umr.edu) about 'EMC test table construction plans', on Thu, 1 Nov 2001: For emissions and immunity you should not use any wood in the table. It will significantly (+/-2 dB up to 1 GHz for emissions , more above, +/-10 dB for immunity up to 1 GHz) change the test result. My experience has shown that Styrofoam is basicly the best material. You mean that it gives the worst-case results? There are a couple of published papers on this issue. As surface material the following worked out fine: - Foamed PVC (rather stiff, low dielectric constant due to the foamed nature), maybe 4 mm thick. - PE sheet, maybe 2 mm thick. Should the test conditions not reflect the actual environment in use of the product, rather than employ these unusual materials? -- Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk --- 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: Request for Input - Third Party Request
Don't know if anybody responded, or not. But first I would change your interface to include analog signals (I firmly believe in never blinding the computer to what's really going on) Second, the only IF temp meters I remember were made by Raychem, or such back in the 70's. But they at least have to have an analog output to interface to your computer. Third, write the testing program in the highest level language possible. (else support will be pure hell) - Robert - Robert A. Macy, PEm...@california.com 408 286 3985 fx 408 297 9121 AJM International Electronics Consultants 619 North First St, San Jose, CA 95112 -Original Message- From: me...@aol.com me...@aol.com To: emc-p...@majordomo.ieee.org emc-p...@majordomo.ieee.org List-Post: emc-pstc@listserv.ieee.org Date: Friday, October 26, 2001 1:20 PM Subject: Request for Input - Third Party Request We are testing 2 coil windings (at a same time) for resistance using 4 wires Kelvin connection. Acceptable (Pass) Value ranges for the parts are: Part A 2.3 - 2.7 Ohm Part B 5.4 - 5.8 Ohms. We want to know if the part is within (good) these ranges or out (bad) of these ranges. We should be able to connect your output to our digital PLC I/O Card, or simply to trigger a relay. (NO RS-232) In the station prior to the testing station, terminals of the coil winding are being dipped into soldering pot resulting on the temperature increase, which then effects our resistance readings. We want (ideally) to measure the temperature of the part using infrared sensor, inputting that into the tester and compensating for the temperature. This would require a tester that would be able to do some computation. Ed --- 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: 120V Ground Faults
Michael, The arcing was between hot and neutral. GFCI outlets would have made no difference. - Robert - Robert A. Macy, PEm...@california.com 408 286 3985 fx 408 297 9121 AJM International Electronics Consultants 619 North First St, San Jose, CA 95112 -Original Message- From: michael.garret...@radisys.com michael.garret...@radisys.com To: emc-p...@majordomo.ieee.org emc-p...@majordomo.ieee.org Cc: Robert Macy m...@california.com List-Post: emc-pstc@listserv.ieee.org Date: Thursday, October 25, 2001 5:52 PM Subject: 120V Ground Faults Robert, From my experience, I think you will find that arcing ground faults are inherently high-resistance in nature and, while dramatic, do not necessarily pull significant amounts of current. Most 15 amp breakers will likely require several seconds/minutes to blow at 60/30 amps, which is what you'd get with a 2/4 ohm arc. In reality, I wouldn't be surprised to see something more like a 10-20 ohm figure being used for this type of phenomenon, which would allow a 15 amp breaker to arc virtually continuously (i.e. the home arc-welder). The fact that arcs are drawn - and sustained - at 120 volts is, I believe, relatively rare. Higher voltage systems (and GFCI outlets) have ground fault systems that rely on the detection of zero sequence (neutral leakage) currents. My understanding is that the decision to require this type of protection on 480 volt systems over 1200 amps was largely due to the increased likelihood they'd be able to draw and sustain an arc, as well as the damage that can be caused at these higher power levels (balanced with the concerns of cost-effectiveness of installing them more broadly). I feel they drew the line in an appropriate place. In my experience, while problems, such as this, do arise, the frequency and relative damage caused by them is relatively small. I think you would have seen a change (like the addition of GFCI about 25 years ago) if the case were otherwise. You should be able to add zero sequence current sensing to your household panel, should you care to do so, for ~$500, but where out-of-the-box systems exist for 480 volt systems, this would need to be a custom design amploying the combination of a sensor relay and a shunt-trip breaker. Of course any nuisance trips you may experience similar to your GFCI would take down your main You can buy a LOT of GFCI breakers for these dollars. Caveat Emptor/Engineer. Regards, Michael Garretson Compliance Engineering Manager RadiSys Corporation +1 503 615-1227 Robert Macy m...@california.com To: Dan Kwok dk...@intetron.com, emc-p...@majordomo.ieee.org Sent by: cc: owner-emc-pstc@majordom Subject: Re: skinny power cords. o.ieee.org 10/25/01 02:36 PM Please respond to Robert Macy It definitely was not supplied by the heater company. It was a high quality UL approved cord. It's just that this cord carbonized and burst into flame as the arc was existing. The flames did immediately extinguish when the arc was stopped by unplugging the cord which is good. But again, it was disturbing that the 15A breaker provided no protection. Anyway, it was a good lesson for this sleeping guy. Now I take electrical distribution inside my home much more seriously. - Robert - Robert A. Macy, PEm...@california.com 408 286 3985 fx 408 297 9121 AJM International Electronics Consultants 619 North First St, San Jose, CA 95112 -Original Message- From: Dan Kwok dk...@intetron.com To: Robert Macy m...@california.com; emc-p...@majordomo.ieee.org emc-p...@majordomo.ieee.org Date: Thursday, October 25, 2001 1:42 PM Subject: Re: skinny power cords. Hi Robert, Recently, I bought several similar heaters for my home. I recall reading in the operation instructions, explicit safety warnings against using extension cords with the heater. Was the extension cord supplied with the heater? - Dan Kwok, P.Eng. Principal Engineer Electromagnetic Compatibility Intetron Consulting, Inc. Ph (604) 432-9874 E-mail dk...@intetron.com Internet http://www.intetron.com - Original Message - From: Robert Macy m...@california.com To: Roman, Dan dan.ro...@intel.com; emc-p...@majordomo.ieee.org Sent: Thursday, October 25, 2001 8:49 AM Subject: Re: skinny power cords. Just have to jump in here with personal experience: In our bedroom we have a deLonghi radiator heater which uses an extension cord (high cost UL approved) heavy guage #12 wire to power it - when it's used. This extension cord plugs into a multi outlet adapter, also heavy duty UL approved
Re: skinny power cords.
It definitely was not supplied by the heater company. It was a high quality UL approved cord. It's just that this cord carbonized and burst into flame as the arc was existing. The flames did immediately extinguish when the arc was stopped by unplugging the cord which is good. But again, it was disturbing that the 15A breaker provided no protection. Anyway, it was a good lesson for this sleeping guy. Now I take electrical distribution inside my home much more seriously. - Robert - Robert A. Macy, PEm...@california.com 408 286 3985 fx 408 297 9121 AJM International Electronics Consultants 619 North First St, San Jose, CA 95112 -Original Message- From: Dan Kwok dk...@intetron.com To: Robert Macy m...@california.com; emc-p...@majordomo.ieee.org emc-p...@majordomo.ieee.org List-Post: emc-pstc@listserv.ieee.org Date: Thursday, October 25, 2001 1:42 PM Subject: Re: skinny power cords. Hi Robert, Recently, I bought several similar heaters for my home. I recall reading in the operation instructions, explicit safety warnings against using extension cords with the heater. Was the extension cord supplied with the heater? - Dan Kwok, P.Eng. Principal Engineer Electromagnetic Compatibility Intetron Consulting, Inc. Ph (604) 432-9874 E-mail dk...@intetron.com Internet http://www.intetron.com - Original Message - From: Robert Macy m...@california.com To: Roman, Dan dan.ro...@intel.com; emc-p...@majordomo.ieee.org Sent: Thursday, October 25, 2001 8:49 AM Subject: Re: skinny power cords. Just have to jump in here with personal experience: In our bedroom we have a deLonghi radiator heater which uses an extension cord (high cost UL approved) heavy guage #12 wire to power it - when it's used. This extension cord plugs into a multi outlet adapter, also heavy duty UL approved. At the time of the incident there was no power being used from this outlet. I was in another room, my wife was sitting on the edge of the bed watching a news blurb on TV when she heard a funny sound, a scritch, scritch. She called to me to come listen. Scritch, scritch, scritch got louder. As I arrived, flames started lapping up the wall from the outlet while still making arcing sounds. The flames were less than 6 inches from curtains. I reached into all this and unplugged the extension cord which luckily stopped the fireworks display. Imagine, if we had not been there. Upon examination, it appeared that an arc had formed between the blades of the extension cord (remember no power at the time). That arc was not sufficient to drop the 15A breaker to the outlet, yet was sufficient to carbonize the UL approved material which further sustained the arc. I posted this to the newsgroup alt.home.repair where a fireman jumped in describing how this exact mechanism is what starts most home fires! Isn't that an encouraging thought! Anyway, a little damn fuse in the plug would not have helped in this circumstance, complete waste of time, much like the main breaker was. - Robert - Robert A. Macy, PEm...@california.com 408 286 3985 fx 408 297 9121 AJM International Electronics Consultants 619 North First St, San Jose, CA 95112 -Original Message- From: Roman, Dan dan.ro...@intel.com To: emc-p...@majordomo.ieee.org emc-p...@majordomo.ieee.org Date: Thursday, October 25, 2001 7:41 AM Subject: RE: skinny power cords. I agreed completely with Scott. A 6 to 9 foot 18AWG cord will handle well in excess of 20A for a short period of time without starting to smoke (heck, it'll handle close to in excess of 60A for a very very short time without bursting into flames--not that it was a good experience finding this out). Point is, the cordage will handle a fault either indefinitely or long enough for the branch circuit breaker to trip provided you are connected to a 15A or 20A branch circuit. Another data point, you routinely pass more current through the cord when doing the earthing test and that uses more current than the cord is rated. Leave the tester on for awhile and the cord does not really heat up either. What this list needs is a power cord manufacturer or agency safety engineer that does power cords to settle this once and for all! Dan -Original Message- From: Scott Lacey [mailto:sco...@world.std.com] Sent: Wednesday, October 24, 2001 7:43 PM To: Gary McInturff Cc: emc-p...@majordomo.ieee.org Subject: RE: skinny power cords. Gary, I believe the answer is that the power cord rating of 6 or 10 amps is the operating current, at which it will have minimum temperature rise. Under fault conditions it will experience a rather dramatic temperature rise that is still well below the melting temperature
Re: skinny power cords.
Yes, I believe it was contamination. There is a tissue box on the night stand above the outlet. Tissue lint is insidious. The extension cord had been plugged in (AND LEFT UNDISTURBED) for a long period of time. Exactly, how the buildup made its way to an inside surface I don't know. But remember, an experienced fireman related that this is how most electrical fires start in his experience - an outlet shorts between blades (or in that area), the breaker does not trip while the arc is sustained, flames develop, and great damage occurs. I was upset that the 15A breaker could care less about the arc sizzling at the outlet. The reason I mention the extension cord is to point out that the plug plugged into the outlet was high quality and not a cheap lamp cord of suspect origin. Yet, this plug still carbonized AND FLAMED! making things much worse. Now, I do maintenance around our home using compressed air can to blow the outlet box clear of everything and unplug everything and wipe all surfaces clean. This has worked, but may not always, since sprays etc used in the area tend to produce a gummy, waxlike deposit on the outlet and there still may be stuff down inside. - Robert - Robert A. Macy, PEm...@california.com 408 286 3985 fx 408 297 9121 AJM International Electronics Consultants 619 North First St, San Jose, CA 95112 -Original Message- From: Jim Eichner jim.eich...@xantrex.com To: emc-p...@majordomo.ieee.org emc-p...@majordomo.ieee.org List-Post: emc-pstc@listserv.ieee.org Date: Thursday, October 25, 2001 12:07 PM Subject: RE: skinny power cords. I'm curious: given that North American plug blades are 1/2 apart, there must have been substantial contamination to aid in 120Vac jumping that far (arcing). Did you identify any sort of contamination or moisture? Jim Eichner, P.Eng. Manager, Engineering Services Xantrex Technology Inc. Mobile Power phone: (604) 422-2546 fax: (604) 420-1591 e-mail: jim.eich...@xantrex.com web: www.xantrex.com -Original Message- From: Robert Macy [mailto:m...@california.com] Sent: Thursday, October 25, 2001 8:50 AM To: Roman, Dan; emc-p...@majordomo.ieee.org Subject: Re: skinny power cords. Just have to jump in here with personal experience: In our bedroom we have a deLonghi radiator heater which uses an extension cord (high cost UL approved) heavy guage #12 wire to power it - when it's used. This extension cord plugs into a multi outlet adapter, also heavy duty UL approved. At the time of the incident there was no power being used from this outlet. I was in another room, my wife was sitting on the edge of the bed watching a news blurb on TV when she heard a funny sound, a scritch, scritch. She called to me to come listen. Scritch, scritch, scritch got louder. As I arrived, flames started lapping up the wall from the outlet while still making arcing sounds. The flames were less than 6 inches from curtains. I reached into all this and unplugged the extension cord which luckily stopped the fireworks display. Imagine, if we had not been there. Upon examination, it appeared that an arc had formed between the blades of the extension cord (remember no power at the time). That arc was not sufficient to drop the 15A breaker to the outlet, yet was sufficient to carbonize the UL approved material which further sustained the arc. I posted this to the newsgroup alt.home.repair where a fireman jumped in describing how this exact mechanism is what starts most home fires! Isn't that an encouraging thought! Anyway, a little damn fuse in the plug would not have helped in this circumstance, complete waste of time, much like the main breaker was. - Robert - Robert A. Macy, PEm...@california.com 408 286 3985 fx 408 297 9121 AJM International Electronics Consultants 619 North First St, San Jose, CA 95112 -Original Message- From: Roman, Dan dan.ro...@intel.com To: emc-p...@majordomo.ieee.org emc-p...@majordomo.ieee.org Date: Thursday, October 25, 2001 7:41 AM Subject: RE: skinny power cords. I agreed completely with Scott. A 6 to 9 foot 18AWG cord will handle well in excess of 20A for a short period of time without starting to smoke (heck, it'll handle close to in excess of 60A for a very very short time without bursting into flames--not that it was a good experience finding this out). Point is, the cordage will handle a fault either indefinitely or long enough for the branch circuit breaker to trip provided you are connected to a 15A or 20A branch circuit. Another data point, you routinely pass more current through the cord when doing the earthing test and that uses more current than the cord is rated. Leave the tester on for awhile and the cord does not really heat up either. What this list needs is a power cord manufacturer or agency safety
Re: skinny power cords.
No soldered connections. The arc was external to the plug between the blades. Carbonizing and then cutting more carbon in the burn track. Remember the arc was *between* the blades, there was no power going through the cord itself. - Robert - Robert A. Macy, PEm...@california.com 408 286 3985 fx 408 297 9121 AJM International Electronics Consultants 619 North First St, San Jose, CA 95112 -Original Message- From: Ron Pickard rpick...@hypercom.com To: m...@california.com m...@california.com Cc: emc-p...@ieee.org emc-p...@ieee.org List-Post: emc-pstc@listserv.ieee.org Date: Thursday, October 25, 2001 11:01 AM Subject: Re: skinny power cords. Hi Robert, In your examination, did you find evidence of compression connections with soldered(tinned) leads? Or, did the compression connections appeared to be loose?. As you might already know, the solder in such a connection cold flows under the pressure of the connection and after a while this connection loosens. In my experience, this loose connection is the source where the arcing occurs. Comments anyone? Best regards, Ron Pickard rpick...@hypercom.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: skinny power cords.
Just have to jump in here with personal experience: In our bedroom we have a deLonghi radiator heater which uses an extension cord (high cost UL approved) heavy guage #12 wire to power it - when it's used. This extension cord plugs into a multi outlet adapter, also heavy duty UL approved. At the time of the incident there was no power being used from this outlet. I was in another room, my wife was sitting on the edge of the bed watching a news blurb on TV when she heard a funny sound, a scritch, scritch. She called to me to come listen. Scritch, scritch, scritch got louder. As I arrived, flames started lapping up the wall from the outlet while still making arcing sounds. The flames were less than 6 inches from curtains. I reached into all this and unplugged the extension cord which luckily stopped the fireworks display. Imagine, if we had not been there. Upon examination, it appeared that an arc had formed between the blades of the extension cord (remember no power at the time). That arc was not sufficient to drop the 15A breaker to the outlet, yet was sufficient to carbonize the UL approved material which further sustained the arc. I posted this to the newsgroup alt.home.repair where a fireman jumped in describing how this exact mechanism is what starts most home fires! Isn't that an encouraging thought! Anyway, a little damn fuse in the plug would not have helped in this circumstance, complete waste of time, much like the main breaker was. - Robert - Robert A. Macy, PEm...@california.com 408 286 3985 fx 408 297 9121 AJM International Electronics Consultants 619 North First St, San Jose, CA 95112 -Original Message- From: Roman, Dan dan.ro...@intel.com To: emc-p...@majordomo.ieee.org emc-p...@majordomo.ieee.org List-Post: emc-pstc@listserv.ieee.org Date: Thursday, October 25, 2001 7:41 AM Subject: RE: skinny power cords. I agreed completely with Scott. A 6 to 9 foot 18AWG cord will handle well in excess of 20A for a short period of time without starting to smoke (heck, it'll handle close to in excess of 60A for a very very short time without bursting into flames--not that it was a good experience finding this out). Point is, the cordage will handle a fault either indefinitely or long enough for the branch circuit breaker to trip provided you are connected to a 15A or 20A branch circuit. Another data point, you routinely pass more current through the cord when doing the earthing test and that uses more current than the cord is rated. Leave the tester on for awhile and the cord does not really heat up either. What this list needs is a power cord manufacturer or agency safety engineer that does power cords to settle this once and for all! Dan -Original Message- From: Scott Lacey [mailto:sco...@world.std.com] Sent: Wednesday, October 24, 2001 7:43 PM To: Gary McInturff Cc: emc-p...@majordomo.ieee.org Subject: RE: skinny power cords. Gary, I believe the answer is that the power cord rating of 6 or 10 amps is the operating current, at which it will have minimum temperature rise. Under fault conditions it will experience a rather dramatic temperature rise that is still well below the melting temperature of the insulation. The breaker or fuse should clear well before the cord is cooked to the point of failure. Scott Lacey --- 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: EFT Failures..Help!
Hope you're using more than one sample. I've been bit by having the one I brought to the lab not being in compliance. Anyway, make certain. - Robert - Robert A. Macy, PEm...@california.com 408 286 3985 fx 408 297 9121 AJM International Electronics Consultants 619 North First St, San Jose, CA 95112 -Original Message- From: Alex McNeil alex.mcn...@ingenicofortronic.com To: emc-p...@majordomo.ieee.org emc-p...@majordomo.ieee.org List-Post: emc-pstc@listserv.ieee.org Date: Monday, October 22, 2001 4:06 AM Subject: EFT Failures..Help! Hi Guys, I am at an EMC test centre today and tomorrow. Unfortunately, my product failed EFT testing on the AC power port at 1KV. This is for various combinations of Line, Neutral and Earth (L, N, E, LN, LE, NE and LNE) My product is Class II, no Earth. It is supplied by an external power supply. This supplies SELV to my product. The power supply manufacturer has stated that his power supply meets EN61000-4-4 for 2KV and has emailed me this report to verify this. Has anyone got a quick solution to my problem so that I can implement here at the EMC test house? Kind Regards Alex McNeil Principal Engineer Tel: +44 (0)131 479 8375 Fax: +44 (0)131 479 8321 email: alex.mcn...@ingenicofortronic.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. --- 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: duty cycle correction factors
20log(d) time is linear, like voltage not the square, like power, thus the 20log - Robert - Robert A. Macy, PEm...@california.com 408 286 3985 fx 408 297 9121 AJM International Electronics Consultants 619 North First St, San Jose, CA 95112 -Original Message- From: Stuart Lopata stu...@timcoengr.com To: emc emc-p...@majordomo.ieee.org List-Post: emc-pstc@listserv.ieee.org Date: Thursday, October 18, 2001 9:45 AM Subject: duty cycle correction factors Part 15.231 devices use a duty cycle correction factor to adjust peak readings. The duty cycle represents the fractional on-time over a given period of time (that must be under some limit). Anyways, given this fractional time, d, how do you make the conversion to dB? 10log(d) or 20log(d)? There have been some misinterpretations, since the readings are made at a span of zero hertz (voltage readings). Normally, a reduction in voltage would use the 20log scale. However, since the duty cycle does not represent a scale down (it represents the off-time versus on-time), the 10log scale seems more appropriate. I have seen conflicting documents, so would like your professional opinions! Thanks, Stuart Lopata --- 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. --- 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.
Printable calendar for 2002 sent by request
Ok, ok. For all those whose virus scanners spit up when seeing files with my mnemonic names - upon request I'll send to you an unzipped version (about 60K total) with every file renamed with the extension *.txt. For example, PRINT_02.BAT will be PRINT_02.BAT.TXT etc Then you can do with it what you want. - Robert - Robert A. Macy, PEm...@california.com 408 286 3985 fx 408 297 9121 AJM International Electronics Consultants 619 North First St, San Jose, CA 95112 --- 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: Printable calendar for 2002
I got two NAV (Norton Antivirus) msgs back from the ieee.org that said my attachment had a virus in it. If so, please let me know, because there is nothing but text files (that I know of) and a simple batch program in that attachment. Very important that *IF* I have a virus, need to know !!! - Robert - PS It's just that Norton Antivirus had showed my system clean, but I had to remove it manually piece by piece because of the way it kept screwing up all my software. This is not one happy camper. --- 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.
Printable calendar for 2002
Apologize for being off topic, but I've attached a printable calendar for 2002. It prints out on 8 1/2 by 11 (for all the metric people) in landscape mode. Very little clutter and has big squares to write in. If you have a DeskJet 500, you can print directly to it. If not, use the text file 2002_46L.LAN Each month is 46 lines with no pagination. - Robert - attachment: 2002_cal.zip
Fluid flow rate
Sorry about this being so far off topic, but I don't know where else to find the largest group of technology professionals who can answer this question: How much water will flow out of a 3/4 inch pipe which is under 60 psi? There is a restriction and the actual inside ID is around 7/16 inch. My guess is more than 5 gal/min. For example, when I get gasoline the tank will fill (20 gal) in less than 2 minutes. So it's got to be somewhere in this range, right? - Robert - Robert A. Macy, PEm...@california.com 408 286 3985 fx 408 297 9121 AJM International Electronics Consultants 619 North First St, San Jose, CA 95112 --- 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: Active loop antenna overload
Move the antenna further away. then use correction factors to calculate what it would have been at the original distance. Magnetic fields decrease as the inverse cube of the distance. So just apply a correction factor to boost the amplitude back up. For example, twice the distance away means the signal will look 1/8 as much or around 18dB smaller. Of course, that assumes the source is a magnetic dipole AND your original measurement distance is at least 3 diameters (diameters of the sensing loop AND diameters of the source loop) away to begin with. [ Also, conductive surfaces and magnetic materials need to be out of the field of interest. Make certain the minimum distance to such interference is at least 3 times the distance between what you're measuring and your sensing loop. ] If the above assumptions don't hold, come back at me. - Robert - Robert A. Macy, PEm...@california.com 408 286 3985 fx 408 297 9121 AJM International Electronics Consultants 619 North First St, San Jose, CA 95112 -Original Message- From: KC CHAN [PDD] kcc...@hkpc.org To: emc-p...@ieee.org List-Post: emc-pstc@listserv.ieee.org Date: Monday, September 24, 2001 12:19 AM Subject: Active loop antenna overload Dear All When doing the magnetic field measurement by a active loop antenna, what we can do if we find the loop antenna is saturated/overloaded? Is there any ways that we can do to overcome this? Best Regards KC Chan --- 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.
Need electrical characteristics of epidermis (skin)
Sorry to post here but am running into a brick wall at trying to find out something as simple as the resistivity and dielectric constant for skin! Does anybody have a source? Need quick, please. - Robert - --- 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: Noise from flourescent light ballasts?
Chris, Fluorescent tubes are noisy anyway, but the old passive ballasts are starting to be replaced with active electronic ballasts. Those electronic widgets actually run at frequencies down near what you're using. Electrically they can be EXTREMELY noisy. The US has no real restrictions. As far as what you observe, the hand can act as a shield, or as an enabler which would enhance a picked up signal putting it right into your electronics. What's important is that your circuit is very susceptible when exposed and not when closed. That implies marginality in your design. You should take a look at just how much you reject and whether that is adequate for your needs. - Robert - Robert A. Macy, PEm...@california.com 408 286 3985 fx 408 297 9121 AJM International Electronics Consultants 619 North First St, San Jose, CA 95112 -Original Message- From: Chris Maxwell chris.maxw...@nettest.com To: EMC-PSTC Internet Forum emc-p...@majordomo.ieee.org List-Post: emc-pstc@listserv.ieee.org Date: Thursday, September 06, 2001 9:22 AM Subject: Noise from flourescent light ballasts? Hi all, We have personally experienced an interesting phenomenon. We build a certain circuit that detects a 20Khz tone. This circuit is housed in a product that has an EMI spray coated case. One of our engineers noticed that our techs on the manufacturing floor were having a difficult time setting up units on the floor. The tone detect circuit kept getting set off for apparantly no reason. However, back in the engineering lab, we have no problems. So we did a little experiment. We took a unit out to the manufacturing floor and opened its case (which is how they work on them in manufacturing). We held it up near the lights. The tone detect circuit went crazy. We put the unit down on the bench. No problem. But, if you leave it opened up on the bench and hold your hand over the board, the circuit goes off again. When we close up the case work, all of these problems go away. So, our obvious solution is to make a modified casework with tweaker holes so that manufacturing personnel can tweak the amplifier pots with the casework closed. But I'm still curious. What's causing the interference? I was wondering if flourescent light ballasts could be giving off an emission in the KHz range. (Maybe that's why holding it to the lights sets it off.) But what about the hand waving? If I assume the ballasts are giving off emissions, can I also assume that the human body can change the local field pattern? Am I barking up the wrong tree? Maybe its the LAN cables in the ceiling? Anybody else have a similar experience or some insight into this? Thanks, Chris Maxwell | Design Engineer - Optical Division email chris.maxw...@nettest.com | dir +1 315 266 5128 | fax +1 315 797 8024 NetTest | 6 Rhoads Drive, Utica, NY 13502 | USA web www.nettest.com | tel +1 315 797 4449 | --- 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. --- 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: 120V appliance on 240V supply
They will deliver less powerabour 50/60 of what you expect. The power supplies in those ovens are quite inexpensive and use a single rectifying diode. When the voltage gets high enough, the microwave bursts on for a short time. Thus, if operated from 50 Hz instead of 60 Hz, the power will drop proportional to the frequency. Don't know about any deleterious effects that would cause concern. - Robert - Robert A. Macy, PEm...@california.com 408 286 3985 fx 408 297 9121 AJM International Electronics Consultants 619 North First St, San Jose, CA 95112 -Original Message- From: Ravinder Ajmani ajm...@us.ibm.com To: emc-p...@ieee.org emc-p...@ieee.org List-Post: emc-pstc@listserv.ieee.org Date: Monday, May 14, 2001 9:24 AM Subject: 120V appliance on 240V supply Hi, I am interested in knowing if a 120V, 60Hz microwave oven can be safely used on a 240V, 50Hz mains supply with a step-down transformer. Regards, Ravinder Email: ajm...@us.ibm.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: http://www.rcic.com/ click on Virtual Conference Hall,
Re: Zo
Did you find out what you need? Somewhere around here I have the equations that closely approximate twisted pair for 26 Awg and 28 Awg wire from DC to 10MHz. They were derived from empirical modeling. You can make various approximations to simplify their use. That includes impedance, loss per length vs frequency, etc. I don't think they take into account being close to conductors, like a shield, or crosstalk between pairs, because that's another analysis, but they're *extremely* useful for predicting attenuation versus frequency for analyzing the expected performance one will get from DSL modems. - Robert - Robert A. Macy, PEm...@california.com 408 286 3985 fx 408 297 9121 AJM International Electronics Consultants 619 North First St, San Jose, CA 95112 -Original Message- From: William D'Orazio dora...@cae.ca To: EMC Posting (E-mail) emc-p...@majordomo.ieee.org List-Post: emc-pstc@listserv.ieee.org Date: Thursday, January 11, 2001 7:20 AM Subject: Zo Does anybody know the characteristic impedance of a twisted pair? Thanks in advance, ...OLE_Obj... William D'Orazio CAE Electronics Ltd. Electrical System Designer Phone: (514) 341-2000 (X4555) Fax: (514)340-5552 Email: dora...@cae.ca --- 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
