re: EN55011 Group 1 and Group 2
Brian, Here is my two cents worth: RF energy generated by Group 1 is intentionally only for internal function. And Group 2 intentionally generates RF for their working objects. Thus an electronic microscope (which is not a smaller bench type test equipment -- see your Email) falls under Group 1. On the other hand, microwave oven and RF medical therapy belong to Group 2. Please correct me if I'm confused. Barry Ma Anritsu Co. Morgan Hill, CA 408-778-2000 -- Original Text -- From: Brian At Work bkundew...@qtm.net, on 10/8/99 12:06 PM: Hello Group, For those of you who are familiar with EN55011 or CISPR11 what criteria is used to determine if a product falls under Group 1 or Group 2? The standards give some examples of product types but there should be a base criteria which was used. Group 1 products seem to be smaller bench type test equipment like signal generators, spectrum analyzers, and such. Group 2 seems to be products that generate a spark or uses RF in some way to heat, melt, or spark erode. The gap between these two groups seem to be wide which leaves a very large gray area. Is there a defined criteria that exists? Please feel free to give me your thoughts so we can draw up our own criteria if necessary. Thank you in advance, Brain Kunde Compliance Testing Center LECO Corp. - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators). - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
RE: Laser Standards
Lou, You are right. This system works extremely well. However, only very few companies have a bona fide library, with a librarian, that can provide this service. The rest of the small companies are struggling with small/inadequate budgets and the local city and county libraries usually do not stock esoteric international standards. How many times have I purchased standards that don't really apply to our products, except in a very peripheral way! I try to ascertain from others the scope of a specific standard and determine whether it really would apply to our products. This forum is great for this sort of information. Then, if the shoe fits, buy the standard. Tania Grant, tgr...@lucent.com tgr...@lucent.com Lucent Technologies, Communications Applications Group -- From: Lou Gnecco [SMTP:l...@tempest-inc.com] Sent: Friday, October 08, 1999 8:43 AM To: emc-p...@majordomo.ieee.org Subject: RE: Laser Standards Group, There is actually a precedent for all this. It is called an Inter-Library Loan and librarians do it all the time, including corporate librarians. It works like this: I need a document, say a EUROPEAN STANDARD. Your Company Library has it. I ask my librarian to ask your librarian for it. If it is ok with your company, your librarian sends it LIBRARY TO LIBRARY, complete with receipts, accountability, and a paper trail. My librarian then checks it out to me, and I become responsible for it. Now I can't just keep it, because it is due back on a certain date and my librarian will get after me to return it. This is what librarians do, and it works. Lou - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators). - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
Re: broadband/narrowband
The definition of a signal being narrowband or broadband is very simple: if a signal's spectrum EXCEEDS the measurement instrument's resolution bandwidth it is defined to be BROADBAND. In case a signal's spectrum is completely contained within the passband of the resolution bandwidth of the instrument (i.e. EMI receiver or spectrum analyzer), it is classified as a narrowband signal. PLEASE recognize that THE ONLY criteria for the determination of a signal being narrowband or broadband is the instruments resolution bandwidth. Thus if the bandwidth is changed, e.g. to a larger value, the signal could become a narrowband signal. This definition has a lot of problems to it but it is the official definition in CISPR and IEC publications. I hope, this helps. Best regards, Werner Schaefer Hewlett-Packard __ Reply Separator _ Subject: broadband/narrowband Author: Non-HP-lou (l...@tempest-inc.com) at HP-Sonoma,mimegw1 List-Post: emc-pstc@listserv.ieee.org Date:10/8/99 6:41 AM -Original Message- From: Muriel Bittencourt de Liz [SMTP:mur...@grucad.ufsc.br] mailto:[SMTP:mur...@grucad.ufsc.br] Sent: Thursday, October 07, 1999 5:43 AM To: Lista de EMC da IEEE Subject: broadband narrowband emissions Group, I'd like to have a clear definition of what are narrowband and broadband emissions. This question may seem very plain for many members of EMC-PSTC, but I always heard/saw this definition for emission and I still couldn't make them clear to me.. Thanks in advance for your attention Regards Muriel *** Muriel: Arun gave a very good explanation, and here is another one: Below is an excerpt from one of our books, PROBLEMS AND SOLUTIONS IN WIRELESS COMMUNICATIONS AND EMC. I have used this explanation in some of my courses, and people seem to understand it pretty well. I hope this helps. *** c Copyright 1999 by TEMPEST INC. Chapter 7. Converting Broadband To Narrowband Units And Vice Versa. This is a source of much confusion to new EMC engineers. Lets look at a part of the frequency spectrum, say from 20 to 30 MHz : (1.) When you only have one frequency, say 25 MHz, and its amplitude is 1 volt rms, the spectrum looks like this: 20 MHz.|_30 MHz .25 MHz (2.) Now lets say you have a waveform composed of 2 signals. One is at 24 MHz and one is at 26 MHz , each one being 1 volt rms. If you look at either signal alone, its amplitude is still 1 volt rms, but if you look at them together, the amplitude of the combined wave form will be somewhat greater. 20 MHz___|__|___30 MHz 24.26. (3.) Now lets say that you have a whole lot of frequencies: 20 MHz.||30 MHz if you take a tiny piece of the spectrum, you may only see one signal _|__ c Copyright 1999 by TEMPEST INC if you take a piece that is 1 MHz wide, you will see several ||| if you take a piece that is 2 MHz wide, you will see even more || and the more you see, the more energy you have. Some signals are broadband. Their spectrum looks like the one in (3.) above. One example is a square wave. A better example is an impulse. How do you describe the amplitude of these signals? If you measure them with a 1 MHz bandwidth you will get one answer, if you measure them with a 10 MHz bandwidth you will get a different answer. This is why we have broadband units. With broadband units we can say that this signal gives you x volts for every megahertz-sized piece of the spectrum that you use to measure it. For example, if the signal in (3) gives you 10 volts when you take a 1 MHz piece, it will give you 20 volts if you take a 2 MHz piece, and 30 volts if you take a 3 MHz piece. The bigger the bandwidth, the more volts you get. In this case, we would say that the signal gives you 10 volts per Megah ertz. Now lets say that you look at this signal with a 10 MHz bandwidth: c Copyright 1999 by TEMPEST INC We would see 10 Volts/MHz x 10 MHz bandwidth = 100 Volts if we look at it with a 2 MHz bandwidth, we would see 10 volts/MHz x 2 MHz = 20 Volts what if we only looked at it with a 500 kHz bandwidth? 500 kHz = 1/2 MHz 10 V/ MHz x 1/2 MHz = 10 x 1/2 = 5 Volts now lets do some problems: **c Copyright 1999 by TEMPEST INC. For more info, see: http://www.tempest-inc.com/pubs1.htm
Re: CE Countries
Here they are: Austria, Belgium, Denmark, Finland, France, Germany, Greece, Holland, Iceland, Ireland, Italy, Luxembourg, Norway, Portugal, Spain, Sweden, Switzerland, UK. John Radomski Compliance Engineer Inter-Tel Integrated Systems Allen Tudor allen_tu...@pairgain.com on 10/08/99 07:23:52 AM Please respond to Allen Tudor allen_tu...@pairgain.com To: emc-p...@majordomo.ieee.org cc:(bcc: John Radomski/Chandler/Inter-Tel) Subject: CE Countries Greetings group, Does anyone have the latest list of countries in the European block who require the CE mark? Thanks. Allen Tudor, Compliance Engineer PairGain Technologies tel: (919)875-3382 6531 Meridien Drive fax: (919)876-1817 Raleigh, NC 27616 email: allen_tu...@pairgain.com - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators). - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
Re: Printed Circuit Board Grounding
I've been out of the EMC game for over six years, but here are a few rules of thumb I seem to remember: 1. Stitch ground every where possible to create as many paths as possible to minimize the impedance from DC to gHz range. 2. Step one reduces overall emissions. 3. Most things done that decrease emissions tend to improve immunity as well. Maybe these simple rules don't apply for ESD, but a simplified answer always produces many more far more detailed answers on this forum. Regards, George Alspaugh umbdenstock%sensormatic@interlock.lexmark.com on 10/08/99 01:50:49 PM Please respond to umbdenstock%sensormatic@interlock.lexmark.com To: emc-pstc%ieee@interlock.lexmark.com cc:(bcc: George Alspaugh/Lex/Lexmark) Subject: Printed Circuit Board Grounding Hello Group, We are having a debate concerning the best practice for grounding of a printed circuit board containing digital logic. These boards are multi-layer with a ground plane and a power plane. One school of thought is to tie the ground plane to chassis ground in many locations, thus reducing the impedance. Another school of thought says to control the point(s) that is (are) tied to ground or risk upsetting of sensitive circuits with an ESD or other immunity event. The concept is that an ESD event may be decoupled to chassis at the I/O ground plane with the use of appropriate circuit elements to control impedances. Now consider the chassis to be steel, and the digital ground plane to be copper. If the digital ground plane is stitched to chassis in several locations, it appears that a lower impedance path (copper vs steel) will encourage the ESD to travel across the ground plane. If the ESD travels across the digital ground plane, there appears to be a good chance of upsetting sensitive circuits. So the thought might be to tie only one point of digital ground to chassis ground, thereby not providing a path for any immunity event to flow across this ground plane. The rest of the above concept is to use moats to segregate key circuits -- digital, I/O, analog, switch-mode power supplies. Again, some say to keep the ground plane in tact to provide the lowest impedance reference possible, so isolation is provided by carving up the power plane. The alternate approach is to carve all the way through, i.e., if you have a moat around a particular circuit, if you are going to isolate, do it for all planes (stack, do not overlap). This latter approach, however, carves up the ground plane which would appear to increase the impedance of the overall ground reference. The argument is that carving up the ground plane is justified by eliminating the coupling of dirty ground to other circuits in an overlap situation. I would like to hear what you do for pcb grounding and why you do it. Don Umbdenstock Sensormatic - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators). - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
RE: CE Countries
The member countries are Austria, Belgium, Denmark, Finland, France, Germany, Greece, Ireland, Italy, Luxembourg, Netherlands, Portugal, Spain, Sweden, the UK. Norway and Switzerland are not members of the EU but do accept the CE mark. I found this at http://europa.eu.int/index.htm a while ago. Jen Hovland Sr. EMC Engineering Technician Regulatory Compliance Phone: (605) 232-2230 x26548 Fax: (605) 232-2814 Email: jenifer.hovl...@gateway.com -Original Message- From: Allen Tudor [SMTP:allen_tu...@pairgain.com] Sent: Friday, October 08, 1999 9:24 AM To: emc-p...@majordomo.ieee.org Subject:CE Countries Greetings group, Does anyone have the latest list of countries in the European block who require the CE mark? Thanks. Allen Tudor, Compliance Engineer PairGain Technologies tel: (919)875-3382 6531 Meridien Drive fax: (919)876-1817 Raleigh, NC 27616 email: allen_tu...@pairgain.com - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators). - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
RE: CE Countries
Allen, I asked this question a short while ago. This should help: The European Economic Area (EEA) includes the fifteen member states of the European Union (EU): * Austria * Belgium * Denmark * Finland * France * Germany * Greece * Ireland * Italy * Luxembourg * Netherlands * Portugal * Spain * Sweden * United Kingdom and three of the four states of the European Free Trade Association (EFTA): * Iceland * Norway * Liechtenstein CE marking is also recognised by Switzerland, which is a member of EFTA but not of the EEA or the EU (the distinction being principally concerned with customs tarrifs). For more details, see http://www.conformance.co.uk/eea.html I was also told that Countries considering membership in the EU but are not yet there are Czech Republic, Hungary, Poland, Slovakia, Turkey -Original Message- From: Allen Tudor [mailto:allen_tu...@pairgain.com] Sent: Friday, October 08, 1999 10:24 AM To: emc-p...@majordomo.ieee.org Subject: CE Countries Greetings group, Does anyone have the latest list of countries in the European block who require the CE mark? Thanks. Allen Tudor, Compliance Engineer PairGain Technologies tel: (919)875-3382 6531 Meridien Drive fax: (919)876-1817 Raleigh, NC 27616 email: allen_tu...@pairgain.com - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators). - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
Printed Circuit Board Grounding
Hello Group, We are having a debate concerning the best practice for grounding of a printed circuit board containing digital logic. These boards are multi-layer with a ground plane and a power plane. One school of thought is to tie the ground plane to chassis ground in many locations, thus reducing the impedance. Another school of thought says to control the point(s) that is (are) tied to ground or risk upsetting of sensitive circuits with an ESD or other immunity event. The concept is that an ESD event may be decoupled to chassis at the I/O ground plane with the use of appropriate circuit elements to control impedances. Now consider the chassis to be steel, and the digital ground plane to be copper. If the digital ground plane is stitched to chassis in several locations, it appears that a lower impedance path (copper vs steel) will encourage the ESD to travel across the ground plane. If the ESD travels across the digital ground plane, there appears to be a good chance of upsetting sensitive circuits. So the thought might be to tie only one point of digital ground to chassis ground, thereby not providing a path for any immunity event to flow across this ground plane. The rest of the above concept is to use moats to segregate key circuits -- digital, I/O, analog, switch-mode power supplies. Again, some say to keep the ground plane in tact to provide the lowest impedance reference possible, so isolation is provided by carving up the power plane. The alternate approach is to carve all the way through, i.e., if you have a moat around a particular circuit, if you are going to isolate, do it for all planes (stack, do not overlap). This latter approach, however, carves up the ground plane which would appear to increase the impedance of the overall ground reference. The argument is that carving up the ground plane is justified by eliminating the coupling of dirty ground to other circuits in an overlap situation. I would like to hear what you do for pcb grounding and why you do it. Don Umbdenstock Sensormatic - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
RE: Laser Standards
Group, There is actually a precedent for all this. It is called an Inter-Library Loan and librarians do it all the time, including corporate librarians. It works like this: I need a document, say a EUROPEAN STANDARD. Your Company Library has it. I ask my librarian to ask your librarian for it. If it is ok with your company, your librarian sends it LIBRARY TO LIBRARY, complete with receipts, accountability, and a paper trail. My librarian then checks it out to me, and I become responsible for it. Now I can't just keep it, because it is due back on a certain date and my librarian will get after me to return it. This is what librarians do, and it works. Lou - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
Re: broadband/narrowband
I couldn't help but jump into this conversation. Almost any type of signal can be classified as Narrow band or broadband. The only true BB signal would be an impulse. It all comes down to the measurement band-width defined by the standard you are testing to. A repetitive signal such as a square wave rich in harmonic content can be considered both NB and BB depending on the measurement bandwidth. For example: ( a simple example): You have 10kHz square wave fed directly into a spectrum analyzer. Measuring the amplitude with the B.W set at 300kHZ would produce a response you would expect from a typical BB signal. Reducing the measurement bandwidth the peak amplitude would begin to drop until all the individual harmonics could bee seen individually. Then you would have a NB signal. Doing the same with a true impulse would give you constant reduction of amplitude until you hit the noise floor of the spectrum analyzer ( theoretically). The standards define NB and BB signals in reference to the technology the standard is written around. What's BB to one technology could be NB to another! My 2 cents! At 09:41 AM 10/8/99 -0400, Lou Gnecco wrote: -Original Message- From:Muriel Bittencourt de Liz [SMTP:mur...@grucad.ufsc.br] mailto:[SMTP:mur...@grucad.ufsc.br] Sent: Thursday, October 07, 1999 5:43 AM To:Lista de EMC da IEEE Subject: broadband narrowband emissions Group, I'd like to have a clear definition of what are narrowband and broadband emissions. This question may seem very plain for many members of EMC-PSTC, but I always heard/saw this definition for emission and I still couldn't make them clear to me.. Thanks in advance for your attention Regards Muriel *** Muriel: Arun gave a very good explanation, and here is another one: Below is an excerpt from one of our books, PROBLEMS AND SOLUTIONS IN WIRELESS COMMUNICATIONS AND EMC. I have used this explanation in some of my courses, and people seem to understand it pretty well. I hope this helps. *** © Copyright 1999 by TEMPEST INC. Chapter 7. Converting Broadband To Narrowband Units And Vice Versa. This is a source of much confusion to new EMC engineers. Lets look at a part of the frequency spectrum, say from 20 to 30 MHz : (1.) When you only have one frequency, say 25 MHz, and its amplitude is 1 volt rms, the spectrum looks like this: 20 MHz.|_30 MHz .25 MHz (2.) Now lets say you have a waveform composed of 2 signals. One is at 24 MHz and one is at 26 MHz , each one being 1 volt rms. If you look at either signal alone, its amplitude is still 1 volt rms, but if you look at them together, the amplitude of the combined wave form will be somewhat greater. 20 MHz___|__|___30 MHz 24.26. (3.) Now lets say that you have a whole lot of frequencies: 20 MHz.||30 MHz if you take a tiny piece of the spectrum, you may only see one signal _|__ © Copyright 1999 by TEMPEST INC if you take a piece that is 1 MHz wide, you will see several ||| if you take a piece that is 2 MHz wide, you will see even more || and the more you see, the more energy you have. Some signals are broadband. Their spectrum looks like the one in (3.) above. One example is a square wave. A better example is an impulse. How do you describe the amplitude of these signals? If you measure them with a 1 MHz bandwidth you will get one answer, if you measure them with a 10 MHz bandwidth you will get a different answer. This is why we have broadband units. With broadband units we can say that this signal gives you x volts for every megahertz-sized piece of the spectrum that you use to measure it. For example, if the signal in (3) gives you 10 volts when you take a 1 MHz piece, it will give you 20 volts if you take a 2 MHz piece, and 30 volts if you take a 3 MHz piece. The bigger the bandwidth, the more volts you get. In this case, we would say that the signal gives you 10 volts per Megahertz. Now lets say that you look at this signal with a 10 MHz bandwidth: © Copyright 1999 by TEMPEST INC We would see 10 Volts/MHz x 10 MHz bandwidth = 100 Volts if we look at it with a 2 MHz bandwidth, we would see 10 volts/MHz x 2 MHz = 20 Volts what if we only looked at it with a 500 kHz bandwidth? 500 kHz = 1/2 MHz 10 V/ MHz x 1/2 MHz = 10 x 1/2 = 5 Volts now lets do some problems: **© Copyright 1999 by TEMPEST INC. For more info, see: http://www.tempest-inc.com/pubs1.htm Regards, Lou . LOUIS T. GNECCO M.S.E.E., PRESIDENT TEMPEST INC. 112 ELDEN ST. HERNDON, VA 20170
CE Countries
Greetings group, Does anyone have the latest list of countries in the European block who require the CE mark? Thanks. Allen Tudor, Compliance Engineer PairGain Technologies tel: (919)875-3382 6531 Meridien Drive fax: (919)876-1817 Raleigh, NC 27616 email: allen_tu...@pairgain.com - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
Fwd:RE: Conduit entry dimensions
forwarded for Eric. Jim Forward Header_ Subject:RE: Conduit entry dimensions Author: Eric Monk intertest.systems...@ieee.org List-Post: emc-pstc@listserv.ieee.org Date: 10/08/99 12:24 AM Hi Richard and group. ELECTRICAL CONDUIT SYSTEMS IN THE UK. Electrical conduit systems in the UK were converted during metrication to their nearest metric equivalent. Sizes refer to outside diameters. The more common sizes are 20 mm (3/4), 25 mm (1) and 32 mm (1 ½). Larger than this there is a tendency to opt for metal trunking. 16 mm must be based on the old 5/8 conduit which I cannot confirm is still available in the UK, until I receive an updated catalogue. Knockout dimensions are simply a clearance hole for the applicable metric diameter of the conduit size recommended for the application. The preferred method of termination at an enclosure is to cut and thread the conduit a distance from the box, equal to the diameter of the conduit. Fit an 'internally' screwed coupling (like an oversize sleeve) to the end of the conduit and secure it to the enclosure with an 'externally' screwed brass bush inserted from inside of the enclosure. (bush is the same diameter as conduit thread) The brass bush has an hexagonal flange larger than the thread to tighten onto the enclosure firmly gripping the edge of the knockout hole between the brass bush and the coupling and providing earth continuity. The inside edges of the brass bush are chamfered and smooth to prevent damage to cable insulation when cables are pulled through the conduit into the enclosure. Variations are to terminate into a threaded elbow or T-piece if this is dictated by space constraints. (ie. bush thro k/o into elbow - conduit into elbow) An alternative is to bring the threaded end of the conduit through the knockout and secure it in the enclosure with a locknut on the outside and an 'internally' screwed bush on the inside - but this is not considered good practice. However the termination is accomplished in practice, the knockout dimensions are the same - Close tolerance clearance hole for the diameter of conduit specified for the application. Regards Eric Monk. Technical Director - E M Consulting Ltd. INTERTest Systems is the trading name of the test laboratory of E M Consulting Ltd. * Your best support in TESTING situations * *INTERTest Systems UK * * International Product Certification * *ONE-STOP-SHOP for ALL testing* *** PO Box 321 - Bucks HP9 1XJ - England - ++44 (0)1494 673438 *** *INTERTest Systems UK is the trading name of * * the test laboratory of E M Consulting Ltd. * - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
broadband/narrowband
-Original Message- From: Muriel Bittencourt de Liz [SMTP:mur...@grucad.ufsc.br] mailto:[SMTP:mur...@grucad.ufsc.br] Sent: Thursday, October 07, 1999 5:43 AM To: Lista de EMC da IEEE Subject: broadband narrowband emissions Group, I'd like to have a clear definition of what are narrowband and broadband emissions. This question may seem very plain for many members of EMC-PSTC, but I always heard/saw this definition for emission and I still couldn't make them clear to me.. Thanks in advance for your attention Regards Muriel *** Muriel: Arun gave a very good explanation, and here is another one: Below is an excerpt from one of our books, PROBLEMS AND SOLUTIONS IN WIRELESS COMMUNICATIONS AND EMC. I have used this explanation in some of my courses, and people seem to understand it pretty well. I hope this helps. *** © Copyright 1999 by TEMPEST INC. Chapter 7. Converting Broadband To Narrowband Units And Vice Versa. This is a source of much confusion to new EMC engineers. Lets look at a part of the frequency spectrum, say from 20 to 30 MHz : (1.) When you only have one frequency, say 25 MHz, and its amplitude is 1 volt rms, the spectrum looks like this: 20 MHz.|_30 MHz .25 MHz (2.) Now lets say you have a waveform composed of 2 signals. One is at 24 MHz and one is at 26 MHz , each one being 1 volt rms. If you look at either signal alone, its amplitude is still 1 volt rms, but if you look at them together, the amplitude of the combined wave form will be somewhat greater. 20 MHz___|__|___30 MHz 24.26. (3.) Now lets say that you have a whole lot of frequencies: 20 MHz.||30 MHz if you take a tiny piece of the spectrum, you may only see one signal _|__ © Copyright 1999 by TEMPEST INC if you take a piece that is 1 MHz wide, you will see several ||| if you take a piece that is 2 MHz wide, you will see even more || and the more you see, the more energy you have. Some signals are broadband. Their spectrum looks like the one in (3.) above. One example is a square wave. A better example is an impulse. How do you describe the amplitude of these signals? If you measure them with a 1 MHz bandwidth you will get one answer, if you measure them with a 10 MHz bandwidth you will get a different answer. This is why we have broadband units. With broadband units we can say that this signal gives you x volts for every megahertz-sized piece of the spectrum that you use to measure it. For example, if the signal in (3) gives you 10 volts when you take a 1 MHz piece, it will give you 20 volts if you take a 2 MHz piece, and 30 volts if you take a 3 MHz piece. The bigger the bandwidth, the more volts you get. In this case, we would say that the signal gives you 10 volts per Megahertz. Now lets say that you look at this signal with a 10 MHz bandwidth: © Copyright 1999 by TEMPEST INC We would see 10 Volts/MHz x 10 MHz bandwidth = 100 Volts if we look at it with a 2 MHz bandwidth, we would see 10 volts/MHz x 2 MHz = 20 Volts what if we only looked at it with a 500 kHz bandwidth? 500 kHz = 1/2 MHz 10 V/ MHz x 1/2 MHz = 10 x 1/2 = 5 Volts now lets do some problems: **© Copyright 1999 by TEMPEST INC. For more info, see: http://www.tempest-inc.com/pubs1.htm Regards, Lou . LOUIS T. GNECCO M.S.E.E., PRESIDENT TEMPEST INC. 112 ELDEN ST. HERNDON, VA 20170 (703) TEMPEST (836-7378) CERTIFIED ELECTROMAGNETIC COMPATIBILITY ENGINEER: CERT.# EMC-000543-NE CERTIFIED ELECTROSTATIC DISCHARGE CONTROL ENGINEER: CERT. # ESD-00143-NE CERTIFIED TEMPEST PROFESSIONAL, LEVEL II .. - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
RE: broadband narrowband emissions
I have to add to all of the previous replies:: Broadband in the sense of EMC : 1 a repeating square wave signal (no sinus) has harmonics in multiple of it's frequency its harmonics descend in amplitude with modulo sin(f)/f function this means that the harmonics in the peak of the sinus ( in the formula) descend linearly with frequency 2 a repeating small width pulse (no sinus) has harmonics in multiples of it's frequency f but the harmonics tend to descend in amplitude much slower. 3 a repeating infinite small pulse has a infinite bandwidth of harmonics on f distance from each other 4 a single pulse with infinite short time (dirac pulse) has infinite harmonics on 0 Hz spaced at even amplitude A ignition engine produces much of the third category pulses, it's repeating period is long (low frequency) and the pulse width is very small. It's frequency range goes well into several 100 of MHz. The spacing of the harmonics however is very close, equal to the ignition frequency (4-100 Hz) If one uses a spectrum analyzer with 10 kHz bandwidth the signal seems to have a continuous spectrum as many harmonics fall into this bandwidth : broadband interference (with 10 Hz bandwidth : many narrow band harmonics) Most frequency measurements are taken with a bandwidth of 120 kHz. so all pulse sources slower then approx. 60 kHz tend to appear as broadband interference . Attention : square waves don't have that much harmonics; it's pulses that do have Another way of generating broadband frequencies is modulation. Not just plain AM or FM modulation but also the kind of modulation that happens in databuses or address buses of microprocessors. Regards, Gert Gremmen Ing. == Ce-test, Qualified testing == Consultants in EMC, Electrical safety and Telecommunication Compliance tests for European standards and ce-marking Member of NEC/IEC voting committee for EMC. Our Web presence: http://www.cetest.nl List of current harmonized standards http://www.cetest.nl/emc-harm.htm 15 great tips for the EMC-designer http://www.cetest.nl/features01.htm -Original Message- From: owner-emc-p...@majordomo.ieee.org [mailto:owner-emc-p...@majordomo.ieee.org] On Behalf Of Muriel Bittencourt de Liz Sent: donderdag 7 oktober 1999 14:43 To: Lista de EMC da IEEE Subject:broadband narrowband emissions Group, I'd like to have a clear definition of what are narrowband and broadband emissions. This question may seem very plain for many members of EMC-PSTC, but I always heard/saw this definition for emission and I still couldn't make them clear to me.. Thanks in advance for your attention Regards Muriel -- == Muriel Bittencourt de Liz GRUCAD - Group for Conception Analysis of Electromagnetic Devices Santa Catarina Federal University - UFSC PO Box: 476 ZIP: 88040-900 - Florianópolis - SC - BRAZIL Phone: +55.48.331.9649 - Fax: +55.48.234.3790 e-mail: mur...@grucad.ufsc.br ICQ#: 9089332 Alternativa Adreso: mur...@esperanto.nu - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators). - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
RE: Hot Surface. Hot air.
Of course a piece of metal is really hot at 70 degrees ! One should keep in mind that safety standards are related to safety, not to prevent discomfort. Even when falling onto it, one may rise (and shine) before a serious burn occurs. 70 degrees C (25+45) is a well established limit throughout many many safety standards and can be used as a general no further test required signal for office and IT equipment. ( seen from the point of customer; not the test house ;)) The heated air issue is very different, remember a sauna where the Finnish (and many others), use to stay for over 30 minutes at over 80 degrees before jumping into the snow, and compare that to the serious injuries one gets when touching the air/vapor mixture coming for a cookery pan. Humidity is an issue here. Air flow speed is too ! Regards, Gert Gremmen Ing. == Ce-test, Qualified testing == Consultants in EMC, Electrical safety and Telecommunication Compliance tests for European standards and ce-marking Member of NEC/IEC voting committee for EMC. Our Web presence: http://www.cetest.nl List of current harmonized standards http://www.cetest.nl/emc-harm.htm 15 great tips for the EMC-designer http://www.cetest.nl/features01.htm -Original Message- From: owner-emc-p...@majordomo.ieee.org [mailto:owner-emc-p...@majordomo.ieee.org] On Behalf Of Israel Yeshurun Sent: donderdag 7 oktober 1999 12:43 To: 'emc-p...@ieee.org' Subject:Hot Surface. Hot air. Dear Group Fellows I would like to raise the following two issues: 1) UL1950 / EN60950 Safety standards, Subclause 5.1 - Heating, Table 16 part 2, specify permissible temperature rise for external surfaces of equipment in Operator Access Area.. For external surfaces, made of metal which may be touched, it allows temperature rise of 45 degrees Kelvin, assuming ambient temperature of 25 degrees Celsius it allows surface temperature of 70 degrees Celsius = 158 degrees Fahrenheit ! Note (4) in this table applies to external surfaces that are not likely to be touched in normal use and measure less than 50 mm, in this case it allows a temperature rise of 75 degrees K, that under 25 degrees C ambient allows 100 degrees C = 212 degrees F !! Now, 70 degrees C for external equipment surface that may be touched seems pretty high to me. 100 degrees C metal surface will, I believe, cause a burn to that part of the human body that touched it. So maybe my interpretation is not true ??and, can someone point another regulatory source for Hot surface permissible temperature ? 2) Regarding Hot air flowing out of equipment, in UL1950 / EN60950 I could not find a requirement or limit for the maximum permissible temperature for it, Can someone point another regulatory source for Hot air permissible temperature ? Note: The equipment I relate to is ITE or Office, but information from Machinery standards or other sources is welcome ! Many Thanks Israel Yeshurun - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators). - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
Metric Conduit
1) Does an EN or IEC standard exist for flexible steel (bendable) electrical conduit? 2) It has been reported that the trade sizes in the UK are 16 and 20 mm with 20 mm being the more common of the two. It has also been reported that the OD is the same as the trade size. Can someone confirm this is also true in other EU member states or any other state other than the US and Canada? - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
RE: Schaffner ESD gun Calibration
To everyone out there in EMC land, We at Schaffner EMC acknowledge that several mistakes were made in handling the calibration inquiry from Mr. Flinders and we find it quite regrettable since we are all working hard to provide the best customer service possible. We value every customer's business and want to be sure that every customer get's the service they need in a timely way. We perform hundreds of calibrations each year and understand that it is an important service to our customers. Additionally, it is an important part of our own business. Steps are being taken to streamline phone inquiries and improve our responsiveness. We sincerely hope that the steps we are taking will prevent this type of problem happening again. Please direct all calibration inquiries for North America to our Springfield, NJ office: (800) 367-5566, they'll be happy to help you. If you have any questions or concerns, please feel free to contact me directly. I apologize in advance if any of you think that this message is too commerical for the discussion group, that's not my intention. I thought it valuable for you all to know that we are listening and take these issues seriously. Greg Senko Sales Manager - Pulsed EMI Schaffner EMC (800) 367-5566 (978) 764-7358 mobile (603) 642 7975 fax gse...@schaffner.com -Original Message- From: owner-emc-p...@majordomo.ieee.org [mailto:randall.flind...@emulex.com] On Behalf Of Flinders, Randall Sent: Tuesday, October 05, 1999 5:36 PM To: 'emc-pstc' Subject:Schaffner ESD gun Calibration Greetings EMC Professionals - I was wondering if anyone out there in complianceland has info on any calibration vendors who provide calibration services for a Schaffner NSG-435 ESD Gun. My numerous attempts at getting a quote from Schaffner have been unsuccessful and I really need to get this thing calibrated before my next QA audit. Any leads or information would be appreciated! Thanks! Sincerely, Randall T. Flinders EMC Engineer Emulex Corporation (714) 513-8012 voice (714) 513-8265 fax randall.flind...@ieee.org __ __ __\ /__ __/ \__ E M U L E X aka.. Chairman Orange County Chapter IEEE EMC Society r.flind...@ieee.org - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
RE: Laser Standards
EN60825-1 (Safety of laser products. Part1. Equipment classification, requirements and user's guide.) gives all the labelling and marking requirements. Chris Colgan EMC Safety TAG McLaren Audio Ltd mailto:chris.col...@tagmclarenaudio.com -Original Message- From: rbus...@es.com [SMTP:rbus...@es.com] Sent: 07 October 1999 22:04 To: emc-p...@majordomo.ieee.org Subject: Laser Standards My company uses a 2 mw laser to align a reverse screen projector system. It is my understanding that this low power laser falls under the classification of Category 1 and is by definition, relatively safe. I thought I would purchase a copy of EN 60825 to ensure that we have address proper labeling and markings. Unfortunately this standard has 6 parts and could cost upwards of $800-1000. Can someone suggest which section I should order to identify the respective marking requirements. Thanks in advance... Rick Busche Evans Sutherland rbus...@es.com - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators). = Authorised on 10/08/99 at 09:43:41; code 37f48bf3E7C47895. The contents of this E-mail are confidential and for the exclusive use of the intended recipient. If you receive this E-mail in error, please delete it from your system immediately and notify us either by E-mail, telephone or fax. You should not copy, forward or otherwise disclose the content of the E-mail. TAG McLaren Audio Ltd, The Summit, 11 Latham Road Huntingdon, Cambs, PE18 6ZU Telephone : 01480 415600 (+44 1480 415600) Facsimile : 01480 52159 (+44 1480 52159) - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
Re: TS 001 reports for power supplies
Hello John, You are correct, in that you don't need a TS001 report, but a CB Scheme report to AS/NZS 3260 is not always acceptable either. The ACA will normally only accept a report from a lab accredited by an organisation that has a MOU with NATA. If your lab isn't recognised by the ACA it will be a little more difficult to make use of your reports. Regards Barry Esmore AUS-TICK (The Australian Compliance Professionals) Phone: + 61 3 9886 1345 Fax: + 61 3 9884 7272 Email: bar...@melbpc.org.au - Original Message - From: Boucher, John j...@bighorn.dr.lucent.com To: emc-p...@ieee.org Sent: Friday, October 08, 1999 7:54 AM Subject: TS 001 reports for power supplies All: In pursuing Australian approvals for ITE, I am getting requests for TS 001 reports for the system power supplies. These PSUs are embedded in the host ITE system (i.e., they are a component of that system), and the PSUs have CB Scheme reports that include the Australian variations. The systems have CB Scheme reports that include the PSU reports. I agree that the end system should have a TS 001 report, and if circuit packs are approved individually, those that connect to a telecom network should have TS 001 reports...but a power supply doesn't seem to fit the scope of TS 001. I have in the past supplied TS 001 reports for PSUs, but it seems silly, and I'd rather not do it unless it really is a requirement. John Boucher Lucent Technologies - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators). - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
Re: Radiated emission 60GHz
Sirs: Try TUV Product Service, in St. Paul, MN. Talk to Erik Borgstrom (651) 638 0242 or Tim O'Shea (651) 638 0279. They were able to go to 40 GHz a few years ago, and I'm pretty sure they could handle 60 GHz. One question would be relevant: What are the limits you are testing to? If memory serves, 461C doesn't normally test anywhere close to 60 GHz. If the limit is too low, then the noise floor and losses of the measuring apparatus can sometimes be higher than the limit you are testing to. Needless to say, that doesn't work too well. Good luck and best regards. Paul Cook NARTE Certified EMC Engineer Alpha EMC Inc 8540 West River Rd Minneapolis, Minnestoa 55444 Tel # (612)-561-2844 Fax #(612)-561-3400 E-mailpaulc...@skypoint.com Specialty - EMC Consulting -Original Message- From: Westin, Amund amund.wes...@dnv.com To: 'emc-pstc' emc-p...@ieee.org List-Post: emc-pstc@listserv.ieee.org Date: Thursday, October 07, 1999 5:35 PM Subject: Radiated emission 60GHz Members, We're looking for a test lab capable to measure radiated emission according to MIL-STD-461C up to 60GHz (yes, 60GHz)? Any suggestion ? Amund a...@dnv.com - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators). - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
Re: Hot Surface. Hot air.
Now, 70 degrees C for external equipment surface that may be touched seems pretty high to me. 100 degrees C metal surface will, I believe, cause a burn to that part of the human body that touched it. So maybe my interpretation is not true ??and, can someone point another regulatory source for Hot surface permissible temperature ? Israel, As others have pointed out - EN 563 can be used as a regulatory source. The standard ... applies to hot surfaces of all products and equipment that must or can be touched during their normal use. That includes the area of safety of machinery as well as any other applications. The standard does not apply, if a large area of the skin (approximately 10% or more of the skin of the whole body) can be in contact with the hot surface. This standard also does not apply to skin contact with more than 10% of the head or contact which could result in burns of vital areas of the face (e.g. burn resulting in the restriction of airways). In these cases severe injuries may occur, even if the surface temperature does not exceed the values specified in this standard. Does the EN 60950 consider these exceptions relevant? For your average office printer, PC, or monitor they probably aren't. There are however some fairly large equipment which are certified to this standard (mainframes?). You stated that 70 degrees C for external equipment surface that may be touched seems pretty high to me. Figure 2 of EN 563 indicates that at 70 degrees C, contact with a smooth uncoated metal surface for more than 1 second will result in a burn. For less than 1 second of contact time, there is no reliable data available (possible burn). Consider any forseeable problems - like someone falling onto your equipment. At 70 degrees, breaking a fall by placing your hands against the equipment could be rather unpleasant. And don't forget head contact. Regards, Matt - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
Re: TS 001 reports for power supplies
Hello John, You are correct, in that you don't need a TS001 report, but a CB Scheme report to AS/NZS 3260 is not always acceptable either. The ACA will normally only accept a report from a lab accredited by an organisation that has a MOU with NATA. If your lab isn't recognised by the ACA it will be a little more difficult to make use of your reports. Regards Barry Esmore AUS-TICK (The Australian Compliance Professionals) Phone: + 61 3 9886 1345 Fax: + 61 3 9884 7272 Email: bar...@melbpc.org.au - Original Message - From: Boucher, John j...@bighorn.dr.lucent.com To: emc-p...@ieee.org Sent: Friday, October 08, 1999 7:54 AM Subject: TS 001 reports for power supplies All: In pursuing Australian approvals for ITE, I am getting requests for TS 001 reports for the system power supplies. These PSUs are embedded in the host ITE system (i.e., they are a component of that system), and the PSUs have CB Scheme reports that include the Australian variations. The systems have CB Scheme reports that include the PSU reports. I agree that the end system should have a TS 001 report, and if circuit packs are approved individually, those that connect to a telecom network should have TS 001 reports...but a power supply doesn't seem to fit the scope of TS 001. I have in the past supplied TS 001 reports for PSUs, but it seems silly, and I'd rather not do it unless it really is a requirement. John Boucher Lucent Technologies - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
Re: Laser Standards
Rick, We have a copy and you can borrow it. I think that the cost of these standards is ridiculous, it is totally unjustified, and that we all ought to circumvent it by informally lending each other copies. There is absolutely nothing illegal about that. Regards, Lou s At 03:03 PM 10/7/1999 -0600, you wrote: My company uses a 2 mw laser to align a reverse screen projector system. It is my understanding that this low power laser falls under the classification of Category 1 and is by definition, relatively safe. I thought I would purchase a copy of EN 60825 to ensure that we have address proper labeling and markings. Unfortunately this standard has 6 parts and could cost upwards of $800-1000. Can someone suggest which section I should order to identify the respective marking requirements. Thanks in advance... Rick Busche Evans Sutherland rbus...@es.com - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators). - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
RE: The Doors
May the Doors of Perception enlighten all of us attending!! Tania Grant, tgr...@lucent.com tgr...@lucent.com Lucent Technologies, Communications Applications Group -- From: Dale Albright [SMTP:da...@emclabs.com] Sent: Thursday, October 07, 1999 1:46 PM To: emc-p...@ieee.org Subject: The Doors No, it is not about the rock group. It is about the doors of GR-1089-CORE. Over the last couple of days I have enjoyed observing multiple opinions and supporting evidence of the proper limit to apply to a product that has no cabinet doors (Table 3-1 Vs Table 3-2). It is clear that at minimum, the emission levels with cabinet doors open must meet the open door requirement and with cabinet doors closed must meet the closed door requirement. Perhaps this is a fine way to limit the shielding effectiveness of the enclosure so that in real life, when the doors have been removed and tossed, the threat of interference remains low. And how about cabinet doors. That type of language seams to indicate a large 7ft cabinet in which rack mount devices are contained. Is the actual housing/chassis of the EUT considered a cabinet ? There does seam to be an indication that another type of door exists - one that is not intended to be opened during EUT operation, maintenance, and/or repair. What type of door is this that remains closed during all of those circumstances. And what is the un-identified operation mode for which it is opened? And now finally for equipment that is not intended to be placed in a cabinet - maybe table-top or open-rack type. Notwithstanding the ultimate decision being driving by the RBOCs, what do you think? See some of you at the conference next week. Regards, Dale Albright EMCI - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
FW: Conduit entry dimensions
Posted for Eric Monk, intertest.systems...@ieee.org :-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-) Ed Price ed.pr...@cubic.com Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA. USA 619-505-2780 (Voice) 619-505-1502 (Fax) Military Avionics EMC Services Is Our Specialty Shake-Bake-Shock - Metrology - Reliability Analysis :-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-) -Original Message- From: Eric Monk [SMTP:intertest.systems...@ieee.org] Sent: Thursday, October 07, 1999 5:25 PM To: WOODS, RICHARD Cc: emc-p...@ieee.org Subject: RE: Conduit entry dimensions Hi Richard and group. ELECTRICAL CONDUIT SYSTEMS IN THE UK. Electrical conduit systems in the UK were converted during metrication to their nearest metric equivalent. Sizes refer to outside diameters. The more common sizes are 20 mm (3/4), 25 mm (1) and 32 mm (1 ½). Larger than this there is a tendency to opt for metal trunking. 16 mm must be based on the old 5/8 conduit which I cannot confirm is still available in the UK, until I receive an updated catalogue. Knockout dimensions are simply a clearance hole for the applicable metric diameter of the conduit size recommended for the application. The preferred method of termination at an enclosure is to cut and thread the conduit a distance from the box, equal to the diameter of the conduit. Fit an 'internally' screwed coupling (like an oversize sleeve) to the end of the conduit and secure it to the enclosure with an 'externally' screwed brass bush inserted from inside of the enclosure. (bush is the same diameter as conduit thread) The brass bush has an hexagonal flange larger than the thread to tighten onto the enclosure firmly gripping the edge of the knockout hole between the brass bush and the coupling and providing earth continuity. The inside edges of the brass bush are chamfered and smooth to prevent damage to cable insulation when cables are pulled through the conduit into the enclosure. Variations are to terminate into a threaded elbow or T-piece if this is dictated by space constraints. (ie. bush thro k/o into elbow - conduit into elbow) An alternative is to bring the threaded end of the conduit through the knockout and secure it in the enclosure with a locknut on the outside and an 'internally' screwed bush on the inside - but this is not considered good practice. However the termination is accomplished in practice, the knockout dimensions are the same - Close tolerance clearance hole for the diameter of conduit specified for the application. Regards Eric Monk. Technical Director - E M Consulting Ltd. INTERTest Systems is the trading name of the test laboratory of E M Consulting Ltd. * Your best support in TESTING situations * *INTERTest Systems UK * * International Product Certification * *ONE-STOP-SHOP for ALL testing* *** PO Box 321 - Bucks HP9 1XJ - England - ++44 (0)1494 673438 *** *INTERTest Systems UK is the trading name of * * the test laboratory of E M Consulting Ltd. * - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
Re: Hot Surface. Hot air.
Hello Israel: Unfortunately, safety standards only address one of the critical parameters, temperature, when specifying requirements for protection against a burn injury. You are absolutely correct that a metal surface with a temperature exceeding 50 C is capable of producing a burn injury. There are four parameters that must be taken into account: 1. temperature 2. thermal conductivity of the material 3. thermal capacity of the material 4 duration of contact One can easily touch aluminum foil at 100 C and higher for an indefinite duration because its thermal capacity is very low. One can easily touch plastic at 100 C for an indefinite duration because its thermal conductivity is very low. One cannot touch a 25 mm or larger cube of aluminum at 50 C for longer than 10 seconds without burning the skin because its thermal conductivity and thermal capacity are high. There is no regulatory source that addresses all four parameters. Instead, you must consider your training in the field of thermodynamics, and you must consider the literature where the burn parameters of human skin are published. If you look, you will find published data relating skin temperature and duration to pain and to skin burns.** Unfortunately, the authors of our various safety standards chose the BOGSAT* method of determining safety rather than doing research. The requirements you mentioned are indeed inadequate. But, you have already determined that. So, using your training as an engineer, you can make your product safe for both the hot surfaces and the hot air in spite of the standard. Best regards, Rich - Richard Nute Product Safety Engineer Hewlett-Packard Company Product Regulations Group AiO Division Tel : +1 858 655 3329 16399 West Bernardo Drive FAX : +1 858 655 4979 San Diego, California 92127 e-mail: ri...@sdd.hp.com - * BOGSAT = Bunch Of Guys Sitting Around Talking. ** Stoll, Alice M., Thermal Properties of Human Skin related to Nondestructive Measurement of Epidermal Thickness, Journal of Investigative Dermatology, September, 1977, pp. 328-332. - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
FW: broadband narrowband emissions
Hello, I quote MIL STD 462 # 4.2.6: A: The EMI meter shall be tuned over a range of * 2 impulse band widths around the centre frequency of emission. A change in peak detector response of 3 dB or less indicates a broad band emission. A change of greater than 3dB indicates a narrow band emission. B: Measure the PRF of the emission. If the PRF is less than or equal to the impulse BW of EMI receiver it is a broad band emission, if greater it is a narrow band emission. Also practically, the easiest way to determine a NB emission is to drop down or increase the measuring BW 1 or 2 steps in a routine EMI receiver sweep around the emission in a broad span; if the emission remains constant, it is NB emission. Broad band emissions would drop approx 10 dB per step change in the bandwidth. Sweep time could also be varied, time domain BB emissions would change with sweep time; frequency domain NB emissions would more or less remain constant. You have to normalise BB emissions to a 1MHz BW, irrespective of actual measurement BW used. Otherwise, people could shonk a broad band CE03 or RE02 test pass. Computer clocks (and its harmonics) and intentional CW or modulated transmitters generally generate frequency domain NB emission. Commutator motors, thermostats, serial comms links generally generate time domain BB emissions. And finally yes, MIL STD 461D and most commercial standards have got around this NB/BB emission discrimination mess by specifying the measurement BW. Hope this helps. Regards Arun Kaore EMC Engineer ADI Limited Test Evaluation Centre Forrester Road, St Marys NSW 2760 P O Box: 315, St Marys NSW 1790 Tel: 61 2 9673 8375 Fax: 61 2 9673 8321 Email: kao...@sg.adi-limited.com.au mailto:kao...@sg.adi-limited.com.au -Original Message- From: Price, Ed [mailto:ed.pr...@cubic.com] mailto:[mailto:ed.pr...@cubic.com] Sent: Friday, 08 October, 1999 4:21 To: 'Muriel Bittencourt de Liz'; Lista de EMC da IEEE Subject:RE: broadband narrowband emissions -Original Message- From: Muriel Bittencourt de Liz [SMTP:mur...@grucad.ufsc.br] mailto:[SMTP:mur...@grucad.ufsc.br] Sent: Thursday, October 07, 1999 5:43 AM To: Lista de EMC da IEEE Subject: broadband narrowband emissions Group, I'd like to have a clear definition of what are narrowband and broadband emissions. This question may seem very plain for many members of EMC-PSTC, but I always heard/saw this definition for emission and I still couldn't make them clear to me.. Thanks in advance for your attention Regards Muriel -- == Muriel Bittencourt de Liz GRUCAD - Group for Conception Analysis of Electromagnetic Devices Santa Catarina Federal University - UFSC PO Box: 476 ZIP: 88040-900 - Florianópolis - SC - BRAZIL Phone: +55.48.331.9649 - Fax: +55.48.234.3790 e-mail: mur...@grucad.ufsc.br mailto:mur...@grucad.ufsc.br ICQ#: 9089332 Alternativa Adreso: mur...@esperanto.nu mailto:mur...@esperanto.nu - Muriel: Narrowband and Broadband are the two extremes of the spectral distribution of a signal's power. The classic NB emission has all of its power contained within a narrow range of the spectrum. Think of a perfect sine wave generator, with no sidebands or frequency instability. But how narrow is narrow? All of the power is
