Re: Ground Hog Day.
Yup, here too. I was just about to call our ISP and tell them to check my mailbox for some EMC-mail magnet or something. I trust it will be fixed by the boys at the Top. A. Bank Chris Dupres wrote: Hi EMC and safety folk. Is it me, or is something re-sending a load of mails from the group over and over again. I clear my mail box, and during the next few hours a whole load of mails dated 20 Feb re-appear in my box. I clear them, and it happens again. I've received the same mails on FCC stuff and CTI about five or six times thus far. They were interesting the FIRST time! Anyone else getting this phenomenon? Chris Dupres Surrey, UK. -- Andrew Bank Custom Standards Services, Inc. http://www.cssinfo.com Engineering Documents and Information Services (800) 699-9277 (734) 930-9277 FAX (734) 930-9088 Ask me about --IEC Standards on CD-ROM (http://www.cssinfo.com/iec.html) --PERINORM - The new International Standards Database (http://www.cssinfo.com/perinorm.html) --The new 1998 ASME Boiler and Pressure Vessel Code (http://www.cssinfo.com/BPV1998.html) These are all available now at great discounts!
Re: Ground Hog Day.
Yes I am getting it too!!
Re: Ground Hog Day.
Hi Chris, The same thing is happening to me. I was wondering if there was a problem with my local server not deleting my files after I download. I was just getting ready to call my local provider when I got your message. Anyone know what's going on? Fred Waechter Chris Dupres wrote: Hi EMC and safety folk. Is it me, or is something re-sending a load of mails from the group over and over again. I clear my mail box, and during the next few hours a whole load of mails dated 20 Feb re-appear in my box. I clear them, and it happens again. I've received the same mails on FCC stuff and CTI about five or six times thus far. They were interesting the FIRST time! Anyone else getting this phenomenon? Chris Dupres Surrey, UK.
RE: FCC Questions.
Hello Chris (and group), I hope no one feels offended by saying hello to the group. :). You are right Chris, as a UK citizen you may certainly have experienced the way our fellow engineers at the other side of the Ocean treat the problem of EMC. I think however that, just as in Europe were other factors as interference limiting were influencing the EMC laws, the same will happen in the US. Asymmetric load in 3-phase cables and excessive neutral current caused by 3th harmonics of the main current were reason for the introduction of the EN 61000-3-2 for limiting harmonics current. This problem is valid anywhere in the world. Dips caused by switching loads and introducing flicker effects in lighting equipment nearby is irritating everywhere. The item of opening the market has the same impact on the global market as it has just in the EC. If you look at the Australian EMC regulations, then you may conclude it is very similar to the ce-system. I think that the way we handle essential safety and EMC-matters in Europe based on the so-called new approach directives using harmonized international standards is an extremely clever chosen system. Combined with the routes of self certification for less critical human safety related issues and the European type test modules which rely (partially) on ISO 9000 we found a means of relatively easy and market conformance to the new directives leading not only to an open market , but to better products. Already now we can see that product quality improves. Customers of me state that the number of service calls for newer products drastically lowers, especially those that lead to a no-error-on-service-dept conclusion. I therefore draw the conclusion that those problems were EMC-related. Please, hello there in the US what do YOU think of this. To provoke some reactions: Don't say that it's not relevant to you, or that US regulations are enough. I personally am very happy to receive US apparatus on my test bank, because it is a lot of work (= money) to get them within EU specs. Every time i am surprised by the number of safety and emc problems US equipment contain. Just point to them with a GSM phone, and they virtually short circuit. ! Regards, Gert Gremmen == CE-test, qualified testing, Consultancy, Compliance tests for EMC and Electrical Safety 15 Great EMC-design tips available ! Visit our site : http://www.cetest.nl The Dutch Electronics Directory http://www.cetest.nl/electronics.htm == -Oorspronkelijk bericht- Van:Chris Dupres [SMTP:chris_dup...@compuserve.com] Verzonden: zondag 22 februari 1998 0:09 Aan:Ing. Gert Gremmen CC: emc-pstc Onderwerp: RE: FCC Questions. Hi Gert. At the end of your interesting response you said: Its my opinion that within a few years, the American market will somehow copy the European set-up. I've worried about this. The Euro rules are in place, as I need not remind you, (but the left hand side of the Atlantic mayneed a reminder), because of the Treaty of Rome in the '60s which brought about the need to get all Euro products to the same technical standard for the purposes of Free Movement Of Goods across borders within Europe. i.e the Common Market. The primary reason for the Euro EMC rules being there is therefore political/trade related, and not the need to reduce EMC emissions - though that is not a bad thing. The USA and other countries round the world have quite different reasons for introducing EMC controls, some of which may protectionist, some born of the need to keep interference down. The reasons are many, and because of this technical standards have a different bias. In order to trade with Europe, the USA and others will need to climb over the CE walls of Fortress Europe which they will almost certainly do, but I doubt that they will need to go as far as, for instance, BSEN 61000-3-2, and -3-3. Harmonics and dips, for their own internal purposes. Just a thought... Chris Duprés Surrey, UK.
Ground Hog Day.
Hi EMC and safety folk. Is it me, or is something re-sending a load of mails from the group over and over again. I clear my mail box, and during the next few hours a whole load of mails dated 20 Feb re-appear in my box. I clear them, and it happens again. I've received the same mails on FCC stuff and CTI about five or six times thus far. They were interesting the FIRST time! Anyone else getting this phenomenon? Chris Dupres Surrey, UK.
RE: FCC Questions.
Some notes to add to this discussion: Not all Class B devices have to be certified (regestered) with the FCC. Many domestically used devices that do not connect to a personal computer are subject to VERIFICATION - where the manufacturer simply tests the product and keeps the test report on file. However, there are labelling requirements and a statement to the user that must be present in the user manual. The typical cost of the FCC test for a verified device is about $1000 - $1600 for one day of testing and $400 for the test report. To determine if your device is subject to Verification, Certification, or Notification, you will need to check the FCC CFR 47, Parts 2 and 15. You can purchase Parts 0-19 from your local government Bookstore, for about $35.00. There are bookstores all over the country, however, here is the Los Angeles store phone number: (213) 239-9844. The document is FCC Code of Federal Regulations 47, Parts 0-19. -Original Message- From: Jon Bertrand [SMTP:j...@cirris.com] Sent: Friday, February 20, 1998 9:13 AM To: emc-pstc Subject: FCC Questions. Hello Everyone, A lot of budding midnight designers ask these questions on the microcontroller newsgroups so I thought I'd ask them here - and learn something :) (If I've missed some FAQ that covers this please let me know.) 1) Say I'm building some microcontroller based widget in my home business that runs model trains (or whatever). It's not an intential transmitter, its typically used in the home. And I want to sell them. Do I need some FCC approval. Specifically do I need to: 1.a) Spend money having someone test emissions. 1.b) File some paperwork with the FCC. 2) If I don't have the money for testing - but I really do know how to keep my microcontroller quiet (i.e I know loop area, di/dt, and maybe even have done lots of other 'approved' products) - and a little in-home testing shows it doesn't bother the rabbit ears or show-up on the AM or FM radio. Would I be in violation of some law if I just sold the darn thing. 2.a) Would I be in violation if it really was quiet to CISPR (i.e. would have passed). (i.e. is there now a CE mark like compliance that lets me self declare and assert who's responsible). 3) How does the FCC verify that I don't pollute the EM band - do they random sample train widgets or wait for someone to complain. Thanks, Jon Bertrand j...@cirris.com
[Fwd: FCC Questions.]
Hi All, Here is my two cents worth. (if it is worth anything) When to test. Any digital device that uses clock speeds equal to or greater than 9 kHz must be tested. Only computers and computer peripherals are allowed Class A levels when they are not home use, all other devices must meet Class B When to involve the FCC. Case 1 If the digital device is not a personal computer or personal computer peripheral the manufacturer must keep a verification report on file. Case 2 If the digital device is home use and is a personal computer or personal computer peripheral the manufacturer can use the FCC Deceleration of Conformity (FCC DoC) or Certification routes to authorization. FCC DoC requires testing be done at an accredited lab and no submittal to FCC. With Certification use a lab listed (listed is not the same as accredited) with the FCC, submit the report and $$$ fee to the FCC for approval after 8 weeks. Electronic copies of the latest CFR 47 Part 15, Subpart B are available at the FCC web site, www.ffc.gov/oet Rick Linford DNB ENGINEERING, INC. ---BeginMessage--- Hi Jon, I'll take the plunge and give you some of my answers below ... From: Jon Bertrand j...@cirris.com Hello Everyone, A lot of budding midnight designers ask these questions on the microcontroller newsgroups so I thought I'd ask them here - and learn something :) (If I've missed some FAQ that covers this please let me know.) 1) Say I'm building some microcontroller based widget in my home business that runs model trains (or whatever). It's not an intential transmitter, its typically used in the home. And I want to sell them. Do I need some FCC approval. Yes. CFR 47 Part 15 specifies not only minimum frequencies at which your little device operates (I believe anything above 7kHz) but also power (I believe anything above picowatts). I'm positive someone here will list the specifics. I unfortunately do not have the standard in front of me. Specifically do I need to: 1.a) Spend money having someone test emissions. Yes. For reason why see answer to 1.b) below. 1.b) File some paperwork with the FCC. Yes. Since your device will be used in a residence, you will need Class B which involves registration. Registration will cost you. 2) If I don't have the money for testing - but I really do know how to keep my microcontroller quiet (i.e I know loop area, di/dt, and maybe even have done lots of other 'approved' products) - and a little in-home testing shows it doesn't bother the rabbit ears or show-up on the AM or FM radio. Would I be in violation of some law if I just sold the darn thing. By the book, yes. See CFR 47 Part 15. CFR I'm sure you know stands for Code of Federal Regulations, i.e. Federal Law. You're also assuming that the only reason you'll get in trouble is for interference. Not really true. Take it to a trade show, have it be the quietest thing around, have some representative from the FCC look for a label or proof of testing and there is none, you're in trouble. What's the probability of this happening? Who knows... 2.a) Would I be in violation if it really was quiet to CISPR (i.e. would have passed). (i.e. is there now a CE mark like compliance that lets me self declare and assert who's responsible). Woaw! Wait a minute. CE mark? Thought is was just FCC. You're going to Europe, haven't tested the device, are assuming it's quiet and yet you're marking it? Don't do it. This is not FCC approval. The FCC only validates testing for the US. It really doesn't approve anything (if I remember a previous discussion about this from way back). 3) How does the FCC verify that I don't pollute the EM band - do they random sample train widgets or wait for someone to complain. Depending upon some factors - both. Remember, the complaint could be from a competitor... I was at a trade show a long time ago where someone was yanked out of their booth by Federal Marshals. Bottom line for whoever is asking you, get it done, get the thing passed, then don't worry about it. Oh yea, don't forget about UL either. ;) Regards, Doug ---End Message--- attachment: vcard.vcf
Hot Wire Ignition Test
Hi, I am working on a research project about ignition of plastics used in electrical equipment. As you all know, UL 746C has a test called hot wire ignition. The test is specified by ASTM D 3874 - Standard Test Method for Ignition of Materials by Hot Wire Sources. I would be grateful if someone provided me the following information: 1. This standard (ASTM) was first published in 1988, under jurisdiction of ASTM Committee D-9 on Electrical and Electronic Insulating Materials. I have not found any research work that provided basis for this test. Does anybody know of any? 2. The standard requires a power density of 0.26 W/mm to be dissipated in 250 mm of Nichrome wire (24 AWG, 0.05 mm in diameter). How these values were established? (By the way, the standard suggests that a current of 60 A and 1.5 V should result in a power density of 0.3 W/mm. I figured out that they meant 6.0 A and 15 V, since the calibration of the wire must be made from 1 to 8 A. Furthermore, a current of 60 A through a 24 AWG nichrome wire is just unfeasible). 3. For those who have ever performed this test, what was the variability of the mean time to ignition between samples? Any additional information regarding this test would be very appreciated. Thanks! Luiz Claudio Bonilla de Araujo Graduate Student - Safety Engineering Texas AM University - College Station - TX http://www.tamu.edu
FCC Questions.
Jon, Some of my FCC knowledge is a little old, but here's what I believe still applies. If your widget uses digital logic clocked at 10kHz or above, it is subject to FCC regulations and all that entails. The FCC does permit self-declaration for some types of products, but you would be in a tough spot if you self-declared without any reasonable emissions testing and data at some kind of EMC test facility. The self-declaration allowed for CE marking does not apply unless you were selling in Europe, and again would have to have the data to back up your self declaration. The FCC does engage in enforcement activities, e.g. sampling products from store shelves. However, it is more likely that a complaint would have to occur before it reached their attention. If it meets requirements, you have to explain why it bore no FCC marking. If it did not meet, and bore no marking, you might be in deep doo doo. If the remore control for my TV set must bear an FCC statement (and it does) there is little doubt that a more powerful microcontroller would be subject as well, even though it is an unintentional radiator. These are only my opinions and are worth what you paid for them. George Alspaugh Lexmark International -- Forwarded by George Alspaugh on 02/20/98 12:31 PM --- Please respond to jonb%cirris@interlock.lexmark.com To: emc-pstc%majordomo.ieee@interlock.lexmark.com cc:(bcc: George Alspaugh) bcc: George Alspaugh Subject: FCC Questions. Hello Everyone, A lot of budding midnight designers ask these questions on the microcontroller newsgroups so I thought I'd ask them here - and learn something :) (If I've missed some FAQ that covers this please let me know.) 1) Say I'm building some microcontroller based widget in my home business that runs model trains (or whatever). It's not an intential transmitter, its typically used in the home. And I want to sell them. Do I need some FCC approval. Specifically do I need to: 1.a) Spend money having someone test emissions. 1.b) File some paperwork with the FCC. 2) If I don't have the money for testing - but I really do know how to keep my microcontroller quiet (i.e I know loop area, di/dt, and maybe even have done lots of other 'approved' products) - and a little in-home testing shows it doesn't bother the rabbit ears or show-up on the AM or FM radio. Would I be in violation of some law if I just sold the darn thing. 2.a) Would I be in violation if it really was quiet to CISPR (i.e. would have passed). (i.e. is there now a CE mark like compliance that lets me self declare and assert who's responsible). 3) How does the FCC verify that I don't pollute the EM band - do they random sample train widgets or wait for someone to complain. Thanks, Jon Bertrand j...@cirris.com
FCC Questions.
Hello Everyone, A lot of budding midnight designers ask these questions on the microcontroller newsgroups so I thought I'd ask them here - and learn something :) (If I've missed some FAQ that covers this please let me know.) 1) Say I'm building some microcontroller based widget in my home business that runs model trains (or whatever). It's not an intential transmitter, its typically used in the home. And I want to sell them. Do I need some FCC approval. Specifically do I need to: 1.a) Spend money having someone test emissions. 1.b) File some paperwork with the FCC. 2) If I don't have the money for testing - but I really do know how to keep my microcontroller quiet (i.e I know loop area, di/dt, and maybe even have done lots of other 'approved' products) - and a little in-home testing shows it doesn't bother the rabbit ears or show-up on the AM or FM radio. Would I be in violation of some law if I just sold the darn thing. 2.a) Would I be in violation if it really was quiet to CISPR (i.e. would have passed). (i.e. is there now a CE mark like compliance that lets me self declare and assert who's responsible). 3) How does the FCC verify that I don't pollute the EM band - do they random sample train widgets or wait for someone to complain. Thanks, Jon Bertrand j...@cirris.com
RE: MOV's
One possibility is a MOV in series with a fuse (or spark gap in some cases.) The MOV limits overvoltage current, the fuse or spark gap provides required voltage standoff. ___ Heber Farnsworth, P.E. Physio-Control Corp, Seattle, USA -Original Message- From: Stewart, Judd [SMTP:stewart.jud...@sd.littondsd.com] Sent: Thursday, February 19, 1998 2:00 PM To: 'EMC-PST' Subject: MOV's Hello from San Diego, Does anyone know of components that will meet the requirements of EN60950 and also function as a MOV. The component will bridge basic insulation in a primary circuit. Thanks Judd Stewart Litton Data Systems 619.623.6639
