FW: Thermocouple alternative?
-Original Message- From: Chris Maxwell [mailto:chris.maxw...@nettest.com] Sent: Monday, January 07, 2002 9:20 AM To: Crabb, John; emc-p...@majordomo.ieee.org Subject: Re: Thermocouple alternative? John, We use T-type thermocouples which are not as ferrous as J and K types, and therefore not as susceptible to electromagnetic fields. Still, we run into problems (we make high-power switching power supplies, by the way). Sometimes noise is coupled into the thermocouple wire. I have fixed this with a choke in the past. I have had difficulty convincing agencies to accept data from non-contact thermal measurement systems, e.g., infrared or optical. The way that I have convinced them is to take side-by-side measurements on something that is not producing strong fields using a thermocouple and the non-contact measuring device. When they saw that the two devices measured the same temperature, they were satisfied. Good Luck, Jeff Jenkins Advanced Energy Industries, Inc. Fort Collins, CO -Original Message- From: Crabb, John [SMTP:jo...@exchange.scotland.ncr.com] Sent: Monday, January 07, 2002 9:02 AM To: emc-p...@majordomo.ieee.org Subject: RE: EMC-related safety issues Seeing that we have got round to the subject of thermocouples, etc, I often use a Solartron SI3535D datalogger with thermocouples for measuring component temperatures, and find quite often that it does not give correct readings when thermocouples are placed on transformers in switching power supplies, high voltage transformers in monitors, etc. I can get a correct reading by switching off the EUT momentarily, obviously removing the source of the problem. Note that the problem can occur even if the thermocouple is not making an electrical connection to the component winding involved. Any suggestions how to overcome this ? My previous antique datalogger didn't have this problem, but it eventually had to be scrapped due to lack of spare parts - and the expectation that a more modern unit would be better !. Regards, John Crabb, Development Excellence (Product Safety) , NCR Financial Solutions Group Ltd., Kingsway West, Dundee, Scotland. DD2 3XX E-Mail :john.cr...@scotland.ncr.com Tel: +44 (0)1382-592289 (direct ). Fax +44 (0)1382-622243. VoicePlus 6-341-2289. --- 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, including any attachments, may contain information that is confidential and proprietary information of Advanced Energy Industries, Inc. The dissemination, distribution, use or copying of this message or any of its attachments is strictly prohibited without the express written consent of Advanced Energy Industries, Inc. --- 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.
standards - water-cooled electrical devices
Hi All, Can anyone recommend standards that do a good job of addressing separation of water from electrical devices? Perhaps submersible pumps, hot tubs, or water-cooled welders? I have a product that does not fall into any of these categories but does contain water-cooled, high-voltage electrical devices. Thanks. Jeff Jenkins Advanced Energy Industries, Inc. Fort Collins, CO _ This message, including any attachments, may contain information that is confidential and proprietary information of Advanced Energy Industries, Inc. The dissemination, distribution, use or copying of this message or any of its attachments is strictly prohibited without the express written consent of Advanced Energy Industries, Inc. --- 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.
voltage dip requirements
Hello Group, I just received a brand new, shiny copy of EN 61000-6-2. The voltage dip / interruption requirements are not clear to me. Table 4 quantifies dip and interruption levels as % reduction. So, when they say a 30% reduction, I assume they mean that the voltage is reduced to 70% of its nominal value, e.g. 120 Vac is reduced to 84 Vac. This is well and good, but it seems illogical to me that the duration of the dip should increase with its severity. For instance, while they specify a 30% reduction for one-half cycle, they specify a 60% reduction for 50 cycles and a 95% reduction for 250 cycles! Say it isn't so! I'm clinging to a desperate hope that they don't mean x, but rather 1-x. Regards, Jeff Jenkins Advanced Energy Industries, Inc. Fort Collins, CO USA --- 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
FW: Scope of EN 61000-4-11
Thank you to all who responded. I have the information I need now. Regards, Jeff Jenkins Advanced Energy Industries, Inc. Fort Collins, CO -Original Message- From: JENKINS, JEFF Sent: Saturday, February 03, 2001 11:41 AM To: emc-p...@ieee.org Subject: Scope of EN 61000-4-11 I have ordered this standard, but I could use a little help while I wait for it to arrive. I have heard rumours that it applies only to single-phase equipment that draws 16A or less. Is this true? Thanks. Jeff Jenkins Advanced Energy Industries, Inc. Fort Collins, CO --- 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
Scope of EN 61000-4-11
I have ordered this standard, but I could use a little help while I wait for it to arrive. I have heard rumours that it applies only to single-phase equipment that draws 16A or less. Is this true? Thanks. Jeff Jenkins Advanced Energy Industries, Inc. Fort Collins, CO --- 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
900 MHz for industrial use
Greetings, I have an internal client asking about using a 900 MHz chip set to perform communications within an industrial product. I am unfamiliar with the rules governing industrial emissions at this frequency. Our products are used worldwide. Your help is appreciated. Regards, Jeff Jenkins Advanced Energy Industries, Inc. Fort Collins, CO USA --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
RE: PCB fuse trace
In addition, there is a concern about where the particles of metal from the blasted trace will end up, or where the curled up trace will go. This may compromise required insulation. As Peter points out, this may be difficult to repeat twice with the same result. Regards, Jeff Jenkins Regulatory Compliance Engineer Advanced Energy Industries, Inc. Fort Collins, CO USA Opinions expressed are my own and are not necessarily shared by Advanced Energy Industries, Inc. or its affiliates. -Original Message- From: Peter Tarver [mailto:ptar...@nortelnetworks.com] Sent: Thursday, September 14, 2000 9:40 AM To: Matsuda, Ken; emc-p...@ieee.org Subject: RE: PCB fuse trace My experience with safety agencies is they do not want to rely on traces opening to act as fuses and no standards have been developed, that I am aware of, to address this issue. Fuses certification gets involved in the metallic alloys used, to the fraction of a percent, the conductor size, additional construction features, such as heat sinking elements for time delay characteristics, tension loading for fast action, blah, blah, blah. Most of these issues are far too difficult to control for pwb traces, especially considering the etching processes don't lend themselves to the level of control necessary to be a reliable fuse of specific ratings. Additionally, the heat sinking from pwb layout of one product to another or varying copper thicknesses in a product line, adding or subtracting ground planes for emc, the variability of soldering processes and location/thermal capacity of components on the pwb make this seem far too cumbersome to want to work with. BTW, this is a very different world from repeated twice, same result single-fault testing, where a pwb trace opens. Regards, Peter L. Tarver, PE ptar...@nortelnetworks.com -Original Message- From: Matsuda, Ken [ mailto:matsu...@curtisinst.com mailto:matsu...@curtisinst.com ] Sent: Thursday, September 14, 2000 7:02 AM To: emc-p...@ieee.org Subject: PCB fuse trace I was wondering if anyone knew a standard for the US, Canada, and Europe that covers PCB board traces that can be used as fuses? Thanks for the help, Ken --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
High frequency overcurrent protection
Hello Group, Are any of you familiar with high-frequency overcurrent protection devices that will satisfy the standards applicable to fuses and/or circuit breakers? Fuses and circuit breakers are generally rated for either DC or 50/60 Hz applications. I have an application that uses a high-frequency (30-40kHz) power distribution buss with power conversion modules (inverters) that plug into the buss. We want to provide overcurrent protection for each individual module. It's easy to imagine a number of different ways to provide overcurrent protection, including but not limited to waveform sampling, current transformers, etc., but I need something that is compliant. . . . Any help would be appreciated. Thanks, Jeff Jenkins Regulatory Compliance Advanced Energy Industries, Inc. Fort Collins, CO USA --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
RE: German to English Translation
Richard, Try this website: http://dict.leo.org/ Regards, Jeff Jenkins Advanced Energy Industries, Inc. Fort Collins, CO USA -Original Message- From: wo...@sensormatic.com [mailto:wo...@sensormatic.com] Sent: Thursday, May 25, 2000 7:07 AM To: emc-p...@majordomo.ieee.org Subject: German to English Translation Would someone please translate the following Germans words into English? versicherte Errichters Thanks, Richard Woods --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
ISM prohibited frequencies
I have a question about ISM prohibited frequencies according to 47 CFR Part 18. Section 18.303 says that operation in the prohibited frequency bands is not allowed. My question is, what is their interpretation of the word operation? 1.) If the equipment in question uses these frequencies only for internal functioning, is it still prohibited? (In other words, the energy does not intentionally leave the equipment enclosure.) 2.) If the equipment sweeps through a prohibited band while it auto-tunes, is this a problem? 3.) What if the fundamental operating frequency of the equipment is outside the prohibited bands, but there is significant harmonic energy within a prohibited band? Thanks, Jeff Jenkins Regulatory Compliance Advanced Energy Industries, Inc. Fort Collins, CO USA --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
RE: Breakdown voltage between pcb layers
Hi David, We have some experience with this at my company, although not involving TNV circuits. My company produces high voltage, high frequency power conversion equipment mainly for the semiconductor manufacturing industry. We are constantly challenging the voltage withstand capabilities of materials, and pcb's are no exception. We use FR-4 pcb material, and for years we have used a voltage withstand guideline of 1000 V/mil for the base material and 500 V/mil for the pre-preg. As another responder has already noted, you should be able to get numbers for your specific material from your supplier. Once you have these numbers, you get to make some easy calculations. The way we do it is to take the required transient withstand voltage (based on the operating voltage and the installation category) and divide it by the voltage withstand guideline for the material in question. This will give you two numbers: one for base material and one for pre-preg. Since you are dividing V by V/mil, the results will be in mils. Now you know how thick the base and pre-preg layers must be. If you have just a two-layer board, the pre-preg number doesn't matter and you can stop reading here. If you have a multi-layer board, read on. . . . You must account for the copper on inner layers, since this subtracts from your insulating material in the z axis (vertical dimension). The guideline we use is 1.4 mils per ounce of copper. So if you're using 2 oz. copper, your trace will be about 2.8 mils high. This gets subtracted from the thickness of the pcb layer. If you calculated that you needed an 18 mil thick pre-preg layer, and you're using 2 oz. copper, you actually need a 21 mil thick pre-preg layer because of the copper thickness. Something to consider: To what tolerance can your pcb manufacturer hold layer thicknesses, especially pre-preg layers? Obviously this affects voltage withstand capability and should be taken into account when making your calculations. If you have through-hole parts or vias in the area of an inner layer ground plane, of course you need to think about inner layer x,y plane (lateral) creepage requirements. Generally speaking, inner layer creepage distances must be the same as outer layers -- but, there is a way around this that allows for reduced inner layer spacings. The trick is to classify the inner layer x,y plane dimensions as through-thickness insulation, owing to epoxy bonding. Then you can reduce the dimension to 0.4 mm in accordance with UL 1950. You may choose not to reduce to this level; we don't. We use 1 mm minimum. The gotcha is that your agency might insist that your pcb manufacturer be certified to UL 796 in order to allow this. (Ours did.) We have used these methods for several years now with great success and acceptance from various agencies. Jeff Jenkins Regulatory Compliance Advanced Energy Industries, Inc. Fort Collins, CO USA -Original Message- From: David Gelfand [mailto:gelf...@memotec.com] Sent: Tuesday, May 23, 2000 9:33 AM To: 'EMC-PSTC Internet Forum' Subject: Breakdown voltage between pcb layers Hello group, We have an emissions problem on a board and I would like to suggest a ground plane in the area of an RJ-45 jack (TNV-1). But we have always asked our PCB designers to leave TNV traces free of ground and power planes to avoid arcing during surge and dialectric strength tests. Does anyone know where to find specs on breakdown voltages between PCB layers? Has anyone successfully used ground planes above or below TNV traces? We are testing to UL1950 and Part 68. Any input would be much appreciated. Thank you, David. David Gelfand Regulatory Approvals Group Leader Memotec Communications Inc. Montreal Canada --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
FCC 47 CFR Part 18
Does anyone know if there are laws that require semiconductor processing equipment and other types of industrial equipment to conform to FCC 47 CFR Part 18? From time to time we get inquiries about this and we're wondering what is behind it. Thanks, Jeff Jenkins Advanced Energy Industries, Inc. - 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).
NEMA 4 cabinet questions
Some questions about using a NEMA 4 cabinet: (1) Is the environment inside the cabinet considered pollution degree 1, no matter what the external environment is? (2) We need to install a water drain at the bottom of the cabinet. Can we use a positive-acting valve without violating the cabinet's NEMA 4 rating? (3) The cabinet doors will need to be opened periodically for maintenance. How does this affect the pollution degree inside the cabinet? By the way, these questions are in the context of certifying the product under the CB 950 scheme. Thanks, Jeff Jenkins Advanced Energy Industries, Inc. - 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).
EN 61010-1 vs. UL 3101-1
Hello Group, Does anyone know the differences between EN 61010-1 and UL 3101-1? Thanks, Jeff Jenkins Advanced Energy Industries, Inc. - 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: UL1950/EN 60 950 Spacings
Peter, We have the same situation with my company's products. We use the nominal line to neutral voltage even when no neutral is present. Our experience has been that the certifying agencies accept this. Best Regards, Jeff Jenkins Senior Regulatory Compliance Engineer Advanced Energy Industries, Inc. Fort Collins, CO USA Opinions are my own, etc. -Original Message- From: pe...@itl.co.il [mailto:pe...@itl.co.il] Sent: Tuesday, July 06, 1999 1:57 PM To: emc-p...@ieee.org Cc: al...@itl.co.il; ico...@itl.co.il; zoh...@itl.co.il; plei...@itl.co.il; sgn...@itl.co.il Subject: UL1950/EN 60 950 Spacings Dear All, The subject standards specify that Tables 3, 4, 5 (clearances) are based on nominal line to neutral supply voltages. For equipment powered by 3 phase (L1,L2,L3 and earth) WITHOUT a neutral, how should the nominal supply voltage be treated? Regards, Peter PETER S. MERGUERIAN MANAGING DIRECTOR PRODUCT TESTING DIVISION I.T.L. (PRODUCT TESTING) LTD. HACHAROSHET 26, P.O.B. 211 OR YEHUDA 60251, ISRAEL TEL: 972-3-5339022 FAX: 972-3-5339019 E-MAIL: pe...@itl.co.il Visit our Website: http://www.itl.co.il - 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).
Analysis of airborne contaminants
Hello, I am trying to quantify the pollution degree at one of our installations. It is an industrial environment and it is suspected that there is some quantity of airborne conductive contaminants. Does anyone know if there is a device or a process that would be useful in determining the amount (and content) of such contaminants? Thanks, Jeff Jenkins Advanced Energy Industries, Inc. - 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: Excessive smoke
John, is the smoke measured in a room of a specified volume? That is to say, how is compliance with the 28% Oxygen Rating Index determined? Jeff -Original Message- From: John Juhasz [mailto:jjuh...@fiberoptions.com] Sent: Thursday, April 22, 1999 6:38 AM To: 'Rich Nute'; 'jeff.jenk...@aei.com' Cc: 'emc-p...@ieee.org' Subject: RE: Excessive smoke Good Answer (with respect to the standards noted below). However, I would like to expand on this discussion, if I may, with regards to telecom equipment in a CO (Central Office) environment and meeting Bellcore specifications (realize that typically equipment that will go into a CO environment will also need to meet UL 19503rd ed.). In the case of Bellcore NEBS GR-63, the content of smoke is measured with regard to 'Oxygen rating index' (should be 28% or greater) during the Fire Resistance testing. The previous version of the specification (TR-NWT-63) specifically measured all the content of the smoke to determine smoke corrosivity. Although the current standard (GR-63) is relaxed, the RBOCs (Regional Bell Operating Companies - becoming less numerous of late) reserve the right to view the video tape of the fire test when considering a product, and if they feel that the product is producing too much smoke (regardless of the oxygen index) they become concerned. They're concerned about bringing down a central office to 'clean' the surrounding equipment from the corrosive elements of the smoke. So those of you who will also need to meet the Bellcore NEBS requirements (telecom equip to be located in a CO) in addition to UL1950 3rd Ed., this will be a concern. John A. Juhasz Product Qualification Compliance Engr. Fiber Options, Inc. 80 Orville Dr. Suite 102 Bohemia, NY 11716 USA Tel: 516-567-8320 ext. 324 Fax: 516-567-8322 -Original Message- From: Rich Nute [mailto:ri...@sdd.hp.com] Sent: Wednesday, April 21, 1999 2:30 PM To: jeff.jenk...@aei.com Cc: emc-p...@ieee.org Subject: Re: Excessive smoke Hi Jeff: If a component abnormal test generates excessive and sustained smoke (several minutes), but does'nt breach reinforced or double insulation, nor emit flame from the enclosure, is it considered a failure? Intuitively, it seems like it would be, because of toxicity, but I have been unable to find anything in the safety standards to support this. I have checked EN 60950, EN 50178, UL 1012, and CSA C22.2 No. 107.1. For the purposes of product safety and compliance with safety standards, smoke is a permitted emission during fault testing. The safety issue is whether a safeguard is damaged or breached due to the heat which produced the smoke. If insulation is not damaged (as per the hi-pot test), and excessive heat or flame does not breach the enclosure (as per the cheesecloth test), then the product is considered acceptable for the purposes of product safety. Typically, product safety standards do not address the toxicity of smoke. This is because all smoke contains toxic materials. The only solution to smoke toxicity is to eliminate smoke, which means eliminating all overheating situations. Which is nearly impossible. However, any smoke from a product is likely create fear and anxiety in the mind of the user and nearby persons. Any smoke in a clean room will likely be cause for scrapping all stock in the clean room. While smoke always contains toxic materials (e.g., carbon monoxide), the concentration of the smoke (toxic material) in the volume of the room together with the room ventilation determines whether or not inhalation of the smoke is likely to cause an injury. If the volume of smoke is small compared to the volume of the room, then it is likely the concentration of toxic material will be below the TLV (threshold limit value) for that material. So, it is a good idea (for the satisfaction of your customers) to eliminate or reduce any significant smoke emissions that might occur during fault testing. Best regards, Rich - Richard Nute Product Safety Engineer Hewlett-Packard Company Product Regulations Group AiO Division Tel : +1 619 655 3329 Effective 6/12/99: +1 858 655 3329 16399 West Bernardo Drive FAX : +1 619 655 4979 Effective 6/12/99: +1 858 655 4979 San Diego, California 92127 e-mail: ri...@sdd.hp.com - - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, j...@gwmail.monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators). - This message is coming from the emc-pstc discussion list. To cancel your
RE: EN 50178 clause 5.2.13
Start from the lowest limit in Table 1 and work up. From your example #1: 30/60 = 1; 35/(1.17*60) = 1; both conditions true, therefore Um 60. From your example #2: 200/120 = 1; NOT true, therefore go to next limit in Table 1; 200/2000 = 1; 205/(1.17*2000) = 1; both conditions true, therefore Um 2000 Regards, Jeff Jenkins Senior Regulatory Compliance Engineer Advanced Energy Industries, Inc. Fort Collins, CO USA 80525 Opinions are my own and not necessarily shared by Advanced Energy Industries, Inc. or its affiliates. -Original Message- From: Arjen Dragt [mailto:adr...@inverpower.com] Sent: Monday, April 19, 1999 3:01 PM To: EMC-PSTC Listserv Subject: EN 50178 clause 5.2.13 In case (b) of this clause, I do not understand how the decisive voltage (classification) is to be correctly calculated. For those of you who have the standard, try using (for example) Udc = 30 V and Udcp = 35. The method outlined in the standard (with the formula given) will indicate that in this case, Um is 2000 Vdc. For a voltage Udc = 200 V, Udcp = 205, the method will indicate that the circuit lies in the Um = 120 V category. Either I am missing part of the picture, or there is something wrong with the way that the formula is laid out. Hopefully somebody can make this clear for me. Arjen - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, j...@gwmail.monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
Excessive smoke
I'm full of questions this week. Here's today's. If a component abnormal test generates excessive and sustained smoke (several minutes), but does'nt breach reinforced or double insulation, nor emit flame from the enclosure, is it considered a failure? Intuitively, it seems like it would be, because of toxicity, but I have been unable to find anything in the safety standards to support this. I have checked EN 60950, EN 50178, UL 1012, and CSA C22.2 No. 107.1. By the way, this product could be used in clean room applications. I am familiar with Semi S2, but it is unclear as to the degree of smoke allowed. Section 19.1 says, The use of combustible and smoke-generating materials in the construction of the process equipment should be limited. In this case, it was a PCB that smoked. Thanks. Jeff Jenkins Senior Regulatory Compliance Engineer Advanced Energy Industries, Inc. Fort Collins, CO USA 80525 Opinions are my own and not necessarily shared by Advanced Energy Industries, Inc. or its affiliates. - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, j...@gwmail.monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
Conductive Paint, Round 2
I need to clarify my earlier question on conductive paint. We bond our enclosure panels together with screws. We use external-tooth starwashers between the screws and sheet metal to achieve a reliable, protective-earth bond. On our painted panels, we mask the paint so that the starwasher makes good contact with the metal. We are now considering using conductive paint without masking, but we would still use starwashers. I don't see how this could be a problem, but it's not something I've seen done before and so I'd like your input. Thanks again, Jeff Jenkins Senior Regulatory Compliance Engineer Advanced Energy Industries, Inc. Fort Collins, CO USA 80525 Opinions are my own and not necessarily shared by Advanced Energy Industries, Inc. or its affiliates. - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, j...@gwmail.monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
Conductive Paint
Hello Group, My company is proposing to use conductive paint on our enclosures, and I would like your input as to the acceptability of this vis-a-vis protective earth bonding of enclosure panels. I am interested in the perspective of both European and North American requirements. This should be a generic question, but if it helps, here are the standards we use: EN 60950 / IEC 950 / UL 1950 / CSA 950 EN 50178 UL 1012 CSA C22.2 No. 107.1 Regards, Jeff Jenkins Senior Regulatory Compliance Engineer Advanced Energy Industries, Inc. Fort Collins, CO USA 80525 Opinions are my own and not necessarily shared by Advanced Energy Industries, Inc. or its affiliates. - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, j...@gwmail.monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
IEC 950 and pulsed outputs
Hello Group, I have some questions about determination of working voltage for IEC 950. I have a high voltage pulsed output. My questions are: 1. Can I calculate an average or rms value based on the duty cycle of the pulse, and use this as my working voltage? I am aware of Table 4, but this doesn't seem to fit because (a) it's a secondary circuit and (b) the peak value exceeds anything in this table. 2. If the answer to question #1 is affirmative, is there a maximum on time that, if exceeded, would force me to use the full value of the output voltage? Thanks, Jeff Jenkins Senior Regulatory Compliance Engineer Advanced Energy Industries, Inc. Fort Collins, CO USA 80525 Opinions are my own and not necessarily shared by Advanced Energy Industries, Inc. or its affiliates. - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, j...@gwmail.monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
NRTL requirement in the NEC?
Hello Group, Has anyone heard of a requirement in the National Electrical Code that power supplies which are components of larger systems be approved by an NRTL? I have an inspector telling me this, but our copy of the NEC is 20 years old, and I can't find it, anyway. In this case, the power supply is part of a rack system. It was my understanding that the supply could be evaluated as a component of the system. Is that not true? Thanks, Jeff Jenkins Senior Regulatory Compliance Engineer Advanced Energy Industries, Inc. Fort Collins, CO USA 80525 Opinions are my own and not necessarily shared by Advanced Energy Industries, Inc. or its affiliates. - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, j...@gwmail.monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
RE: Varistors to ground
This information is very timely since I am currently working on a project that requires varistors to ground. The varistors are not approved. How does one size the spark gap firing voltage and the fuse value? I am concerned with the fuse opening when the equipment sees a transient. Also, if the equipment contains a circuit breaker, is the fuse necessary? Thanks, Jeff Jenkins Senior Regulatory Compliance Engineer Advanced Energy Industries, Inc. Fort Collins, CO USA 80525 Opinions are my own and not necessarily shared by Advanced Energy Industries, Inc. or its affiliates. -Original Message- From: Volker Gasse [mailto:ga...@de.ibm.com] Sent: Tuesday, December 15, 1998 3:34 AM To: emc-p...@majordomo.ieee.org Subject: RE: Varistors to ground The mentioned Cenelec decision is taken from the 'List of decisions from CENELEC Operational Staff Meeting for Electronic Equipment (OSM/EE)'. Here representatives from EU Testhouses meet to discuss interpretations of clauses in safety standards such as EN 60950 for IT products. These decisions are to be followed by all European testhouses. However, those decisions should be interpretations/clarifications to the existing standards, but not addition of new requirements. For EN 60950, Clause 1.5.1, Decision 98/2 states: 'A combination of a varistor in series with a spark gap (Gas-Tube) [between the mains and the protective earth] complying with Basic Insulation, and with a fuse will be accepted for a. Pluggable equipment Type B and permanently connected equipment: by all countries b. Pluggable equipment Type A: by all countries except DK, UK and SE. For pluggable equipment Type A two fuses are required.' (To be sure that even by non-polarized plugs a fuse is provided) This interpretation is an extension to a decision which was already issued in 1/94: 'If a Varistor is separately approved according to Publications IEC 601051-1 and IEC 601051-2, it can be accepted without a protective device. If a Varistor is not separately approved, a protective device against the short-circuit is required. Varistors tested according to CECC 42200 are considered as acceptable in the same way as tested to IEC 601051. Varistors between the mains and the protective earth cannot be accepted by the following countries: Pluggable equipment, type A: Austria, Belgium, Denmark, Finland, Norway, Sweden, United Kingdom.' The new decision is not part of the upcoming safety standard for IT products, IEC 60950 3rd edition, which is likely to be available beginning of next year. One of the reasons for requiring the spark gap in series with the varistor is a possible increase in leakage current if the varistor has been exposed to several mains transients. It should be noted, that IEC/EN 60950 does not require the use of transient suppressing components. Concerning the mit freundlichen Gruessen/ best regards Volker Gasse IBM Germany, Technical Relations/Product Safety, Tel: +49 7031-16-6796, Fax: -6916, e-mail: ga...@de.ibm.com Mail: 3114/7103-91, D-70548 Stuttgart, Germany -- Forwarded by Volker Gasse/Germany/IBM on 15.12.98 11:20 --- owner-emc-p...@majordomo.ieee.org on 15.12.98 02:11:00 Please respond to jeich...@statpower.com To: j...@bighorn.dr.lucent.com cc: emc-p...@majordomo.ieee.org Subject: RE: Varistors to ground John: Sorry I can't help, but I am interested in what replies you get. I also wonder what force the Decision carries. Is it a mandatory part of the Low Voltage Directive? How does it relate to the LVD or to the various EN's in force under the LVD? Thanks in advance for any light you can shed on these murky waters! Regards, Jim Eichner Statpower Technologies Corporation jeich...@statpower.com http://www.statpower.com Any opinions expressed are those of my invisible friend, who really exists. Honest. -Original Message- From: Boucher, John [SMTP:j...@bighorn.dr.lucent.com] Sent: Monday, December 14, 1998 9:07 AM To: 'emc-p...@ieee.org' Subject: Varistors to ground All: I have received a copy of a CENELEC Decision (dated 6/98) regarding the use of varistors between mains conductors and ground. This particular Decision is written in a rather unclear fashion (at least its unclear to me...I tend to be rather literal in my interpretations of written requirements), and I am struggling with defining the actual requirements. If anyone out there has received this Decision, and believes they are clear about what the actual bottom line requirements are, please let me know. I have muddled through some of the issues, but need some confirmation on a couple of points (see the questions below). It may seem to some that the answers to these questions are straight-forward in the Decision, but I have studied this Decision (maybe too much) and find these points unclear. 1) Is this Decision only for pluggable equipment type A, or is the spark-gap / fuse requirement in effect for
low-watt transformer fusing
Hi folks, I have a question about transformer fusing. I have an application that uses a 10W transformer connected across 400Vac mains. It is my understanding that this requires a fuse rated to at least 400V, which would mean 500V because that's the next larger size available. However, the smallest amperage fuse available at that voltage rating is 100mA. This by far exceeds the transformer rating. I thought about performing the EN 60742 test of loading the transformer until the primary current is 2.1 x 100 mA = 210 mA and taking thermal measurements, but I am quite sure the transformer will burn up under this large a load. The standards being used to evaluate this product are: EN 50178 UL 1012 CSA C22.2 No. 107.1 Any suggestions? Regards, Jeff Jenkins Senior Regulatory Compliance Engineer Advanced Energy Industries, Inc. Fort Collins, CO USA 80525 Opinions are my own and not necessarily shared by Advanced Energy Industries, Inc. or its affiliates. - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, j...@gwmail.monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
water-cooled electrodes
I would like to know if anyone in the group has been involved with the AGENCY APPROVAL of a product containing a water-cooled live electrode or coil, and what had to be done to make this safe in the eyes of the agency. My company is occasionally involved with this sort of thing, and some feel that we are being overly conservative and perhaps unnecessarily burdening our products with extra cost. To date we have only CE-marked such products and have had no third-party involvement. Partial list of concerns: (1) Is it considered necessary to completely isolate the water-cooled live component from circuitry by locating it in a separate chamber? (2) Single-fault safety when circuitry is in the same enclosure as the coil -- if the tube ruptures and the box fills up with water, this is a hazard as water is rightly considered a conductive element. Drains are sometimes used to avoid this, but there is still the problem of water spraying. Splash guards and the like may be used but this involves some expense. Is copper tubing considered inherently unsafe, i.e. something that is expected to rupture? (3) If we use de-ionized water (and stainless steel tubing to avoid the copper corrosion problem), can we assume the water acts as a protective impedance? Could we prove this by filling the chamber with de-ionized water, applying RF, and measuring the leakage current? How much RF leakage current is permissible? (4) Are water fittings considered inherently unsafe? We have been unable to find any agency-approved fittings. (5) Has anyone considered (or accepted) putting a ferrite around the water tubing to form an inductor, thus limiting the RF current in the water? Or coiling the tubing to create an air-core inductor? (6) I once received an RF burn from an experimental system with a water-cooled cathode. This was in a crude garage shop atmosphere (not our company). The cathode was immersed in water that was sourced from a faucet, so it was ordinary tap water. The supply was 400kHz, 5kW. The water supply hose was ordinary garden hose. Between the faucet and the cathode were two lengths of garden hose with brass fittings. I inadvertently touched the fitting that connected the two hoses together, about ten feet from the cathode. The only grounding at the time was whatever was achieved at the faucet. We later provided some grounding at the fittings and supplementary grounding at the faucet. All this prompts the question: Is it considered sufficient protection if the bulkhead fittings are fitted to a grounded enclosure? Are starwashers or the like required? (7) Is it necessary to provide a SUPPLEMENTARY ground for the enclosure containing the water-cooled coil/electrode? (8) What if, instead of running water THROUGH the coil, the entire coil is IMMERSEDin water in a metal enclosure? Would double ground connections be sufficient, assuming the leakage current is within allowable limits? (9) Is it allowable to connect neoprene hose to the coil? I have some doubts about neoprene's capacity to withstand RF fields. What hose materials would be considered safe/reliable? (10) Is a drain required? If so, must it be large enough to drain the water at the maximum rate at which it could accumulate, or is the pressure relief provided by the drain sufficient? Then there's the question of equipment orientation . . . must a drain be provided to serve each potential physical orientation of the installed equipment? These are just a few of the questions that have come to mind as I've considered water-cooled systems in the past. I would appreciate your inputs on these and other related issues you may think of. Thanks for your time, Jeff Jenkins Senior Regulatory Compliance Engineer Advanced Energy Industries, Inc. Fort Collins, CO USA 80525 Opinions are my own and not necessarily shared by Advanced Energy Industries, Inc. or its affiliates. - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, j...@gwmail.monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
Agency approvals on components in CE mar
It is my understanding that the European Commission has stated that a manufacturer has the freedom to determine the acceptability of components used in CE marked products. (Or words to that effect.) I would conclude that this would remove the need for using European agency approved components in safety critical locations. Any reputable agency approval, or appropriate evaluation by the manufacturer, would be acceptable. Does anyone know of where I can obtain this statement in writing? I'd like to have something to back this up. Also, I welcome comments on the conclusions I have drawn based on this alleged EC statement. Regards, Jeff Jenkins Senior Regulatory Compliance Engineer Advanced Energy Industries, Inc. Fort Collins, CO USA - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.com with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, ri...@sdd.hp.com, or roger.volgst...@compaq.co (the list administrators).
Searching for an accredited IEC65 test l
I am looking for an accredited test laboratory that is capable of performing the component tests called out in IEC 65:1985, sections 14.1 and 14.2. (Which cover resistors and capacitors.) Thank you, Jeff Jenkins Senior Compliance Engineer Advanced Energy Industries, Inc. Fort Collins, CO.
