Re: EMC/Harmonics requirements
Does this mean that products that are currently being certified against a product or family standard, such as ITE equipment (EN55022) or ISM equipment (EN55011) as opposed to a generic standard have to meet the requirements of the EN61000-3 specs ?? Neither of these standards mention testing harmonics/flicker or the IEC 555 specs. Mark mbri...@elliottlabs.com __ Reply Separator _ Subject: EMC/Harmonics requirements Author: george.da...@unisys.com at PMDF Date:8/22/97 10:40 AM To All: For information. The European Union has put out a notice to all national committees aimed at clarifying the implementation dates for the harmonics and flicker standards. (Reference TC741 JPV/is/970722 dated 1997-07-10) They have also referenced the 555 series standards and in their minds clarified the relationship between the two harmonics standards. The notice is copied below for your information. Please note the IEC 555 -2 and 555-3 are withdrawn and obsolete. This means CENELEC is not using an international standard for those products covered. Dave George Taking into account the above, for products originally not falling within the scope of EN 60555-2/EN 60555-3 but covered by EN 61000-3-2/EN 61000-3-3, presumption of conformity to the ERs of the EMC Directive exists and is confirmed on the basis of a manufacturer's declaration based on the generic EMC standards up to 2001-01-01. In this context reference is made to Note 2 to Table I of EN 50021-1 (relating to emission in the a.c. mains supply and in particular harmonics) which reads: Note 2: Applicable to apparatus covered within the scope of EN 60555-2 and EN 60555-3. Limits for apparatus not currently covered by EN 60555-2 and EN 60555-3 are under consideration.' In consequence the levels given in these two standards applicable to the relevant phenomena can be used for conformity assessment purposes under the manufacturer's responsibility. Received: from 192.168.190.1 by ALPHA.CORP.SCIATL.COM (PMDF V4.3-13 #7203) id 01imqt38notc000...@alpha.corp.sciatl.com; Fri, 22 Aug 1997 14:59:15 -0500 (EST) Received: from [199.172.136.3] by gatekeeper.sciatl.com for doug.kea...@sciatl.com id PAA14535; Fri Aug 22 15:04:07 1997 Received: (from daemon@localhost) by ruebert.ieee.org (8.7.5/8.7.3) id LAA10936; Fri, 22 Aug 1997 11:42:35 -0400 (EDT) Date: Fri, 22 Aug 1997 11:40:31 -0400 From: George, David L george.da...@unisys.com Subject: EMC/Harmonics requirements Sender: owner-emc-p...@majordomo.ieee.org Reply-to: George, David L george.da...@unisys.com Message-id: c=US%a=_%p=UNISYS%l=tr_exchange_1-970822154031z-2...@tr-exchange-2.tr.un isys.c om X-Envelope-to: Kealey, Doug%SA-B08@ccmail.corp.sciatl.com MIME-version: 1.0 X-Mailer: Microsoft Exchange Server Internet Mail Connector Version 4.0.995.52 Content-type: text/plain; charset=us-ascii Content-transfer-encoding: 7bit Precedence: bulk X-Resent-To: Multiple Recipients emc-p...@majordomo.ieee.org X-Listname: emc-pstc X-List-Description: Product Safety Tech. Committee, EMC Society X-Info: Help requests to emc-pstc-requ...@majordomo.ieee.org X-Info: [Un]Subscribe requests to majord...@majordomo.ieee.org X-Moderator-Address: emc-pstc-appro...@majordomo.ieee.org
Heavy Industrial Peripherals
My company manufactures large main-frame computer devices for commercial and military simulation environments. As such, our IGs (Image Generators) are CE marked and tested to Heavy Industrial immunity and emission levels. Attached to these IGs, are off-the-shelf peripheral devices such as monitors, printers and terminals. These commercial devices would not be expected to pass the 10V/m radiated immunity or other portions of EN 50082-2, as they are typically defined as Light Industrial. Magnetic immunity for the display devices would pose another significant risk of non compliance. As a system integrator how can this issue be resolved? Can someone comment as to the availability of Heavy Industrial peripheral devices. Do they exist? Are there suggestions for commercial peripheral devices which have successfully been used in these test environments? Thanks in advance Rick Busche Evans Sutherland Salt Lake City, Utah rbus...@es.com
Values for hazardous currents.
Hello from San Diego: Mike Conn suggests that 1 mA through the heart muscle can induce fibrillation, and that anything greater than 5 mA through the hands is a dangerous current. I think that 50 uA is a better value of current applied to the heart muscle that is likely to induce fibrillation. This is why leakage current from patient-connected equipment is limited to 10 uA. Note that physical blows to the chest can induce fibrillation. During open-chest surgery, simply touching the heart muscle can induce fibrillation. This is because the heart muscle works much the same way the wave works in a ballpark when the fans rise to their feet and raise their arms. They do so as the folks adjacent to them rise. So, too, for the heart muscle. It gets an initial trigger at the sinoatrial node. The initial muscle contraction at the sinoatrial node spreads along the atrium to the atrioventricular (central wall) node. At this point, the contractions divide to either side of the ventricals, passing around the outside of the heart cavities back to the starting point. Any trigger to any relaxed heart muscle can cause it to contract, and thereby spread out of sync to the other parts of the muscle. This is fibrillation. The 5 mA number came from the work of Karl Geiges of UL in his study of leakage current from radio receivers in the late '40s. Geiges and Charles Dalziel, University of California Berkeley, studied let-go currents. Geiges tested UL personnel. Dalziel tested graduate students. Independently, they concluded that 5 mA was the maximum allowable current that persons of all ages could let go. (Geiges work is published in a UL monograph. Dalziel's work is published in the IRE and AIEE journals of the time.) Since Dalziel was the inventor of the GFCI, it follows that the trip current for the GFCI is 5 mA. The issue is, What is dangerous? Many years ago, Claude Haggard, Medford, Oregon, taught and demonstrated the dangers of electricity to various groups, from school children to granges. He demonstrated arm-to-hand can't let go using a conductive arm-band and a defective electric drill in his hand. He would freeze at from 7 to 12 mA. But, he was not injured. Following the demonstration, he was as good as new! I enjoyed lunch with him following one of his demonstrations. But, Haggard was very careful by adjusting the current up to the point where he was just frozen, and no more. And, he was very careful that the current path was down the arm, and not across the thorax. He also demonstrated the effectiveness of the GFCI -- without any current limit. He would hold the defective drill and touch a grounded panel with the upper part of the arm. Almost no sensation. (I haven't had the nerve to try this!) So, more than 5 mA is not dangerous in that it does not cause an injury. But, being frozen is scary. Injury doesn't occur until the onset of fibrillation, about 50 mA hand-to-hand. Best regards, Rich - Richard Nute Quality Department Hewlett-Packard Company Product Regulations Group San Diego Division (SDD) Tel : 619 655 3329 16399 West Bernardo Drive FAX : 619 655 4979 San Diego, California 92127 e-mail: ri...@sdd.hp.com -
Re: Heavy Industrial Peripherals
Rick, Do you really need the Heavy Industrial rating? If you look at the actual environment, you may find it considerably more benign than the usual steel mill, railway switchyard, etcetera. If this is the case, I suggest you consider the less stringent Light Industrial requirements. Cortland == Original Message Follows Date: 09-Sep-97 15:13:25 MsgID: 1055-22656 ToID: 72146,373 From: Rick Busche INTERNET:rbus...@es.com Subj: Heavy Industrial Peripherals Chrg: $0.00 Imp: Norm Sens: StdReceipt: NoParts: 1 My company manufactures large main-frame computer devices for commercial and military simulation environments. As such, our IGs (Image Generators) are CE marked and tested to Heavy Industrial immunity and emission levels. Attached to these IGs, are off-the-shelf peripheral devices such as monitors, printers and terminals. These commercial devices would not be expected to pass the 10V/m radiated immunity or other portions of EN 50082-2, as they are typically defined as Light Industrial. Magnetic immunity for the display devices would pose another significant risk of non compliance. As a system integrator how can this issue be resolved? Can someone comment as to the availability of Heavy Industrial peripheral devices. Do they exist? Are there suggestions for commercial peripheral devices which have successfully been used in these test environments? Thanks in advance Rick Busche Evans Sutherland Salt Lake City, Utah rbus...@es.com == End of Original Message =
re: Values for hazardous currents.
I will make only one comment on this issue and this comment is not a statement from UL but rather a fellow IEEE member. Rich Nute stated Injury doesn't occur until the onset of fibrillation, about 50 mA hand-to-hand. Sorry Rich, this is simply not true. There are a terribly large number of injuries every year resulting directly and indirectly from much lower currents. Injuries as a consequence of startle effect can be very serious. In addition, small children by the hundreds are shocked and suffer nuerological damage or worse as a consequence of currents significantly less than 50 mA. As engineers working to develop effective, safe products that improve our world, we have to keep in mind that there are all types of people out there that use or abuse electrical products including the children and the physically frail and that in many cases the injuries suffered are an indirect result of shock. Sorry if this seems preachy, no offense intended. Mike Windler Underwriters Laboratories Inc. International EMC Services E-mail: windl...@ul.com Fax:847-272-8864 Phone: 847-272-8800 (ext. 43409) - Original Text From: Rich Nute ri...@sdd.hp.com, on 9/9/97 4:24 PM: Hello from San Diego: Mike Conn suggests that 1 mA through the heart muscle can induce fibrillation, and that anything greater than 5 mA through the hands is a dangerous current. I think that 50 uA is a better value of current applied to the heart muscle that is likely to induce fibrillation. This is why leakage current from patient-connected equipment is limited to 10 uA. Note that physical blows to the chest can induce fibrillation. During open-chest surgery, simply touching the heart muscle can induce fibrillation. This is because the heart muscle works much the same way the wave works in a ballpark when the fans rise to their feet and raise their arms. They do so as the folks adjacent to them rise. So, too, for the heart muscle. It gets an initial trigger at the sinoatrial node. The initial muscle contraction at the sinoatrial node spreads along the atrium to the atrioventricular (central wall) node. At this point, the contractions divide to either side of the ventricals, passing around the outside of the heart cavities back to the starting point. Any trigger to any relaxed heart muscle can cause it to contract, and thereby spread out of sync to the other parts of the muscle. This is fibrillation. The 5 mA number came from the work of Karl Geiges of UL in his study of leakage current from radio receivers in the late '40s. Geiges and Charles Dalziel, University of California Berkeley, studied let-go currents. Geiges tested UL personnel. Dalziel tested graduate students. Independently, they concluded that 5 mA was the maximum allowable current that persons of all ages could let go. (Geiges work is published in a UL monograph. Dalziel's work is published in the IRE and AIEE journals of the time.) Since Dalziel was the inventor of the GFCI, it follows that the trip current for the GFCI is 5 mA. The issue is, What is dangerous? Many years ago, Claude Haggard, Medford, Oregon, taught and demonstrated the dangers of electricity to various groups, from school children to granges. He demonstrated arm-to-hand can't let go using a conductive arm-band and a defective electric drill in his hand. He would freeze at from 7 to 12 mA. But, he was not injured. Following the demonstration, he was as good as new! I enjoyed lunch with him following one of his demonstrations. But, Haggard was very careful by adjusting the current up to the point where he was just frozen, and no more. And, he was very careful that the current path was down the arm, and not across the thorax. He also demonstrated the effectiveness of the GFCI -- without any current limit. He would hold the defective drill and touch a grounded panel with the upper part of the arm. Almost no sensation. (I haven't had the nerve to try this!) So, more than 5 mA is not dangerous in that it does not cause an injury. But, being frozen is scary. Injury doesn't occur until the onset of fibrillation, about 50 mA hand-to-hand. Best regards, Rich - Richard Nute Quality Department Hewlett-Packard Company Product Regulations Group San Diego Division (SDD) Tel : 619 655 3329 16399 West Bernardo Drive FAX : 619 655 4979 San Diego, California 92127 e-mail: ri...@sdd.hp.com -
Y capacitors and Supplementary Insulation
Hello fellow Homologator's: I have a question about Y capacitors used to bridge Supplementary or Reinforced insulation. The IEC 384-14 standard addresses this. My question relates specifically to bridging these barriers in ITE equipment, and application of the IEC 950 standards. 1) Is there a minimum distance through insulation requirement called out in the IEC 384-14 standard? A few people I have talked to say there is, but I have not been able to find it. (Maybe one of the other IEC 384 standards?) 2) The creepage and clearance distances called out in IEC 384-14 and IEC 950 are not the same. The 384-14 standard calls out larger external creepage and clearance distances for the caps than application of the 950 standard would. For example, table VII in IEC 384 calls out a minimum 4.0mm creepage distance, and the IEC 950 (table 6) standard would call out a minimum creepage of 2.5mm assuming material group III. How does one resolve this discrepancy when laying out the board? UL's standard response would probably be that the end-product standard takes precedence, in this case UL 1950. But what about Europe (EN 60950)? Australia (AS/NZS 3260)? 3) Every decision I have seen for EN 60950 product using Y caps to provide a supplementary barrier specifies a minimum of Y2 capacitor. Why can't a Y3 capacitor be used? Does this have to do with concerns about the overvoltage category? The reasoning does not seem to be clearly spelled out anywhere I have looked. The only difference between Y3 and Y2 capacitors that I can see is that the Y2 capacitor is subject to surge testing before the applicable endurance test, and the Y3 capacitor is not. Therefor, it would seem to me that a proper choice of capacitor would depend on the types of transients and surges that one would see, but this is not clearly spelled out in the 384-14 standard anywhere that I have seen. Do any other standard apply? Anyone with experiences using these types of capacitors in ITE equipment, your comments would be most appreciated!! Thank you for your help! Mel Pedersen Midcom, Inc. Homologations Engineer Phone: (605) 882-8535 mpeder...@midcom.anza.com Fax: (605) 886-6752
Re: Tetanization and fibrillation (was GFI history)
This is why I like this email service. I learn so much! Thanks to all of the contributors Hans __ Reply Separator _ Subject: Re: Tetanization and fibrillation (was GFI history) Author: richn-at-sdd (ri...@sdd.hp.com) at HP-ColSprings,mimegw5 List-Post: emc-pstc@listserv.ieee.org Date:9/9/97 10:36 AM Hello from San Diego: Several messages have suggested some values of current that cause ventricular fibrillation. The values are all over the map, and are much lower than those reported in the research literature. Here are some better facts together with the source of those facts. snip
