RE: Define Continuous DC Voltage - defibrillation
For those who want to skip it, this is not product safety, just a digression from the electric shock topic. As for why the chest thumping works, take the heel of your hand and whack yourself on the side of the head. You'll notice the effect as quite a few cells depolarize. That's the general idea. If you get the heart's attention without doing serious damage, it may pause and restart. As for the PQRST stuff, you asked for it. Now we are getting into vector graphics. Picture two cells, side by side, and depolarize one. You can imagine a time related voltage vector appear and go away. Now picture more cells, and depolarization flowing in a wave across them. The vector gets more interesting both in direction and time. Next, go to three dimensions and place it in a chest. That's what we are working with. Put electrodes on the arms and watch it on a scope and you will get an EKG. Of course you only have one dimension (plus time) represented on the scope. Lets try a few more to get images of that vector in other dimensions. In fact, we do it twelve times to get the standard 12 lead EKG recording. Namely: I - left arm to right arm II - left foot to right arm III - left foot to left arm AVR - right arm to (feet, left arm) AVL - left arm to (feet, right arm) AVF - left foot to (arms, right foot) V1 thru V6 - measurements from leads spread across the chest from between the nipples to the right of the sternum around beneath the left breast to the side of the chest. Each lead one at a time is measured to all limb leads connected together. If you can picture it, the first six measurements give six vector readings in the plane of the limbs, the second six give vector readings in a quadrant cross section of the chest perpendicular to the first six. You actually get a pretty good set of three dimensional readings. Now. Put an arrow through a board, throw it in the ocean and watch what it does as a nice wave goes by. Describe the motion of that vector to someone and see if he can deduce what the wave looks like. Its not random. As each similar wave goes by, you get the same vector path. You can even match vector paths with different types of waves. That's what we do with an EKG. In fact there is a connection between heart activity and the waveshape. However it's sort of remote. What really happens is, we find a normal heart generates a typical pattern. Consider heart disease like an AV block and the pattern changes. That's what its all about. Pattern recognition. A good electrocardiologist has this immense image recognition system in his head and matches EKG patterns to disease. He will in fact generate a picture of where the vector is pointing in time and space and use it to imagine weak or damaged tissue affecting or modifying its path. All that leads to the scope trace and talking about it. If we take the I lead as the typical view and start describing it time wise, we start with P, a small positive hump which corresponds with the atrial contraction Q R S, the negative, positive, negative pulse caused by ventricular contraction and the movement of the voltage vector during that time. T, another smaller slower hump from the repolarization of the ventricles I can't help mentioning an EKG machine I once had which was absolutely amazing. It had NO amplifiers. It was called an Einthoven string galvanometer. It consisted of a large C shaped magnet whose poles tapered down to a very narrow gap. Between that gap stretched a fine gold plated glass fiber which connected to the attenuator (that's right attenuator) and lead selector. There was a hole drilled from the top of the C through the tips of the poles and out the bottom with a light source on one side and moving photo film on the other. It produced a strip chart recording of the movement of the fiber, which of course was the EKG current deflected by the magnetic field. The machine used electricity, for the light bulb and the film motor. It's amazing to think of the skill and ingenuity used to make a millivolt recorder back in those days. If I'm not mistaken, Einthoven was the inventor of the 12 lead EKG recording technique. Bob Johnson -Original Message- From: Bill Owsley [mailto:ows...@cisco.com] Sent: Tuesday, November 20, 2001 12:53 PM To: robertj; 'Bill Owsley'; 'Gary McInturff'; 'Gregg Kervill'; 'Rich Nute' Cc: jrbar...@lexmark.com; emc-p...@majordomo.ieee.org Subject: RE: Define Continuous DC Voltage - defibrillation excellent - now if you'll go through the PQRST complex also... - Bill Robert, Thanks for this very interesting piece of data. I've often wonder what atrioventricular fibrillation is, you provide some insight on that as well. If it is a reset of sorts then how did the thumping of the chest ever work? I suppose it can also fall into the category of just being better than nothing at all. I can be learned wrong and always look for a better understanding. Its been awhile but I believe the information came from one
RE: Methods Equipment; Surge Dips
To answer the below -- KT has had the equipment for about 10 years. For rental -- call Transient Specialists at 866-364-7368. For robustness -- need to know the load. Large in-rush currents are generally no problem. I agree about the Pacific Power units -- we evaluated them here some years ago -- they were one of the few AC sources that weren't upset with transients on the output stage coming back from an EUT. Mike Hopkins -Original Message- From: Ehler, Kyle [mailto:keh...@lsil.com] Sent: Tuesday, November 20, 2001 3:57 PM To: 'Mike Hopkins'; Ehler, Kyle; 'wmf...@aol.com'; emc-p...@ieee.org Subject: RE: Methods Equipment; Surge Dips True, but did KT have this equipment 4yrs ago? Does anyone you know of rent this equipment? We also have a Schaffner tap switcher, but it eats itself under heavy loads. Is the KT stuff more robust under heavy startup loads? The Pacific Power equipment I use has never broke down. Worth the weight just for that... kyle -Original Message- From: Mike Hopkins [mailto:mhopk...@thermokeytek.com] Sent: Tuesday, November 20, 2001 2:47 PM To: 'Ehler, Kyle'; 'wmf...@aol.com'; emc-p...@ieee.org Subject: RE: Methods Equipment; Surge Dips Seems to me this is the hard way to do it. KeyTek has a product that is a tap switcher for the required levels and will pass the in-rush currents required. It's a much smaller package. Also, other manufacturers have systems that are basically software controlled switches -- bring in the AC levels you require via a variac or some other transformer and simply switch between them Mike Hopkins -Original Message- From: Ehler, Kyle [mailto:keh...@lsil.com] Sent: Tuesday, November 20, 2001 1:19 PM To: 'wmf...@aol.com'; emc-p...@ieee.org Subject: RE: Methods Equipment; Surge Dips Hi William, I dont know about renting equipment for the tests. You can probably find it. For the -4-11 (dip/dropout) test; Depending on your load, your site wiring has to be up to snuff. The power sources for doing the dip and dropout test are hefty stuff. My lab uses a three-phase powered source to deliver a max of 16A into a single phase capacitive (SMPS) load. I have a Pacific Power 140 TMX and an AMX 390. The 140 does flicker/harmonics and can do dip/dropout within its output limits (about 10A inrush). Any loads beyond a 10A inrush gets dip/dropout tested by the 390. The 140 is totally pc controlled but can be programmed through the front panel. It is a handy doer. The 390 is the heavy (up to 20A inrush) and I program it through the front panel for the desired dips and dropouts. There are some models that are computer attached (RS232 or IEEE488) and you execute software programmed routines for the test. Mitigation? Most EUT's can easily withstand half and single cycle drop, many can take a little more (up to 5 cycles) before going seriously anemic. Same is true for sags if the mains are wide range input. If you fail, you reselect the product's power supply, or beef up the input bulk capacitance (assuming SMPS type) or adjust the monitoring circuitry (i.e. remote sense, power good signal) for slower response and/or higher threshold. For the -4-5 (surge) test; We use a schaffner NSG 650 attached to a pc running the schaffner surge software. The surges are delivered to the EUT through a CDN 110 coupler. The cross coupling changes are manual jumpers. We also have a Haefely Psurge 4010 and 32.1 coupling filter for heavy loads. The cross coupling changes are automatic. The EUT supply cord length has to be no longer than .8M to the surge generator. make a custom cable This test series can damage your EUT, so you might want to do this test last. Mitigation of failures takes on a myriad of possibilities. Wiring length, TVSS absorber capacity, etc. It is hard to say without knowing more about your product. Do you also need to do the -4-4 (EFT) test? All this test gear is large and heavy, particularly the power sources and stepping xformers. Perhaps someone else can elucidate on exceptions to Class A rules? I gotta go, Happy Hunting, Kyle Ehler KCØIQE mailto:kyle.eh...@lsil.com mailto:kyle.eh...@lsil.com Assistant Design Engineer LSI Logic Storage Systems Div. 3718 N. Rock Road U.S.A. Wichita, Kansas 67226 Ph. 316 636 8657 Fax 316 636 8321 -Original Message- From: wmf...@aol.com [ mailto:wmf...@aol.com mailto:wmf...@aol.com ] Sent: Monday, November 19, 2001 10:29 AM To: emc-p...@ieee.org Subject: Methods Equipment; Surge Dips Esteemed listmembers, In gearing-up for testing under the auspices of EN61326:97, I'm trying to understand two immunity tests: EN61000-4-5 (surge immy) and -4-11 (dips immy). Is there test equipment one can rent to conduct these tests? What sort of mitigation steps are typical. Is anyone aware of any exceptions for this testing under ClassA rules? Thanks in advance... Wm Flanigan Standards Engineer Ameritherm Inc
RE: Methods Equipment; Surge Dips
True, but did KT have this equipment 4yrs ago? Does anyone you know of rent this equipment? We also have a Schaffner tap switcher, but it eats itself under heavy loads. Is the KT stuff more robust under heavy startup loads? The Pacific Power equipment I use has never broke down. Worth the weight just for that... kyle -Original Message- From: Mike Hopkins [mailto:mhopk...@thermokeytek.com] Sent: Tuesday, November 20, 2001 2:47 PM To: 'Ehler, Kyle'; 'wmf...@aol.com'; emc-p...@ieee.org Subject: RE: Methods Equipment; Surge Dips Seems to me this is the hard way to do it. KeyTek has a product that is a tap switcher for the required levels and will pass the in-rush currents required. It's a much smaller package. Also, other manufacturers have systems that are basically software controlled switches -- bring in the AC levels you require via a variac or some other transformer and simply switch between them Mike Hopkins -Original Message- From: Ehler, Kyle [mailto:keh...@lsil.com] Sent: Tuesday, November 20, 2001 1:19 PM To: 'wmf...@aol.com'; emc-p...@ieee.org Subject: RE: Methods Equipment; Surge Dips Hi William, I dont know about renting equipment for the tests. You can probably find it. For the -4-11 (dip/dropout) test; Depending on your load, your site wiring has to be up to snuff. The power sources for doing the dip and dropout test are hefty stuff. My lab uses a three-phase powered source to deliver a max of 16A into a single phase capacitive (SMPS) load. I have a Pacific Power 140 TMX and an AMX 390. The 140 does flicker/harmonics and can do dip/dropout within its output limits (about 10A inrush). Any loads beyond a 10A inrush gets dip/dropout tested by the 390. The 140 is totally pc controlled but can be programmed through the front panel. It is a handy doer. The 390 is the heavy (up to 20A inrush) and I program it through the front panel for the desired dips and dropouts. There are some models that are computer attached (RS232 or IEEE488) and you execute software programmed routines for the test. Mitigation? Most EUT's can easily withstand half and single cycle drop, many can take a little more (up to 5 cycles) before going seriously anemic. Same is true for sags if the mains are wide range input. If you fail, you reselect the product's power supply, or beef up the input bulk capacitance (assuming SMPS type) or adjust the monitoring circuitry (i.e. remote sense, power good signal) for slower response and/or higher threshold. For the -4-5 (surge) test; We use a schaffner NSG 650 attached to a pc running the schaffner surge software. The surges are delivered to the EUT through a CDN 110 coupler. The cross coupling changes are manual jumpers. We also have a Haefely Psurge 4010 and 32.1 coupling filter for heavy loads. The cross coupling changes are automatic. The EUT supply cord length has to be no longer than .8M to the surge generator. make a custom cable This test series can damage your EUT, so you might want to do this test last. Mitigation of failures takes on a myriad of possibilities. Wiring length, TVSS absorber capacity, etc. It is hard to say without knowing more about your product. Do you also need to do the -4-4 (EFT) test? All this test gear is large and heavy, particularly the power sources and stepping xformers. Perhaps someone else can elucidate on exceptions to Class A rules? I gotta go, Happy Hunting, Kyle Ehler KCØIQE mailto:kyle.eh...@lsil.com mailto:kyle.eh...@lsil.com Assistant Design Engineer LSI Logic Storage Systems Div. 3718 N. Rock Road U.S.A. Wichita, Kansas 67226 Ph. 316 636 8657 Fax 316 636 8321 -Original Message- From: wmf...@aol.com [ mailto:wmf...@aol.com mailto:wmf...@aol.com ] Sent: Monday, November 19, 2001 10:29 AM To: emc-p...@ieee.org Subject: Methods Equipment; Surge Dips Esteemed listmembers, In gearing-up for testing under the auspices of EN61326:97, I'm trying to understand two immunity tests: EN61000-4-5 (surge immy) and -4-11 (dips immy). Is there test equipment one can rent to conduct these tests? What sort of mitigation steps are typical. Is anyone aware of any exceptions for this testing under ClassA rules? Thanks in advance... Wm Flanigan Standards Engineer Ameritherm 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/ 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
RE: Methods Equipment; Surge Dips
Seems to me this is the hard way to do it. KeyTek has a product that is a tap switcher for the required levels and will pass the in-rush currents required. It's a much smaller package. Also, other manufacturers have systems that are basically software controlled switches -- bring in the AC levels you require via a variac or some other transformer and simply switch between them Mike Hopkins -Original Message- From: Ehler, Kyle [mailto:keh...@lsil.com] Sent: Tuesday, November 20, 2001 1:19 PM To: 'wmf...@aol.com'; emc-p...@ieee.org Subject: RE: Methods Equipment; Surge Dips Hi William, I dont know about renting equipment for the tests. You can probably find it. For the -4-11 (dip/dropout) test; Depending on your load, your site wiring has to be up to snuff. The power sources for doing the dip and dropout test are hefty stuff. My lab uses a three-phase powered source to deliver a max of 16A into a single phase capacitive (SMPS) load. I have a Pacific Power 140 TMX and an AMX 390. The 140 does flicker/harmonics and can do dip/dropout within its output limits (about 10A inrush). Any loads beyond a 10A inrush gets dip/dropout tested by the 390. The 140 is totally pc controlled but can be programmed through the front panel. It is a handy doer. The 390 is the heavy (up to 20A inrush) and I program it through the front panel for the desired dips and dropouts. There are some models that are computer attached (RS232 or IEEE488) and you execute software programmed routines for the test. Mitigation? Most EUT's can easily withstand half and single cycle drop, many can take a little more (up to 5 cycles) before going seriously anemic. Same is true for sags if the mains are wide range input. If you fail, you reselect the product's power supply, or beef up the input bulk capacitance (assuming SMPS type) or adjust the monitoring circuitry (i.e. remote sense, power good signal) for slower response and/or higher threshold. For the -4-5 (surge) test; We use a schaffner NSG 650 attached to a pc running the schaffner surge software. The surges are delivered to the EUT through a CDN 110 coupler. The cross coupling changes are manual jumpers. We also have a Haefely Psurge 4010 and 32.1 coupling filter for heavy loads. The cross coupling changes are automatic. The EUT supply cord length has to be no longer than .8M to the surge generator. make a custom cable This test series can damage your EUT, so you might want to do this test last. Mitigation of failures takes on a myriad of possibilities. Wiring length, TVSS absorber capacity, etc. It is hard to say without knowing more about your product. Do you also need to do the -4-4 (EFT) test? All this test gear is large and heavy, particularly the power sources and stepping xformers. Perhaps someone else can elucidate on exceptions to Class A rules? I gotta go, Happy Hunting, Kyle Ehler KCØIQE mailto:kyle.eh...@lsil.com mailto:kyle.eh...@lsil.com Assistant Design Engineer LSI Logic Storage Systems Div. 3718 N. Rock Road U.S.A. Wichita, Kansas 67226 Ph. 316 636 8657 Fax 316 636 8321 -Original Message- From: wmf...@aol.com [ mailto:wmf...@aol.com mailto:wmf...@aol.com ] Sent: Monday, November 19, 2001 10:29 AM To: emc-p...@ieee.org Subject: Methods Equipment; Surge Dips Esteemed listmembers, In gearing-up for testing under the auspices of EN61326:97, I'm trying to understand two immunity tests: EN61000-4-5 (surge immy) and -4-11 (dips immy). Is there test equipment one can rent to conduct these tests? What sort of mitigation steps are typical. Is anyone aware of any exceptions for this testing under ClassA rules? Thanks in advance... Wm Flanigan Standards Engineer Ameritherm 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/ 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.
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RE: Define Continuous DC Voltage - defibrillation
At 12:56 PM 11/20/2001 , Gary McInturff wrote: urn:schemas-microsoft-com:office:office xmlns:w = urn:schemas-microsoft-com:office:word xmlns:st1 = urn:schemas-microsoft-com:office:smarttags Robert, Thanks for this very interesting piece of data. I've often wonder what atrioventricular fibrillation is, you provide some insight on that as well. If it is a reset of sorts then how did the thumping of the chest ever work? I suppose it can also fall into the category of just being better than nothing at all. I have learned the chest thump, the pre-cordial thump, is for witnessed events. ex: Why doesn't CPR teach the pre-cordial thump? The pre-cordial thump is a technique that involves a firm blow to the chest above the heart using a closed 'fist'. This method is only taught in particular settings, for example the electrical industry and it is recommended that the pre-cordial thump only be administered in the event of an arrest witnessed by an individual trained in the procedure. Furthermore, ARC guidelines recommend that the pre-cordial thump is not a technique suitable for laypeople to be trained in or to administer. http://www.cpr2000.qas.qld.gov.au/faq/ or MEF influences pacemaker rate, causes diastolic depolarisation, and affects action potential repolarisation. It contributes to the positive chronotropic response of the heart to stretch, transient-stretch induced ectopic excitation (including sudden cardiac death after moderate precordial impact - Commotio cordis) and arrhythmogenesis in pressure or volume overloaded hearts. On the other hand, if used appropriately, pre-cordial impact can be a highly efficient means of mechanical pacemaking and cardioversion. Mechanisms of cardiac MEF include stretch-activation of ion channels, mechanical modulation of Ca2+ handling, and interaction with mechano-sensitive non-myocytes of the heart. We study these mechanisms in isolated cardiac cells, cell pairs, culture and tissue. Methods include the single and double whole cell patch clamp techniques, fluorescence microscopy, and optical mapping (currently under development). Interventions involve axial stretch of isolated cells, swelling, local membrane deformation, pharmacological block of ion channels, etc. As part of Professor Denis Nobles BHF Chair for Cardiovascular Physiology we also make extensive use of mathematical modelling for data interpretation, hypothesis formation and design of experimental protocols. http://www.physiol.ox.ac.uk/Graduate_Studies/Research_Interests/kohl2000.html It is related to the rare newspaper article of someone getting hit in the chest with a ball and dropping dead. Speculation has it that the timing was un-lucky and hit at the moment that the heart timing could be stopped. The pre-cordial thump is the reverse. EMT's in this state are not taught the technique. - Bill I can be learned wrong and always look for a better understanding. Its been awhile but I believe the information came from one of the product safety seminars in the Seattle (Rich N. I'm staring pretty hard at you for the moment) area and I don't know really remember the speaker, but it made a great deal of sense to me at the time and obviously most of it stuck with me. (You'll notice I am not taking any blame even if my information is wrong) Thanks Gary -Original Message- From: robertj [mailto:robe...@ma.ultranet.com] Sent: Tuesday, November 20, 2001 9:12 AM To: 'Bill Owsley'; 'Gary McInturff'; 'Gregg Kervill'; 'Rich Nute' Cc: jrbar...@lexmark.com; emc-p...@majordomo.ieee.org Subject: RE: Define Continuous DC Voltage - defibrillation I also have not encountered the theory about chest compression controlling fibrillation. Since defibrillation is also controlled during open heart surgery by paddles directly applied to the heart and through the use of wire catheters from implantable defibrillators, it is not the only means. I thought it might be interesting to describe the heart function in electrical terms since that is the basis of understanding for most of us in this group. Heart muscle can be viewed as a simple free running flip-flop oscillator. When cut into pieces, each piece of heart muscle will automatically fire (contract) at its own natural rate. It can be triggered earlier by input from neighboring tissue. Once it fires, it goes through a relaxation stage when it is quite resistant to triggering by neighboring tissue. This firing at a cellular level is call depolarization. It is caused by the cell wall suddenly becoming permeable to sodium and potassium ions and loosing its charge (which of course is a current flow). The cell then takes time to recharge by pumping ions back across the cell wall. The master clock for the heart is the sinoatrial (SA) node (the sinus node mentioned by Gary). This node sets the pace for the heart in response to assorted hormone and brain inputs. It is located in the right atrium. Remember the heart has four chambers. The right atrium is a collecting spot
RE: Methods Equipment; Surge Dips
Hi William, I dont know about renting equipment for the tests. You can probably find it. For the -4-11 (dip/dropout) test; Depending on your load, your site wiring has to be up to snuff. The power sources for doing the dip and dropout test are hefty stuff. My lab uses a three-phase powered source to deliver a max of 16A into a single phase capacitive (SMPS) load. I have a Pacific Power 140 TMX and an AMX 390. The 140 does flicker/harmonics and can do dip/dropout within its output limits (about 10A inrush). Any loads beyond a 10A inrush gets dip/dropout tested by the 390. The 140 is totally pc controlled but can be programmed through the front panel. It is a handy doer. The 390 is the heavy (up to 20A inrush) and I program it through the front panel for the desired dips and dropouts. There are some models that are computer attached (RS232 or IEEE488) and you execute software programmed routines for the test. Mitigation? Most EUT's can easily withstand half and single cycle drop, many can take a little more (up to 5 cycles) before going seriously anemic. Same is true for sags if the mains are wide range input. If you fail, you reselect the product's power supply, or beef up the input bulk capacitance (assuming SMPS type) or adjust the monitoring circuitry (i.e. remote sense, power good signal) for slower response and/or higher threshold. For the -4-5 (surge) test; We use a schaffner NSG 650 attached to a pc running the schaffner surge software. The surges are delivered to the EUT through a CDN 110 coupler. The cross coupling changes are manual jumpers. We also have a Haefely Psurge 4010 and 32.1 coupling filter for heavy loads. The cross coupling changes are automatic. The EUT supply cord length has to be no longer than .8M to the surge generator. make a custom cable This test series can damage your EUT, so you might want to do this test last. Mitigation of failures takes on a myriad of possibilities. Wiring length, TVSS absorber capacity, etc. It is hard to say without knowing more about your product. Do you also need to do the -4-4 (EFT) test? All this test gear is large and heavy, particularly the power sources and stepping xformers. Perhaps someone else can elucidate on exceptions to Class A rules? I gotta go, Happy Hunting, Kyle Ehler KCØIQE mailto:kyle.eh...@lsil.com Assistant Design Engineer LSI Logic Storage Systems Div. 3718 N. Rock Road U.S.A. Wichita, Kansas 67226 Ph. 316 636 8657 Fax 316 636 8321 -Original Message- From: wmf...@aol.com [mailto:wmf...@aol.com] Sent: Monday, November 19, 2001 10:29 AM To: emc-p...@ieee.org Subject: Methods Equipment; Surge Dips Esteemed listmembers, In gearing-up for testing under the auspices of EN61326:97, I'm trying to understand two immunity tests: EN61000-4-5 (surge immy) and -4-11 (dips immy). Is there test equipment one can rent to conduct these tests? What sort of mitigation steps are typical. Is anyone aware of any exceptions for this testing under ClassA rules? Thanks in advance... Wm Flanigan Standards Engineer Ameritherm 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.
RE: Methods Equipment; Surge Dips
Hi all, John Crabb asked me about my previous response (see below). He brings up some points that I don't have experience with. I wasn't sure how to answer it. I was hoping that someone else could address his concern. For our AC powered equipment, we have never needed to add varistors, MOV's, sidactors, TVS's ... to the AC mains for surge protection. The existing input filter (which carries its own safety approvals) has been sufficient.So... I have never run into the component restriction that John points out below. If anybody else has, maybe they could address John's question better than I? However, we have used Sidactors, TVSs and/or MOVs on signal lines and Telecom lines with good results. The only major problems that we have had are due to mismatch between power dissipation specs for a fuse and MOV in a telecom circuit. There were some instances where the MOV would burn before the fuse would blow during power cross testing. Chris -Original Message- From: Crabb, John [SMTP:jo...@exchange.scotland.ncr.com] Sent: Tuesday, November 20, 2001 12:13 PM To: Chris Maxwell Subject: RE: Methods Equipment; Surge Dips Chris, we have been considering using Harris (Littelfuse) LA series varistors to overcome a surge problem, but it is being highlighted to us that there is a CENELEC OSM Decision that several European countries do not accept the use of varistors between the mains and the protective earth. Have you ever come across this restriction, and if so, how did you get round it ? (I gather UL and CSA have no such concerns). 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.
RE: Define Continuous DC Voltage - defibrillation
Robert, Thanks for this very interesting piece of data. I've often wonder what atrioventricular fibrillation is, you provide some insight on that as well. If it is a reset of sorts then how did the thumping of the chest ever work? I suppose it can also fall into the category of just being better than nothing at all. I can be learned wrong and always look for a better understanding. Its been awhile but I believe the information came from one of the product safety seminars in the Seattle (Rich N. I'm staring pretty hard at you for the moment) area and I don't know really remember the speaker, but it made a great deal of sense to me at the time and obviously most of it stuck with me. (You'll notice I am not taking any blame even if my information is wrong) Thanks Gary -Original Message- From: robertj [mailto:robe...@ma.ultranet.com] Sent: Tuesday, November 20, 2001 9:12 AM To: 'Bill Owsley'; 'Gary McInturff'; 'Gregg Kervill'; 'Rich Nute' Cc: jrbar...@lexmark.com; emc-p...@majordomo.ieee.org Subject: RE: Define Continuous DC Voltage - defibrillation I also have not encountered the theory about chest compression controlling fibrillation. Since defibrillation is also controlled during open heart surgery by paddles directly applied to the heart and through the use of wire catheters from implantable defibrillators, it is not the only means. I thought it might be interesting to describe the heart function in electrical terms since that is the basis of understanding for most of us in this group. Heart muscle can be viewed as a simple free running flip-flop oscillator. When cut into pieces, each piece of heart muscle will automatically fire (contract) at its own natural rate. It can be triggered earlier by input from neighboring tissue. Once it fires, it goes through a relaxation stage when it is quite resistant to triggering by neighboring tissue. This firing at a cellular level is call depolarization. It is caused by the cell wall suddenly becoming permeable to sodium and potassium ions and loosing its charge (which of course is a current flow). The cell then takes time to recharge by pumping ions back across the cell wall. The master clock for the heart is the sinoatrial (SA) node (the sinus node mentioned by Gary). This node sets the pace for the heart in response to assorted hormone and brain inputs. It is located in the right atrium. Remember the heart has four chambers. The right atrium is a collecting spot for the returning blood and when it contracts, moves the blood next door to the right ventricle. The right ventricle pumps into the lungs. The left atrium holds returning oxygenated blood and pushes it into the left ventricle which pumps into the rest of the body. Obviously the ventricles are the workhorses. When the sinoatrial node fires, a wave of depolarization spreads over both atria (1/10 of a second), but is protected from reaching the ventricles by a layer of insulation. At the base of the right atrium it reaches the atrioventricular (AV) node. This is a delay line (another 1/10 of a second) and passes the signal to the left and right bundle branches which are special conductors to get the signal quickly to all parts of the ventricles. The AV delay provides the time for the atria to finish filling the ventricles before the much more significant contraction of the ventricles. Since all these conductors are live tissues, injury or irritation, depending on where it occurs, can cause all sorts of problems like fast or slow rhythms, lack of coordination of atria and ventricles, etc. One solution is implantable pacemakers which in their simplest forms electrically trigger the ventricles (the atria are left to themselves since they are not as important). Fibrillation occurs when something (like electric shock or irritation) triggers a piece of heart muscle. This in turn triggers neighboring cells. Unfortunately when the coordinated signal arrives from elsewhere, the cells which have just fired can't respond since they have not gone through their refractory period. These misfired cells then wait (while other parts are recovering) and having waited too long, fire on their own again. When several locations of the heart are doing this, the heart just quivers instead of making a coordinated pumping effort. The fix is to provide an electrical jolt which doesn't bother with triggering, it just hits all the cells with enough energy to force depolarization anyway. Then all cells together go through their refractory period and are ready for a coordinated trigger (if it still exists). This is why very high shock levels can avoid causing fibrillation. Defibrillators have come a long way from the old days when they just applied a severe 60 cycle AC shock. These days they try to provide a minimal level impulse coordinated with any residual heart beat to force the heart into unified action. The impulse can be applied with external paddles, and now is available as a built in
RE: Define Continuous DC Voltage - defibrillation
excellent - now if you'll go through the PQRST complex also... - Bill At 12:11 PM 11/20/2001 , robertj wrote: I also have not encountered the theory about chest compression controlling fibrillation. Since defibrillation is also controlled during open heart surgery by paddles directly applied to the heart and through the use of wire catheters from implantable defibrillators, it is not the only means. I thought it might be interesting to describe the heart function in electrical terms since that is the basis of understanding for most of us in this group. Heart muscle can be viewed as a simple free running flip-flop oscillator. When cut into pieces, each piece of heart muscle will automatically fire (contract) at its own natural rate. It can be triggered earlier by input from neighboring tissue. Once it fires, it goes through a relaxation stage when it is quite resistant to triggering by neighboring tissue. This firing at a cellular level is call depolarization. It is caused by the cell wall suddenly becoming permeable to sodium and potassium ions and loosing its charge (which of course is a current flow). The cell then takes time to recharge by pumping ions back across the cell wall. The master clock for the heart is the sinoatrial (SA) node (the sinus node mentioned by Gary). This node sets the pace for the heart in response to assorted hormone and brain inputs. It is located in the right atrium. Remember the heart has four chambers. The right atrium is a collecting spot for the returning blood and when it contracts, moves the blood next door to the right ventricle. The right ventricle pumps into the lungs. The left atrium holds returning oxygenated blood and pushes it into the left ventricle which pumps into the rest of the body. Obviously the ventricles are the workhorses. When the sinoatrial node fires, a wave of depolarization spreads over both atria (1/10 of a second), but is protected from reaching the ventricles by a layer of insulation. At the base of the right atrium it reaches the atrioventricular (AV) node. This is a delay line (another 1/10 of a second) and passes the signal to the left and right bundle branches which are special conductors to get the signal quickly to all parts of the ventricles. The AV delay provides the time for the atria to finish filling the ventricles before the much more significant contraction of the ventricles. Since all these conductors are live tissues, injury or irritation, depending on where it occurs, can cause all sorts of problems like fast or slow rhythms, lack of coordination of atria and ventricles, etc. One solution is implantable pacemakers which in their simplest forms electrically trigger the ventricles (the atria are left to themselves since they are not as important). Fibrillation occurs when something (like electric shock or irritation) triggers a piece of heart muscle. This in turn triggers neighboring cells. Unfortunately when the coordinated signal arrives from elsewhere, the cells which have just fired can t respond since they have not gone through their refractory period. These misfired cells then wait (while other parts are recovering) and having waited too long, fire on their own again. When several locations of the heart are doing this, the heart just quivers instead of making a coordinated pumping effort. The fix is to provide an electrical jolt which doesn t bother with triggering, it just hits all the cells with enough energy to force depolarization anyway. Then all cells together go through their refractory period and are ready for a coordinated trigger (if it still exists). This is why very high shock levels can avoid causing fibrillation. Defibrillators have come a long way from the old days when they just applied a severe 60 cycle AC shock. These days they try to provide a minimal level impulse coordinated with any residual heart beat to force the heart into unified action. The impulse can be applied with external paddles, and now is available as a built in part of implanted pacemakers so the impulse can be applied directly to the heart using the pacing electrodes. Bob Johnson -Original Message- From: owner-emc-p...@majordomo.ieee.org [mailto:owner-emc-p...@majordomo.ieee.org] On Behalf Of Bill Owsley Sent: Monday, November 19, 2001 1:22 PM To: Gary McInturff; 'Gregg Kervill'; 'Rich Nute' Cc: jrbar...@lexmark.com; emc-p...@majordomo.ieee.org Subject: RE: Define Continuous DC Voltage I've never seen cardiac function or resuscitation explained this way... and I'm an EMT-D. The D is for defibrillator and the EMT is for emergency medical technician. And with very few exceptions, the rest of the medical aspects of this discussion have been suspect. As my kids say - don't go there... - Bill At 12:02 PM 11/19/2001 , Gary McInturff wrote: From a few courses several years back. The heart has something called the Sinus node (spelling could be wrong) The responsibility of that node is to control the
RE: Quality Assurance and product approvals
You are all making some excellent points. It would seem that many of us share commonality. Perhaps that is one of the underlying purposes of the quality organizations. When followed, the effects are positive and things move correctly, and in synch, but when exceptions are present... In my case, the compliance group and the engineering group are one. This obviously has good and bad implications. Brian makes an excellent point that has at times caused my hackles to raise more than once...the independence (or lack thereof) between the compliance department and the engineering department. In the company documents filed by two of these quality agencies, i.e. ISO 900x, A2LA, TUV or COMPASS, there is a clause that specifically mentions the requirement for this independence. Or, is it more of a 'suggestion'? There does not however, seem to be an audit check for departmental independence. I recently have become an ISO auditor, and I am uncertain there is, UNLESS I want to take it upon myself to press the issue. Since I work in the department, I cannot be assigned the task of auditing it, but I could express my concerns with the person assigned the audit of the EMC/Safety/Design engineering department. Hmm... I dont recall where these clauses are, but the purpose behind them is to express the importance of functional isolation between the interests of the two groups. In our case, this causes a disastrous effect on scheduling and allocation of resources because the conflicts are quick to rise and there is a weak attempt to resist. At times, we find ourselves pulled in two directions simultaneously. The 'Janus'..? All the planning, procedures and methods in the world cannot overcome this conflict if no one is willing to meet the challenge and push the issue. (as in our case) My poor boss has been subdued...and our compliance group is eternaly the whipping boy. I see the problem, but I am ineffective at fighting off the 800Lb gorilla's because they do not believe a lab rat...could read, think and speak. Ah, but I can AUDIT, or cause focus by another auditor...that would attract the attention of the QA folks (who seem to be beyond reproach). In the end, the quality of our output is in the hands of the lab rats who, take it upon themselves to ensure the letter of the standards are adhered to despite the conflict associated with the work. That makes it a thankless job, with little if any, appreciation. Ha!! what's that you say...you want a medal? -for driving up COSTS and delaying product release!!! If it were'nt for the beaurocracy...you would not have a job. [Ehler, Kyle] (my words) -Original Message- From: Brian McAuliffe [mailto:bally...@iolfree.ie] Sent: Tuesday, November 20, 2001 4:36 AM To: 'EMC-PSTC Discussion Group' Subject: RE: Quality Assurance and product approvals I think the point raised by Gary re: where the Compliance group fits into the organisation structure is more important than procedures/process, although I disagree with him about where that should be. Let me explain. Having a good working relationship with Engineering is indeed critical, however from my experience I believe it essential for the Compliance group to be organisationally independent of Engineering. If not, then there are always conflicts of interest when allocating the (usually limited) Compliance resources between: Engineering - there are 4 design reviews this week and preparation required for a safety pre-compliance test next week; Operations - the agency auditor is visiting next week and there is some prep needed; Sales/Marketing - the Russian approval is expiring in 2 weeks and you need to re-apply, prepare doc pack, etc. How do you prioritise without getting slack from at least one functional head ?? Obviously if the Compliance group is actually a group and not just 1 or 2 persons, then with a good understanding of the roles amongst the group members the above does not really pose a problem. However I do NOT believe this is the case, particularly in the current climate of lay-offs, with us Compliance folk are becoming less essential. Unless the role of the Compliance group is very narrow and involves only support of one function (which I doubt), I feel that an independent Compliance group is essential. It should be functionally independent to any other group and reporting to the MD, or, reporting to the QA Director/Manager. This will mean you can realistically argue for adequate resouces to do a professional job for all those groups requiring your services. You will have somebody independent at the right level in the organisation supporting the Compliance group - essential when $$$ are involved. Let's face it, no RD Manager is going to approve headcount for a 2nd Compliance Engineer whose primary function is to do audits of the production facility to ensure critical components are controlled as they should, and, to support Sales/Marketing to achieve product approvals
RE: Define Continuous DC Voltage - defibrillation
I also have not encountered the theory about chest compression controlling fibrillation. Since defibrillation is also controlled during open heart surgery by paddles directly applied to the heart and through the use of wire catheters from implantable defibrillators, it is not the only means. I thought it might be interesting to describe the heart function in electrical terms since that is the basis of understanding for most of us in this group. Heart muscle can be viewed as a simple free running flip-flop oscillator. When cut into pieces, each piece of heart muscle will automatically fire (contract) at its own natural rate. It can be triggered earlier by input from neighboring tissue. Once it fires, it goes through a relaxation stage when it is quite resistant to triggering by neighboring tissue. This firing at a cellular level is call depolarization. It is caused by the cell wall suddenly becoming permeable to sodium and potassium ions and loosing its charge (which of course is a current flow). The cell then takes time to recharge by pumping ions back across the cell wall. The master clock for the heart is the sinoatrial (SA) node (the sinus node mentioned by Gary). This node sets the pace for the heart in response to assorted hormone and brain inputs. It is located in the right atrium. Remember the heart has four chambers. The right atrium is a collecting spot for the returning blood and when it contracts, moves the blood next door to the right ventricle. The right ventricle pumps into the lungs. The left atrium holds returning oxygenated blood and pushes it into the left ventricle which pumps into the rest of the body. Obviously the ventricles are the workhorses. When the sinoatrial node fires, a wave of depolarization spreads over both atria (1/10 of a second), but is protected from reaching the ventricles by a layer of insulation. At the base of the right atrium it reaches the atrioventricular (AV) node. This is a delay line (another 1/10 of a second) and passes the signal to the left and right bundle branches which are special conductors to get the signal quickly to all parts of the ventricles. The AV delay provides the time for the atria to finish filling the ventricles before the much more significant contraction of the ventricles. Since all these conductors are live tissues, injury or irritation, depending on where it occurs, can cause all sorts of problems like fast or slow rhythms, lack of coordination of atria and ventricles, etc. One solution is implantable pacemakers which in their simplest forms electrically trigger the ventricles (the atria are left to themselves since they are not as important). Fibrillation occurs when something (like electric shock or irritation) triggers a piece of heart muscle. This in turn triggers neighboring cells. Unfortunately when the coordinated signal arrives from elsewhere, the cells which have just fired can't respond since they have not gone through their refractory period. These misfired cells then wait (while other parts are recovering) and having waited too long, fire on their own again. When several locations of the heart are doing this, the heart just quivers instead of making a coordinated pumping effort. The fix is to provide an electrical jolt which doesn't bother with triggering, it just hits all the cells with enough energy to force depolarization anyway. Then all cells together go through their refractory period and are ready for a coordinated trigger (if it still exists). This is why very high shock levels can avoid causing fibrillation. Defibrillators have come a long way from the old days when they just applied a severe 60 cycle AC shock. These days they try to provide a minimal level impulse coordinated with any residual heart beat to force the heart into unified action. The impulse can be applied with external paddles, and now is available as a built in part of implanted pacemakers so the impulse can be applied directly to the heart using the pacing electrodes. Bob Johnson -Original Message- From: owner-emc-p...@majordomo.ieee.org [mailto:owner-emc-p...@majordomo.ieee.org] On Behalf Of Bill Owsley Sent: Monday, November 19, 2001 1:22 PM To: Gary McInturff; 'Gregg Kervill'; 'Rich Nute' Cc: jrbar...@lexmark.com; emc-p...@majordomo.ieee.org Subject: RE: Define Continuous DC Voltage I've never seen cardiac function or resuscitation explained this way... and I'm an EMT-D. The D is for defibrillator and the EMT is for emergency medical technician. And with very few exceptions, the rest of the medical aspects of this discussion have been suspect. As my kids say - don't go there... - Bill At 12:02 PM 11/19/2001 , Gary McInturff wrote: From a few courses several years back. The heart has something called the Sinus node (spelling could be wrong) The responsibility of that node is to control the timing of the electric wave front if you will. The heart actually has about three pulses. Looking at a heart
EL (Electro Luminescent) considerations.
Hi Group, Could anyone tell me a little more about the safety implications/standards for the use of EL wire/sheet. Specifically when powered from a battery source,i.e. battery-inverter-EL, and the EL wire/sheet outer insulation is exposed. Thank you in advance, Enci --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
RE: Quality Assurance and product approvals
Morning Brian, et al. I don't have a large heartburn about the exact organizational chart location I have been in them all - well not actually sales I do have some standards* - and I find the debate very valuable! Location doesn't really create or fix all that many problems. You kind of trade one set of problems for the other. The absolute point of criticality is that the corporation has to have understand what it needs to get a product to market. That is established in the products requirement document, others may have different names. The things this group does, including Safety, EMC, and NEBS, among others are quite simply product requirements just like everything else in the document, in our case the ability to pass packets at line rate without packet loss, or maybe implementing spanning tree protocols etc. Take a look back at recent discussions about whether or not a DOC by itself was sufficient to accept product. The answer was generally no. That can affect a bottom line and that always gets attention from the highest levels. Why? Because some of the product features couldn't be independently verified and products aren't being purchased without it. We just stopped purchases of some very expensive pieces of equipment because of some operational bugs AND because of problems with their radiated emissions. That affected that companies bottom line for the quarter and that gets everybody's attention. Once the feature issue is understood then things start falling into place quite nicely. Making that understood is probably one of the more critical items we have to face, and it can be done from any organization. When the various prototype, pilot, or alpha builds are being planned they include the units I need for my job - that will range from three to six depending on the NEBS requirements, and these aren't inexpensive pieces of equipment. Schedules are a sneaking little tool. When being laid out its not a hard sale to point out that not having EUT's and having them on fixed dates starts putting day to day slips into the production release of the product. It also clearly identifies when more bodies are needed to implement the schedule. Something the big guys can evaluate very effectively. You're correct about the design review meetings and I spend a lot of time either in them or responding via e-mail or cell phone to them. Its not perfect but works very well. If I train the engineers well they become somewhat self monitoring and learn to get quick verifications when they have concerns. Spokane is an absolutely wonderful place to live but it means that for those tests I need to witness - EMC and NEBS etc, I spend a great deal of time in rectangular tubes at 30,000 feet trying to get to a rectangular box at the end of the day - traveling is so much fun - but a laptop, a very good electronic Engineering change process, a cell phone, and some first rate engineers and lab rats and it works very well - again independent of what organization I'm in. So get the features defined at step one, that will drive the allocations, tasks and schedules. The work with some great people who understand engineering and the full product development process - yes even sales has its good points, but empire builders are expressly excluded, and then work from anywhere. History has given me a strong preference for being inside the engineering department but your choice is just as. Gary *(It was a joke folks complain to me directly off line). -Original Message- From: Brian McAuliffe [mailto:bally...@iolfree.ie] Sent: Tuesday, November 20, 2001 2:36 AM To: 'EMC-PSTC Discussion Group' Subject: RE: Quality Assurance and product approvals I think the point raised by Gary re: where the Compliance group fits into the organisation structure is more important than procedures/process, although I disagree with him about where that should be. Let me explain. Having a good working relationship with Engineering is indeed critical, however from my experience I believe it essential for the Compliance group to be organisationally independent of Engineering. If not, then there are always conflicts of interest when allocating the (usually limited) Compliance resources between: Engineering - there are 4 design reviews this week and preparation required for a safety pre-compliance test next week; Operations - the agency auditor is visiting next week and there is some prep needed; Sales/Marketing - the Russian approval is expiring in 2 weeks and you need to re-apply, prepare doc pack, etc. How do you prioritise without getting slack from at least one functional head ?? Obviously if the Compliance group is actually a group and not just 1 or 2 persons, then with a good understanding of the roles amongst the group members the above does not really pose a problem. However I do NOT believe this is the case, particularly in the current climate of lay-offs, with us Compliance folk
RE: 80/80 rule for euro compliance?
Actually, Vilfredo Pareto (1848-1923) was an Italian economist. He observed that 80% of the economy was driven by 20% of the consumers, i.e. 20% of the customers account for 80% of the turnover. Two decades ago I was involved in an effort to create a data bank of IBM typewriter service customers. Some customers (e.g. banks) owned many units, and placed many calls for service, while fewer calls came from individuals owning one machine. It became evident that 20% of the customers accounted for 80% of the service calls. The data base was set up to maintain the phone numbers of only the most active 20%, as this required 80% less computer space. When a call came in, the customer was asked for their phone number. If it was one of the 20%, the operator then saw a full screen of data as to the name, address and service history of the customer, saving time on the phone keying data. It would probably be correct to say that 80% of the work is done by 20% of the workers; however, it would still take 100% of effort to complete 100% of the work. George Alspaugh Gregg Kervill gkervill%eu-link@interlock.lexmark.com on 11/14/2001 08:03:00 AM Please respond to Gregg Kervill gkervill%eu-link@interlock.lexmark.com To: 'Doug McKean' dmckean%corp.auspex@interlock.lexmark.com, 'EMC-PSTC Discussion Group' emc-pstc%majordomo.ieee@interlock.lexmark.com cc:(bcc: George Alspaugh/Lex/Lexmark) Subject: RE: 80/80 rule for euro compliance? Liars, Damn Liars and . I sounds like the Pareto's law from management statistics You can do 80% of the work with 20% of the effort... I think someone requoted it once as You an fool some of the people all of the time. Cynically yours Gregg --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server. --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
RE: Methods Equipment; Surge Dips
Hi Wm (my guess is William), Didn't see a response to your question. Got lots to do today, so I'll be quick and dirty. (Well I thought I would...as you can see it wasn't so quick but it is dirty :-) Test equipment... Surge Testing... There are quite a few companies that make equipment that can test this. Haefley, Compliance Design, Schaffner and Keytek come to mind. We use a Keytek CE-Master. It will handle most power line surge testing that would be required. However, it won't do the 10/700 waveforms for telecom surge (unless they have a new unit or new module). It also may have trouble surge testing signal lines and other non-power lines unless you get the proper coupling/decoupling network. Dips Interrupt (also known as Power Quality Failure (PQF) testing... Same manufacturers as above. We use the CE-master for this test as well. (This is not a commercial for CE-master...it's just what we have.) One caveat regarding dip and interrupt testing is that you need a power source capable of high in-rush capacities to power the device under test. We use a typical wall outlet with a non-current limited isolation transformer to make 230VAC. If you use a current limited 110-230VAC converter, it may not be able to provide enough in-rush to test fairly. (check out the manual, it will explain)Oh yeah, I just remembered. Most of the standards say to test for 1 cycle of 50Hz. The CE-master will not generate 50Hz for you, instead it will only pass your 60Hz through it. We get around this by testing for two cycles of 60Hz instead of one cycle of 50Hz. It's a worst case, and keeps us from having to buy a 50Hz inverter (that isn't current limited...see above). Mitigation techniques... Surge. Depends upon the surge level needed to pass and the sensitivity of your equipment. Protection could be provided by the typical EMC filtering that you already have. (i.e. a power line filter with caps and chokes). If the surge is too powerful for your existing filter, you can either get a surge rated input filter or put a surge protection device on (watchout for your leakage current specs for safety). I recommend either a TVS or Sidactor. I used to worry about Sidactor availability as they were only available in 2,500 piece quantities, but are now available in small quantities from Digikey. Some manufacturers: TVS diodesSemtech, Protek Sidactors... Teccor, Rachem Polyswitch. Dips Interrupts. Main mitigation technique here is bulk capacitance to provide enough hold-up time so that your equipment doesn't power down during a small dip or interrupt. If you are using a power supply in your design, check out its hold-up time spec. So far, from our experience it appears that a supply with at least a 15milllisecond hold-up time will get you through the test. In rare instances, in-rush limiting may be required. Probably not. Exemptions? Class A is an emissions classification under the standard (EN 61326-1). Using Class A as an immunity classification may lead you down the wrong path. I would suggest considering immunity independently of emissions and classifying the equipment for immunity as industrial (annex A), controlled EM environments (annex B) or portable (annex C). Once you have picked the correct annex, the question to test or not to test will be answered. In order to determine the test level and performance criterion, use the annex picked above and then refer to Table 2 and classify your equipment as for essential operation, continuous unmonitored operation, continuous monitored operation or non-continuous operation. There is also a Table 1 which specifies an absolute minimum immunity level for EN 61326-1 classified equipment. I use this as a benchmark, but usually test to higher levels as specified in the annexes. I hope there was something useful in there for you. Chris Maxwell | Design Engineer - Optical Division email chris.maxw...@nettest.com | dir +1 315 266 5128 | fax +1 315 797 8024 NetTest | 6 Rhoads Drive, Utica, NY 13502 | USA web www.nettest.com | tel +1 315 797 4449 | -Original Message- From: wmf...@aol.com [SMTP:wmf...@aol.com] Sent: Monday, November 19, 2001 11:29 AM To: emc-p...@ieee.org Subject: Methods Equipment; Surge Dips Esteemed listmembers, In gearing-up for testing under the auspices of EN61326:97, I'm trying to understand two immunity tests: EN61000-4-5 (surge immy) and -4-11 (dips immy). Is there test equipment one can rent to conduct these tests? What sort of mitigation steps are typical. Is anyone aware of any exceptions for this testing under ClassA rules? Thanks in advance... Wm Flanigan Standards Engineer Ameritherm 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:
[Fwd: Student Design Contest from IEEE EMC Education Committee]
I'd like to pass this on to the group. Bob Heller 3M Product Safety, 76-1-01 St. Paul, MN 55107-1208 Tel: 651- 778-6336 Fax: 651-778-6252 - Forwarded by Robert E. Heller/US-Corporate/3M/US on 11/20/2001 05:46 AM - Greetings, Original Message Subject: Student Design Contest from IEEE EMC Education Committee List-Post: emc-pstc@listserv.ieee.org Date: Tue, 13 Nov 2001 14:44:26 -0600 From: Robert Nelson robert.m.nel...@ndsu.nodak.edu Dear IEEE EMC Education Committee members (and interested folks), The Education Committee of the IEEE EMC (Electromagnetic Compatibility) Society is sponsoring the third annual EMC Student Design Competition, and would like to invite students you know to enter. In a nutshell the contest involves registering to receive a noisy circuit (electrically noisy, that is), and designing appropriate fixes to make the circuit quieter. Your students might win $900 plus a trip to the 2002 International IEEE EMC Symposium to be held in Minneapolis, MN in August 2002! Additional information about the contest is available either from the home page for the IEEE EMC Society ( http://www.ewh.ieee.org/soc/emcs/ ), (noting that there are two links dealing with the contest) or from the home page for the Education Committee ( http://www.ewh.ieee.org/soc/emcs/edu/index.html ). Please go to the link discussing the Contest. You might also want to peruse an article written about the 2001 contest. This is available via the link on the page http://www.ewh.ieee.org/soc/emcs/edu/edurpts.htm If you have any questions, please contact Ahmad Fallah ( ahmadfal...@ieee.org ). Thanks for passing this on! Sincerely, Dr. Bob Nelson Secretary, IEEE EMC Education Committee North Dakota State University Dept. of Electrical and Computer Eng. Fargo, ND 58105 V: (701)-231-7619 F: (701)-231-8677 E-mail: r.m.nel...@ieee.org --- 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.
SV: Walkie-Talkie in Thailand
Hello KC Chan, In Thailand the bands 26.960 - 27.410 MHz, 77.9875 - 79 MHz and 244.9875 - 246 MHz are designated as Citizens Band (CB). The bands 79 - 79.9875 MHz and 246 - 247 MHz are reserved for similar purposes. You may download the Thai frequency allocation table from http://www.ptd.go.th/services_eng.htm Links to this kind of information may often be found on the ITU page: http://www7.itu.int/treg/profiles2/CntryPrfiles/guide.asp Best regards Helge Knudsen Test Approval manager Niros Telecommunication Hirsemarken 5 DK-3520 Farum Denmark Tel +45 44 34 22 51 Fax +45 44 99 28 08 email h.knud...@niros.com -Oprindelig meddelelse- Fra: KC CHAN [PDD] [mailto:kcc...@hkpc.org] Sendt: 20. november 2001 08:13 Til: emc-p...@majordomo.ieee.org Emne: Walkie-Talkie in Thailand Hi I got an enquiry about the walkie-talkie in Thailand. Does anyone know the frequency band for this purpose in Thailand, and where I can get more information about this. Thank You KC Chan --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server. --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
RE: Quality Assurance and product approvals
I think the point raised by Gary re: where the Compliance group fits into the organisation structure is more important than procedures/process, although I disagree with him about where that should be. Let me explain. Having a good working relationship with Engineering is indeed critical, however from my experience I believe it essential for the Compliance group to be organisationally independent of Engineering. If not, then there are always conflicts of interest when allocating the (usually limited) Compliance resources between: Engineering - there are 4 design reviews this week and preparation required for a safety pre-compliance test next week; Operations - the agency auditor is visiting next week and there is some prep needed; Sales/Marketing - the Russian approval is expiring in 2 weeks and you need to re-apply, prepare doc pack, etc. How do you prioritise without getting slack from at least one functional head ?? Obviously if the Compliance group is actually a group and not just 1 or 2 persons, then with a good understanding of the roles amongst the group members the above does not really pose a problem. However I do NOT believe this is the case, particularly in the current climate of lay-offs, with us Compliance folk are becoming less essential. Unless the role of the Compliance group is very narrow and involves only support of one function (which I doubt), I feel that an independent Compliance group is essential. It should be functionally independent to any other group and reporting to the MD, or, reporting to the QA Director/Manager. This will mean you can realistically argue for adequate resouces to do a professional job for all those groups requiring your services. You will have somebody independent at the right level in the organisation supporting the Compliance group - essential when $$$ are involved. Let's face it, no RD Manager is going to approve headcount for a 2nd Compliance Engineer whose primary function is to do audits of the production facility to ensure critical components are controlled as they should, and, to support Sales/Marketing to achieve product approvals worldwide. (To bring this back to procedures/process) There also needs to be a 'document' which highlights: 1. What services the Compliance group offer; 2. The inputs (from other groups) required, and the outputs to be expected from each service; 3. Turnaround time (this will never be 100% accurate) With a document such as this published it raises awareness among each of the functions that the Compliance group do have organisation-wide responsibilites and are not at the beck and call of just one group. It forces them to plan for compliance also. It gives the Compliance group more credibility and visibility, and maybe people will start to appreciate the . Brian -Original Message- From: owner-emc-p...@majordomo.ieee.org [mailto:owner-emc-p...@majordomo.ieee.org]On Behalf Of Gary McInturff Sent: 19 November 2001 16:35 To: 'Tania Grant'; am...@westin-emission.no; 'EMC-PSTC Discussion Group' Subject: RE: Quality Assurance and product approvals Bottom line is that each program generates a set of milestones that identify a function, set of equipment required, and timeframe for getting them done, and there are a set of generic test suites, but generally the whole process is documented at very non-descript level. The rest of this is rational for the way it happens. Over the course of my career ( companies of 40 - to 1,000 employees) this function has 1) grown in scope, first just safety, then safety and EMC, then safety, EMC and DVT, currently its safety, EMC, DVT, and NEBS. 2) It has been shuffled from place to place. Engineering, QA, manufacturing, to marketing. I have always been able to direct it back to what I believe is the correct department - Engineering. Principally for, conservation of resources - I already have some lab rats ( I say this with humor they have saved me much time and grief over the years) , and equipment, I may have to expand the equipment set marginally but I don't have to duplicate it. Probably just as important, is that inside of engineering I have the most timely input into the design changes or recommendations up front. Being located with the design engineers gives us both immediate and personal contact. They can stop into my office, and do quite regularly, to ask questions or seek advice, and I can do the same. As for formality of process it has always been more a series of milestones rather than explicitly documented processes for the vary reason Tania states - things change and they can change rapidly. I do have a series of boilerplate tests such as temperature, etc but occasionally those tests end up confirming - not predicting - what the safety agencies find. I try to find the very earliest point at which I can submit product to the safety agencies and the product is not always 100% functional from a design perspective, but 100% representative
RE: John Woodgate Departure
Dear all, I guess I should have known better than to open a can of worms and then have the audacity to take a day off!! I returned today ( Tuesday) to find my in-folder overflowing with opinions on this matter. It is quite obvious that John's presence is treasured by quite a large percentage of the list. However, there has been noticeable shift in the tone of the messages addressing the issue in that there is some degree of casting the administrator as the villain of the peace here (contrary to the Hollywood norm which always has the English guy as the villain!). This is neither right nor fair (I am not talking about Hollywood anymore although it wouldn't do them any harm to take notes!!). It was certainly not the intention of my original posting and my appeal was to both John and the list admin. My apologies to the list administrator for this misunderstanding and unfortunate change in ethos. I think it best we leave the matter to John and the administrator to resolve. To this end, Chris Maxwell writes .. If there is any peacemaking to be done here, I suggest that John and the admin in question work it out off-line. Agreed. Chris adds... I suggest that if a third party get involved, that it also be off-line. (I suggest Tania. She'll straighten them out :-)) So ... what are you saying Chris .. Kofi Annan not good enough for you? But seriously, let us not point fingers and leave the gentlemen to work it out. The most we can do is appeal to John to reconsider HIS decision. Best regards everyone. - Chris -- Don't you just love the swooshing sound deadlines make as they go flying past! _ This message has been checked for all known viruses by Star Internet delivered through the MessageLabs Virus Scanning Service. For further information visit http://www.star.net.uk/stats.asp or alternatively call Star Internet for details on the Virus Scanning Service. --- 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.
Walkie-Talkie in Thailand
Hi I got an enquiry about the walkie-talkie in Thailand. Does anyone know the frequency band for this purpose in Thailand, and where I can get more information about this. Thank You KC Chan --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
Re: Quality Assurance and product approvals
Hi Tania, I just finished writing a procedure on agency certifications for a client (prompted by their ISO 9000 audit). It became partly glossary partly encyclopedia so sales, marketing, etc could find definitions and explanations of what the agencies are and why we need the certifications. It identifies the different levels types of certifications why they are needed by various parties. It outlines who does what, as far as design (initial ongoing), purchasing (ongoing - no stealth changes of critical parts), parts/materials inventory (traceability), etc. It defines who gets notified of new certifications what records are kept for how long. I agree with you completely that it would be never-ending to try to write a procedure to allow the untrained to do it all, so it does not explain how to conduct a project at any agency except in the most basic terms (tell the agency what you want to certify, get their cost estimate, write PO, provide samples documentation, assist as needed). Much can be gained by having such a document, which will seem basic for any competent compliance engineer. It will so nice to refer people to the procedure for the routine questions, instead of doing Agency 101 for the umpteenth time. Mike Harris/Teccom -Original Message- From: Tania Grant taniagr...@msn.com To: am...@westin-emission.no am...@westin-emission.no; 'EMC-PSTC Discussion Group' emc-p...@majordomo.ieee.org Date: Monday, November 19, 2001 1:18 AM Subject: Re: Quality Assurance and product approvals Amund, Since I transferred, over more than 20 years ago, from Quality Assurance to Regulatory compliance/product safety, I will share with you my opinions and my experience. However, I would also be interested in hearing about the experience of others. In my opinion, QA and regulatory compliance are different enough functions that require different experiences and disciplines that would not necessarily make it effective for a QA organization to either write or enforce procedures on the regulatory compliance functions. That does not mean that regulatory compliance shouldn't have a more formal process and a procedure to go with it. For myself, I know that having a QA background made me a more effective regulatory guru at the company. But I don't see how the two can be meshed under the same umbrella without diluting one or the other. Both require focus but it would be a rare Janus that could manage this effectively. However, the regulatory processes could, and should, be integrated into the whole engineering design process;-- and so should the QA process. Thus, the two can and should help each other, but I just don't see that a QA oversight by itself would make the regulatory process better or more effective. Now, I have a problem with your statement ...have your companies made procedures which in details describes the product approval process from beginning to end ? You are quite right that any procedure should describe a process in detail from beginning to end. This lends itself quite well to any and all test procedures, assembly of various parts, and other such functions where the same process is repeated over and over again. However, with the regulatory approval process, each product is different enough, that a procedure, especially one that is detailed, would not work. And the approval process is not always from the beginning to end but very often just a test or two have to be repeated, but not all, and sometimes you just notify the authorities about this and that, and sometimes you don't, but only document it or write up a justification why a particular test is not required. So how do you write a procedure around this? If I had to religiously do all this, I would be writing a procedure practically every time I was submitting a new or providing changes to a product. And I sure as heck would have been very upset if someone else (say from QA) were writing these procedures for me, especially since they wouldn't know what was required, or how to achieve this. A procedure describes how something is done. If I don't know how to do it, I shouldn't be working in that position. If the QA person is writing such a procedure (and assuming they are effective at it, which is problematic) then they should be working in that position and not me. Thus, I am not in favor of procedures. However, I am very much in favor of regulatory compliance plans that should be written for each new product, or a major regulatory up-date to a product. This compliance plan is really a communication device that informs Marketing, Engineering, QA, etc., the regulatory strategy: what the requirements are for this particular product, for which countries, to which standards, where the various tests will be performed, the approximate time assuming only one sample is
