Re: EN 61000-3-3 compliant heater controller
I know it is not fair. But the PSUs in question were not ours, and the problem was at a customers facility, so revealing any technical details of the problem and fix will be breaching confidentiality agreements. John Woodgate wrote: I read in !emc-pstc that Andrew Carson acar...@uk.xyratex.com wrote (in 3c4fd4e8.31a84...@uk.xyratex.com) about 'EN 61000-3-3 compliant heater controller', on Thu, 24 Jan 2002: As much as I can say, was a large number (600+) of switch mode supplies, installed in such a manner that their front end emc filters were ineffective. It was not on a European or US distribution distribution and once a simple fix was in place, near perfect sine waves. You can't get way with that! 'Simple fix' indeed. If you know of a simple fix, you tell! (;-) -- Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk After swimming across the Hellespont, I felt like a Hero. PLEASE do NOT copy news posts to me by E-MAIL! --- 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. -- Andrew Carson - Senior Compliance Engineer, Xyratex, UK Phone: +44 (0)23 9249 6855 Fax: +44 (0)23 9249 6014 --- 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: EN 61000-3-3 compliant heater controller
I read in !emc-pstc that Andrew Carson acar...@uk.xyratex.com wrote (in 3c4fd4e8.31a84...@uk.xyratex.com) about 'EN 61000-3-3 compliant heater controller', on Thu, 24 Jan 2002: As much as I can say, was a large number (600+) of switch mode supplies, installed in such a manner that their front end emc filters were ineffective. It was not on a European or US distribution distribution and once a simple fix was in place, near perfect sine waves. You can't get way with that! 'Simple fix' indeed. If you know of a simple fix, you tell! (;-) -- Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk After swimming across the Hellespont, I felt like a Hero. PLEASE do NOT copy news posts to me by E-MAIL! --- 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: EN 61000-3-3 compliant heater controller
Dear Ghery
I don't think I disagree very much with what you said below.
John Woodgate's summary yesterday was most interesting. He analysed the
reasons why harmonic mitigation at system and site level were not being
employed and concluded that:
It is almost axiomatic that the best overall economic solution (least total
cost to the end-user) is the informed use of ALL technical solutions -
mitigation at equipment, site and system level.
Unfortunately, many regulations do not necessarily appear to embody the best
engineering approach to solving the problem they are supposed to be
addressing.
Regards, Keith
In a message dated 23/01/02 16:21:36 GMT Standard Time,
ghery.pet...@intel.com writes:
Subj:RE: EN 61000-3-3 compliant heater controller
Date:23/01/02 16:21:36 GMT Standard Time
From:ghery.pet...@intel.com (Pettit, Ghery)
Sender:owner-emc-p...@majordomo.ieee.org
Reply-to: A HREF=mailto:ghery.pet...@intel.com;ghery.pet...@intel.com/A
(Pettit, Ghery)
To:cherryclo...@aol.com ('cherryclo...@aol.com'),
ghery.pet...@intel.com (Pettit, Ghery)
CC:emc-p...@majordomo.ieee.org
One key reason the US (and others) computer industry objects to IEC
61000-3-2 is that it was jammed down our throats with little or no input
from anyone other than the power providers. They conveniently set the
limits so that the full cost of resolving the problem would fall on
producers (and consumers) of devices utilizing the power they provide. No
standards were made that would require better design of the power
distribution system or consideration of facility level mitigation measures.
Fixing the power supply of a personal computer to meet the requirements in
IEC 61000-3-2 is simple - spend money. The choke needed represents about a
10% cost adder to the power supply. This is simply a cost, like taxes on
businesses, that is passed on to the consumer of the product. Fixing the
problem costs money, but typically large equipment to fix a problem over a
larger area is more economical than fixing it one load at a time.
Let us agree to disagree. I remain an opponent of IEC 61000-3-2 as written
and hope that TC77/SC77A does a better job with the version they are
working on and that it better represents a compromise between those who
would put the entire burden on the loads (as they have already done) and
those who would do nothing.
Ghery Pettit, NCE
Re: EN 61000-3-3 compliant heater controller
As much as I can say, was a large number (600+) of switch mode supplies, installed in such a manner that their front end emc filters were ineffective. It was not on a European or US distribution distribution and once a simple fix was in place, near perfect sine waves. John Woodgate wrote: I read in !emc-pstc that Andrew Carson acar...@uk.xyratex.com wrote (in 3c4eb53a.152e0...@uk.xyratex.com) about 'EN 61000-3-3 compliant heater controller', on Wed, 23 Jan 2002: Suppose we could have a little competition, who's seen the worst level of harmonic distortion, I think number 2 will take some beating. That's electronic pornography! Are you at liberty to say what (generically, no type numbers) produced those waveforms? -- Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk After swimming across the Hellespont, I felt like a Hero. PLEASE do NOT copy news posts to me by E-MAIL! --- 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. -- Andrew Carson - Senior Compliance Engineer, Xyratex, UK Phone: +44 (0)23 9249 6855 Fax: +44 (0)23 9249 6014 --- 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: EN 61000-3-3 compliant heater controller
I read in !emc-pstc that cherryclo...@aol.com wrote (in 16b.79458de.298 03...@aol.com) about 'EN 61000-3-3 compliant heater controller', on Wed, 23 Jan 2002: They seem to me to be an excellent idea, and can help avoid the need for improving a legacy mains distribution or buying EN 61000-3-2 compliant equipment. NO! Because the EMCD operates exclusively at product level, the use of external mitigation does not permit conformity. The present IEC/EN61000-3-2 requires products to conform in a stand-alone configuration, with no external aids. This is one of the major points of contention at present in the discussions leading to the Second Edition of IEC/EN61000-3-2. -- Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk After swimming across the Hellespont, I felt like a Hero. PLEASE do NOT copy news posts to me by E-MAIL! --- 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: EN 61000-3-3 compliant heater controller
I read in !emc-pstc that Andrew Carson acar...@uk.xyratex.com wrote (in 3c4eb53a.152e0...@uk.xyratex.com) about 'EN 61000-3-3 compliant heater controller', on Wed, 23 Jan 2002: Suppose we could have a little competition, who's seen the worst level of harmonic distortion, I think number 2 will take some beating. That's electronic pornography! Are you at liberty to say what (generically, no type numbers) produced those waveforms? -- Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk After swimming across the Hellespont, I felt like a Hero. PLEASE do NOT copy news posts to me by E-MAIL! --- 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: EN 61000-3-3 compliant heater controller
One key reason the US (and others) computer industry objects to IEC 61000-3-2 is that it was jammed down our throats with little or no input from anyone other than the power providers. They conveniently set the limits so that the full cost of resolving the problem would fall on producers (and consumers) of devices utilizing the power they provide. No standards were made that would require better design of the power distribution system or consideration of facility level mitigation measures. Fixing the power supply of a personal computer to meet the requirements in IEC 61000-3-2 is simple - spend money. The choke needed represents about a 10% cost adder to the power supply. This is simply a cost, like taxes on businesses, that is passed on to the consumer of the product. Fixing the problem costs money, but typically large equipment to fix a problem over a larger area is more economical than fixing it one load at a time. Let us agree to disagree. I remain an opponent of IEC 61000-3-2 as written and hope that TC77/SC77A does a better job with the version they are working on and that it better represents a compromise between those who would put the entire burden on the loads (as they have already done) and those who would do nothing. Ghery Pettit, NCE -Original Message- From: cherryclo...@aol.com [mailto:cherryclo...@aol.com] Sent: Wednesday, January 23, 2002 2:27 AM To: ghery.pet...@intel.com Cc: emc-p...@majordomo.ieee.org Subject: Re: EN 61000-3-3 compliant heater controller Dear Ghery I am well aware of the undersized neutral problem, but given that we have a legacy of buildings with undersized neutrals it is not a simple or low-cost solution to uprate all their neutrals. Anyway, harmonics in the mains distribution cause many more problems than simply overheating neutrals – waveform distortion is a greater worry. Since your negative approach to the need for harmonics control was similar to views expressed in an article in Conformity Update 08-06-00, I originally quoted from Mr van den Bergh's reply to that article. Mathieu van den Bergh is not just any ordinary old consultant, he is a member of the TC77/SC77A Working Group that is responsible for IEC 61000-3-2 and appears to have a great deal of experience and knowledge in the area of harmonics. He is also based in the US, where most of the 'denial' of harmonics problems seems to arise, despite well-known problems with harmonics in the USA. I would have assumed that since you are knowledgeable in the field of harmonics you would already know Mr Van den Bergh and would already have discussed your concerns with him and (hopefully) come to some kind of agreement. Since he appears to be an expert in these matters, I hope you will not mind me quoting a little more from his August 19 2000 reply to Conformity Update: A number of studies in countries including Switzerland, the UK, France, Scandinavian countries, Japan, and the USA, have shown that harmonic distortion has increased from about 2 - 2.5% in the late 70's - early 80's to about 4 - 4.5% in the mid-late 90's with distortion in heavily industrialised areas reaching 6 - 7%!! It has also been proven through many studies and observations that harmonics related problems increase significantly when distortion levels exceed 5% and that they become very serious and costly when distortion approaches 10%. It has been generally accepted therefore that distortion is increasing at 0.1 - 0.15% per year in industrialized nations. If no action is taken it is to be expected that distortion levels will start to exceed critical levels within a few years. Notice Mr van den Bergh is referring here to waveform distortion, not neutral currents or zero-phase flux in transformers, both of which are problems only for individual sites not the distribution network as a whole. He goes on... The proliferation of electronic equipment with switch mode supplies falls in the same category as the lighting related problems about 20 years ago. I agree with you that the harmonics problem can be ameliorated by actions taken at the power distribution network level, or by actions at the load level, but I have not investigated their relative economic cases. But whichever method is adopted, the customer pays the bill eventually and I have more confidence in the highly competitive world of electronic products to come up with a cost-effective solution in a timely manner. I have some knowledge of power-factor correction techniques in switch-mode supplies, and some of them can cost very little indeed. So I really don't know why the US computer industry is making such a fuss about controlling harmonic emissions. It reminds me of the fuss the auto industry made about compulsory seat belts, catalytic converters, etc., or the fuss the VDU monitor industry made about meeting MPR2 – all those things that were stridently opposed by manufacturers as needless added expense, or even impossible – yet we now
Re: EN 61000-3-3 compliant heater controller
Dear Gregg I know of a number of companies that make these 'active harmonic cancellation' units. They are often called 'active harmonic filters' although their operating principle is not based on filtering. They seem to me to be an excellent idea, and can help avoid the need for improving a legacy mains distribution or buying EN 61000-3-2 compliant equipment. Sadly they aren't free. Regards, Keith Armstrong In a message dated 23/01/02 14:00:16 GMT Standard Time, gr...@test4safety.com writes: Subj:RE: EN 61000-3-3 compliant heater controller Date:23/01/02 14:00:16 GMT Standard Time From:gr...@test4safety.com (Gregg Kervill) Sender:owner-emc-p...@majordomo.ieee.org Reply-to: A HREF=mailto:gr...@test4safety.com;gr...@test4safety.com/A (Gregg Kervill) To:cherryclo...@aol.com, ghery.pet...@intel.com CC:emc-p...@majordomo.ieee.org, b...@lyons.demon.co.uk I know that one should not advertise BUT I think that Claude Lyons (A HREF=mailto:b...@lyons.demon.co.uk; b...@lyons.demon.co.uk/A) has a solution to this by injecting a difference current to balance the distortion. I simple terms like the Current Dumping amplifiers. Comments Bill? rom: owner-emc-p...@majordomo.ieee.org [mailto:owner-emc-p...@majordomo.ieee.org]On Behalf Of cherryclo...@aol.com Sent: Wednesday, January 23, 2002 5:27 AM To: ghery.pet...@intel.com Cc: emc-p...@majordomo.ieee.org Subject: Re: EN 61000-3-3 compliant heater controller Dear Ghery I am well aware of the undersized neutral problem, but given that we have a legacy of buildings with undersized neutrals it is not a simple or low-cost solution to uprate all their neutrals. Anyway, harmonics in the mains distribution cause many more problems than simply overheating neutrals – waveform distortion is a greater worry. Since your negative approach to the need for harmonics control was similar to views expressed in an article in Conformity Update 08-06-00, I originally quoted from Mr van den Bergh's reply to that article. Mathieu van den Bergh is not just any ordinary old consultant, he is a member of the TC77/SC77A Working Group that is responsible for IEC 61000-3-2 and appears to have a great deal of experience and knowledge in the area of harmonics. He is also based in the US, where most of the 'denial' of harmonics problems seems to arise, despite well-known problems with harmonics in the USA. I would have assumed that since you are knowledgeable in the field of harmonics you would already know Mr Van den Bergh and would already have discussed your concerns with him and (hopefully) come to some kind of agreement. Since he appears to be an expert in these matters, I hope you will not mind me quoting a little more from his August 19 2000 reply to Conformity Update: A number of studies in countries including Switzerland, the UK, France, Scandinavian countries, Japan, and the USA, have shown that harmonic distortion has increased from about 2 - 2.5% in the late 70's - early 80's to about 4 - 4.5% in the mid-late 90's with distortion in heavily industrialised areas reaching 6 - 7%!! It has also been proven through many studies and observations that harmonics related problems increase significantly when distortion levels exceed 5% and that they become very serious and costly when distortion approaches 10%. It has been generally accepted therefore that distortion is increasing at 0.1 - 0.15% per year in industrialized nations. If no action is taken it is to be expected that distortion levels will start to exceed critical levels within a few years. Notice Mr van den Bergh is referring here to waveform distortion, not neutral currents or zero-phase flux in transformers, both of which are problems only for individual sites not the distribution network as a whole. He goes on... The proliferation of electronic equipment with switch mode supplies falls in the same category as the lighting related problems about 20 years ago. I agree with you that the harmonics problem can be ameliorated by actions taken at the power distribution network level, or by actions at the load level, but I have not investigated their relative economic cases. But whichever method is adopted, the customer pays the bill eventually and I have more confidence in the highly competitive world of electronic products to come up with a cost-effective solution in a timely manner. I have some knowledge of power-factor correction techniques in switch-mode supplies, and some of them can cost very little indeed. So I really don't know why the US computer industry is making such a fuss about controlling harmonic emissions. It reminds me of the fuss the auto industry made about compulsory seat belts, catalytic converters, etc., or the fuss the VDU monitor industry made about meeting MPR2 – all those things that were stridently opposed by manufacturers
Re: EN 61000-3-3 compliant heater controller
I read in !emc-pstc that cherryclo...@aol.com wrote (in 3d.180a271a.297 fe...@aol.com) about 'EN 61000-3-3 compliant heater controller', on Wed, 23 Jan 2002: Mathieu van den Bergh is not just any ordinary old consultant, he is a member of the TC77/SC77A Working Group that is responsible for IEC 61000-3-2 and appears to have a great deal of experience and knowledge in the area of harmonics. That is true, but his views are not necessarily shared by other members of the WG, some of whom are equally expert. He is also based in the US, where most of the 'denial' of harmonics problems seems to arise, despite well-known problems with harmonics in the USA. I think we are getting close to an invasion of privacy here; the country of residence of Mathieu or anyone else is not relevant to any technical argument. [snip] Since he appears to be an expert in these matters, I hope you will not mind me quoting a little more from his August 19 2000 reply to Conformity Update: A number of studies in countries including Switzerland, the UK, France, Scandinavian countries, Japan, and the USA, have shown that harmonic distortion has increased from about 2 - 2.5% in the late 70's - early 80's to about 4 - 4.5% in the mid-late 90's with distortion in heavily industrialised areas reaching 6 - 7%!! Those last figures are probably true, but are not the whole truth. Electricity suppliers can, if they wish, and very often do, accept by special contract the connection of large non-linear loads which, *on their dedicated supply* result in high levels of voltage distortion. It has also been proven through many studies and observations that harmonics related problems increase significantly when distortion levels exceed 5% and that they become very serious and costly when distortion approaches 10%. Indeed. Below 10%, in fact. Problems start to show up if 8% is closely approached. It has been generally accepted therefore that distortion is increasing at 0.1 - 0.15% per year in industrialized nations. While that is again, possibly true, the word 'therefore' seems unjustified. The point here is that voltage distortion on the **public low-voltage supply** (which is what IEC/EN61000-3-2 is about) varies from place to place and time to time, over a range of perhaps 2% to near 6%. So any 'rate of rise' depends rather a lot on when and where the raw data were collected. Furthermore, the uncertainty associated with a rise of 0.1% per annum almost certainly embraces zero and may even extend into negative values. The reason is that while the *number* of non- linear loads connected is, beyond reasonable doubt, increasing, the *power* per load is decreasing. For example, there is concern in some quarters that even certain very large TV sets now have a power consumption of less than 75 W and thus are not subject to limits in IEC/EN61000-3-2. If no action is taken it is to be expected that distortion levels will start to exceed critical levels within a few years. We heard that in 1991, and I believe it had been stated several times before that. We hear it again at almost every meeting of the WG. The 'day of reckoning' seems always 5 years or so away, probably because of the compensating effect of reducing power consumption. Notice Mr van den Bergh is referring here to waveform distortion, not neutral currents or zero-phase flux in transformers, both of which are problems only for individual sites not the distribution network as a whole. He goes on... The proliferation of electronic equipment with switch mode supplies falls in the same category as the lighting related problems about 20 years ago. I agree with you that the harmonics problem can be ameliorated by actions taken at the power distribution network level, This can be done to some extent. It's not very practicable when the harmonic content varies rather rapidly. or by actions at the load level, but I have not investigated their relative economic cases. Evidence has been presented that the *annual* cost of harmonic mitigation ONLY at product level is of the same order as the capital cost of mitigation ONLY at supply system level, which would clearly involve equipment having a lifetime much longer than one year. But passive mitigation only at system level has the disadvantage of not reacting (!) to rapid changes, while active mitigation at system level is still experimental. Furthermore, governmental approval for investment in system level mitigation is unlikely in many European countries. Unfortunately, elements in the European supply industry are opposed to mitigation at *site* level, which for light industry is an attractive proposition. The reasons for the opposition are unconvincing, to say the least. It is almost axiomatic that the best overall economic solution (least total cost to the end-user) is the
RE: EN 61000-3-3 compliant heater controller
I know that one should not advertise BUT I think that Claude Lyons (b...@lyons.demon.co.uk) has a solution to this by injecting a difference current to balance the distortion. I simple terms like the Current Dumping amplifiers. Comments Bill? -Original Message- From: owner-emc-p...@majordomo.ieee.org [mailto:owner-emc-p...@majordomo.ieee.org]On Behalf Of cherryclo...@aol.com Sent: Wednesday, January 23, 2002 5:27 AM To: ghery.pet...@intel.com Cc: emc-p...@majordomo.ieee.org Subject: Re: EN 61000-3-3 compliant heater controller Dear Ghery I am well aware of the undersized neutral problem, but given that we have a legacy of buildings with undersized neutrals it is not a simple or low-cost solution to uprate all their neutrals. Anyway, harmonics in the mains distribution cause many more problems than simply overheating neutrals – waveform distortion is a greater worry. Since your negative approach to the need for harmonics control was similar to views expressed in an article in Conformity Update 08-06-00, I originally quoted from Mr van den Bergh's reply to that article. Mathieu van den Bergh is not just any ordinary old consultant, he is a member of the TC77/SC77A Working Group that is responsible for IEC 61000-3-2 and appears to have a great deal of experience and knowledge in the area of harmonics. He is also based in the US, where most of the 'denial' of harmonics problems seems to arise, despite well-known problems with harmonics in the USA. I would have assumed that since you are knowledgeable in the field of harmonics you would already know Mr Van den Bergh and would already have discussed your concerns with him and (hopefully) come to some kind of agreement. Since he appears to be an expert in these matters, I hope you will not mind me quoting a little more from his August 19 2000 reply to Conformity Update: A number of studies in countries including Switzerland, the UK, France, Scandinavian countries, Japan, and the USA, have shown that harmonic distortion has increased from about 2 - 2.5% in the late 70's - early 80's to about 4 - 4.5% in the mid-late 90's with distortion in heavily industrialised areas reaching 6 - 7%!! It has also been proven through many studies and observations that harmonics related problems increase significantly when distortion levels exceed 5% and that they become very serious and costly when distortion approaches 10%. It has been generally accepted therefore that distortion is increasing at 0.1 - 0.15% per year in industrialized nations. If no action is taken it is to be expected that distortion levels will start to exceed critical levels within a few years. Notice Mr van den Bergh is referring here to waveform distortion, not neutral currents or zero-phase flux in transformers, both of which are problems only for individual sites not the distribution network as a whole. He goes on... The proliferation of electronic equipment with switch mode supplies falls in the same category as the lighting related problems about 20 years ago. I agree with you that the harmonics problem can be ameliorated by actions taken at the power distribution network level, or by actions at the load level, but I have not investigated their relative economic cases. But whichever method is adopted, the customer pays the bill eventually and I have more confidence in the highly competitive world of electronic products to come up with a cost-effective solution in a timely manner. I have some knowledge of power-factor correction techniques in switch-mode supplies, and some of them can cost very little indeed. So I really don't know why the US computer industry is making such a fuss about controlling harmonic emissions. It reminds me of the fuss the auto industry made about compulsory seat belts, catalytic converters, etc., or the fuss the VDU monitor industry made about meeting MPR2 – all those things that were stridently opposed by manufacturers as needless added expense, or even impossible – yet we now find them in all the products we buy even though they still cost less in real terms than they did before. I suspect the real reason for the computer industry's denial of harmonics problems, or else blaming them on a poor distribution system, is that US computer manufacturers simply want to make one model they can sell world-wide – so they want whatever is permitted in their main market (the US) to be permitted everywhere else. Would you agree with this? Regards, Keith Armstrong In a message dated 22/01/02 17:34:47 GMT Standard Time, ghery.pet...@intel.com writes: Subj:RE: EN 61000-3-3 compliant heater controller Date:22/01/02 17:34:47 GMT Standard Time From:ghery.pet...@intel.com (Pettit, Ghery) Sender:owner-emc-p...@majordomo.ieee.org Reply-to: ghery.pet...@intel.com (Pettit, Ghery) To:cherryclo...@aol.com
Re: EN 61000-3-3 compliant heater controller
Time for some sarcasm, Harmonics is a total imaginary situations, It never causes real problems and I never recorded two attached distorted wave forms ! This issues had nothing to do with neutral currents, it was that distorted wave form causing the problem Suppose we could have a little competition, who's seen the worst level of harmonic distortion, I think number 2 will take some beating. My two pennies worth on a wet wednesday afternoon. Andrew Carson - Senior Compliance Engineer, Xyratex, UK Phone: +44 (0)23 9249 6855 Fax: +44 (0)23 9249 6014 inline: harm2.jpginline: harm1.jpg
Re: EN 61000-3-3 compliant heater controller
.
Do you expect me to believe that personal computers cause significant
harmonics problems? There is no evidence of this in the U.S. If there is
in Europe, then you are admitting that your power distribution system
design is deficient. Lousy design on the part of the power providers is
fixed by saddling the manufacturers of the load with the full expense of
the solution? Sorry. I don't buy that approach. A facilities solution is
usually more economical than fixing the 'problem' at each individual load.
Quoting a few consultants is nice, but doesn't prove a case. I remain a
total skeptic on this matter. IEC 61000-3-2 needs (and is getting) a
complete overhaul. IEC 61000-3-3 should be withdrawn. Flicker is real, no
doubt, but this issue gets more attention than it deserves in the home
environment.
Ghery Pettit
-Original Message-
From: cherryclo...@aol.com [mailto:cherryclo...@aol.com]
Sent: Tuesday, January 22, 2002 2:23 AM
To: ghery.pet...@intel.com
Cc: emc-p...@majordomo.ieee.org
Subject: Re: EN 61000-3-3 compliant heater controller
Dear Ghery
There is plenty of evidence, for harmonic problems, especially in large
cities and large office buildings.
For example, an electricity supply engineer told me that in the financial
district in London there are buildings where they cannot fit any power
factor correction capacitors to the fluorescent luminaires - because they
fail within days due to the waveform distortion caused by harmonic
currents.
So they have buildings drawing 100's of kA of lighting current at a low
power factor ( 0.6 I understand). I also understand they have overheating
problems with cables under the Thames connecting the two halves of London,
due to harmonic currents.
In the early 90's I spoke with a USA-based consultant who told me about a
number of problems (e.g. completely burnt-out neutral cables) he had seen
in buildings in the US where they had installed lots of single-phase
equipment.
'Banana Skin' No. 102 in the EMC + Compliance journal, Oct 2000 (read it in
the archives at www.compliance-club.com) describes harmonic overheating
problems with low-voltage lighting installations in hotels and public
buildings that has Fane Murray, a lighting consultant in the UK, very
concerned indeed.
I understand that the power distribution in the USA is generally less
susceptible to waveform distortion than in Europe, nevertheless I
understand that the US has its own harmonics problems – Mathieu van den
Bergh, of Computer and Networking Services Inc., California said in August
2000:
a) for many years the US has had IEEE-Std-519 which has recommendations
for harmonic limits which are not much different from IEC 61000-3-2;
b) the US lighting industry has voluntarily implemented ANSI harmonics
standards for fluorescent lamp ballasts that are more stringent than IEC
61000-3-2, as the direct result of serious harmonics problems in large
office buildings;
c) the US Government has issued several large scale procurement
requisitions for Information Technology that included far more stringent
harmonics requirements than those in IEC 61000-3-2.
Time does not permit me to go through my files to provide a longer list of
real-life problems with harmonics.
Regards, Keith Armstrong
RIn a message dated 21/01/02 23:54:36 GMT Standard Time,
ghery.pet...@intel.com writes:
Subj:RE: EN 61000-3-3 compliant heater controller
Date:21/01/02 23:54:36 GMT Standard Time
From:ghery.pet...@intel.com (Pettit, Ghery)
Sender:owner-emc-p...@majordomo.ieee.org
Reply-to: A HREF=mailto:ghery.pet...@intel.com;ghery.pet...@intel.com/A
(Pettit, Ghery)
To:j...@jmwa.demon.co.uk ('John Woodgate'), emc-p...@majordomo.ieee.org
So rather than educating the public on the cause of flicker, we get
saddled
with a useless design requirement. Typical bureaucracy - don't fix the
problem, make it LOOK like you're doing something, at someone else's
expense. Just like the harmonics standard - fix a problem that doesn't
exist.
RE: EN 61000-3-3 compliant heater controller
I don't have much to say about flicker, but maybe I can reduce your skepticism about harmonics. I have had three experiences regarding failures caused by third harmonic currents. The first was with mercury vapor lighting fixtures. An array of 1000w 277v single phase ballasts in hibay lighting for warehouses were connected as a delta load on a three phase 277/480 volt supply. The third harmonic current circulating in the loads overheated the ballasts to the point of boiling the potting compound. The ballast (about ten pounds) would burst the aluminum container and fall from the ceiling, which caught people's attention. The solution was to replace them with a better ballast and fuse each fixture. I participated in this investigation in 1968 as a co-op student. This also resulted in electrical code changes. The second incident (1980s) was the burnout of a three phase distribution transformer from third harmonic currents circulating in the delta primary (where it is hidden from overcurrent protection). This was at a manufacturing location of a computer company where the loads were racks of computers preparing for shipment. The solution was to regularly audit load currents at the facility and assure sufficient margin to protect transformers and neutrals. The third incident (1980s) was the overheating of neutral conductors in office modular partitions. Partitions carried two of three phases of 120/208v supply to single phase outlets for desktop computers. The combination of the unbalanced neutral current (which normally in a balanced system without harmonics would equal the phase current that would typically go back the third phase) plus the third harmonic current (which adds from each phase in the neutral) overheated the neutral conductor (which has no overcurrent protection). Insulation damage resulted. The solution was to work with the partition manufacturers to design a three phase model so the neutral (when single phase loads were reasonably balanced across three phases) carried mostly just harmonic currents. This was all in the days before standards for harmonics were established. Desktop minicomputers at that time also consumed much more power. A solution of using four pole breakers with overcurrent in the neutral and series overcurrent in delta loads would have also solved the electrical distribution risks, but the solution chosen worldwide was to regulate harmonic content of load currents. So, as you see, there were some real risks and failures in harmonics, but the problem does not appear regularly today due to standards compliance. Bob Johnson -Original Message- From: owner-emc-p...@majordomo.ieee.org [mailto:owner-emc-p...@majordomo.ieee.org] On Behalf Of Pettit, Ghery Sent: Tuesday, January 22, 2002 12:25 PM To: 'cherryclo...@aol.com'; Pettit, Ghery Cc: emc-p...@majordomo.ieee.org Subject: RE: EN 61000-3-3 compliant heater controller Keith, Many times the neutral cable problems result from using a smaller gauge wire for the neutral in the mistaken assumption that the neutral doesn't carry any significant current (true if the 3 phase load is balanced - when did you last see that?). Harmonics may make that problem worse, but the fundamental frequency current can be a problem, as well. The solution, used by many building designers, is to use the same size wire for the neutral as for the phase conductors. Do you expect me to believe that personal computers cause significant harmonics problems? There is no evidence of this in the U.S. If there is in Europe, then you are admitting that your power distribution system design is deficient. Lousy design on the part of the power providers is fixed by saddling the manufacturers of the load with the full expense of the solution? Sorry. I don't buy that approach. A facilities solution is usually more economical than fixing the 'problem' at each individual load. Quoting a few consultants is nice, but doesn't prove a case. I remain a total skeptic on this matter. IEC 61000-3-2 needs (and is getting) a complete overhaul. IEC 61000-3-3 should be withdrawn. Flicker is real, no doubt, but this issue gets more attention than it deserves in the home environment. Ghery Pettit
RE: EN 61000-3-3 compliant heater controller
Keith,
Many times the neutral cable problems result from using a smaller gauge wire
for the neutral in the mistaken assumption that the neutral doesn't carry
any significant current (true if the 3 phase load is balanced - when did you
last see that?). Harmonics may make that problem worse, but the fundamental
frequency current can be a problem, as well. The solution, used by many
building designers, is to use the same size wire for the neutral as for the
phase conductors.
Do you expect me to believe that personal computers cause significant
harmonics problems? There is no evidence of this in the U.S. If there is
in Europe, then you are admitting that your power distribution system design
is deficient. Lousy design on the part of the power providers is fixed by
saddling the manufacturers of the load with the full expense of the
solution? Sorry. I don't buy that approach. A facilities solution is
usually more economical than fixing the 'problem' at each individual load.
Quoting a few consultants is nice, but doesn't prove a case. I remain a
total skeptic on this matter. IEC 61000-3-2 needs (and is getting) a
complete overhaul. IEC 61000-3-3 should be withdrawn. Flicker is real, no
doubt, but this issue gets more attention than it deserves in the home
environment.
Ghery Pettit
-Original Message-
From: cherryclo...@aol.com [mailto:cherryclo...@aol.com]
Sent: Tuesday, January 22, 2002 2:23 AM
To: ghery.pet...@intel.com
Cc: emc-p...@majordomo.ieee.org
Subject: Re: EN 61000-3-3 compliant heater controller
Dear Ghery
There is plenty of evidence, for harmonic problems, especially in large
cities and large office buildings.
For example, an electricity supply engineer told me that in the financial
district in London there are buildings where they cannot fit any power
factor correction capacitors to the fluorescent luminaires - because they
fail within days due to the waveform distortion caused by harmonic currents.
So they have buildings drawing 100's of kA of lighting current at a low
power factor ( 0.6 I understand). I also understand they have overheating
problems with cables under the Thames connecting the two halves of London,
due to harmonic currents.
In the early 90's I spoke with a USA-based consultant who told me about a
number of problems (e.g. completely burnt-out neutral cables) he had seen in
buildings in the US where they had installed lots of single-phase equipment.
'Banana Skin' No. 102 in the EMC + Compliance journal, Oct 2000 (read it in
the archives at www.compliance-club.com) describes harmonic overheating
problems with low-voltage lighting installations in hotels and public
buildings that has Fane Murray, a lighting consultant in the UK, very
concerned indeed.
I understand that the power distribution in the USA is generally less
susceptible to waveform distortion than in Europe, nevertheless I understand
that the US has its own harmonics problems – Mathieu van den Bergh, of
Computer and Networking Services Inc., California said in August 2000:
a) for many years the US has had IEEE-Std-519 which has recommendations for
harmonic limits which are not much different from IEC 61000-3-2;
b) the US lighting industry has voluntarily implemented ANSI harmonics
standards for fluorescent lamp ballasts that are more stringent than IEC
61000-3-2, as the direct result of serious harmonics problems in large
office buildings;
c) the US Government has issued several large scale procurement requisitions
for Information Technology that included far more stringent harmonics
requirements than those in IEC 61000-3-2.
Time does not permit me to go through my files to provide a longer list of
real-life problems with harmonics.
Regards, Keith Armstrong
In a message dated 21/01/02 23:54:36 GMT Standard Time,
ghery.pet...@intel.com writes:
Subj:RE: EN 61000-3-3 compliant heater controller
List-Post: emc-pstc@listserv.ieee.org
Date:21/01/02 23:54:36 GMT Standard Time
From:ghery.pet...@intel.com (Pettit, Ghery)
Sender:owner-emc-p...@majordomo.ieee.org
Reply-to: ghery.pet...@intel.com mailto:ghery.pet...@intel.com (Pettit,
Ghery)
To:j...@jmwa.demon.co.uk ('John Woodgate'), emc-p...@majordomo.ieee.org
So rather than educating the public on the cause of flicker, we get saddled
with a useless design requirement. Typical bureaucracy - don't fix the
problem, make it LOOK like you're doing something, at someone else's
expense. Just like the harmonics standard - fix a problem that doesn't
exist.
Ghery Pettit
RE: EN 61000-3-3 compliant heater controller
I almost agree John :^] --Original Message- -From: owner-emc-p...@majordomo.ieee.org -[mailto:owner-emc-p...@majordomo.ieee.org]On Behalf Of John Woodgate -Sent: Tuesday, January 22, 2002 2:37 AM -To: emc-p...@majordomo.ieee.org -Subject: Re: EN 61000-3-3 compliant heater controller - - - -I read in !emc-pstc that Pettit, Ghery ghery.pet...@intel.com wrote -(in D9223EB959A5D511A98F00508B68C20C0226B8A3@ORSMSX108) about 'EN -61000-3-3 compliant heater controller', on Mon, 21 Jan 2002: - -So rather than educating the public on the cause of flicker, -we get saddled -with a useless design requirement. - -'Educating the public' is a project which always causes disaster. It -simply isn't industry's job to do that. I think that industry has gone a long way - I remember twisting bare wires from two or more power cords together and holding them in the mains socket with match sticks. But that was in the UK in the 'good-old days' of 3A, 5A and 15A (2 and 3 pin) sockets and multiway outlets did not exist. True there are still disasters (the poodle in the microwave) but the fat that public education lags industry practices does not mean we must not try. In fact - public education is supported implicitly by the industry (and standards) requirements to supply operator warnings and instructions. Agree - I have a 'soggy' mains supply and each time one of our LASER printers kicks 'IN' the UPS's on that supply let out a squawk. PLEASE do not let ANYONE try to tell me that intermittent non-compliances are OK - THEY are totally unacceptable! PARTICULARLY DURING CONFERENCE CALLS. SET FLAME OFF : ^ ) - -Besides, it isn't a 'useless' requirement. The reason I gave is the -reason that repetitive voltage changes are called 'flicker'. But they -are undesirable in themselves: they can disturb the operation of -equipment. - - Typical bureaucracy - don't fix the -problem, make it LOOK like you're doing something, at someone else's -expense. Just like the harmonics standard - fix a problem -that doesn't -exist. - I believe that there are some countries (I think that Bill Lyons can support this) that place a surcharge on third harmonic offenders. -Harmonics DO cause problems. Even in USA, where, because of the design -of the distribution system, harmonics are less threatening -than in other -countries, there are still problems with hot neutrals due to summation -of triplen harmonics. --- -Regards, John Woodgate, OOO - Own Opinions Only. -http://www.jmwa.demon.co.uk -After swimming across the -Hellespont, I felt like a Hero. -PLEASE do NOT copy news posts to me by E-MAIL! - - --- 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: EN 61000-3-3 compliant heater controller
Dear Ghery
There is plenty of evidence, for harmonic problems, especially in large
cities and large office buildings.
For example, an electricity supply engineer told me that in the financial
district in London there are buildings where they cannot fit any power factor
correction capacitors to the fluorescent luminaires - because they fail
within days due to the waveform distortion caused by harmonic currents.
So they have buildings drawing 100's of kA of lighting current at a low power
factor ( 0.6 I understand). I also understand they have overheating problems
with cables under the Thames connecting the two halves of London, due to
harmonic currents.
In the early 90's I spoke with a USA-based consultant who told me about a
number of problems (e.g. completely burnt-out neutral cables) he had seen in
buildings in the US where they had installed lots of single-phase equipment.
'Banana Skin' No. 102 in the EMC + Compliance journal, Oct 2000 (read it in
the archives at www.compliance-club.com) describes harmonic overheating
problems with low-voltage lighting installations in hotels and public
buildings that has Fane Murray, a lighting consultant in the UK, very
concerned indeed.
I understand that the power distribution in the USA is generally less
susceptible to waveform distortion than in Europe, nevertheless I understand
that the US has its own harmonics problems – Mathieu van den Bergh, of
Computer and Networking Services Inc., California said in August 2000:
a) for many years the US has had IEEE-Std-519 which has recommendations for
harmonic limits which are not much different from IEC 61000-3-2;
b) the US lighting industry has voluntarily implemented ANSI harmonics
standards for fluorescent lamp ballasts that are more stringent than IEC
61000-3-2, as the direct result of serious harmonics problems in large office
buildings;
c) the US Government has issued several large scale procurement requisitions
for Information Technology that included far more stringent harmonics
requirements than those in IEC 61000-3-2.
Time does not permit me to go through my files to provide a longer list of
real-life problems with harmonics.
Regards, Keith Armstrong
In a message dated 21/01/02 23:54:36 GMT Standard Time,
ghery.pet...@intel.com writes:
Subj:RE: EN 61000-3-3 compliant heater controller
Date:21/01/02 23:54:36 GMT Standard Time
From:ghery.pet...@intel.com (Pettit, Ghery)
Sender:owner-emc-p...@majordomo.ieee.org
Reply-to: A HREF=mailto:ghery.pet...@intel.com;ghery.pet...@intel.com/A
(Pettit, Ghery)
To:j...@jmwa.demon.co.uk ('John Woodgate'), emc-p...@majordomo.ieee.org
So rather than educating the public on the cause of flicker, we get saddled
with a useless design requirement. Typical bureaucracy - don't fix the
problem, make it LOOK like you're doing something, at someone else's
expense. Just like the harmonics standard - fix a problem that doesn't
exist.
Ghery Pettit
Re: EN 61000-3-3 compliant heater controller
I read in !emc-pstc that Pettit, Ghery ghery.pet...@intel.com wrote (in D9223EB959A5D511A98F00508B68C20C0226B8A3@ORSMSX108) about 'EN 61000-3-3 compliant heater controller', on Mon, 21 Jan 2002: So rather than educating the public on the cause of flicker, we get saddled with a useless design requirement. 'Educating the public' is a project which always causes disaster. It simply isn't industry's job to do that. Besides, it isn't a 'useless' requirement. The reason I gave is the reason that repetitive voltage changes are called 'flicker'. But they are undesirable in themselves: they can disturb the operation of equipment. Typical bureaucracy - don't fix the problem, make it LOOK like you're doing something, at someone else's expense. Just like the harmonics standard - fix a problem that doesn't exist. Harmonics DO cause problems. Even in USA, where, because of the design of the distribution system, harmonics are less threatening than in other countries, there are still problems with hot neutrals due to summation of triplen harmonics. -- Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk After swimming across the Hellespont, I felt like a Hero. PLEASE do NOT copy news posts to me by E-MAIL! --- 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: EN 61000-3-3 compliant heater controller
So rather than educating the public on the cause of flicker, we get saddled with a useless design requirement. Typical bureaucracy - don't fix the problem, make it LOOK like you're doing something, at someone else's expense. Just like the harmonics standard - fix a problem that doesn't exist. Ghery Pettit Opinions expressed are my own and may not necessarily reflect those of my employer... -Original Message- From: John Woodgate [mailto:j...@jmwa.demon.co.uk] Sent: Monday, January 21, 2002 2:28 PM To: emc-p...@majordomo.ieee.org Subject: Re: EN 61000-3-3 compliant heater controller I read in !emc-pstc that Ken Javor ken.ja...@emccompliance.com wrote (in 20020121193650.LDSV11289.femail7.sdc1.sfba.home.com@[65.11.150.27] ) about 'EN 61000-3-3 compliant heater controller', on Mon, 21 Jan 2002: I have some questions which are just for my own education. I understand Mr. Woodgate's comments and they make sense to me. But I wonder why there is a problem in the first place. I assumed that the lack of compliance was certain, because I have no up- front evidence to sustain a doubt. I believe all power in Europe is at 200 Volts or higher, which makes an 800 Watt heater a four Amp device. I don't believe inrush on a heater is greatly in excess of steady-state current, Suppose, just as an example, it's an 800 W IR lamp, used as a heater? therefore the mechanism is switching a four Amp load on and off every few minutes. Why is this a problem requiring specification control in the first place? Because lamp flicker is a disturbance that worries people and they often complain to the electricity suppliers. Some elderly people get very worried about the supply breaking down or causing a fire. The reference single-phase supply impedance used for IEC/EN61000-3-3 is 0.47 ohms (actually 0.4 + j0.25 ohms). So switching a 4 A load causes a dmax (maximum relative voltage drop, based on 230 V) of 0.8%. That is not likely to result in a Pst or Plt failure to comply, so there IS something we don't know - maybe a high inrush current or a faulty measurement. -- Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk After swimming across the Hellespont, I felt like a Hero. PLEASE do NOT copy news posts to me by E-MAIL! --- 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: EN 61000-3-3 compliant heater controller
I read in !emc-pstc that Ken Javor ken.ja...@emccompliance.com wrote (in 20020121193650.LDSV11289.femail7.sdc1.sfba.home.com@[65.11.150.27] ) about 'EN 61000-3-3 compliant heater controller', on Mon, 21 Jan 2002: I have some questions which are just for my own education. I understand Mr. Woodgate's comments and they make sense to me. But I wonder why there is a problem in the first place. I assumed that the lack of compliance was certain, because I have no up- front evidence to sustain a doubt. I believe all power in Europe is at 200 Volts or higher, which makes an 800 Watt heater a four Amp device. I don't believe inrush on a heater is greatly in excess of steady-state current, Suppose, just as an example, it's an 800 W IR lamp, used as a heater? therefore the mechanism is switching a four Amp load on and off every few minutes. Why is this a problem requiring specification control in the first place? Because lamp flicker is a disturbance that worries people and they often complain to the electricity suppliers. Some elderly people get very worried about the supply breaking down or causing a fire. The reference single-phase supply impedance used for IEC/EN61000-3-3 is 0.47 ohms (actually 0.4 + j0.25 ohms). So switching a 4 A load causes a dmax (maximum relative voltage drop, based on 230 V) of 0.8%. That is not likely to result in a Pst or Plt failure to comply, so there IS something we don't know - maybe a high inrush current or a faulty measurement. -- Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk After swimming across the Hellespont, I felt like a Hero. PLEASE do NOT copy news posts to me by E-MAIL! --- 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: EN 61000-3-3 compliant heater controller
I have some questions which are just for my own education. I understand Mr. Woodgate's comments and they make sense to me. But I wonder why there is a problem in the first place. I believe all power in Europe is at 200 Volts or higher, which makes an 800 Watt heater a four Amp device. I don't believe inrush on a heater is greatly in excess of steady-state current, therefore the mechanism is switching a four Amp load on and off every few minutes. Why is this a problem requiring specification control in the first place? -- From: Leszek Langiewicz leszek_langiew...@phogenix.com To: emc-p...@majordomo.ieee.org Subject: EN 61000-3-3 compliant heater controller Date: Mon, Jan 21, 2002, 12:01 PM Dear list-members, Would anybody know of the shelf controller design to meet EN61000-3-3 for 500W heater. Thanks in advance for your support. Best Regards, Leszek M. Langiewicz Homologation / Power Distribution Phogenix Imaging, LLC A joint venture of Kodak and HP Phogenix Imaging LLC 16275 Technology Dr. San Diego, CA 92127-1815 www.phogenix.com Phone: (858) 798-8004 Cell: (858) 722-8004 Fax: (858) 798-8113 E-mail: leszek_langiew...@phogenix.com -Original Message- From: John Woodgate [mailto:j...@jmwa.demon.co.uk] Sent: Sunday, January 20, 2002 6:30 AM To: emc-p...@majordomo.ieee.org Subject: Re: Corrective Actions for EN 61000-3-3 Plt; Pst Failures I read in !emc-pstc that IEEE-EMC User Group ieee-...@itl.co.il wrote (in 2D1037012914D4118DB8204C4F4F5020275AB4@ITLLTD01) about 'Corrective Actions for EN 61000-3-3 Plt; Pst Failures', on Sun, 20 Jan 2002: A product (800W input power) having a heating element that is controlled by ON/OFF action (1-2 sec. interval) of a thermostat failed the subject requirements due to large input current variation resulting from the above action. It's unusual to have such a powerful heater in a product with such a low thermal inertia that the thermostat cycle is as short as 1 to 2 s. What will be a practical corrective action in this case? To answer properly, more details about the product would be required. It might be possible to split the heating element into two parts, not necessarily of equal powers, and to have one permanently on (apart from an over-temperature cut-out) while the other one is switched in and out by the thermostat. The cycle time should then become much longer, and the 'dmax' value is reduced. Another solution is to use the electronic control method known as 'burst firing', in which the thermostat switches on a control circuit that sends trains of complete cycles of the supply current to the heater. With different designs, the switching of the load is either very fast (e.g. 5-cycle bursts of current, lasting 100 ms on 50 Hz mains) or very slow. In either case, the Pst value is low. -- Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk After swimming across the Hellespont, I felt like a Hero. --- 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. --- 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:
