Re: Question: Discharge capacitance 0.1 uF
On Fri, 6 Sep 2002 16:19:52 +0900, Michael Jang mich...@certitek.com wrote: I have a question for Discharge of capacitors in the primary circuit' (Related to 60950 standard) Standard Equipment is considered to comply if any capacitor having a marked or nominal capacitance exceeding 0.1 uF and connected to the PRIMARY CIRCUIT has a means of discharge resulting in a time constant not exceeding: - 1 s for Pluggable equipment type A; and - 10 s for Permanently connected equipment and for pluggable equipment type B. --- Why does not consider up to 0.1 uF? # maybe too late, but... I think we can apply the limits for Limited Current Circuit to capacitors connected to the primary circuit, too, and capacitors up to 0.1uF are considered there. A capacitor which: - capacitance = 0.1uF for voltage = 450V, or - stored charge = 45uC for 450V voltage = 15kV, or - stored energy = 350mJ for 15kV voltage. will become a Limited Current Circuit (2.4.1). So, for voltage up to 450V d.c. (i.e. up to 318V a.c.), capacitor up to 0.1uF will become a Limited Current Circuit, hence the voltage is not Hazardous Voltage (1.2.8.4) - no additional condition would be required for the capacitor connected to the primary circuit. However, capacitor larger than 0.1uF would not comply with the requirements for Limited Current Circuit, and the voltage could be thought as Hazardous Voltage. I think that is why the discharge requirement which, under certain condition, allow capacitor exceeding 0.1uF connected to the primary circuit was specified. Regards, Tom -- Tomonori Sato vef00...@nifty.ne.jp URL: http://member.nifty.ne.jp/tsato/ --- 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com 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: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list --- 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com 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: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Re: Immunity severity levels
Alan, You will find that 61000-4-3 only gives you the test method and some suggested test levels. You don't test to any of the 61000-4 series, you test to whichever standard calls them up, for example EN 50081,50082, the generic standards, or EN 55024, ITE immunity. These standards call up the methods from the 61000-4 series and tell you what level should be applied. You need to look through the Official Journal of the EC (OJEC) list of standards and find the particular immunity standard that applies to your product. One place you can find the list is at www.yorkemc.co.uk. Luke Turnbull alan.hud...@amsjv.com 09/18/02 06:14pm With regard to radiated emission immunity and EN61000-4-3 (or IEC 801-3) I believe there are different field strengths used, depending on the environment in which the apparatus being tested is to be used. I believe equipment to be used in a well-protected environment may be tested at a lower immunity level than equipment to be used in an unprotected environment. I've ordered a copy of 61000-4-3, but while I'm waiting I'd like to know ASAP: 1) What are the definitions of the levels? 2) What field strengths are used for the various levels? (I think level 2 is 3V/m and level 3 is 10V/m) Regards, Alan --- 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com 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: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list --- 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com 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: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
RE: CE Marking for Passive speakers
John By the wider issue I was referring to your assertion that The EMC Guidelines document explains that having no active components is NOT grounds for exemption from the EMC Directive. If this were the case then it would have far reaching implications for many industries since all Electromagnetically Benign equipment might require testing. Furthermore I imagine this would have legal implications for the UK Government appointed Competent Body which advised my company that benign equipment is exempt. This Competent Body helped us compile a list of products within our range to which this exclusion applied. Item 17 of the following web page shows this to be the case in UK law: http://www.hmso.gov.uk/si/si1992/Uksi_19922372_en_1.htm Thanks Ian Gordon -Original Message- From: John Woodgate [mailto:j...@jmwa.demon.co.uk] Sent: 18 September 2002 09:47 To: emc-p...@majordomo.ieee.org Subject: Re: CE Marking for Passive speakers I read in !emc-pstc that Gordon,Ian ian.gor...@edwards.boc.com wrote (in E1BA0362B28ED211A1E80008C71EA306018190AA@EXC_EAS01) about 'CE Marking for Passive speakers' on Wed, 18 Sep 2002: Thus whilst I agree with your view on loudspeakers, I don't concur with your view of the wider issue. What 'wider issue'? The discussion was about loudspeakers and headphones. I'm not suggesting that digital watches should be CE-marked. -- Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk Interested in professional sound reinforcement and distribution? Then go to http://www.isce.org.uk 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com 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: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list _ This e-mail has been scanned for viruses by the WorldCom Internet Managed Scanning Service - powered by MessageLabs. For further information visit http://www.worldcom.com _ This e-mail has been scanned for viruses by the WorldCom Internet Managed Scanning Service - powered by MessageLabs. For further information visit http://www.worldcom.com --- 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com 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: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
RE: Question: Discharge capacitance 0.1 uF
Hi Charles, Warren Seems that a few of us know what DOES happen and the longterm results, but quite a few others don't believe that it does - and that even it does then it is not very important. The difference between reality and theory! I suggest that the non-believers try it for themselves - by unplugging a suitable piece of equipment and picking it up - AND then touching the pins of the plug! (the unplugging process may need to be repeated a few times until the capacitor is disconnected when the mains is high at the time of disconnection and so gets a decent charge!) However before they do try it, I suggest they wear safety boots and also use a piece of equipment which can then be discarded due to the damage it received when it fell on the foot and/or the ground! Regards John Allen -Original Message- From: Grasso, Charles [mailto:charles.gra...@echostar.com] Sent: 18 September 2002 19:07 To: 'John Allen'; emc-p...@majordomo.ieee.org Subject: RE: Question: Discharge capacitance 0.1 uF Hi All, From personal experience I can tell you that the involuntary reaction to a shock can have serious consequences to the sales of a company. In a former life - a previous employer OEM'd a PC from a Korean Company. The PC had all the relevant marks but somehow the resistor that was supposed to bleed off the caps didn't make it into production. A customer , moving said model from one location to another, touched the mains terminals and felt a shock. The customer fell over, the PC landed on the customer, the customer sued and the story ended up in the papers. The sales of PCs essentially died after that. - All for the sake of one resistor. Best Regards Charles Grasso Senior Compliance Engineer Echostar Communications Corp. Tel: 303-706-5467 Fax: 303-799-6222 Cell: 303-204-2974 Email: charles.gra...@echostar.com; mailto:charles.gra...@echostar.com; %20 Email Alternate: chasgra...@ieee.org mailto:chasgra...@ieee.org -Original Message- From: John Allen [mailto:john.al...@era.co.uk] Sent: Wednesday, September 18, 2002 11:11 AM To: emc-p...@majordomo.ieee.org Subject: Question: Discharge capacitance 0.1 uF Hello Folks Tomonori Sato commented However, I think discharge from 0.1uF capacitor charged to the mains peak voltage can be quite uncomfortable. I believe that to be true from personal experience and from having to investigate the results of a number of such incidents, and so would remind member of a point that I made several years ago on this forum: The primary shock almost certainly will NOT hurt a person, but the involuntary reaction TO the shock may well have much more seriousconsequences. This type of shock is often encountered by people who pick up equipment which they have just unplugged from the AC mains in order to carry it elsewhere. If they then touch the pins of the plug there are numerous reported incidences of them involuntarily dropping the unit - and that can possibly be on their own feet - and from a height of about 3ft/1m! If the unit is more than a couple of pounds (about one kilo) then the injury to t! he feet can be substantial. Worse situations could occur in industrial equipment when a service engineer opens a cabinet to perform a service operation - the reaction from the shock could cause him to strike touch other hazardous electrical or mechanical parts (which probably should also not be there, I do agree!) which then cause him serious actual injury. These types of incident do not make the equipment supplier very popular to say the least, and could result in product liability claims. The main basis for the claims would be that the supplier had not adequately assessed the hazards and taken the appropriate simple precautions which are easily and cheaply available - fit a bleeder resistor across the capacitor, or use a filter with a resistor already built in (or with transformer/inductor windings directly across the capacitor - which achieve the same result) ! Again from personal experience I can say that it is a very embarassing and un! comfortable experience to have to write to an injured or anno! yed person, or to his employer, to say sorry, but that is what the safety standard allows. It is just not good business sense. Therefore, regardless of the requirements of the various standards and this argument over capacitor value and/or charging voltage, I firmly believe that the use of bleeder resistors should be considered effectively mandatory, and have always recommended it to engineers I have advised on product safety. Regards John Allen Technical Consultant Electromagnetics, Safety and Reliability Group ERA Technology Ltd Cleeve Rd Leatherhead Surrey KT22 7SA Tel: +44 (0) 1372-367025 (Direct) +44 (0) 1372-367000 (Switchboard) Fax: +44 (0) 1372-367102 (Fax) -- Replies to this message may be posted in the following public forum: Question:
Re: Clock frequencies
Doesn't sound like you're missing anything. We are just talking about different things. Common disease, here! Certainly, for the same directive gain, the aperture of an antenna is smaller at higher frequencies. However, I'm not holding gain constant, but size. If the two antennas are the same physical size (and properly phased) the size in wavelengths -- and thus directive gain -- will be greater at the higher frequency. You may have two devices with nominal 30 cm-long antennas, one for 915 Mhz, two half waves collinear, close spaced, and one for 2.4 GHz, with 5 half waves. The 2.4 GHz antenna's gain will be about 6 dBd, I think, more than the 915 Mhz antenna at about 2 dBd. But this may not be why the limit levels off. Cortland --- 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com 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: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Re: Clock frequencies
The increase in gain of a fixed length wire antenna is given in the ARRL handbook and is less than monotonic with increasing frequency, further it comes at a high price for a broadcast antenna: the main lobe veers away from an optimal toroidal pattern and begins to align with the wire. But I am not sure that has any bearing whatsoever on the issue of deriving a microwave radiated emission limit. The issue as I see it is this: If I build a 900 MHz link, and a 2.4 GHz link, the antennas for the 2.4 GHz link will be shorter by the ratio of their wavelengths, for the same gain. That means the shorter antenna's effective aperture has decreased, and it is less efficient as a receiver. In turn that means it can stand a higher level of radiated rfi. Which means to me, other things equal, that the radiated rfi limit should increase with increasing frequency. What am I missing? -- From: Cortland Richmond 72146@compuserve.com To: Ken Javor ken.ja...@emccompliance.com, ieee pstc list emc-p...@ieee.org Subject: Re: Clock frequencies Date: Wed, Sep 18, 2002, 8:34 PM An antenna of some physical size will indeed have gain increasing with frequency. There is some justification, a 1 GHz antenna being reasonably small, for assuming that antennas will have similar sizes -- and increasing gain -- above 960 MHz. However, I suspect that the original limit was simply an extrapolation, not many users existing there to be affected by Part 15 devices, from the limit _below_ 960 MHz. Cortland --- 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com 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: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
RE: Current from Car 12V cigarette lighter socket / 42 VDC
-Original Message- From: Jim Eichner [mailto:jim.eich...@xantrex.com] Sent: Wednesday, September 18, 2002 1:36 PM To: 'Ken Javor'; Jim Eichner; 'EMC-PSTC - forum' Subject: RE: Current from Car 12V cigarette lighter socket Thanks. The solution you propose is in the works. The SAE is working on a completely different style connector for power connections to 12Vdc, and 2 other styles for 42Vdc and 120Vac connectors. This effort is just getting off the ground however. Jim Eichner, P.Eng. Manager, Engineering Services Xantrex Technology Inc. e-mail: jim.eich...@xantrex.com web: www.xantrex.com Pardon the slight topic shift, but when will we be seeing 42 VDC automotive systems? I understand that there has already been some fleet vehicle production with the 42 VDC standard, but when will it be introduced to the consumer market? Regards, Ed Ed Price ed.pr...@cubic.com Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military Avionics EMC Is Our Specialty Shake-Bake-Shock - Metrology - Reliability Analysis --- 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com 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: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Re: Clock frequencies
An antenna of some physical size will indeed have gain increasing with frequency. There is some justification, a 1 GHz antenna being reasonably small, for assuming that antennas will have similar sizes -- and increasing gain -- above 960 MHz. However, I suspect that the original limit was simply an extrapolation, not many users existing there to be affected by Part 15 devices, from the limit _below_ 960 MHz. Cortland --- 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com 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: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Re: USB Immunity Specs??
When confronted by confused designers, I explain the USB feature I call the common-mode noise detector. USB detects a new device connection via a very simple non-differential circuit, even though the communication is otherwise differential. This problem was made noticable by the insistance of the designer to abide by the original USB specification of a floated capacitor-coupled shield on the peripheral connector, spoiling the effectiveness of an otherwise suitable shielded/screened cable. Anyway, this circuit happily responds to common mode transients, such as EFT/ESD and the like. What happens next is the software, responding to a new device signal, becomes confused when it finds a peripheral ALREADY enumerated (logged into the driver) and doesn't know what to do (really due to poor stress-testing of the software). Some of the first USB drivers of Window95 would do very entertaining things, drop into random sections of the communication protocol, or the infamous blue screen of death. If your test system is still running Windows95, you will have no chance to pass. Microsoft stopped supporting that driver. I found that Windows98 was much better, but not foolproof. USB (and Firewire) unsuitable as they are, have crept into industrial applications that the designers considered primarily from a software functionality point of view. Eric Lifsey --- 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com 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: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Re: Clock frequencies
Following this thread, I looked up the FCC limits and see they are flat above 960 MHz. I have a question for the forum. Given that a broadcast type omni-directional antenna factor increases monotonically with increasing frequency, why is the limit flat? The only way I could justify a flat limit is if antenna gain is presumed to increase with increasing frequency. This doesn't seem likely with commercial applications for microwave communications, such as LANs or cordless phones. Another possibility is that receiver sensitivity is increasing with increasing frequency, but that doesn't seem terribly likely, either. Why doesn't the limit increase with increasing frequency, or stair-step as it does below 960 MHz? -- From: Pettit, Ghery ghery.pet...@intel.com To: 'John Woodgate' j...@jmwa.demon.co.uk, emc-p...@majordomo.ieee.org Subject: RE: Clock frequencies Date: Wed, Sep 18, 2002, 4:51 PM John, Cable emissions seldom are a significant factor above 1 GHz. Besides, we're supposed to tune for maximum smoke, not minimum grin. There are products on the market today that meet the FCC limits, but would not meet the tighter limits being proposed. There are no interference complaints from these products. What problem are we trying to fix with limits tighter than the FCC's? Ghery -Original Message- From: John Woodgate [mailto:j...@jmwa.demon.co.uk] Sent: Wednesday, September 18, 2002 1:53 PM To: emc-p...@majordomo.ieee.org Subject: Re: Clock frequencies I read in !emc-pstc that Pettit, Ghery ghery.pet...@intel.com wrote (in d9223eb959a5d511a98f00508b68c20c12515...@orsmsx108.jf.intel.com) about 'Clock frequencies' on Wed, 18 Sep 2002: CISPR SC I meets next week in Christchurch, New Zealand and this will be a topic of discussion at the meetings. We on the US delegation will be trying to keep the voices for tighter limits from being successful. It's really not something worth having a big argument about. To change the measured result by 6 dB, just move one of the cables a few cm. This Emperor really DOESN'T have any clothes.(;-) -- Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk Interested in professional sound reinforcement and distribution? Then go to http://www.isce.org.uk 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com 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: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list --- 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com 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: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list --- 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com 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: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Re: Current from Car 12V cigarette lighter socket
Eichner informed me that indeed, I have been scooped by the SAE and this in the works. -- From: John Woodgate j...@jmwa.demon.co.uk To: emc-p...@majordomo.ieee.org Subject: Re: Current from Car 12V cigarette lighter socket Date: Wed, Sep 18, 2002, 4:33 PM I read in !emc-pstc that Ken Javor ken.ja...@emccompliance.com wrote (in 0h2n005m8hj...@mtaout04.icomcast.net) about 'Current from Car 12V cigarette lighter socket' on Wed, 18 Sep 2002: An excellent post. Seems like a solution here would be for the newer electrical outlet to be designed differently and not mate with the older male cigarette lighter insert, and then provide an adapter that would take the cigarette lighter insert to the new electrical outlet. Then the 8 Amp limit could be relaxed for appliances with the new plug, and any old devices would still be taken care of. And your next question, for $64 000, is, 'Why didn't SAE think of that?' (;-) -- Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk Interested in professional sound reinforcement and distribution? Then go to http://www.isce.org.uk 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com 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: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list --- 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com 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: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Re: Immunity severity levels
Alan, Level 1: (1V/M)Low-level electromagnetic radiation environment. Levels typical of local radio/television stations located at more than 1 km, and transmitters/receivers of low power. Level 2: (3V/M)Moderate electromagnetic radiation environment. Low power portable transceivers (typically less than 1 W rating) are in use, but with restrictions on use in close proximity to the equipment. A typical commercial environment. Level 3: (10V/M) Severe electromagnetic radiation environment. Portable transceivers (2 W rating or more) are in use relatively close to the equipment but not less than 1m. High power broadcast transmitters are in close proximity to the equipment and ISM equipment may be located close by. A typical industrial environment. Level x: (Special) Level x is an open level which might be negotiated and specified in the product standard or equipment specification. Regards Joe Martin Applied Biosystems alan.hud...@amsjv.com Sent by: To: emc-p...@majordomo.ieee.org owner-emc-pstc@majordomcc: o.ieee.org Subject: Immunity severity levels 09/18/2002 10:14 AM Please respond to alan.hudson With regard to radiated emission immunity and EN61000-4-3 (or IEC 801-3) I believe there are different field strengths used, depending on the environment in which the apparatus being tested is to be used. I believe equipment to be used in a well-protected environment may be tested at a lower immunity level than equipment to be used in an unprotected environment. I've ordered a copy of 61000-4-3, but while I'm waiting I'd like to know ASAP: 1) What are the definitions of the levels? 2) What field strengths are used for the various levels? (I think level 2 is 3V/m and level 3 is 10V/m) Regards, Alan --- 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com 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: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list --- 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com 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: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Re: Medical equipment and EN61000-3-2
I read in !emc-pstc that dave.osb...@philips.com wrote (in of6ce386fe.d271bb0a-on86256c38.0070a...@diamond.philips.com) about 'Medical equipment and EN61000-3-2' on Wed, 18 Sep 2002: Hospitals, just like large office buildings are rarely directly connected to the public low-voltage distribution system. Their electricity is normally provided by a MV transformer. This is not necessary true in lesser developed countries. It's also a matter of how you define 'hospital'. Some equipment may be used in a health centre or day unit, which is not a large building and is likely to have no more than a commercial LV supply, maybe 200 A 3-phase in UK. -- Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk Interested in professional sound reinforcement and distribution? Then go to http://www.isce.org.uk 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com 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: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Re: Immunity severity levels
Alan, Level 1: (1V/M)Low-level electromagnetic radiation environment. Levels typical of local radio/television stations located at more than 1 km, and transmitters/receivers of low power. Level 2: (3V/M)Moderate electromagnetic radiation environment. Low power portable transceivers (typically less than 1 W rating) are in use, but with restrictions on use in close proximity to the equipment. A typical commercial environment. Level 3: (10V/M) Severe electromagnetic radiation environment. Portable transceivers (2 W rating or more) are in use relatively close to the equipment but not less than 1m. High power broadcast transmitters are in close proximity to the equipment and ISM equipment may be located close by. A typical industrial environment. Level x: (Special) Level x is an open level which might be negotiated and specified in the product standard or equipment specification. Regards Joe Martin Applied Biosystems alan.hud...@amsjv.com Sent by: To: emc-p...@majordomo.ieee.org owner-emc-pstc@majordomcc: o.ieee.org Subject: Immunity severity levels 09/18/2002 10:14 AM Please respond to alan.hudson With regard to radiated emission immunity and EN61000-4-3 (or IEC 801-3) I believe there are different field strengths used, depending on the environment in which the apparatus being tested is to be used. I believe equipment to be used in a well-protected environment may be tested at a lower immunity level than equipment to be used in an unprotected environment. I've ordered a copy of 61000-4-3, but while I'm waiting I'd like to know ASAP: 1) What are the definitions of the levels? 2) What field strengths are used for the various levels? (I think level 2 is 3V/m and level 3 is 10V/m) Regards, Alan --- 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com 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: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list --- 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com 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: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list --- 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
Re: Breaker panel lockout-tagout
I'm not an authority, but I would think that this is against both the fire code and common sense. If an emergency developed such as electric shock or fire and the breaker could not be manually opened, i see it as tantamount to the locking of fire escape doors and many liability concerns. The object of locking out a single breaker is to prevent THAT breaker from being energized accidently. Warren Birmingham Epsilon-Mu Consultants (510) 793-4806 email: war...@epsilon-mu.com website: http://www.epsilon-mu.com On Wednesday, Sep 18, 2002, at 10:29 US/Pacific, lcr...@tuvam.com wrote: Group, Is anyone aware of an authoritative position on the acceptability (or not) of applying a lock to a breaker panel cover (and so affecting access to other, unrelated, breakers behind the same cove) to achieve OSHA compliant Lockout/Tagout rather than applying the lock to breaker directly? -Lauren Crane TUV America --- 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com 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: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list --- 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com 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: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Re: Question: Discharge capacitance 0.1 uF
Many line filters do indeed have a bleeder resistor built in. There are a few which do not, and I am familiar with one Delta filter that does not. We added the bleeder across the terminals of the filter and it was approved by UL. It just has to be done in accordance with accepted construction practices. This particular filter is and IEC plug type so the leads are not saliently exposed unless the cord is left attached. None the less I agree with John that it is not a good idea to ignore because one instance will get you a lot of word-of-mouth bad press and sales are hard-enough to come by so to speak. Warren Birmingham Epsilon-Mu Consultants (510) 793-4806 email: war...@epsilon-mu.com website: http://www.epsilon-mu.com On Wednesday, Sep 18, 2002, at 10:11 US/Pacific, John Allen wrote: Hello Folks Tomonori Sato commented However, I think discharge from 0.1uF capacitor charged to the mains peak voltage can be quite uncomfortable. I believe that to be true from personal experience and from having to investigate the results of a number of such incidents, and so would remind member of a point that I made several years ago on this forum: The primary shock almost certainly will NOT hurt a person, but the involuntary reaction TO the shock may well have much more seriousconsequences. This type of shock is often encountered by people who pick up equipment which they have just unplugged from the AC mains in order to carry it elsewhere. If they then touch the pins of the plug there are numerous reported incidences of them involuntarily dropping the unit - and that can possibly be on their own feet - and from a height of about 3ft/1m! If the unit is more than a couple of pounds (about one kilo) then the injury to t! he feet can be substantial. Worse situations could occur in industrial equipment when a service engineer opens a cabinet to perform a service operation - the reaction from the shock could cause him to strike touch other hazardous electrical or mechanical parts (which probably should also not be there, I do agree!) which then cause him serious actual injury. These types of incident do not make the equipment supplier very popular to say the least, and could result in product liability claims. The main basis for the claims would be that the supplier had not adequately assessed the hazards and taken the appropriate simple precautions which are easily and cheaply available - fit a bleeder resistor across the capacitor, or use a filter with a resistor already built in (or with transformer/inductor windings directly across the capacitor - which achieve the same result) ! Again from personal experience I can say that it is a very embarassing and un! comfortable experience to have to write to an injured or anno! yed person, or to his employer, to say sorry, but that is what the safety standard allows. It is just not good business sense. Therefore, regardless of the requirements of the various standards and this argument over capacitor value and/or charging voltage, I firmly believe that the use of bleeder resistors should be considered effectively mandatory, and have always recommended it to engineers I have advised on product safety. Regards John Allen Technical Consultant Electromagnetics, Safety and Reliability Group ERA Technology Ltd Cleeve Rd Leatherhead Surrey KT22 7SA Tel: +44 (0) 1372-367025 (Direct) +44 (0) 1372-367000 (Switchboard) Fax: +44 (0) 1372-367102 (Fax) -- Replies to this message may be posted in the following public forum: Question: Discharge capacitance 0.1 uF --- 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com 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: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list --- 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy
Re: Clock frequencies
Neil, Section 15.33 of FCC Part 15 Frequency Range of Radiated Measurements provides you with this information. Regards Joe Martin Applied Biosystems Neil Helsby neilhe@solid-state-logTo: emc-p...@majordomo.ieee.org ic.comcc: Sent by: Subject: Clock frequencies owner-emc-pstc@majordom o.ieee.org 09/18/2002 03:53 AM Please respond to Neil Helsby I read somewhere, and now cannot find, a reference to FCC requirements with respect to the relationship between clock frequency and highest emissions scan frequency. Can anyone help, preferably pointing to the FCC document? I also seem to remember similar comments being considered by the EU. Can anyone advise on these? Many thanks, Neil Helsby ** This email and any files transmitted with it are confidential and intended solely for the use of the individual or entity to whom they are addressed. If you have received this email in error please notify the system manager. This footnote also confirms that this email message has been swept by MIMEsweeper for the presence of computer viruses. www.mimesweeper.com ** --- 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com 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: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list --- 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com 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: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list --- 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and
Repeat postings
I am getting multiple postings, even I think into the next day. --- 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com 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: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
RE: safety testing in the USA
There has been some good responses to this post. And it is, in general, true that a manufacturer is not mandated, by law, to have the product LISTED by an appropriate Safety Testing Agency (NRTL). However, it may be required by the local inspection agency prior to installation. (This was covered in other posts). However, if you, as the customer, requests that the product be tested and listed by an applicable NRTL, and the vendor is not willing to have the product tested for compliance with the appropriate standard(s), then you should RUN to the nearest exit and find another vendor. Assume that a vendor, who is not willing to have their product tested and listed for by an appropriate testing agency, is hiding something and the vendor is aware that the product would not comply if tested. OO John Shinn, P.E. Manager, Lab Operations Sanmina-SCI -Original Message- From: owner-emc-p...@majordomo.ieee.org [mailto:owner-emc-p...@majordomo.ieee.org]On Behalf Of rob.humph...@reuters.com Sent: Thursday, September 19, 2002 7:46 AM To: emc-p...@majordomo.ieee.org Subject: safety testing in the USA Group, I am in discussions with a potential supplier of IT equipment, Its our usual policy to request testing to a listed standard such as UL 60950 for safety in North America. The supplier has replied that this is not mandatory. Is he correct? what compels safety testing for IT equipment in this geography? is it mandated by law? Thanks in advance for your opinions Rob - --- Visit our Internet site at http://www.reuters.com Any views expressed in this message are those of the individual sender, except where the sender specifically states them to be the views of Reuters Ltd. --- 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com 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: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list --- 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com 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: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Re: Question: Discharge capacitance 0.1 uF
Hi Tom: So, for voltage up to 450V d.c. (i.e. up to 318V a.c.), capacitor up to 0.1uF will become a Limited Current Circuit, hence the voltage is not Hazardous Voltage (1.2.8.4) - no additional condition would be required for the capacitor connected to the primary circuit. Electric shock (or electrically-stimulated sensation) is a function of BOTH voltage and current. For an electric shock to occur, the source must exceed, say, 30 V rms and 0.5 mA rms. As a general rule, we say that any voltage not exceeding 30 V rms is not hazardous, regardless of current. We identify this voltage as ELV or SELV. Likewise, we say that any current not exceeding 0.5 mA rms is not hazardous, regardless of voltage. We identify this current as Limited Current. Furthermore, Limited Current addresses capacitors charged to voltages exceeding 42.4 V dc. In this case, we control the capacitance, or the charge, or the stored energy, and deem the transient discharge current equivalent to a steady state current. In the case of an across-the-line capacitor installed on the supply side of the power switch, the capacitor can be charged to the peak of the line voltage if the plug is disconnected at the peak of the line voltage. As has already been noted in this forum, the discharge is not a pleasant sensation, and may very well result in an involuntary reaction, depending on the individual. By comparison, the sensation from 3.5 mA steady-state leakage current (allowed by some standards for Class I equipment) is also not a pleasant sensation and may result in an involuntary reaction. The initial discharge current of a charged capacitor is limited only by the body resistance. Regardless of capacitance value, the initial current is the same. The effect of capacitance value is the duration of the current. If the current has a short duration, the body will not sense it. Assuming all bodies have the same resistances, then the duration of the current is a function of the value of the capacitance. The standards happen to draw the line at 0.1 uF. Any value less than 0.1 uF is deemed acceptable. Any value greater than 0.1 uF is deemed unacceptable. Consequently, for capacitors less than 0.1 uF, the discharge time is short and the body is less likely to sense the current. If the capacitor is more than 0.1 uF, the discharge time is long, and body is likely to sense the current. Another factor, of course, is the magnitude of the voltage to which the capacitor is charged. If the capacitor is charged to the peak of the 230 V mains, the discharge is almost always sensed. The same capacitor charged to the peak of a 120 V mains is barely detectable. The lower the voltage, the lower the initial current. The fact that the initial discharge current is limited only by body resistance also applies to leakage current through Y capacitors. At the moment the body is inserted into the circuit, the initial current is limited only by the body resistance. Thereafter, the current is the steady-state current due to the capacitive reactance. However, the Y capacitors are much smaller in value, and therefore the discharge is much shorter in time. (You can test this by putting a switch in series with the leakage current; if the switch closes at the peak of the line voltage, you will feel an initial sharp sensation.) By the way, the sensation of leakage current from a Y capacitor is greater than the sensation of leakage current from a resistor whose value is equal to the value of capacitive reactance. This is due to the same phenomenon, namely the initial discharge of the capacitance. Best regards, Rich --- 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com 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: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Compliance Engineering Position
Greetings, The Applied Biosystems Division located in the Houston Texas area has the following opening in the Compliance Engineering Department: Duties include leading EMC and product safety engineering functions, including working with manufacturing and RD to determine requirements for implementing and monitoring regulations. Collect and analyze data that help determine compliance engineering issues, trends and improvements. This position requires the knowledge and skills normally acquired through the successful completion of a BSEE degree and/or electronics background. 3-7 years product safety and/or EMC experience preferred. Computer literate. Understanding of manufacturing processes. Minimum 5 years experience demonstrating communication, organization and engineering skills. Please forward your resumes directly to: Joe Martin Applied Biosystems marti...@appliedbiosystems.com 850 Lincoln Centre Dr. Foster City, CA 94404 (650) 638-5695 --- 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com 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: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
RE: safety testing in the USA
Another interesting point that can be made is I didn't say it was law, I said List it or I won't buy it. Depending on the product (basically, if there's a Listed competitor product on the market), you can make it happen. In the US, often a Listing mark is enforced by marketing more than law. Many retail stores have the requirement of products they put on the shelf to be Listed, thereby passing on the liability, and reducing their insurance costs. just my 2 cents (I've got the paystub to prove it) Sam -Original Message- From: owner-emc-p...@majordomo.ieee.org [mailto:owner-emc-p...@majordomo.ieee.org]On Behalf Of rob.humph...@reuters.com Sent: Thursday, September 19, 2002 9:46 AM To: emc-p...@majordomo.ieee.org Subject: safety testing in the USA Group, I am in discussions with a potential supplier of IT equipment, Its our usual policy to request testing to a listed standard such as UL 60950 for safety in North America. The supplier has replied that this is not mandatory. Is he correct? what compels safety testing for IT equipment in this geography? is it mandated by law? Thanks in advance for your opinions Rob - --- Visit our Internet site at http://www.reuters.com Any views expressed in this message are those of the individual sender, except where the sender specifically states them to be the views of Reuters Ltd. --- 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com 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: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list --- 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com 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: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
RE: Current from Car 12V cigarette lighter socket / 42 VDC
The Darnell Group is a market research/publishing/advertising entity that has been tracking the automotive industry changeover from 12V to 42V, as well as other power supply issues. They were offering a free web-newsletter called the power-pulse (or something like that). I subscribed to it. The newsletter was interesting; but its main focus was to try to get me to buy their marketing reports on the power supply industry. One of these reports dealt with the 42V changeover. I didn't buy it; since we don't make much automotive equipment. However, if anyone is interested; Darnell Group has the information for a small fee :-) 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 | --- 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com 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: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Re: safety testing in the USA
Hi Rob: I am in discussions with a potential supplier of IT equipment, Its our usual policy to request testing to a listed standard such as UL 60950 for safety in North America. The supplier has replied that this is not mandatory. Is he correct? what compels safety testing for IT equipment in this geography? is it mandated by law? I am going to interpret your statement of safety testing as meaning safety certification. In the USA, there are two sets of regulations that are mandated by law: 1. Workplace regulations (OSHA). 2. Electrical installation regulations (NEC). Between these two sets of regulations, almost every sales situation is covered. Each of these has two alternatives: 1. Test each unit in place. 2. Third-party certification. Technically, your supplier is correct. Third-party safety certification is NOT mandatory (because testing each unit in place is the alternative). Practically, your supplier is wrong. Third-party safety certification avoids testing each unit in place. In the USA, governments cannot mandate testing by a private party (which is the case of third-party safety certification houses). Consequently, the regulations promulgated under various laws prescribe testing in place, with an alternative of third- party certification to a national standard, i.e., an ANSI standard. Best regards, Rich --- 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com 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: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Re: EN60065 mains switches
I read in !emc-pstc that Tyra, John john_t...@bose.com wrote (in 418fbd441c22d5118d860003470d43160543e...@cupid.bose.com) about 'EN60065 mains switches' on Thu, 19 Sep 2002: Here is another issue where you will get conflicting opinions but I believe that just because it is notified in the OJ does not mean every country will adopt it at the same time. You need to be careful as there are some countries still working with the 5th edition so if you have a CB certificate and report done by a NCB it may not be accepted in a country which has not adopted that particular version of the standard..This is a particular concern with countries outside the EU, i.e. AsiaAny other opinions? Notification causes immediate adoption in all EU countries and the former EFTA countries simultaneously. Other countries may indeed not adopt the standard at that time. -- Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk Interested in professional sound reinforcement and distribution? Then go to http://www.isce.org.uk 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com 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: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Re: CE Marking for Passive speakers
I read in !emc-pstc that Tyra, John john_t...@bose.com wrote (in 418fbd441c22d5118d860003470d43160543e...@cupid.bose.com) about 'CE Marking for Passive speakers' on Thu, 19 Sep 2002: John, the added cost in our case is the fact that we include a copy of the DoC with every product. Not required I know but done here as a matter of policy this adds a couple of pennies to each product which adds up in the long run. Just print it as part of the instruction leaflet, not as a separate document. -- Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk Interested in professional sound reinforcement and distribution? Then go to http://www.isce.org.uk 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com 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: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
RE: Question: Discharge capacitance 0.1 uF
Hi John, Even theory has to comply with practice, so i took my soldering iron... I have to admit that modern capacitors do keep their charge too long. I did some test with newer Y and X caps of 0.1 uF and they keep their charge way too long - over 1 minute - without notable loss of voltage ( 10%) (real life voltages choosen :310V) Probably the quality of the dielectricum has been improved, or the use of paper has been abandoned in favor of modern equivalent plastics. (any one knows ?). Of course the increased leakage of the older caps was not meant to be part of the specs, and this is again a good example of how relying on hidden specifications may in time lead to undesired results: standards ignoring the effect of increased leakage resistance. I also tried the discharge between two fingers, and found the result to be unpleasant at least. Time to change standards... Gert Gremmen ce-test, qualified testing -Original Message- From: owner-emc-p...@majordomo.ieee.org [mailto:owner-emc-p...@majordomo.ieee.org]On Behalf Of John Allen Sent: Thursday, September 19, 2002 9:24 AM To: 'Grasso, Charles'; 'Warren Birmingham' Cc: emc-p...@majordomo.ieee.org Subject: RE: Question: Discharge capacitance 0.1 uF Hi Charles, Warren Seems that a few of us know what DOES happen and the longterm results, but quite a few others don't believe that it does - and that even it does then it is not very important. The difference between reality and theory! I suggest that the non-believers try it for themselves - by unplugging a suitable piece of equipment and picking it up - AND then touching the pins of the plug! (the unplugging process may need to be repeated a few times until the capacitor is disconnected when the mains is high at the time of disconnection and so gets a decent charge!) However before they do try it, I suggest they wear safety boots and also use a piece of equipment which can then be discarded due to the damage it received when it fell on the foot and/or the ground! Regards John Allen -Original Message- From: Grasso, Charles [mailto:charles.gra...@echostar.com] Sent: 18 September 2002 19:07 To: 'John Allen'; emc-p...@majordomo.ieee.org Subject: RE: Question: Discharge capacitance 0.1 uF Hi All, From personal experience I can tell you that the involuntary reaction to a shock can have serious consequences to the sales of a company. In a former life - a previous employer OEM'd a PC from a Korean Company. The PC had all the relevant marks but somehow the resistor that was supposed to bleed off the caps didn't make it into production. A customer , moving said model from one location to another, touched the mains terminals and felt a shock. The customer fell over, the PC landed on the customer, the customer sued and the story ended up in the papers. The sales of PCs essentially died after that. - All for the sake of one resistor. Best Regards Charles Grasso Senior Compliance Engineer Echostar Communications Corp. Tel: 303-706-5467 Fax: 303-799-6222 Cell: 303-204-2974 Email: charles.gra...@echostar.com; Email Alternate: chasgra...@ieee.org -Original Message- From: John Allen [mailto:john.al...@era.co.uk] Sent: Wednesday, September 18, 2002 11:11 AM To: emc-p...@majordomo.ieee.org Subject: Question: Discharge capacitance 0.1 uF Hello Folks Tomonori Sato commented However, I think discharge from 0.1uF capacitor charged to the mains peak voltage can be quite uncomfortable. I believe that to be true from personal experience and from having to investigate the results of a number of such incidents, and so would remind member of a point that I made several years ago on this forum: The primary shock almost certainly will NOT hurt a person, but the involuntary reaction TO the shock may well have much more seriousconsequences. This type of shock is often encountered by people who pick up equipment which they have just unplugged from the AC mains in order to carry it elsewhere. If they then touch the pins of the plug there are numerous reported incidences of them involuntarily dropping the unit - and that can possibly be on their own feet - and from a height of about 3ft/1m! If the unit is more than a couple of pounds (about one kilo) then the injury to t! he feet can be substantial. Worse situations could occur in industrial equipment when a service engineer opens a cabinet to perform a service operation - the reaction from the shock could cause him to strike touch other hazardous electrical or mechanical parts (which probably should also not be there, I do agree!) which then cause him serious actual injury. These types of incident do not make the equipment supplier very popular to say the least, and could result in product liability claims. The main basis for the claims would be that the supplier had not
RE: safety testing in the USA
Here is a very good discussion of the leagalities. http://www.conformity.com/A02F18.pdf Richard Woods Sensormatic Electronics Tyco International -Original Message- From: Gary McInturff [mailto:gary.mcintu...@worldwidepackets.com] Sent: Thursday, September 19, 2002 12:40 PM To: rob.humph...@reuters.com; EMC-PSTC (E-mail) Subject: RE: safety testing in the USA Rob. Required is an interesting term, and this is a long debate involving OSHA, National Electrical Code, fire codes and when and if anybody inspects the equipment before its installed. There are places that you probably would be alright, some that you wouldn't probably be caught even if it wasn't right, and then there are places like the City of LA that seems to have a pretty rigorous inspection policy. They by the way can give you a City of LA inspection, but it isn't of any real value outside of LA. Then there are customers that use the safety marks in an attempt to reduce their liability by showing they have done what any reasonable manufacturer would do to protect customers. So short pragmatic answer, in my opinion, yes you need it. Gary The debate rages on -Original Message- From: rob.humph...@reuters.com [mailto:rob.humph...@reuters.com] Sent: Thursday, September 19, 2002 7:46 AM To: emc-p...@majordomo.ieee.org Subject: safety testing in the USA Group, I am in discussions with a potential supplier of IT equipment, Its our usual policy to request testing to a listed standard such as UL 60950 for safety in North America. The supplier has replied that this is not mandatory. Is he correct? what compels safety testing for IT equipment in this geography? is it mandated by law? Thanks in advance for your opinions Rob - --- Visit our Internet site at http://www.reuters.com Any views expressed in this message are those of the individual sender, except where the sender specifically states them to be the views of Reuters Ltd. --- 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com 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: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list --- 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com 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: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list --- 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com 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: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
RE: EMC immunity requirements in Canada?
Hi Warren, As I understand the FCC Part 15 regs there are NO immunity requirements. Indeed the FCC have in the past allowed the market to dictate the quality of the EM design. Has there been a change?? Best Regards Charles Grasso Senior Compliance Engineer Echostar Communications Corp. Tel: 303-706-5467 Fax: 303-799-6222 Cell: 303-204-2974 Email: charles.gra...@echostar.com; Email Alternate: chasgra...@ieee.org -Original Message- From: Warren Birmingham [mailto:war...@comfortjets.com] Sent: Thursday, September 19, 2002 10:59 AM To: am...@westin-emission.no Cc: emc-p...@majordomo.ieee.org Subject: Re: EMC immunity requirements in Canada? The Canadians accept FCC data, which DOES include immunity requirements. There are no testing standards for immunity, only that the device must accept any interference for normal operation. See the labeling requirements for verification and certification in Part 15. Warren Birmingham Epsilon-Mu Consultants (510) 793-4806 email: war...@epsilon-mu.com website: http://www.epsilon-mu.com On Thursday, Sep 19, 2002, at 05:22 US/Pacific, am...@westin-emission.no wrote: As far as I remember, US (FCC) do only have emission (radiated / conducted) requirements. What about Canada (IC) do they have immunity requirements in addition ? Best regards Amund Westin, Oslo/ NORWAY --- 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com 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: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list --- 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com 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: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
RE: Looking for good USB EMI suppression techniques
Hi It is my understanding that the USB guidelines provide for EMI filtering at the output. That is to say: for USB1 - ferrite beads and caps, for USBII a common mode choke is recommended. Take a look in there. Also, USB is a differential signal so appropriate design on the board needs to be considered Best Regards Charles Grasso Senior Compliance Engineer Echostar Communications Corp. Tel: 303-706-5467 Fax: 303-799-6222 Cell: 303-204-2974 Email: charles.gra...@echostar.com; Email Alternate: chasgra...@ieee.org -Original Message- From: Darrell Locke [mailto:dlo...@advanced-input.com] Sent: Thursday, September 19, 2002 11:15 AM To: 'Dan Pierce'; emc-p...@majordomo.ieee.org Subject: RE: Looking for good USB EMI suppression techniques You can't do much filtering on the USB lines due to signal integrity. We have achieved good results with careful attention to PCB layout (an adequete ground plane, don't even try 2-layer) and shielding, especially with the cable. Darrell Locke Advanced Input Devices -Original Message- From: Dan Pierce [mailto:dpie...@openglobe.net] Sent: Wednesday, September 18, 2002 8:17 AM To: emc-p...@majordomo.ieee.org Subject: Looking for good USB EMI suppression techniques Greetings: I am looking for a good design practice regarding USB transmission lines. I commonly have problems with 120.00MHz and 252.00MHz. Thanks in advance. Daniel J. Pierce Sr. Design Engineer OpenGlobe, Inc. (An Escient Technologies Affiliate) 6325 Digital Way Indianapolis, IN 46278 mailto:dpie...@openglobe.net P: (317) 616.6587 F: (317) 616.6587 --- 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com 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: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list --- 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com 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: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
RE: Question: Discharge capacitance 0.1 uF
Gert Thanks for that investigation that I have not had the time for recently! Now, maybe, the standards writing committees will begin to take this issue on board and do something about it as the problem is generally technically trivial to solve - the major issue then being to ensure that the bleeder device is always across the capacitor, and is not isolated from it by a switch or contactor that the operator can put in the open position before disconnecting the supply. (The latter point can particularly apply to some filtered IEC, or similar, power inlets with integral switches where the bleeder could be on the opposite side of the contacts to the capacitor). John Allen Technical Consultant Electromagnetics, Safety and Reliability Group ERA Technology Ltd Cleeve Rd Leatherhead Surrey KT22 7SA Tel: +44 (0) 1372-367025 (Direct) +44 (0) 1372-367000 (Switchboard) Fax: +44 (0) 1372-367102 (Fax) -Original Message- From: Gert Gremmen [mailto:g.grem...@cetest.nl] Sent: 19 September 2002 11:57 To: John Allen Cc: emc-p...@majordomo.ieee.org Subject: RE: Question: Discharge capacitance 0.1 uF Hi John, Even theory has to comply with practice, so i took my soldering iron... I have to admit that modern capacitors do keep their charge too long. I did some test with newer Y and X caps of 0.1 uF and they keep their charge way too long - over 1 minute - without notable loss of voltage ( 10%) (real life voltages choosen :310V) Probably the quality of the dielectricum has been improved, or the use of paper has been abandoned in favor of modern equivalent plastics. (any one knows ?). Of course the increased leakage of the older caps was not meant to be part of the specs, and this is again a good example of how relying on hidden specifications may in time lead to undesired results: standards ignoring the effect of increased leakage resistance. I also tried the discharge between two fingers, and found the result to be unpleasant at least. Time to change standards... Gert Gremmen ce-test, qualified testing -Original Message- From: owner-emc-p...@majordomo.ieee.org [mailto:owner-emc-p...@majordomo.ieee.org]On Behalf Of John Allen Sent: Thursday, September 19, 2002 9:24 AM To: 'Grasso, Charles'; 'Warren Birmingham' Cc: emc-p...@majordomo.ieee.org Subject: RE: Question: Discharge capacitance 0.1 uF Hi Charles, Warren Seems that a few of us know what DOES happen and the longterm results, but quite a few others don't believe that it does - and that even it does then it is not very important. The difference between reality and theory! I suggest that the non-believers try it for themselves - by unplugging a suitable piece of equipment and picking it up - AND then touching the pins of the plug! (the unplugging process may need to be repeated a few times until the capacitor is disconnected when the mains is high at the time of disconnection and so gets a decent charge!) However before they do try it, I suggest they wear safety boots and also use a piece of equipment which can then be discarded due to the damage it received when it fell on the foot and/or the ground! Regards John Allen -Original Message- From: Grasso, Charles [mailto:charles.gra...@echostar.com] Sent: 18 September 2002 19:07 To: 'John Allen'; emc-p...@majordomo.ieee.org Subject: RE: Question: Discharge capacitance 0.1 uF Hi All, From personal experience I can tell you that the involuntary reaction to a shock can have serious consequences to the sales of a company. In a former life - a previous employer OEM'd a PC from a Korean Company. The PC had all the relevant marks but somehow the resistor that was supposed to bleed off the caps didn't make it into production. A customer , moving said model from one location to another, touched the mains terminals and felt a shock. The customer fell over, the PC landed on the customer, the customer sued and the story ended up in the papers. The sales of PCs essentially died after that. - All for the sake of one resistor. Best Regards Charles Grasso Senior Compliance Engineer Echostar Communications Corp. Tel: 303-706-5467 Fax: 303-799-6222 Cell: 303-204-2974 Email: charles.gra...@echostar.com; mailto:charles.gra...@echostar.com; %20 Email Alternate: chasgra...@ieee.org mailto:chasgra...@ieee.org -Original Message- From: John Allen [mailto:john.al...@era.co.uk] Sent: Wednesday, September 18, 2002 11:11 AM To: emc-p...@majordomo.ieee.org Subject: Question: Discharge capacitance 0.1 uF Hello Folks Tomonori Sato commented However, I think discharge from 0.1uF capacitor charged to the mains peak voltage can be quite uncomfortable. I believe that to be true from personal experience and from having to investigate the results of a number of such incidents, and so would remind member of a point that I made several years ago on this forum: The primary shock almost certainly will NOT hurt a person, but the involuntary reaction TO the shock
RE: Current from Car 12V cigarette lighter socket / 42 VDC
Well that's the $1M question, isn't it! My involvement is tangential at best, but my understanding is that the effort is not going to be coordinated as a grand simultaneous roll-out. Rather each mfr of cars, trucks, boats, etc, will get around to it based on their own needs. The drivers for this effort vary widely - vehicle emissions, increased electrical loads, drive-by-wire technology, etc. - and the 42Vdc agenda for a given mfr is to some extent determined by the agenda for those features or regulations. There is much technology still to be developed and much standardization work still to be done, but the work is well in progress. Is there anyone on the forum who has a more inside view of this and can share some information with us? In the meantime, have a look at the web. Searching on 42V can yield a lot of hits. Here's one I found that summarizes things a bit: http://www.sae.org/42volt/dual_higher_sum.pdf Jim Eichner, P.Eng. Manager, Engineering Services Xantrex Technology Inc. e-mail: jim.eich...@xantrex.com web: www.xantrex.com Any opinions expressed are those of my invisible friend, who really exists. Honest. No really. Confidentiality Notice: This email message, including any attachments, is for the sole use of the intended recipient(s) and may contain confidential and privileged information. Any unauthorized review, use, disclosure or distribution is prohibited. If you are not the intended recipient, please contact the sender by reply e-mail and destroy all copies of the original message. -Original Message- From: Price, Ed [mailto:ed.pr...@cubic.com] Sent: Wednesday, September 18, 2002 6:42 PM To: 'EMC-PSTC - forum' Subject: RE: Current from Car 12V cigarette lighter socket / 42 VDC Pardon the slight topic shift, but when will we be seeing 42 VDC automotive systems? I understand that there has already been some fleet vehicle production with the 42 VDC standard, but when will it be introduced to the consumer market? Regards, Ed Ed Price ed.pr...@cubic.com Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (Fax) Military Avionics EMC Is Our Specialty Shake-Bake-Shock - Metrology - Reliability Analysis --- --- 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com 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: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Re: Pulse Dialing
In a message dated 9/19/2002, Matt Aschenberg writes: Our engineering team is looking for a spec that defines U.S pulse dialing. Any suggestions? Hi Matt: As you may know, there are no regulatory requirements for pulse dialing in FCC part 68. This means that any requirements you apply will be self-imposed. Simply stated, US pulse dialing uses a 60/40 break/make ratio and a nominal 10 pulses per second. Thus, each pulse consists of a nominal 60 mS break followed by a 40 mS make. The number of pulses corresponds to the digit dialed, except that a 0 is ten pulses. If you want a detailed specification for pulse dialing, you can use TIA/EIA-470-B, Telephone Sets With Loop Signalling. Joe Randolph Telecom Design Consultant Randolph Telecom, Inc. 781-721-2848 http://www.randolph-telecom.com
RE: Looking for good USB EMI suppression techniques
You can't do much filtering on the USB lines due to signal integrity. We have achieved good results with careful attention to PCB layout (an adequete ground plane, don't even try 2-layer) and shielding, especially with the cable. Darrell Locke Advanced Input Devices -Original Message- From: Dan Pierce [mailto:dpie...@openglobe.net] Sent: Wednesday, September 18, 2002 8:17 AM To: emc-p...@majordomo.ieee.org Subject: Looking for good USB EMI suppression techniques Greetings: I am looking for a good design practice regarding USB transmission lines. I commonly have problems with 120.00MHz and 252.00MHz. Thanks in advance. Daniel J. Pierce Sr. Design Engineer OpenGlobe, Inc. (An Escient Technologies Affiliate) 6325 Digital Way Indianapolis, IN 46278 mailto:dpie...@openglobe.net P: (317) 616.6587 F: (317) 616.6587 --- 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com 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: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Re: EMC immunity requirements in Canada?
The Canadians accept FCC data, which DOES include immunity requirements. There are no testing standards for immunity, only that the device must accept any interference for normal operation. See the labeling requirements for verification and certification in Part 15. Warren Birmingham Epsilon-Mu Consultants (510) 793-4806 email: war...@epsilon-mu.com website: http://www.epsilon-mu.com On Thursday, Sep 19, 2002, at 05:22 US/Pacific, am...@westin-emission.no wrote: As far as I remember, US (FCC) do only have emission (radiated / conducted) requirements. What about Canada (IC) do they have immunity requirements in addition ? Best regards Amund Westin, Oslo/ NORWAY --- 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com 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: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
RE: safety testing in the USA
Some states (e.g., North Carolina), counties (e.g., Orange, CA) and cities (e.g., Los Angeles and San Francisco)have a legal requirement that all electrical products for sale must be Listed. Some local electrical codes (e.g., Oregon) require electrical equipment be Listed. Since my company sells products virtually everywhere in the USA, we List all of our products including those powered by Class 2 sources. I recommend that you do the same unless you know for a fact that your target locality has no legal requirements for Listing. Richard Woods Sensormatic Electronics Tyco International -Original Message- From: rob.humph...@reuters.com [mailto:rob.humph...@reuters.com] Sent: Thursday, September 19, 2002 10:46 AM To: emc-p...@majordomo.ieee.org Subject: safety testing in the USA Group, I am in discussions with a potential supplier of IT equipment, Its our usual policy to request testing to a listed standard such as UL 60950 for safety in North America. The supplier has replied that this is not mandatory. Is he correct? what compels safety testing for IT equipment in this geography? is it mandated by law? Thanks in advance for your opinions Rob - --- Visit our Internet site at http://www.reuters.com Any views expressed in this message are those of the individual sender, except where the sender specifically states them to be the views of Reuters Ltd. --- 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com 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: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list --- 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com 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: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Re: Measuring AC Line Impedance
Hi Dave: I had the same question some time back, and came up with the following process. 1) For the resistive component, I applied a resistive load to the AC line, and calculated R = dV/dI 2) For the inductive component, I measured the transient current through an 'X' capacitor at the moment it was touched across the AC line. This requires a storage scope, and a current sense resistor or current probe. Amplitude accuracy is not important, since you're concerned with the period of the ringing. There is a big spike of current, followed by several cycles of ringing. I calculated the line inductance from the ringing frequency. For those who want more precision: - If you know the resonant frequency of the 'X' capacitor assembly, you can calculate the stray inductance, and adjust the line inductance accordingly. - Once you calculate the line inductance, you can correct the steady state impedance in step 1. Patrick Lawler plaw...@west.net On Thu, 19 Sep 2002 08:06:18 -0400, Spencer, David H david.spen...@usa.xerox.com wrote: I'm trying to characterize the 50Hz AC line impedance of my facility, for comparison to the values specified in IEC61000-3-3. I've come across generic short circuit values for the Resistive and Inductive components. However, I need to determine exactly what these values are ideally through a combination of measurement and calculation. So far, I've taken a large resistive load and measured the voltage drop on the AC line. From that I calculated the total impedance of the AC line. However, as you may suspect, with a resistive load, the power factor is 1.0. So I can't vectorly, calculate the resistive and inductive components. Is anyone familiar with a method to measure and calculate those values. The generic values I have for short circuit condition (which include 4 wires in a magnetic conduit) come out higher than my measured values, and those do not include the motor generator source. --- 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com 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: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
RE: safety testing in the USA
Rob. Required is an interesting term, and this is a long debate involving OSHA, National Electrical Code, fire codes and when and if anybody inspects the equipment before its installed. There are places that you probably would be alright, some that you wouldn't probably be caught even if it wasn't right, and then there are places like the City of LA that seems to have a pretty rigorous inspection policy. They by the way can give you a City of LA inspection, but it isn't of any real value outside of LA. Then there are customers that use the safety marks in an attempt to reduce their liability by showing they have done what any reasonable manufacturer would do to protect customers. So short pragmatic answer, in my opinion, yes you need it. Gary The debate rages on -Original Message- From: rob.humph...@reuters.com [mailto:rob.humph...@reuters.com] Sent: Thursday, September 19, 2002 7:46 AM To: emc-p...@majordomo.ieee.org Subject: safety testing in the USA Group, I am in discussions with a potential supplier of IT equipment, Its our usual policy to request testing to a listed standard such as UL 60950 for safety in North America. The supplier has replied that this is not mandatory. Is he correct? what compels safety testing for IT equipment in this geography? is it mandated by law? Thanks in advance for your opinions Rob - --- Visit our Internet site at http://www.reuters.com Any views expressed in this message are those of the individual sender, except where the sender specifically states them to be the views of Reuters Ltd. --- 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com 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: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list --- 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com 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: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
RE: Question: Discharge capacitance 0.1 uF
(the unplugging process may need to be repeated a few times until the capacitor is disconnected when the mains is high at the time of disconnection and so gets a decent charge!) At a former employer, we monitored the wave form with a 'scope, and repeatedly opened and closed the connection to the power line until disconnection could be seen to have occurred at (or very near) the peak of the wave form, then watched the discharge. None of us EVER felt tempted enough to question the 'scope display and experience the discharge personally - and we went to some trouble to arrange things so we would not do. Anyone who had doubted the necessity of the test was converted by seeing the potential for trouble. Cortland --- 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com 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: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
RE: EN60065 mains switches
Here is another issue where you will get conflicting opinions but I believe that just because it is notified in the OJ does not mean every country will adopt it at the same time. You need to be careful as there are some countries still working with the 5th edition so if you have a CB certificate and report done by a NCB it may not be accepted in a country which has not adopted that particular version of the standard..This is a particular concern with countries outside the EU, i.e. AsiaAny other opinions? -Original Message- From: John Woodgate [mailto:j...@jmwa.demon.co.uk] Sent: Wednesday, September 18, 2002 4:49 PM To: emc-p...@majordomo.ieee.org Subject: Re: EN60065 mains switches I read in !emc-pstc that Tyra, John john_t...@bose.com wrote (in 418fbd441c22d5118d860003470d43160543e...@cupid.bose.com) about 'EN60065 mains switches' on Wed, 18 Sep 2002: Also be aware that the published 7th edition of IEC60065 eliminates the need for a switch which is in line with the current edition of UL6500. Unfortunately it will probably be several years before all the countries adopt this edition of the standard It is already adopted as EN 60065:2002. If it hasn't already been 'notified' in the Official Journal, it soon will be. -- Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk Interested in professional sound reinforcement and distribution? Then go to http://www.isce.org.uk 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com 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: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list --- 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com 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: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Re: Measuring AC Line Impedance
In a message dated 9/19/2002, you write: So far, I've taken a large resistive load and measured the voltage drop on the AC line. From that I calculated the total impedance of the AC line. However, as you may suspect, with a resistive load, the power factor is 1.0. So I can't vectorly, calculate the resistive and inductive components. Hi Dave: I am not familiar with the specific measurement you are trying to make, so the following may not be applicable to your situation. However, some of the basic concepts may be useful. In the telecom business it is sometimes necessary to know the complex impedance presented by a 2-wire port. In theory, if you drive the port with a voltage source applied through a known resistance, you can calculate the complex impedance of the port based on measurements of the following two things: 1) The voltage drop across the source resistor 2) The phase of the current through the resistor, relative to the phase of the source I designed a simple fixture to measure the voltage and phase, then derived the necessary equations and created a spreadsheet to calculate the complex impedance. Soon after completing my measurements this way, I got a good price on a used test instrument that makes this measurement directly. I was very pleased to find that the values measured by the test instrument matched my calculated values almost exactly. This gave me good confidence in my earlier test method, even though I no longer need to use it. It might be possible for you to adapt this method for the test you want to make. If so, I would be happy to send you a copy of the equations and a copy of the spreadsheet I used. Since this was developed internally for my own use, the notes are a little sketchy, but I think I could fill in the gaps with a telephone conversation. While I am not familiar with the details of the test you are trying to perform, I can see that one possible complication would occur if the test is supposed to be performed under a specified load condition. In that case, you would have to find a way to ensure that the AC impedance of your load does not affect the measured impedance of the mains. I think there are ways to accomplish this either with a test fixture or by making the spreadsheet calculations take the load impedance into account. Joe Randolph Telecom Design Consultant Randolph Telecom, Inc. 781-721-2848 http://www.randolph-telecom.com HTMLFONT FACE=arial,helveticaFONT SIZE=2In a message dated 9/19/2002, you write:BR BR BR BLOCKQUOTE TYPE=CITE style=BORDER-LEFT: #ff 2px solid; MARGIN-LEFT: 5px; MARGIN-RIGHT: 0px; PADDING-LEFT: 5pxSo far,nbsp; I've taken a large resistive load and measured the voltage drop onBR the AC line.nbsp; From that I calculated the total impedance of the AC line.BR However, as you may suspect, with a resistive load, the power factor is 1.0.BR So I can't vectorly, calculate the resistive and inductive components.nbsp; BR /BLOCKQUOTEBR BR BR Hi Dave:BR BR I am not familiar with the specific measurement you are trying to make, so the following may not be applicable to your situation.nbsp; However, some of the basic concepts may be useful.BR BR In the telecom business it is sometimes necessary to know the complex impedance presented by a 2-wire port.nbsp; In theory, if you drive the port with a voltage source applied through a known resistance, you can calculate the complex impedance of the port based on measurements of the following two things:BR BR 1) The voltage drop across the source resistorBR 2) The phase of the current through the resistor, relative to the phase of the sourceBR BR I designed a simple fixture to measure the voltage and phase, then derived the necessary equations and created a spreadsheet to calculate the complex impedance.BR BR Soon after completing my measurements this way, I got a good price on a used test instrument that makes this measurement directly.nbsp; I was very pleased to find that the values measured by the test instrument matched my calculated values almost exactly.nbsp; This gave me good confidence in my earlier test method, even though I no longer need to use it.BR BR It might be possible for you to adapt this method for the test you want to make.nbsp; If so, I would be happy to send you a copy of the equations and a copy of the spreadsheet I used.nbsp; Since this was developed internally for my own use, the notes are a little sketchy, but I think I could fill in the gaps with a telephone conversation.BR BR While I am not familiar with the details of the test you are trying to perform, I can see that one possible complication would occur if the test is supposed to be performed under a specified load condition.nbsp; In that case, you would have to find a way to ensure that the AC impedance of your load does not affect the measured impedance of the mains.nbsp; I think there are ways to accomplish this either with a test fixture or by
Re: EMC immunity requirements in Canada?
Amund, Like the US, Canada has just radiated and conducted emissions requirements. The pertinent standard for Digital Apparatus is Industry Canada's ICES-003 Issue 3, dated November 22, 1997. This standard may be downloaded from: http://strategis.ic.gc.ca/SSG/1/sf00020e.html and the implementation/interpretation guide from: http://strategis.ic.gc.ca/SSG/1/sf01006e.html You may want to refer to three web pages on our company's web site about international electromagnetic compatibility (EMC), electromagnetic interference (EMC), and electrostatic discharge (ESD) requirements: * http://www.dbicorporation.com/ite.htm for information technology equipment (ITE). * http://www.dbicorporation.com/generic.htm for generic devices used in residential, commercial, and light industrial areas. * http://www.dbicorporation.com/industry.htm for generic devices used in industry. John Barnes KS4GL dBi Corporation http://www.dbicorporation.com/ --- 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com 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: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
RE: CE Marking for Passive speakers
I wish to thank everyone for taking the time to consider my questions. There were a many good points brought up and it gave me some new issues to consider, i.e. immunity testing for intense. As I expected the opinion was split and I have to admit that I am still not convinced that CE Marking is required for these type of products. In order to avoid the possibility of being questioned upon import into the EU I am going to recommend that we CE Mark our products until told otherwise and continue to pursue further clarification from the authorities. I will be happy to share any info I receive. John, the added cost in our case is the fact that we include a copy of the DoC with every product. Not required I know but done here as a matter of policy this adds a couple of pennies to each product which adds up in the long run. Best regards, John -Original Message- From: John Woodgate [mailto:j...@jmwa.demon.co.uk] Sent: Thursday, September 19, 2002 7:04 AM To: emc-p...@majordomo.ieee.org Subject: Re: CE Marking for Passive speakers I read in !emc-pstc that Gordon,Ian ian.gor...@edwards.boc.com wrote (in E1BA0362B28ED211A1E80008C71EA306018190AE@EXC_EAS01) about 'CE Marking for Passive speakers' on Thu, 19 Sep 2002: By the wider issue I was referring to your assertion that The EMC Guidelines document explains that having no active components is NOT grounds for exemption from the EMC Directive. If this were the case then it would have far reaching implications for many industries since all Electromagnetically Benign equipment might require testing. Furthermore I imagine this would have legal implications for the UK Government appointed Competent Body which advised my company that benign equipment is exempt. This Competent Body helped us compile a list of products within our range to which this exclusion applied. 'Benign' is NOT the same as 'passive', which is what was asserted. A torch/flashlight with an incandescent lamp is benign, because it is inconceivable that it would either emit anything or suffer from lack of immunity. But even just a *junction box* for high-speed data cable can both emit stuff and let external disturbances into the cabling. I showed how a loudspeaker can both emit and be disturbed by and external emission. -- Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk Interested in professional sound reinforcement and distribution? Then go to http://www.isce.org.uk 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com 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: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list --- 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com 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: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Re: EMC immunity requirements in Canada?
The Canadians accept FCC data, which DOES include immunity requirements. There are no testing standards for immunity, only that the device must accept any interference for normal operation. See the labeling requirements for verification and certification in Part 15. Warren Birmingham Epsilon-Mu Consultants (510) 793-4806 email: war...@epsilon-mu.com website: http://www.epsilon-mu.com On Thursday, Sep 19, 2002, at 05:22 US/Pacific, am...@westin-emission.no wrote: As far as I remember, US (FCC) do only have emission (radiated / conducted) requirements. What about Canada (IC) do they have immunity requirements in addition ? Best regards Amund Westin, Oslo/ NORWAY --- 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com 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: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list --- 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com 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: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Re: Measuring AC Line Impedance
I read in !emc-pstc that Spencer, David H david.spen...@usa.xerox.com wrote (in 052106A55179D611B34300096BB02E3F8B1D@USAMCMS4) about 'Measuring AC Line Impedance' on Thu, 19 Sep 2002: Is anyone familiar with a method to measure and calculate those values. The generic values I have for short circuit condition (which include 4 wires in a magnetic conduit) come out higher than my measured values, and those do not include the motor generator source. Put a large capacitor (mains voltage rated) across the mains and measure the voltage change; it may actually increase. You need about 50 uF to get a decent change on 120 V 60 Hz mains. With that result and the one with the resistive load, you can calculate the source impedance as an R and L in series. I'd be interested to learn the result. -- Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk Interested in professional sound reinforcement and distribution? Then go to http://www.isce.org.uk 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com 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: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Re: Question: Discharge capacitance 0.1 uF
I read in !emc-pstc that John Allen john.al...@era.co.uk wrote (in BFE68AB0084CD311B4FB00508B014C8703CF9BEE@MERCURY) about 'Question: Discharge capacitance 0.1 uF' on Thu, 19 Sep 2002: Now, maybe, the standards writing committees will begin to take this issue on board and do something about it Are you saying that the present requirements (e.g. in EN60065) are unsatisfactory? In what way? -- Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk Interested in professional sound reinforcement and distribution? Then go to http://www.isce.org.uk 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com 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: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Re: Medical equipment and EN61000-3-2
Patrick, I don't know whether or not hospital power systems fall within the scope of EN61000-3-2:2001. But in any case, compliance with EN61000-3- 2 is not required under the Medical Devices Directive. The only harmonized EMC standard under the MDD is EN 60601-1-2:1993, which does not have any harmonics requirements. Medical equipment is, of course, specifically exempted from the EMC Directive. Regards, Jon Griver http://www.601help.com The Medical Device Developers Guide to IEC 60601-1. On 18 Sep 2002 at 12:55, plaw...@west.net wrote: The scope of EN61000-3-2:2001 says that the standard deals with harmonic currents injected into the public low-voltage distribution system. I can see that residences and offices are connected to the public system. However, I don't know about distribution to hospitals. Are their power requirements specialized enough that their electricity is provided by a MV transformer? This would exempt hospital-only medical products from the harmonic current requirements. Or are their different levels of hospitals, some fed by LV transformers, some fed by MV transformers? Patrick Lawler plaw...@west.net --- 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com 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: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list --- 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com 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: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Pulse Dialing
Hello all, I am certain there are more than a few telecom gurus on this list. Maybe you can help me out. Our engineering team is looking for a spec that defines U.S pulse dialing. Any suggestions? Thanks for your help, Mat Aschenberg --- 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com 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: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
RE: Question: Discharge capacitance 0.1 uF
John - I respectfully disagree that the standards bodies need to do anything. It is the designers that must be aware of the advancements of technology (such as described by Gert) and update their practices accordingly. [Low ESR / High Q caps are a good thing.] While I have no doubt about the potential effects of reaction hazards (I've put two fingers across a circuit calibrated to deliver 3.5 mA at 120V line potential; the infamous Walter Skuggevig apparatus), the safety standards should not be prescriptive. Regards, Peter L. Tarver, PE Product Safety Manager Sanmina-SCI Homologation Services San Jose, CA peter.tar...@sanmina-sci.com -Original Message- From: John Allen Sent: Thursday, September 19, 2002 4:13 AM Gert Thanks for that investigation that I have not had the time for recently! Now, maybe, the standards writing committees will begin to take this issue on board and do something about it as the problem is generally technically trivial to solve - the major issue then being to ensure that the bleeder device is always across the capacitor, and is not isolated from it by a switch or contactor that the operator can put in the open position before disconnecting the supply. John Allen --- 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com 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: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
RE: EMC immunity requirements in Canada?
No. Richard Woods Sensormatic Electronics Tyco International -Original Message- From: am...@westin-emission.no [mailto:am...@westin-emission.no] Sent: Thursday, September 19, 2002 8:22 AM To: emc-p...@majordomo.ieee.org Subject: EMC immunity requirements in Canada? As far as I remember, US (FCC) do only have emission (radiated / conducted) requirements. What about Canada (IC) do they have immunity requirements in addition ? Best regards Amund Westin, Oslo/ NORWAY --- 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com 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: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
safety testing in the USA
Group, I am in discussions with a potential supplier of IT equipment, Its our usual policy to request testing to a listed standard such as UL 60950 for safety in North America. The supplier has replied that this is not mandatory. Is he correct? what compels safety testing for IT equipment in this geography? is it mandated by law? Thanks in advance for your opinions Rob - --- Visit our Internet site at http://www.reuters.com Any views expressed in this message are those of the individual sender, except where the sender specifically states them to be the views of Reuters Ltd. --- 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com 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: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
RE: Question: Discharge capacitance 0.1 uF
Hi Charles, Warren Seems that a few of us know what DOES happen and the longterm results, but quite a few others don't believe that it does - and that even it does then it is not very important. The difference between reality and theory! I suggest that the non-believers try it for themselves - by unplugging a suitable piece of equipment and picking it up - AND then touching the pins of the plug! (the unplugging process may need to be repeated a few times until the capacitor is disconnected when the mains is high at the time of disconnection and so gets a decent charge!) However before they do try it, I suggest they wear safety boots and also use a piece of equipment which can then be discarded due to the damage it received when it fell on the foot and/or the ground! Regards John Allen -Original Message- From: Grasso, Charles [mailto:charles.gra...@echostar.com] Sent: 18 September 2002 19:07 To: 'John Allen'; emc-p...@majordomo.ieee.org Subject: RE: Question: Discharge capacitance 0.1 uF Hi All, From personal experience I can tell you that the involuntary reaction to a shock can have serious consequences to the sales of a company. In a former life - a previous employer OEM'd a PC from a Korean Company. The PC had all the relevant marks but somehow the resistor that was supposed to bleed off the caps didn't make it into production. A customer , moving said model from one location to another, touched the mains terminals and felt a shock. The customer fell over, the PC landed on the customer, the customer sued and the story ended up in the papers. The sales of PCs essentially died after that. - All for the sake of one resistor. Best Regards Charles Grasso Senior Compliance Engineer Echostar Communications Corp. Tel: 303-706-5467 Fax: 303-799-6222 Cell: 303-204-2974 Email: charles.gra...@echostar.com; mailto:charles.gra...@echostar.com; %20 Email Alternate: chasgra...@ieee.org mailto:chasgra...@ieee.org -Original Message- From: John Allen [mailto:john.al...@era.co.uk] Sent: Wednesday, September 18, 2002 11:11 AM To: emc-p...@majordomo.ieee.org Subject: Question: Discharge capacitance 0.1 uF Hello Folks Tomonori Sato commented However, I think discharge from 0.1uF capacitor charged to the mains peak voltage can be quite uncomfortable. I believe that to be true from personal experience and from having to investigate the results of a number of such incidents, and so would remind member of a point that I made several years ago on this forum: The primary shock almost certainly will NOT hurt a person, but the involuntary reaction TO the shock may well have much more seriousconsequences. This type of shock is often encountered by people who pick up equipment which they have just unplugged from the AC mains in order to carry it elsewhere. If they then touch the pins of the plug there are numerous reported incidences of them involuntarily dropping the unit - and that can possibly be on their own feet - and from a height of about 3ft/1m! If the unit is more than a couple of pounds (about one kilo) then the injury to t! he feet can be substantial. Worse situations could occur in industrial equipment when a service engineer opens a cabinet to perform a service operation - the reaction from the shock could cause him to strike touch other hazardous electrical or mechanical parts (which probably should also not be there, I do agree!) which then cause him serious actual injury. These types of incident do not make the equipment supplier very popular to say the least, and could result in product liability claims. The main basis for the claims would be that the supplier had not adequately assessed the hazards and taken the appropriate simple precautions which are easily and cheaply available - fit a bleeder resistor across the capacitor, or use a filter with a resistor already built in (or with transformer/inductor windings directly across the capacitor - which achieve the same result) ! Again from personal experience I can say that it is a very embarassing and un! comfortable experience to have to write to an injured or anno! yed person, or to his employer, to say sorry, but that is what the safety standard allows. It is just not good business sense. Therefore, regardless of the requirements of the various standards and this argument over capacitor value and/or charging voltage, I firmly believe that the use of bleeder resistors should be considered effectively mandatory, and have always recommended it to engineers I have advised on product safety. Regards John Allen Technical Consultant Electromagnetics, Safety and Reliability Group ERA Technology Ltd Cleeve Rd Leatherhead Surrey KT22 7SA Tel: +44 (0) 1372-367025 (Direct) +44 (0) 1372-367000 (Switchboard) Fax: +44 (0) 1372-367102 (Fax) -- Replies to this message may be posted in the following public forum: Question:
Re: Measuring AC Line Impedance
In a message dated 9/19/2002, you write: So far, I've taken a large resistive load and measured the voltage drop on the AC line. From that I calculated the total impedance of the AC line. However, as you may suspect, with a resistive load, the power factor is 1.0. So I can't vectorly, calculate the resistive and inductive components. Hi Dave: I am not familiar with the specific measurement you are trying to make, so the following may not be applicable to your situation. However, some of the basic concepts may be useful. In the telecom business it is sometimes necessary to know the complex impedance presented by a 2-wire port. In theory, if you drive the port with a voltage source applied through a known resistance, you can calculate the complex impedance of the port based on measurements of the following two things: 1) The voltage drop across the source resistor 2) The phase of the current through the resistor, relative to the phase of the source I designed a simple fixture to measure the voltage and phase, then derived the necessary equations and created a spreadsheet to calculate the complex impedance. Soon after completing my measurements this way, I got a good price on a used test instrument that makes this measurement directly. I was very pleased to find that the values measured by the test instrument matched my calculated values almost exactly. This gave me good confidence in my earlier test method, even though I no longer need to use it. It might be possible for you to adapt this method for the test you want to make. If so, I would be happy to send you a copy of the equations and a copy of the spreadsheet I used. Since this was developed internally for my own use, the notes are a little sketchy, but I think I could fill in the gaps with a telephone conversation. While I am not familiar with the details of the test you are trying to perform, I can see that one possible complication would occur if the test is supposed to be performed under a specified load condition. In that case, you would have to find a way to ensure that the AC impedance of your load does not affect the measured impedance of the mains. I think there are ways to accomplish this either with a test fixture or by making the spreadsheet calculations take the load impedance into account. Joe Randolph Telecom Design Consultant Randolph Telecom, Inc. 781-721-2848 http://www.randolph-telecom.com
Re: EMC immunity requirements in Canada?
Amund: Industry Canada does not have immunity requirements for Class A/B products. Regards Kevin Keegan KES Associates Ottawa Canada - Original Message - From: am...@westin-emission.no To: emc-p...@majordomo.ieee.org Sent: Thursday, September 19, 2002 8:22 AM Subject: EMC immunity requirements in Canada? As far as I remember, US (FCC) do only have emission (radiated / conducted) requirements. What about Canada (IC) do they have immunity requirements in addition ? Best regards Amund Westin, Oslo/ NORWAY --- 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com 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: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list --- 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com 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: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Re: Radiated Immunity Testing
Be careful about using the antenna factor. The published antenna factor is a receive antenna factor, and for what you are trying to do you need the transmit antenna factor. You can calculate one from the other if you know the frequency, but they are not identical. I can provide that derivation. You should also know how the antenna factor was measured - if any attenuation was used to reduce vswr. Usually antennas will have vswr specified separately from antenna factor, which leads me to believe that quite a bit of attenuation is used to remove that source of error. Likely someone on this forum has direct experience calibrating antennas. All the factors you mentioned you can measure or get from a spec sheet, except chamber effects. I though the whole point of the chamber was to be anechoic enough to allow for that quiet zone calibration. That would mean to me there are no chamber effects. -- From: richwo...@tycoint.com To: emc-p...@majordomo.ieee.org Subject: Radiated Immunity Testing Date: Thu, Sep 19, 2002, 7:11 AM Using the antenna factor of a particular antenna, one can compute the theoretical power required to create a specified E-field at a specified distance. Without over specifying the power amplifier (assume Class A), what minimum safety factor should be added to the theoretical values to account for impedance mismatches, cable loss, directional coupler loss, compact anechoic chamber effects (3 m) including loading of the antenna, the allowed 6 dB field variation and any other effects. Richard Woods Sensormatic Electronics Tyco International --- 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com 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: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list --- 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com 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: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
EMC immunity requirements in Canada?
As far as I remember, US (FCC) do only have emission (radiated / conducted) requirements. What about Canada (IC) do they have immunity requirements in addition ? Best regards Amund Westin, Oslo/ NORWAY --- 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com 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: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Radiated Immunity Testing
Using the antenna factor of a particular antenna, one can compute the theoretical power required to create a specified E-field at a specified distance. Without over specifying the power amplifier (assume Class A), what minimum safety factor should be added to the theoretical values to account for impedance mismatches, cable loss, directional coupler loss, compact anechoic chamber effects (3 m) including loading of the antenna, the allowed 6 dB field variation and any other effects. Richard Woods Sensormatic Electronics Tyco International --- 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com 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: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Measuring AC Line Impedance
I'm trying to characterize the 50Hz AC line impedance of my facility, for comparison to the values specified in IEC61000-3-3. I've come across generic short circuit values for the Resistive and Inductive components. However, I need to determine exactly what these values are ideally through a combination of measurement and calculation. So far, I've taken a large resistive load and measured the voltage drop on the AC line. From that I calculated the total impedance of the AC line. However, as you may suspect, with a resistive load, the power factor is 1.0. So I can't vectorly, calculate the resistive and inductive components. Is anyone familiar with a method to measure and calculate those values. The generic values I have for short circuit condition (which include 4 wires in a magnetic conduit) come out higher than my measured values, and those do not include the motor generator source. Thanks for any information David Spencer Xerox Corporation --- 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com 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: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
RE: Question: Discharge capacitance 0.1 uF
Gert Thanks for that investigation that I have not had the time for recently! Now, maybe, the standards writing committees will begin to take this issue on board and do something about it as the problem is generally technically trivial to solve - the major issue then being to ensure that the bleeder device is always across the capacitor, and is not isolated from it by a switch or contactor that the operator can put in the open position before disconnecting the supply. (The latter point can particularly apply to some filtered IEC, or similar, power inlets with integral switches where the bleeder could be on the opposite side of the contacts to the capacitor). John Allen Technical Consultant Electromagnetics, Safety and Reliability Group ERA Technology Ltd Cleeve Rd Leatherhead Surrey KT22 7SA Tel: +44 (0) 1372-367025 (Direct) +44 (0) 1372-367000 (Switchboard) Fax: +44 (0) 1372-367102 (Fax) -Original Message- From: Gert Gremmen [mailto:g.grem...@cetest.nl] Sent: 19 September 2002 11:57 To: John Allen Cc: emc-p...@majordomo.ieee.org Subject: RE: Question: Discharge capacitance 0.1 uF Hi John, Even theory has to comply with practice, so i took my soldering iron... I have to admit that modern capacitors do keep their charge too long. I did some test with newer Y and X caps of 0.1 uF and they keep their charge way too long - over 1 minute - without notable loss of voltage ( 10%) (real life voltages choosen :310V) Probably the quality of the dielectricum has been improved, or the use of paper has been abandoned in favor of modern equivalent plastics. (any one knows ?). Of course the increased leakage of the older caps was not meant to be part of the specs, and this is again a good example of how relying on hidden specifications may in time lead to undesired results: standards ignoring the effect of increased leakage resistance. I also tried the discharge between two fingers, and found the result to be unpleasant at least. Time to change standards... Gert Gremmen ce-test, qualified testing -Original Message- From: owner-emc-p...@majordomo.ieee.org [mailto:owner-emc-p...@majordomo.ieee.org]On Behalf Of John Allen Sent: Thursday, September 19, 2002 9:24 AM To: 'Grasso, Charles'; 'Warren Birmingham' Cc: emc-p...@majordomo.ieee.org Subject: RE: Question: Discharge capacitance 0.1 uF Hi Charles, Warren Seems that a few of us know what DOES happen and the longterm results, but quite a few others don't believe that it does - and that even it does then it is not very important. The difference between reality and theory! I suggest that the non-believers try it for themselves - by unplugging a suitable piece of equipment and picking it up - AND then touching the pins of the plug! (the unplugging process may need to be repeated a few times until the capacitor is disconnected when the mains is high at the time of disconnection and so gets a decent charge!) However before they do try it, I suggest they wear safety boots and also use a piece of equipment which can then be discarded due to the damage it received when it fell on the foot and/or the ground! Regards John Allen -Original Message- From: Grasso, Charles [mailto:charles.gra...@echostar.com] Sent: 18 September 2002 19:07 To: 'John Allen'; emc-p...@majordomo.ieee.org Subject: RE: Question: Discharge capacitance 0.1 uF Hi All, From personal experience I can tell you that the involuntary reaction to a shock can have serious consequences to the sales of a company. In a former life - a previous employer OEM'd a PC from a Korean Company. The PC had all the relevant marks but somehow the resistor that was supposed to bleed off the caps didn't make it into production. A customer , moving said model from one location to another, touched the mains terminals and felt a shock. The customer fell over, the PC landed on the customer, the customer sued and the story ended up in the papers. The sales of PCs essentially died after that. - All for the sake of one resistor. Best Regards Charles Grasso Senior Compliance Engineer Echostar Communications Corp. Tel: 303-706-5467 Fax: 303-799-6222 Cell: 303-204-2974 Email: charles.gra...@echostar.com; mailto:charles.gra...@echostar.com; %20 Email Alternate: chasgra...@ieee.org mailto:chasgra...@ieee.org -Original Message- From: John Allen [mailto:john.al...@era.co.uk] Sent: Wednesday, September 18, 2002 11:11 AM To: emc-p...@majordomo.ieee.org Subject: Question: Discharge capacitance 0.1 uF Hello Folks Tomonori Sato commented However, I think discharge from 0.1uF capacitor charged to the mains peak voltage can be quite uncomfortable. I believe that to be true from personal experience and from having to investigate the results of a number of such incidents, and so would remind member of a point that I made several years ago on this forum: The primary shock almost certainly will NOT hurt a person, but the involuntary reaction TO the shock
Re: EN60065 mains switches
I read in !emc-pstc that Colgan, Chris chris.col...@tagmclaren.com wrote (in AE0F4BD08FEAD211895900805FE67B1F01425A8B@CAT) about 'EN60065 mains switches' on Thu, 19 Sep 2002: I'm all for using the 7th edition but it is not mentioned in the LVD List of Harmonised Standards yet. Any idea when it will be? No, but I would have expected to have heard already if there was any hold-up on technical grounds. It has happened before that notification has been delayed simply due to a backlog in the Commission's administration. They shut down for August, I believe. -- Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk Interested in professional sound reinforcement and distribution? Then go to http://www.isce.org.uk 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com 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: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Re: CE Marking for Passive speakers
I read in !emc-pstc that Gordon,Ian ian.gor...@edwards.boc.com wrote (in E1BA0362B28ED211A1E80008C71EA306018190AE@EXC_EAS01) about 'CE Marking for Passive speakers' on Thu, 19 Sep 2002: By the wider issue I was referring to your assertion that The EMC Guidelines document explains that having no active components is NOT grounds for exemption from the EMC Directive. If this were the case then it would have far reaching implications for many industries since all Electromagnetically Benign equipment might require testing. Furthermore I imagine this would have legal implications for the UK Government appointed Competent Body which advised my company that benign equipment is exempt. This Competent Body helped us compile a list of products within our range to which this exclusion applied. 'Benign' is NOT the same as 'passive', which is what was asserted. A torch/flashlight with an incandescent lamp is benign, because it is inconceivable that it would either emit anything or suffer from lack of immunity. But even just a *junction box* for high-speed data cable can both emit stuff and let external disturbances into the cabling. I showed how a loudspeaker can both emit and be disturbed by and external emission. -- Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk Interested in professional sound reinforcement and distribution? Then go to http://www.isce.org.uk 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com 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: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
RE: Question: Discharge capacitance 0.1 uF
Hi John, Even theory has to comply with practice, so i took my soldering iron... I have to admit that modern capacitors do keep their charge too long. I did some test with newer Y and X caps of 0.1 uF and they keep their charge way too long - over 1 minute - without notable loss of voltage ( 10%) (real life voltages choosen :310V) Probably the quality of the dielectricum has been improved, or the use of paper has been abandoned in favor of modern equivalent plastics. (any one knows ?). Of course the increased leakage of the older caps was not meant to be part of the specs, and this is again a good example of how relying on hidden specifications may in time lead to undesired results: standards ignoring the effect of increased leakage resistance. I also tried the discharge between two fingers, and found the result to be unpleasant at least. Time to change standards... Gert Gremmen ce-test, qualified testing -Original Message- From: owner-emc-p...@majordomo.ieee.org [mailto:owner-emc-p...@majordomo.ieee.org]On Behalf Of John Allen Sent: Thursday, September 19, 2002 9:24 AM To: 'Grasso, Charles'; 'Warren Birmingham' Cc: emc-p...@majordomo.ieee.org Subject: RE: Question: Discharge capacitance 0.1 uF Hi Charles, Warren Seems that a few of us know what DOES happen and the longterm results, but quite a few others don't believe that it does - and that even it does then it is not very important. The difference between reality and theory! I suggest that the non-believers try it for themselves - by unplugging a suitable piece of equipment and picking it up - AND then touching the pins of the plug! (the unplugging process may need to be repeated a few times until the capacitor is disconnected when the mains is high at the time of disconnection and so gets a decent charge!) However before they do try it, I suggest they wear safety boots and also use a piece of equipment which can then be discarded due to the damage it received when it fell on the foot and/or the ground! Regards John Allen -Original Message- From: Grasso, Charles [mailto:charles.gra...@echostar.com] Sent: 18 September 2002 19:07 To: 'John Allen'; emc-p...@majordomo.ieee.org Subject: RE: Question: Discharge capacitance 0.1 uF Hi All, From personal experience I can tell you that the involuntary reaction to a shock can have serious consequences to the sales of a company. In a former life - a previous employer OEM'd a PC from a Korean Company. The PC had all the relevant marks but somehow the resistor that was supposed to bleed off the caps didn't make it into production. A customer , moving said model from one location to another, touched the mains terminals and felt a shock. The customer fell over, the PC landed on the customer, the customer sued and the story ended up in the papers. The sales of PCs essentially died after that. - All for the sake of one resistor. Best Regards Charles Grasso Senior Compliance Engineer Echostar Communications Corp. Tel: 303-706-5467 Fax: 303-799-6222 Cell: 303-204-2974 Email: charles.gra...@echostar.com; Email Alternate: chasgra...@ieee.org -Original Message- From: John Allen [mailto:john.al...@era.co.uk] Sent: Wednesday, September 18, 2002 11:11 AM To: emc-p...@majordomo.ieee.org Subject: Question: Discharge capacitance 0.1 uF Hello Folks Tomonori Sato commented However, I think discharge from 0.1uF capacitor charged to the mains peak voltage can be quite uncomfortable. I believe that to be true from personal experience and from having to investigate the results of a number of such incidents, and so would remind member of a point that I made several years ago on this forum: The primary shock almost certainly will NOT hurt a person, but the involuntary reaction TO the shock may well have much more seriousconsequences. This type of shock is often encountered by people who pick up equipment which they have just unplugged from the AC mains in order to carry it elsewhere. If they then touch the pins of the plug there are numerous reported incidences of them involuntarily dropping the unit - and that can possibly be on their own feet - and from a height of about 3ft/1m! If the unit is more than a couple of pounds (about one kilo) then the injury to t! he feet can be substantial. Worse situations could occur in industrial equipment when a service engineer opens a cabinet to perform a service operation - the reaction from the shock could cause him to strike touch other hazardous electrical or mechanical parts (which probably should also not be there, I do agree!) which then cause him serious actual injury. These types of incident do not make the equipment supplier very popular to say the least, and could result in product liability claims. The main basis for the claims would be that the supplier had not
RE: EN60065 mains switches
I'm all for using the 7th edition but it is not mentioned in the LVD List of Harmonised Standards yet. Any idea when it will be? Cheers Chris -Original Message- From: John Woodgate [SMTP:j...@jmwa.demon.co.uk] Sent: Wednesday, September 18, 2002 9:47 PM To: emc-p...@majordomo.ieee.org Subject: Re: EN60065 mains switches I read in !emc-pstc that Colgan, Chris chris.col...@tagmclaren.com wrote (in AE0F4BD08FEAD211895900805FE67B1F01425A89@CAT) about 'EN60065 mains switches' on Wed, 18 Sep 2002: I know that engineers familiar with EN60065 are rarer than hen's teeth but maybe someone out there can help me... Clause 14.6.2 allows for no mains switch to be fitted if the product can be switched on or off or both automatically. Do you think that an audio amplifier that utilises an input signal detect circuit to automatically switch on fulfils the requirements of this clause? You should be looking at the 2002 edition, in which 14.6.2 is not about that. This 14.6 gets re-hashed in every edition, so you must use the up- to-date edition. In this case, the relevant text is in 8.9.1! An all- pole disconnect device is required, but it can be the mains plug or appliance coupler. So your audio amplifier is quite OK - to the 2002 edition. Do you *really* want to know about how it would fare under the previous edition? (;-) -- Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk Interested in professional sound reinforcement and distribution? Then go to http://www.isce.org.uk 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com 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: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list ** Please visit us at www.tagmclaren.com ** The contents of this E-mail are confidential and for the exclusive use of the intended recipient. If you receive this E-mail in error, please delete it from your system immediately and notify us either by E-mail, telephone or fax. You should not copy, forward or otherwise disclose the content of the E-mail. Important Note: Any typographical, clerical or other error in this communication is subject to correction without any liability on the part of TAG McLaren Audio Limited. Any orders placed shall be subject to acceptance by TAG McLaren Audio Limited on its standard terms and conditions of sale which shall govern the contract for the sale and purchase of the products ordered to the exclusion of any other terms and conditions. TAG McLaren Audio Ltd The Summit, 11 Latham Road Huntingdon, Cambs, PE29 6ZU Telephone : 01480 415600 (+44 1480 415600) Facsimile : 01480 52159 (+44 1480 52159) ** Please visit us at www.tagmclaren.com ** --- 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: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com 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: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
