So rather than educating the public on the cause of flicker, we get saddled with a useless design requirement. Typical bureaucracy - don't fix the problem, make it LOOK like you're doing something, at someone else's expense. Just like the harmonics standard - fix a problem that doesn't exist.
Ghery Pettit Opinions expressed are my own and may not necessarily reflect those of my employer... -----Original Message----- From: John Woodgate [mailto:j...@jmwa.demon.co.uk] Sent: Monday, January 21, 2002 2:28 PM To: emc-p...@majordomo.ieee.org Subject: Re: EN 61000-3-3 compliant heater controller I read in !emc-pstc that Ken Javor <ken.ja...@emccompliance.com> wrote (in <20020121193650.LDSV11289.femail7.sdc1.sfba.home.com@[65.11.150.27]> ) about 'EN 61000-3-3 compliant heater controller', on Mon, 21 Jan 2002: >I have some questions which are just for my own education. I understand Mr. >Woodgate's comments and they make sense to me. But I wonder why there is a >problem in the first place. I assumed that the lack of compliance was certain, because I have no up- front evidence to sustain a doubt. > I believe all power in Europe is at 200 Volts >or higher, which makes an 800 Watt heater a four Amp device. I don't >believe inrush on a heater is greatly in excess of steady-state current, Suppose, just as an example, it's an 800 W IR lamp, used as a heater? >therefore the mechanism is switching a four Amp load on and off every few >minutes. Why is this a problem requiring specification control in the first >place? Because lamp flicker is a disturbance that worries people and they often complain to the electricity suppliers. Some elderly people get very worried about the supply breaking down or causing a fire. The reference single-phase supply impedance used for IEC/EN61000-3-3 is 0.47 ohms (actually 0.4 + j0.25 ohms). So switching a 4 A load causes a dmax (maximum relative voltage drop, based on 230 V) of 0.8%. That is not likely to result in a Pst or Plt failure to comply, so there IS something we don't know - maybe a high inrush current or a faulty measurement. -- Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk After swimming across the Hellespont, I felt like a Hero. PLEASE do NOT copy news posts to me by E-MAIL! ------------------------------------------- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson: pstc_ad...@garretson.org Dave Heald davehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server. ------------------------------------------- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson: pstc_ad...@garretson.org Dave Heald davehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
