I have some questions which are just for my own education. I understand Mr. Woodgate's comments and they make sense to me. But I wonder why there is a problem in the first place. I believe all power in Europe is at 200 Volts or higher, which makes an 800 Watt heater a four Amp device. I don't believe inrush on a heater is greatly in excess of steady-state current, therefore the mechanism is switching a four Amp load on and off every few minutes. Why is this a problem requiring specification control in the first place?
---------- >From: "Leszek Langiewicz" <leszek_langiew...@phogenix.com> >To: <emc-p...@majordomo.ieee.org> >Subject: EN 61000-3-3 compliant heater controller >Date: Mon, Jan 21, 2002, 12:01 PM > > > Dear list-members, > > Would anybody know of the shelf controller design to meet EN61000-3-3 > for 500W heater. > Thanks in advance for your support. > > > Best Regards, > Leszek M. Langiewicz > Homologation / Power Distribution > Phogenix Imaging, LLC > A joint venture of Kodak and HP > Phogenix Imaging LLC 16275 Technology Dr. San Diego, CA 92127-1815 > www.phogenix.com > Phone: (858) 798-8004 Cell: (858) 722-8004 Fax: (858) 798-8113 > E-mail: leszek_langiew...@phogenix.com > > -----Original Message----- > From: John Woodgate [mailto:j...@jmwa.demon.co.uk] > Sent: Sunday, January 20, 2002 6:30 AM > To: emc-p...@majordomo.ieee.org > Subject: Re: Corrective Actions for EN 61000-3-3 Plt; Pst > Failures > > > I read in !emc-pstc that IEEE-EMC User Group <ieee-...@itl.co.il> wrote > (in <2D1037012914D4118DB8204C4F4F5020275AB4@ITLLTD01>) about 'Corrective > Actions for EN 61000-3-3 Plt; Pst Failures', on Sun, 20 Jan 2002: >>A product (800W input power) having a heating element that is > controlled by >>ON/OFF action (1-2 sec. interval) of a thermostat failed the subject >>requirements due to large input current variation resulting from the > above >>action. > > It's unusual to have such a powerful heater in a product with such a low > thermal inertia that the thermostat cycle is as short as 1 to 2 s. > >>What will be a practical corrective action in this case? > > To answer properly, more details about the product would be required. It > might be possible to split the heating element into two parts, not > necessarily of equal powers, and to have one permanently on (apart from > an over-temperature cut-out) while the other one is switched in and out > by the thermostat. The cycle time should then become much longer, and > the 'dmax' value is reduced. > > Another solution is to use the electronic control method known as 'burst > firing', in which the thermostat switches on a control circuit that > sends trains of complete cycles of the supply current to the heater. > With different designs, the switching of the load is either very fast > (e.g. 5-cycle bursts of current, lasting 100 ms on 50 Hz mains) or very > slow. In either case, the Pst value is low. > -- > Regards, John Woodgate, OOO - Own Opinions Only. > http://www.jmwa.demon.co.uk > After swimming across the Hellespont, I felt like a Hero. > > ------------------------------------------- > This message is from the IEEE EMC Society Product Safety > Technical Committee emc-pstc discussion list. > > Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ > > To cancel your subscription, send mail to: > majord...@ieee.org > with the single line: > unsubscribe emc-pstc > > For help, send mail to the list administrators: > Michael Garretson: pstc_ad...@garretson.org > Dave 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. > ------------------------------------------- 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.
