Just out of curiosity, where does the designation "220V come from? If you measure the potential difference between two phases of a three-phase system, you get 208V. If you measure the difference between the two phases in a residential or light commercial area, you would probably get 240V.
So, where does the term "220V" come from? Thanks, Max Kelson Evans & Sutherland -----Original Message----- From: Brian Harlowe [mailto:brian.harl...@vgscientific.com] Sent: Thursday, May 03, 2001 1:48 AM To: 'emc-p...@ieee.org' Subject: RE: AC Power Primer? Hi everybody Just to add a little more fuel to the flames! We supplied an Instrument to a well known semiconductor Manufacturer in Oregon which was powered from two 220 volt phases. I marked the rating plate as 220 volt one phase as has been suggested. However the local inspector made us change it to 220 volt two phase. So what is the correct definition. Brian Harlowe Thermo V.G. Scientific Tel +44 (0)1342 327211 Fax +44 (0)1342 315074 > -----Original Message----- > From: rbus...@es.com > Sent: 02 May 2001 21:31 > To: emc-p...@majordomo.ieee.org > Subject: AC Power Primer? > > > I am in the process of assisting our publications group with documenting > an > ac power configuration. As simple as this sounds, it turns out there are > varying opinions in our engineering group regarding the naming convention > for input power, in particular single phase verses two phase. > > We all probably agree that a phase to neutral connection is single phase > and > devices that use all thee phases, whether they are 208V 60Hz or 400V 50Hz, > are truly three phase. The discussion heats up when you are talking about > a > phase to phase connection on a three phase distribution (208 or 400V). Is > this called single phase or two phase? It has been suggested that in the > European community it is called two phase, while in the U.S. we call it > single phase. I am looking for opinions or discussion on this issue. > > On a related note in the U.S. we have 240V 60Hz (two 120V drops) coming > into > our into our homes. This is provided by a transformer with a center taped > winding. On the outside legs of the transformer we have 240V but between > either outside leg and neutral (center tap) we have 120V. I would call > this > a single phase system with two additive (in phase) 120V windings. Again > others have called this two phase. > > My apologies to the group if this is a stupid question. Its just one of > those nagging questions. > > Rick Busche > Evans & Sutherland > Salt Lake City, Utah > > rbus...@es.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: > 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: > http://www.rcic.com/ click on "Virtual Conference Hall," ------------------------------------------- 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: http://www.rcic.com/ click on "Virtual Conference Hall," ------------------------------------------- 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: http://www.rcic.com/ click on "Virtual Conference Hall,"