Ghery - He is correct. There are DELTA configured transformers with one phase earthed in the US. This is referred to as "corner grounded."
Refer to http://saskpower.apogee.net/foe/ftdttd.asp for a brief on the applications. The site is incomplete (overall), but has some useful information. Regards, Peter L. Tarver, PE Product Safety Manager Sanmina-SCI Homologation Services [email protected] -----Original Message----- From: [email protected] [mailto:[email protected]]On Behalf Of Pettit, Ghery Sent: Monday, December 17, 2001 8:01 AM To: '[email protected]'; Crabb, John; 'Bill Lawrence'; 'EMC-PSTC Forum' Subject: RE: Three phase delta system in USA Horst, Not correct. From past experience, the 480 VAC 60 Hz delta system runs with all three phases floating. This is also done on ships so that a fault to ground on a single phase does not disrupt the system. Ghery Pettit Intel -----Original Message----- From: [email protected] [mailto:[email protected]] Sent: Monday, December 17, 2001 6:05 AM To: Crabb, John; 'Bill Lawrence'; 'EMC-PSTC Forum' Subject: Three phase delta system in USA I also learned, that there is a three-phase delta system in USA with 500 Vac per phase. One phase (L3) is earthed. Is this system very often used in USA? Is it correct information, that L3 is always earthed and not L1 or L2. Horst Haug -----Ursprüngliche Nachricht----- Von: [email protected] [mailto:[email protected]]Im Auftrag von Crabb, John Gesendet: Montag, 17. Dezember 2001 11:28 An: 'Bill Lawrence'; 'EMC-PSTC Forum' Betreff: RE: 2 Phases in North America Bill - you absolutely correct in describing the North American system as "single-phase, 3 wire". After all, that is how it is described in Annex V, Figure V.4 of IEC60950:1999 - and there is NO WAY that IEC TC74 could be wrong, is there ? (especially since the US committee must have voted yes, to include this change, the purpose of which was to educate those of us who weren't too clear on the subject). Fortunately I am on holiday (vacation) from tonight until January 3, so to all our readers, best wishes for the Christmas season, and a happy and prosperous 2002. John Crabb, Development Excellence (Product Safety) , NCR Financial Solutions Group Ltd., Kingsway West, Dundee, Scotland. DD2 3XX E-Mail :[email protected] Tel: +44 (0)1382-592289 (direct ). Fax +44 (0)1382-622243. VoicePlus 6-341-2289. -----Original Message----- From: Bill Lawrence [mailto:[email protected]] Sent: 14 December 2001 22:33 To: 'Wagner, John P (John)'; 'Robert Johnson'; 'Cortland Richmond' Cc: 'Barry Esmore'; 'EMC-PSTC Forum' Subject: RE: 2 Phases in North America Two Phase / 5 Wire (4 "hots" and a neutral) was a common power distribution in US cities in the early part of this century. Many early motors are "2-phase" motors. I learned about this when helping with connection of these motors to run on a 3 phase power system via a special "Scott-T" transformer connection. The correct designation for the 120/240 power system described is "Single Phase / 3 Wire". Bill Lawrence ------------------------------------------- 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: [email protected] with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson: [email protected] Dave Heald [email protected] For policy questions, send mail to: Richard Nute: [email protected] Jim Bacher: [email protected] 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.
