Richard, This power system is denoted as a 3-phase delta high leg. It is an older distribution system and is derived from a 240 vac, 3-phase delta, 3W+G. Basically, what they have done is center tapped one of the 240 volt windings and anchored that to ground. This gives 120/240 for standard equipment, but also gives 3-phase 240 vac for industrial machines. It is very common in older systems in the Northeastern US.
If you have any questions, please let me know. Thanks, Bryan. From: Richard Meyette To: [email protected] Sent: 6/5/03 7:51 PM Subject: 3-Phase Power Question Here's a question for the power engineers in the group. I measured the following phase voltages for the 3-phase power lines feeding a breaker box: phase to phase (all three phases) = 240V phase to neutral (2 of 3 phases) = 120V phase to neutral (1 of 3 phases) = 208V Normally you would expect the phase to phase voltages to measure 208V and the phase to neutral voltages to measure 120V for a Y-connected transformer. What kind of power transformer configuration would provide these phase voltages? Thanks in advance to anyone who can shed some light on this, Richard Meyette [email protected] 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: Ron Pickard: [email protected] Dave Heald: [email protected] For policy questions, send mail to: Richard Nute: [email protected] Jim Bacher: [email protected] Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc 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: Ron Pickard: [email protected] Dave Heald: [email protected] For policy questions, send mail to: Richard Nute: [email protected] Jim Bacher: [email protected] Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
