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A graphical representation of a delta high-leg is shown in figure 12-12 of the following document: http://www.mikeholt.com/instructor2/img/product/pdf/1038325200sample.pdf Best regards, Ron Wellman At 06:44 AM 7/26/2004, Robert Johnson wrote: >http://www.ieee-pses.org/symposium > http://www.emc2004.org/ >-------------------------------------------------- > >The world power description tables (see http://www.safetylink.com/)are not >much help on three phase. > >What you describe sounds like a three phase center grounded delta supply. >Belize standard voltages are 100/220V 60 Hz. I'll assume 120/240V for your >case. >That means a center tap on one leg of the delta is grounded. This provides >120v from neutral to phase A and 120 volt neutral to phase B, with 240V >phase A to B (conventional household supplies) >The third phase, C, is 240 volts from A or B and 208 volts from neutral >(thus the term high line). Often the supply is done with only two >transformers, omitting a supply transformer for phase A-C to save costs but >with reduced power and slightly less balanced phase voltages (you can ignore >that fact). >This means you actually have a 240 volt three phase supply, not a 208 volt >one. >Let's see if I can draw a crude text vector diagram. > C > /|\ > / | \ > / | \ > / | \ > / | \ > / | \ > 240 208 240 > / | \ > / | \ > A---120---N---120---B > -------240-------- >Keep in mind, the info you provided is not near enough to assure a match >with what I described above. > >In any case, if you have three phases 240 volts apart, you can simply >connect delta loads wired for 240 without much worry. Likewise for 208 >volts. > >Bob Johnson >ITE Safety > >-----Original Message----- >From: [email protected] >[mailto:[email protected]] On Behalf Of John McAuley >Sent: Monday, July 26, 2004 6:45 AM >To: EMC-PSTC (E-mail) >Subject: Three Phase Power in Belize > >http://www.ieee-pses.org/symposium > http://www.emc2004.org/ >-------------------------------------------------- > >Dear Group > >A friend of mine is doing development/charity work in Belize and is trying >to hook up some old lathes, milling machines etc of European origin to their >supply. He has limited electrical knowledge being from a mechanical >background. He tells me that the supply is "high line". Apparently this >means that they have two phases at 120 V and a third line at 208 V!! >Apparently there are 3 phase machines already running on this supply. He has >measured the phase voltages and has confirmed the levels. The machines were >rewired for a 120V/208V system. > >Is anyone familiar with this connection system? Is there a voltage offset on >the neutral? I can't find reference to it on the internet. I would like to >be in a position to teach him how the identify the phase voltages so that he >can connect up the machines without generating any more smoke. > >Many Thanks > >John McAuley > >------------------------------------------- > >This message is from the IEEE Product Safety Engineering Society >emc-pstc discussion list. > >IEEE PSES Main Website: http://www.ieee-pses.org/ > >To post a message send your e-mail to [email protected] > >Instructions for use of the list server: > > http://listserv.ieee.org/listserv/request/user-guide.html > >List rules: http://www.ieee-pses.org/listrules.html > >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] > >All emc-pstc postings are archived and searchable on the web at: > > http://www.ieeecommunities.org/emc-pstc > >------------------------------------------- > >This message is from the IEEE Product Safety Engineering Society >emc-pstc discussion list. > >IEEE PSES Main Website: http://www.ieee-pses.org/ > >To post a message send your e-mail to [email protected] > >Instructions for use of the list server: > > http://listserv.ieee.org/listserv/request/user-guide.html > >List rules: http://www.ieee-pses.org/listrules.html > >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] > >All emc-pstc postings are archived and searchable on the web at: > > http://www.ieeecommunities.org/emc-pstc This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. IEEE PSES Main Website: http://www.ieee-pses.org/ To post a message send your e-mail to [email protected] Instructions for use of the list server: http://listserv.ieee.org/listserv/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html 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] All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
