Right. And each phase is 277V. Now take three phases, 120 degrees
(electrical degrees) out of phase, and connect them in a 'Y' with a common
neutral. If you then measure the voltage between any two terminals (other
than neutral), you'd get 480V. In other words, you're measuring the voltage
between any two phases. Or am I misunderstanding you here?

> -----Original Message-----
> From: Ned Seith [mailto:ned@NEDTRON.COM]
> Sent: Friday, July 27, 2001 2:11 PM
> To: PICLIST@MITVMA.MIT.EDU
> Subject: Re: [EE]: Transformerless PSU
>
>
> Phil,
>
> The 277 Vac is taken from 3 phase transformers and used to power
> fluorescent lights in extremely large facilities such as
> airports, high
> rise buildings, sports arenas, etc. Most extremely large
> facilities have a
> 277 volt bus that powers the entire facilities lighting. The 277 volt
> scheme presents a tremendous cost savings as individual lamp
> ballasts are
> not required. Other benefits include centralized power factor
> control and
> other power saving controls. LSI Lighting / Prescolite of San Leandro,
> California, USA is the world leader in 277 V bus power
> control technology.
>
> Sincerely,
> Ned Seith
> Nedtronics
> 59 3rd Street
> Gilroy, CA 95020
> (408) 842-0858
> G O T    G A R L I C ?
> GILROY GARLIC FESTIVAL 2001 STARTS TODAY!
>  >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
> At 10:59 AM 7/27/01 -0500, you wrote:
> >sounds like the phase voltage of a three-phase 480V
> Y-connected supply....
> >
> >
> > > -----Original Message-----
> > > From: Douglas Butler [mailto:dbutler@IMETRIX.COM]
> > > Sent: Friday, July 27, 2001 11:50 AM
> > > To: PICLIST@MITVMA.MIT.EDU
> > > Subject: Re: [EE]: Transformerless PSU
> > >
> > >
> > > > malfunctioning solid state controllers that provided 120
> > > Vac to "Exit
> > > > Lamps" from a 277 Vac main in all the international airports
> > > > throughout the
> > > > free world! Prior to this project, I didn't know that
> the typical
> > > > international airport has 2,000 "Exit Lamps".
> > >
> > > What an odd voltage!  I design stuff for seaports all over
> > > the world but
> > > I have never run into 277Vac.  Is this some derivative of airplane
> > > wiring?
> > >
> > > Sherpa Doug
> > >
> > > --
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> >
> >
>
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