A resend of a response I mailed yesterday that didn't echo out yet.
> ---------- > From: Tarver, Peter > Sent: Tuesday, February 24, 1998 1:19 PM > To: emc-pstc Discussion Group > Subject: Delta transformer grounding (was: RE: GFCI in IT (three > phase) Networks) > > Doug - > > Delta-delta transformers are popular with the utilities for economy's > sake (they are less expensive than WYE transformers) For similar > reasons, some industrial applications distribute and use power within > their plants on delta feeds. > > In office environments, however, it's typical to use a WYE connected > secondary, i.e., 120Y/208V, for general appliance use and other WYE > connected configurations for lighting and other power. > > When a delta transformer is grounded, it typically occurs at either a > "corner", where two secondaries are electrically connected, or > "center-grounded" at the center of one of the secondaries. It is my > understanding that the latter case is typical for power provided to > homes in the US and is also referred to as "split-phase." > > Regards, > > Peter L. Tarver > Nortel > [email protected] > > ---------- > From: Doug McKean[SMTP:[email protected]] > Sent: Tuesday, February 24, 1998 11:11 AM > > As a result of this very interesting discussion, > I have to ask this embarrassingly simple questions. > > If delta configurations are the most common in the US > (I'm assuming this) for polyphase systems, > where does "ground" get connected? > > If the delta is basically NOT referenced to ground, > how then do GFCIs operate? > > Are the transformers of a delta centertapped for 120vac? > > Sorry for these simple questions, I'm not a power guy. > Only school info from long ago. > > Regards, Doug > >
