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 >
