Re: 3 phase power (was Re: Wireless home LAN - WiFi vs Bluetooth?

[Doug McGarrett <dmcgarrett@optonline.net>]

On 07/31/2019 09:08 PM, rhkramer@gmail.com wrote:
> An update | correction | recollection ;-)
>
> On Tuesday, July 30, 2019 11:34:43 AM rhkramer@gmail.com wrote:
> > I have seen diagrams in NEC code books for a different arrangement to get
> > 120 volt 3 phase power, but I don't recall ever actually encountering that
> > in real life.
>
> Oh, wow, how quickly I forget -- I did encounter systems like that, often for
> lighting in industrial applications,  And, further, iirc, we could (and did)
> buy and install florescent light (and maybe HID?) fixtures designed to work on
> 208 volts, which we connected phase to phase in that kind of system.
>
> Of course, I could be misremembering.
>
> > In that case, iirc, 120 volt loads are connected from a hot
> > tap to the neutral wire (the 4th wire of the 3 phase arrangement), and you
> > get (nominally) 208 volts (RMS) connecting phase to phase.  I have seen
> > things like motors that were rated like 240 / 208 volts (or something like
> > that).
Three-phase power comes in two varieties: delta and wye (Y). In delta, 
there are only three wires, and you get power across any two of the
three phases. In the wye configuration, you get power from one phase of
the three to the center of the wye.
If I remember right, and I'm not sure I do, you get 208 VAC across two
points of the delta, and I THINK you get 120 VAC from an end point to 
the center of the wye.

--doug