Hmmmm. I'll try some ASCII art.
C
/ \
/ \
/ \
/ \
/ \
/ \
/ \
/ \
A--------n--------B
Phases A and B are the 120 legs, n is neutral, C is the third phase.
The angle between A and B is 180 degrees, while the angles CAB, ABC,
and BCA are each 120 degrees. A-n is 120 volts; B-n is 120; C-n is
208 (and at 90 degrees to A-n and B-n, FWIW); A-B is 240; B-C is 240;
C-A is 240. (these are all RMS values. peak voltage is 1.414 times
as large.)
You can imagine this whole triangle spinning about the n connection
and the position of each vertex shows the instantaneous angle and
voltage of that particular phase. The peak voltage (to neutral) of
phases A and B is 169; C is 294.
PFM! (pure magic)
Donald.
> Date: Fri, 12 Oct 2001 09:54:32 -0400 (EDT)
> From: "Timothy R. Hoerning" <hoerni@cooper.edu>
>
> On Thu, 11 Oct 2001, Donald H Locker wrote:
>
> > neutral. A normal house has just one leg of the 220 (230/240) brought
> > in with a center-tap. Adding the third phase is a simple matter of
> > adding another connection to the transformer and bringing it into the
> > house. (And then adding a third phase to the power panel, the
> > metering system, and the branch subsystem.) Everything else can stay
> > the same. Really!
>
> How can this be? The two phases coming into the normal house should be
> 180 degrees out of phase. But in a three phase system the phases need to
> be 120 degree out of phase (relative to the adjascent phase). I don't
> understand how what your saying could work.
///
/// shop-talk@autox.team.net mailing list
/// To unsubscribe send a plain text message to majordomo@autox.team.net
/// with nothing in it but
///
/// unsubscribe shop-talk
///
///
|