On Monday, September 9, 2019 at 8:12:03 PM UTC-4, wrote:
using a grounded conductor (AKA Neutral) into two 120VAC circuits.
Medium voltage is typically single phase when it hits the distribution
transformer, either as single ended wye distribution (one hot and one
neutral) or delta distribution (2 hots) but that is still single phase
if the 3d phase is not present on the hubs. The output of the
transformer is also single phase that gets divided with a center tap.
That is how professionals describe it, no matter what contortions
people go through to explain it to morons.
Not this professional, who I've cited before. An IEEE fellow, professor
of electrical engineering, power industry consultant, presenting
a paper at a power engineering conference:
https://www.researchgate.net/publica...condary_Models
Center-Tapped Transformer and 120-/240-V Secondary Models
Distribution engineers have treated the standard ldquosingle-phaserdquo distribution transformer connection as single phase because, from the primary side of the transformer, these connections are single phase and, in the case of standard rural distribution, single phase line to ground. However, with the advent of detailed circuit modeling, we are beginning to see distribution modeling and analysis being accomplished past the transformer to the secondary, which now brings into focus the reality that standard 120-/240-V secondary systems are not single-phase line-to-ground systems, but they are three-wire systems with two phases and one ground wire. Furthermore, the standard 120-/240-V secondary system is different from the two-phase primary system in that the secondary phases are separated by 180deg instead of three phases separated by 120deg"
And then he proceeds to analyze the circuit back to the transformer,
treating it as two voltage sources that are 180 deg out of phase,
applying basic electrical engineering principles. Exactly what I've
said. And you have to treat it that way, there is no other way to
correctly analyze it, which is the point of the paper.
I'm sure he could and would answer the simple questions I posed too,
about changing the phase of Ralph's old 90 deg two phase power to 79 deg,
130 deg, 179 deg or 180 deg, which none of you can answer. I can answer
them, the professor can too, because we understand definitions and
approach it all logically and systematically. We don't rely on an
example of one implementation from 100 years ago and claim that is
what defines phases. That;s the beauty and elegance of science,
it all fits together, we don't make it up as we go.
Sine(wt)
Sine(wt+ O)
O = 90 deg, you have Ralph's example
O = 180 deg, you have split-phase
O = 360 deg, you have two sources in perfect sync
In your world, for some unknown reason, when O=180, we must fall into
some mysterious black hole, where the same rules that apply everywhere
else, no longer apply. In my experience, science and engineering does
not work that way.