On Friday, November 29, 2013 11:24:24 AM UTC-5, bud-- wrote:
On 11/28/2013 12:32 PM, wrote:

On Thursday, November 28, 2013 11:38:40 AM UTC-5, bud-- wrote:

On 11/27/2013 6:35 PM, wrote:



Neither will the IEEE power engineers:



http://ieeexplore.ieee.org/xpl/artic...number=4520128



"Distribution engineers have treated the standard "singlephase" 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 secondary systems are not single phase

line to ground systems, instead they are three wire systems with two phases and one ground

wires. Further, the standard 120/240 secondary is different from the two phase primary system

in that the secondary phases are separated by 180 degrees instead of three phases separated

by 120 degrees."



Not obvious what the author has in mind in the minimal summary of his paper.



It's clear to me:



"Which now brings into focus the reality that standard 120/240 secondary systems are not single phase line to ground systems, instead they are three wire systems with two phases and one ground wires. Further, the standard 120/240 secondary is different from the two phase primary system in that the secondary phases are separated by 180 degrees instead of three phases separated by 120 degrees."



He's saying that in fact you have two phases and that's how

you have to analyze it.



He is proposing that you consider them 2 phases to analyze it.



And says that is a change from how "distribution engineers" view

split-phase.





He clearly says the standard way of looking at split-phase, 3-wire

supplies is they are single phase.





He didn't say that at all.



"Distribution engineers have treated the standard "singlephase"

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."



He is suggesting a change from that view.





Everyone here but you (that has

provided an opinion) agrees with that.



The author suggests a departure where the 2 hot wires are considered

separate phases for "modeling".



He did not say it's just for modeling.



It is not really clear what he is saying when all we have is a summary

of the paper.



But he says he is proposing a change from how split-phase is viewed by

"distribution engineers".



And for modeling, if you are looking at

the *currents* in the 3 wires, you have to consider them separate phases

because the currents will be 180 degrees out of phase only if the loads

are resistive. Not obvious what the author is saying beyond that.



So, how can you consider them separate phases if they are

really not separate phases?



The currents are not necessarily 180 degrees out of phase even though

the voltages are. That is not something new. I have analyzed currents in

a split phase system without considering the voltages are different

"phases".



You can analyze them any way you want. It doesn't change what is there.



The summary does not indicate if he is talking about more than that.



What more does he need to talk about:

"Which now brings into focus the reality that standard 120/240 secondary systems are not single phase line to ground systems, instead they are three wire systems with two phases and one ground wires. Further, the standard 120/240 secondary is different from the two phase primary system in that the secondary phases are separated by 180 degrees instead of three phases separated by 120 degrees."

It's as clear as can be. He doesn't say, that there really are
not two phases present, but we can pretend there are. He says the
*reality* is there are two phases.









But, alas, I don't see where the author's suggestion has been accepted..



The paper confirms what the rest of us have been saying.





How about these white papers from electrical eqpt manufactuers that

clearly talk about two phases being present:



http://www.behlman.com/applications/AC%20basics.pdf



It is a way of referring to the wires. And a way that is consistent

through the piece with 3-phase diagrams.



And a way that says you have two phases, Phase A and B, and that they
are 180 deg out of phase with each other.



A single 120V circuit has a "Phase A" wire? What is the point of that?



We're not looking at just a single 120V circuit. We're looking at
a 3 wire circuit.







http://www.samlexamerica.com/support...Circuit s.pdf





Also uses "Hot Leg L1 and L2".



Sure. I have no problem with that. But why skip the elephant in the room:

"The primary side of the Distribution Transformer is connected between Ground and one of the 2400V, 7.2 kV, 12.47 kV, 13.2 kV or 13.8 kV
phases of the utility company's 3-Phase Distribution Network. The secondary of the Distribution Transformer has a grounded center tap and is
wound in a manner that supplies two 120 VAC phases which are 180° out of phase with each other (Split Phases)

The center-tapped configuration of the secondary side of the Distribution Transformer provides following voltages to the Service Entrance Panel:
• 120 VAC between the Hot Leg L1 (Phase A, Red wire) and the grounded, center tapped Neutral (White wire). The oscilloscope trace of the
voltage waveform between the Hot Leg L1 and Neutral shows the voltage rising in the Positive direction at the start of the waveform
• 120 VAC between the Hot Leg L2 (Phase B, Black wire) and the grounded, center tapped Neutral (White wire). Please note that the
corresponding oscilloscope trace of the voltage waveform between the Hot Leg L2 and Neutral shows the voltage rising in the Negative
direction at the start of the waveform. This indicates that the two 120 VAC voltages are 180 degrees out of phase
• 240 VAC between the Hot Leg L1 (Phase A, Red wire) and the Hot Leg L2 (Phase B, Black wire)"






Find me a 2 phase panel.


What something is commonly called doesn't change physics or electrical
engineering. It's like saying because you call something Kleenex,
it isn't actually a piece of soft tissue paper.





Other opinions here all disagree with you.

That isn't true either. We had one poster describing how
transformers are used to create phases in farm pump applications
that agreed with me. I also believe nightcrawler said he agreed with me.





Some of us are involved in

power distribution.

Your IEEE paper agrees with us.

It agrees only with what it's been *called* by the power
industry and clearly says that while it's called single phase,
in reality you have two phases and that is how you need to
model it. That is what the paper is about.



You can call it whatever you want to. IMHO calling the legs "phases"

adds to confusion.



But I don't really care.

You must, because you're still posting. And I'm still waiting for
a answer to the simple question of your definition of the term "phase".
Why is it that despite me having asked 12 times now, not one of those
arguing against me can even define it? How can you talk about something
you won't define?

And why no response to my detailed example of going from 3 phase,
to two phases that then looks just like a split-phase service?
Here's another example. People here have brought up
the 100 year old two phase system where the phases were 90 deg
apart. OK, I'll play that game. So we have two phase wires, A
and B and a neutral. Phase B is 90 deg apart from Phase A. Everyone
here seems to agree that two phases are present, right?

So, now let's make phase B 120 deg apart. Still two phase? Let's
make it 280 deg apart. Still two phase? Let's make it 170 deg.
Still two phase? Let's make it 180 deg apart, still two phase?
And if it's suddenly no longer two phase, why not and by what definition
of the term "phase"? And if it is two phase, then it's also electrically
indistinguishable from split-phase 240/120 coming into your house
from the service. That is the reality and that is exactly what the IEEE
author is saying. A phase difference of 180 deg is just one special
case of a phase relationship.