On Tuesday, September 10, 2019 at 11:41:08 PM UTC-4, Ralph Mowery wrote:
In article ,
says...
No people in the trade where there is life on the line use very
specific terms. Blurring them to make concepts understandable for new
students or homeowners is not what they choose to do.
Arguing with Trader is like wresting with a pig
That is why I try to stay out of it. I just as I thought we would have
another 400 postings on the 2 phase thing.
If that's the case, why did you join Clare in taking the bait from
an obvious troll? Not only was it a troll, the post was clearly
a joke, not serious.
The 2 phase electrical power system is well defined. Any other
discussion is just a twist of what the uninformed try to make out of it.
You know you're getting really annoying. You have no technical
grounding in this and don't know what you're talking about.
We've been polite and reasonable. I tried to explain to you
that just because 100 years ago there was *one* example of a two
phase power system, that does not define what two phase is.
Joe tried to explain it to you too, saying that it's like
seeing a propane truck and then insisting that defines what a
truck is, that there can be no other trucks. Or saying that
because there was an implementation of 3 phase 480V, 60 hz,
that defines that 3 phase is and that if you had a system
with 3 phases at 400V, 50hz, or with theoretical phase angles
other than 120 degrees, that three phases are not still there.
If I took that 100 year old 90 deg two phase implementation and
move one winding by ten degrees, made it 100 instead of 90 deg,
would we still have two phases present? Or would the world
collapse into some kind of black hole?
No one disputes
that a hundred years ago there was a two phase power system.
That has nothing whatever to do with what the service coming
into a house looks like, what it is or isn't. I even gave you
an IEEE fellow, a professor of electrical engineering with
40 years experience, a guy who consults for power companies
as a source where he writes exactly about this issue, saying
that 240/120 is really a two phase power source. He gave this
paper at a power industry conference and it's published by the
IEEE, ie it's been peer reviewed:
https://www.researchgate.net/publica...condary_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. What all of this means is that analysis software and methods must now deal with an electrical system requiring a different set of algorithms than those used to model and analyze the primary system. This paper will describe the modeling and analysis of the single-phase center-tapped transformer serving 120- and 240-V single-phase loads from a three-wire secondary.
Just as you may say water boils at 212 deg F or 100 deg C. It only does
that when under a specific pressure and is pure water.
Water can actually boil over a range of less than room temperature to
several humdred degrees depending on how much pressure it is under.
even just exposed to the normal air, it will boil at a higher
temperature at places lower than sea level and lower temperature at the
top of a mountain.
Thanks for helping prove our point. Yes, water will boil at
different temperatures depending on the pressure. To apply this
to your case, your position is that water can only boil at 212F
because water was boiled in
Philadelphia in 1920 at 212F, end of story. Inquiring, intelligent
minds look at things like that and ask, what if it was at two
atmospheres pressure, what would change? would it still boil at
212F? And that's why I've posed those simple questions about
your example of two phase power from 100 years ago, to try to
get you to look at it logically. to analyze what is there, why
it was called two phase and how it relates to 240/120 today.
Here are those simple questions again;
Let's take your second example of what you
say was the old two phase power, ie 90 deg phase difference, three wires with
a common return. I changed the phase difference to 70 deg by rotating
one of the windings on the generator. Are there
still two phases there? Now I change it to 179 deg, are there still
two phases there? I change it to 181, are there still two phases there?
I change it to 180 deg, are there still two phases
there? And how is the latter any electrically different than the
3 wire 240/120V service going into a home? Describe how I could tell
from the panel in your house which of the two I had, the old
90 deg two phase morphed or split-phase and how they are
electrically different, how they behave differently?
But sadly neither you nor anyone else on the other side of this
will answer those simple questions, for obvious reasons. I've
answered all the questions put to me. You can do that when you
understand the electrical principles. For some reason, you prefer
to wander in the wilderness.