On Wed, 25 Jul 2018 17:33:57 -0700 (PDT), trader_4
wrote:

On Wednesday, July 25, 2018 at 1:25:32 PM UTC-4, wrote:
On Wed, 25 Jul 2018 08:14:37 -0700 (PDT), trader_4
wrote:

On Tuesday, July 24, 2018 at 12:41:18 PM UTC-4, wrote:
On Tue, 24 Jul 2018 02:45:45 -0700 (PDT), trader_4
wrote:

On Monday, July 23, 2018 at 10:14:18 PM UTC-4, wrote:
On Mon, 23 Jul 2018 17:47:02 -0700 (PDT), trader_4
wrote:

On Monday, July 23, 2018 at 8:24:43 PM UTC-4, wrote:
I've never seen a two-phase residential panel at lowes or home depot.Â* Since they're so common, would you provide a link to one at homedepot.com or lowes.com?


OK, It has been 45 years since I have worked as an electrician. Perhaps the proper term should be dual phase or split phase. Does that work for you? I really didn't expect I'd be waking anyone up by responding to a 7 year old post.

We went through this round and round a few years ago. I was somewhere close
to your position. I said something along the lines that there are in fact
two phases present, 180 degrees apart. But that they are derived from one
of the three phases coming down the street and commonly referred to as
split-phase. But when you spit-something, what do you get? Two things.
I wouldn't call it a two phase panel though, that's not the common term
for it. But it is very common to refer to each of the hots as a phase.

I even found a presentation a power industry engineer made at
a conference where he made the case that to correctly analyze a split-phase
system you have to treat it like what it is, a system with two phases.

The other argument is that if I start with a 3 phase system going into
a building, everyone agrees that there are 3 phases there, right? You can see
them on an oscilloscope. Now let;s remove one. How many phases now?
Two. Now instead of the phases being 120 apart, let's move one so that
they are 180 apart. How many phases now? Two. And if you look at it on a
a scope, it looks exactly like a split-phase gsystem going into the
same building and it behaves exactly like it. Electrically you can't
distinguish one from the other, they are the same thing.

That's my case, others will probably draw different conclusions.

There is single phase, 2 phase (that I doubt anyone here has ever
seen) and 3 phase. If you only use 2 legs of a 3 phase circuit, it is
single phase.

You have to start with the electrical engineering
definition of phase. It's simply the relationship between two periodic
waveforms. That's how we got the term three phase power to begin with.
It's based on the fact that the power is being generated as three separate
waveforms which are separated by 120 degrees.

Here is a good discussion going back and forth:

https://forum.allaboutcircuits.com/t...-phase.105861/


I agree with Wbahn, the group moderator there, he's saying it's about semantics.
And note whenever anyone is challenged as to why it can't be called two phase,
it all falls back to arguments, like "but two phase was 90 deg phase difference
and it doesn't exist anymore". When challenged along the lines of how you
define phase, why if you change 90 to 180, which is just one of the many
possibilities, it suddenly can't be called two phases anymore, they have
no electrical engineering answer, no definition, it's just that they
say it isn't. Change the phase angle
from 90 to 95, would it still be two phases? Why when it reaches 180 is
it no longer two phases? When it's at 185, would it be two phases again?

The argument Wbahn makes about a single shaft generator, instead of
supplying 3 phase, make one that supplies 2 phases, at the 90
deg if you like. Two windings, differing by 90 deg, supplying two
hots with a common neutral. Would that be two phases? If not,
why not? And if yes, then why isn't it two phases if I change the
phase angle to 180? If you agree that there are two phases still
there, then that is indistinguishable from the split-phase service
that enters your house. It's all about semantics and you have to
start with the definition of phase. Phase is simply the relationship
between two periodic waveforms.



Here, from MIT, an introduction to power systems, where they start out
with the simple case of a power system with two phases.
Note it's only about two voltage sources connected to two
loads, with two voltage sources that can be at any phase angle.
Nothing about where the voltage source originated from or what the phase angle
is. Nothing about magic happening at 180 degrees, where it's no longer
a two phase system. It's the completely general electrical engineering
case of what defines a two phase power system and how you analyze it.

https://ocw.mit.edu/courses/electric...061S11_ch3.pdf

Make those two voltage sources be the two sides of the transformer on the
pole at your house and it;s the split-phase service that serves your house.







Where you ground that does not change the number of phases.
In fact 3 phase center tapped delta is just your regular single phase
center tapped transformer connected to a delta primary with another
transformer (or two) providing the 3d phase.
OTOH if you corner grounded that delta you would have 2 (hot)
ungrounded conductors and a neutral with 2 pole breakers but it is
clearly still 3 phase.
Two phase is a totally different breed of cat with 2 phases (4 wires)
90 degrees out of phase. This will usually be 2 transformers center
tapped with the center taps grounded (5 wire).
Split phase is a type of motor winding, perhaps the most common for AC
compressors and other applications that use a start capacitor and no
run capacitor. The "phase" is "split" by a start winding 90 degrees
out of phase with the run winding.

How you generate it doesn't matter. When this came up last time, I
even gave you a presentation made by a power engineer at a power industry
conference, about how split-phase service needs to be analyzed as a
two phase system, because that is actually what it is. I believe it
was also published, because I found it online. I don't think he got
laughed out of the room, but at the very least it was a power industry
source that said exactly what I'm saying. I just looked for it again,
couldn't find it. I'll look again later.


It is single phase. There is only one secondary winding derived from a
single phase primary. The fact that you center tap that winding and
ground that tap does not magically add a phase.

Yes it does, it creates two voltage sources that are 180 deg out of
phase with each other. Why didn't you address the example in that other
forum? I take two single winding generators, connect them on a single
shaft at the power station. One winding is 180 deg out of phase with
the other, they share a common neutral. Now you have two windings,
does that make it two phase?




I suppose the unknowing can call it anything they want but
professionals call your typical home service 120/240 single phase.

Do you ever read what I post? From my first post:

We went through this round and round a few years ago. I was somewhere close
to your position. I said something along the lines that there are in fact
two phases present, 180 degrees apart. But that they are derived from one
of the three phases coming down the street and commonly referred to as
split-phase. But when you spit-something, what do you get? Two things.
I wouldn't call it a two phase panel though, that's not the common term
for it. But it is very common to refer to each of the hots as a phase.

So, I really don't understand the problem here.

And then we heard from someone who at least thinks he's a *professional*,
Ed's Electric, saying:

"No, professionals call it single-phase. Unless you want people to think you voted for Hillary, you should use the proper terminology."


I provided links to Siemens, Square D, etc. where they call their panels used
for split-phase service "single phase". Funny I didn't see you correcting
that guy, but here you are all over me, when I agreed that I would CALL IT
split-phase service, because that most accurately describes what it is.
I've said I would not call it two
phase service, because that is not the convention. But that doesn't change
how you ANALYZE it or what's there. This is like arguing that you have
to only describe what we commonly call tissues as Kleenex. Or maybe as
"tissues", that you can't describe them as a very soft, thin paper product
that;s made from trees and used to blow your nose. I'm sure there are
industry specs, details that more accurately describe tissues too, if
you look into it. So, we can't say that tissues are really that, you
can only say Kleenex because that's what the most common used term is?
It's exactly what the poster in that other forum said, it's a question
of semantics.



If I used your logic, a string of Christmas tree lights is "100 split
phases" because I would see a separate little 1.2v wave form across
each of the 100 bulbs on a scope and each one would be 180 degrees out
of phase from the bulb on the other side of the common lead on the
scope.

If you define what the voltages you're looking at in that circuit,
the polarity, V1 across bulb one, V2 across bulb two, V3 across
four bulbs, etc, you could attach a scope and show the various
waveforms. Some would be 1.2V, some would be 4.8V, some would
have one polarity, some would have the other depending on how
you defines the polarity of the measurement points and you could display
them on a scope. You could do it for a class in electrical basics.
Then ask the class to analyze the relationships of those waveforms on
a test. If a student was asked about your two bulb example, to
explain what he sees in the picture from the scope and he answered:

Both are 60 hz sinusoidal waveforms, both are 1.2V, one is 180 degrees
out of phase with the other, is he wrong? Is that an incorrect answer?


And note I've asked others here to give their definition of single phase,
two phase, three phase and N phase power. Tell us how split-phase isn't
really two phase, using your definition. So far, no one has been able to
do it.

I can't tell you in simple terms why a nectarine isn't a peach either
but they are not the same.
Did you see the term "split phase" in those panel manufacturer's
descriptions? I didn't.

Then why didn't you correct Ed's Electric when he said that professionals
never call it single phase? Instead you winked at him.


He said "No, professionals call it single-phase. Unless you want
people to think you voted for Hillary, you should use the proper
terminology."
Punctuation matters too.

Note the period between "No" and the next sentence,

They had single phase and 3 phase. They didn't
say "2 phase" either since that is really a thing, having absolutely
NOTHING to do with 120/240.
I really don't care anymore. You can sound stupid if you want, your
choice but 120/240 is single phase to the people who do this for a
living. It is only homeowners and hacks who call it anything else.

Guess the folks at Siemens surge protection, which is part of their
power business must be hacks:

https://w3.usa.siemens.com/powerdist...rst-surge.aspx

You are he
Siemens USA
Power Distribution
Product Portfolio
Surge Protection
FirstSurge„¢

Features & Benefits
UL 1449 Listed, Type 2, Surge Protective Device (SPD)

Rated for 120/240 split phase panels up to 400A

Surge Current Capacities:
- 60,000 A
- 100,000 A
- 140,000 A

3-stage commercial grade notification

These folks who make power conversion products are stupid too?

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

120 / 240 VAC SINGLE
SPLIT PHASE &
MULTI-WIRE BRANCH
CIRCUITS
Excerpt from G4 InverCharge
Series Manual

1.1 Service Entrance Panel For 120 / 240 VAC Split Phase AC Power Distribution
Fig. 1 below illustrates the residential 120 / 240 VAC, Single Split Phase, 3- Pole, 4 Wire Grounding System, which was inherited from Edison's
early DC distribution networks.
120 / 240 VAC Split Phase Electrical power from the utility (called Service)is fed through an electrical power meter to a load center / breaker panel
for further distribution. This panel is called the Service Entrance Panel. This panel normally has the following components:

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


I agree the panel makers that I saw all do call it single phase.
Which I have no problem with either, because I'm not arguing about
what it's called. That it's derived from one phase of what comes out
of the power plant, I agree, I'm fine with calling it single phase or
split phase. I'm just saying that doesn't mean that it doesn't look
and act just like a two phase, 180 system.

VIJAY SHARMA is not an electrician and he seems to live in India. I am
not sure I think his "white paper" accurately reflects American
nomenclature for circuits here. Just the fact that he calls "2 phase"
a "180 degree system" seems to show he may not really understand what
he is talking about all the time.
"2 phase" has a 90 degree phase angle difference.