It is actually on 5 wires and there is a neutral there. Two phase does still exist in some archaic industrial equipment in the North east the last I heard.
How did you get 181 degrees? If it comes from a separate system, yes it would be 2 phase.
The problem is you did not change it to 180. You just sampled a different place on the same single phase wine wave.
There is 1, 2 or 3 phase power in the US distribution system. Nothing else. I do understand you could have circuits operating at any number of different phase relationships but that will be in the electronIC world, not US power distribution. It is a different culture with words that are used differently. (I have lived in both) That is why you can find very well credentialed people who do not speak "electrician". I bet they think a "city hub" is a bus station and a "hickey" is something you don't want to see on your daughter's neck. ;-)
Yes you did, by using a center tap you now have two voltage sources that are 180 deg out of phase. You're getting hung up on how something is created. Electrons in three wires don't care how they were created, what the source was. AGain, if you took the old 90 deg two phase, that had two phases you say. If I made it 179 would that be two phases? 181? Then why not 180?
If you walk
AGain, I don't know how many times I have to say this. What it's called does not change what's there. And I didn't say to call it two phase power. Neither did the IEEE Power Engineering paper I cited. We are simply saying that electrically that's what you really have and how you can analyze it.
Why does that matter? The electrons in the cable don't care if the other phase at some deg of separation was generated from another winding on the same shaft, another generator that you somehow managed to keep in perfect synch, or via an entirely electronic method, eg synthesize it electronically like you would with a UPS.
N Phase Power - A power delivery system that uses N related voltage sources, that are periodic waveforms of the same frequency, differing only in phase.
That simple engineering definition neatly covers it all, one, two, three, N phase.
If it comes from a separate system, yes
Separate system? Where did that requirement come from? Three phase AFAIK is generated from 3 windings on the same shaft, separated by 120 deg. Do diesel 3 phase generators have 3 motors? What's does a "separate system" even mean? They can't be really separate and be locked at a fixed phase separation.
Of course I'm changing it to 180. I take your old 90 deg two phase generator that you say was two phase. I move the second winding from
90 to 179. I think you're saying that's still 179. So, now I shut it off, rotate the one coil 1 more deg, it's at 180. I start it up again, is there now just one phase simply because it's 180, not 179?
Which doesn't change how electrons behave or how systems are analyzed. What you choose to call it does not change what is really there. You also seem to dismiss the existence of Electrical Engineering, which is the field of expertise that includes power engineering, it's everything that flows out of Maxwell's Equations, from a generator to radio waves. That IEEE Fellow that wrote the paper analyzing exactly what we're talking about that you continue to dismiss is one of them.
It is a different culture with words
I gave you my definition of N phase power that neatly covers it all, from one phase to N phase. I'm still waiting for your general definition, that covers and explains the differences, as opposed, to relying on "that's what we call it as a definition". I said in the first post I would not *call* our residential power 240/120 two phase. I don't see anyone doing that either. But electrically that is what you have with a center tapped transformer. It behaves as, looks like and is two voltage sources that are 180 deg out of phase with each other that share a neutral.
You sure can't model what's going on over that service with only one voltage source. Describe the simple circuit schematic, using ideal voltage sources, that you'd use to model it. I can give you mine, it's exactly the circuit diagram shown in the IEEE paper describing the analysis of what we're talking about, which is two ideal voltage sources. You take one 120V ideal voltage source and connect it's negative side to the positive side of another 120V ideal voltage source. Explain how to model it with a just a single ideal voltage source.
A center tapped transformer essentially creates two coils with one end connected together. Put two windings on the same shaft at the generator and feed it to the house over three wires, shared neutral, with a 90 deg phase difference between the two coils. Would there then be two phases entering the homeowner;s house?
Yes or no?
Would there still be two phases there if I rotate one generator coil so that it's 179 deg phase difference instead of 90?
Yes or no?
If it's 180 phase difference, then what? If that is still two phases, then it's electrically identical to what's coming into the house from the center tapped transformer.
All those are simple, very obvious questions a student would ask a teacher. Note that when you apply electrical engineering uniformly, you don't wind up with bizarre unexplainable singularities. And again, I don't care what most of the industry chooses to call it, that evolved from a historical perspective and from their perspective that what enters the house is derived from a single phase off of their
3 phases. I acknowledged that in my first post. It's like Kleenex or tissue, then saying that because it's commonly called Kleenex, it can't be also called tissue or more importantly described or analyzed as a soft paper product made from trees. If I take one phase from some power source and put it into an electronic black box that has six phases coming out the other side, synthesized, is there only one because there was only one coming in? If five of them are at 90, 120, 150, 210, 240 would those be legitimate phases but the one at 180 isn't? Don't phases have equal rights and treatment under the laws of electricity?
It's normal to what things to be simpler, however reality doesn't always cooperate. The word "phase" has a meaning and wanting things to be simpler doesn't change that.
If 2 lines have the same voltage and same phase, connecting them will have no effect. Now, I have access to line1 and line2 on a 240V receptacle (10-30), so connecting them together should no nothing (I really know enough not to try that).
The windings are still in phase. If they were out of phase, like the windings in a GFCI transformer the resulting line to line voltage would be zero because they would buck each other.
As I am going to say for the last time, you look at a system from end to end, not from halfway in between the ends.
If I'm the one who's dumb, why is it that I'm the only one here who can give you a simple, logical, straightforward definition of N phase power? I asked, no one could even define it. I gave it to you:
N Phase Power - A power delivery system that uses N related voltage sources, that are periodic waveforms of the same frequency, differing only in phase.
Following your logic that you have to analyze a whole system, then we can't use electrical engineering tools to analyze the output stage in an audio amplifier unless we know the whole "system" from end to end. We can't identify phase relationships in a part of a circuit, without going all the way back to the generator???
And I keep giving you the opportunity to go all the way back to the generator, asking the simple questions a beginning elec engineering student or even a high school student might ask a teacher. Questions you won't answer, step by step, because you get cornered by the truth. I answer all your questions.
Put two windings on the same shaft at the generator and feed it to the house over three wires, shared neutral, with a 90 deg phase difference between the two coils. Would there then be two phases entering the homeowner;s house?
Yes or no?
Would there still be two phases there if I rotate one generator coil so that it's 179 deg phase difference instead of 90?
Yes or no?
If it's 180 phase difference, then what? Is that still two phases?
And if that is still two phases, then it's electrically identical to what's coming into the house from the center tapped transformer. Electrons and engineering don't care how it was created, only what is actually there. As I said before, from an engineering perspective, let's say I have a black box that has five phases coming out of it, at 120,
150, 180, 210, 240. They are electronically synthesized as you would in a uninterruptable power supply. Do you need to know what drives it for there to be 6 phases there? Why does it matter if it's powered by a DC battery, single phase or 3 phase? Is the 180 one not a legitimate phase, just because it's at 180?
The other poster raised another good point. If there are not two phases present, then I should be able to take any two receptacles in a house and parallel them. Fact is you can't, because they are 180 deg out of PHASE with each other.
They are NOT 180 degrees out of phase, If they were, the line to line voltage would be zero. You are just looking at the 2 halves of a 240v sine wave. Draw a sine wave. look at the center point and you see what I mean. It is one sine wave, about 168 P/P (120 RMS) and from the center point each side is the compliment of the other but it is still one sine wave. Until you understand that you will remain confused.
To make the 2 sides of that transformer 180 degrees out of phase you would need to wind it in the opposite direction and we know it is just one winding. Your generator scenario also would require that they both be in phase so the voltage would add or the resulting end to end voltage would be zero, even though both were putting out 120.
In fact the farther you take 2 windings out of phase, the lower the line to line voltage will be, hence 208 on regular 120 degree put of phase 3P wye. (Sq/Rt of 3).
The line to line of a 2 phase from the two 90 degrees out would be around 168 (120* sq/rt 2)
Just to be clear, this argument started after someone referred to single phase service as 2-phase service. If you call the power company and ask to have 180° 2-phase electric service installed, they'll tell you they only offer single and three phase...though there might be some 90° 2-phase installations still in operation. Furthermore, if you connect a dual trace scope up a certain way, it will look like you have two phases. While that's a nice parlor trick that might make a slow student scratch their head, the truth is that there is only one phase on the transformer secondary.
But I do have one question, I understand the advantage of 120° 3-phase and 90° 2-phase for starting motors but what is the advantage of your 180° 2-phase over standard single phase 120/240 service?
phase service as 2-phase service. If you call the power company and a sk to have 180° 2-phase electric service installed, they'll tell you t hey only offer single and three
n operation. Furthermore, if you connect a dual trace scope up a certain wa y, it will look like you have two phases. While that's a nice parlor trick that might make a slow student
sformer secondary.
It's not a parlor trick. Are you going to tell this power industry enginee r, an electrical engineer with 40 years experience, a Life Fellow of the IEEE, who presented the below paper at an industry conference of his peers, that he's wrong too? I don't see either you or Fretwell addressing it. He addresses exactly wha t we're talking about and says that 240/120 HAS TO BE ANALYZED AS A TWO PHASES, because that is exactly what it is. Then he proceeds to do exactly that in the paper. I provided a link where you can see where he does exactly that, and works through the math. He teaches electrical engineering.
Abstract: Distribution engineers have treated the standard "singlephase" distribution transformer connection as single phase because from the primary side of th e transformer these connections are single phase and in the case of standar d 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. Whic h 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 s ystems with two phases and one ground wires. Further, the standard 120/240 secondary is different from the two phase primary system in that the second ary phases are separated by 180 degrees instead of three phases separated b y 120 degrees. What all of this means is that analysis software and methods must now deal with an electrical system requiring a different set of algor ithms than those used to model and analyze the primary system. This paper w ill describe the modeling and analysis of the single-phase center tap trans former serving 120 Volt and 240 Volt single-phase loads from a three-wire s econdary.
W. H. Kersting Milsoft Utility Solutions, USA W. H. Kersting (SM'64, F'89, Life Fellow 2003) was born in Santa Fe, NM. He received the BSEE degree from New Mexico State University, Las Cruces, and the MSEE degree from Illinois Institute of Technology. He joined the facul ty at New Mexico State University in 1962 and served as Professor of Electr ical Engineering and Director of the Electric Utility Management Program un til his retirement in 2002. He is currently a consultant for Milsoft Utilit y Solutions. He is also a partner in WH Power Consultants, Las Cruces, NM.
I also note that I gave everyone here days to just define one phase, two ph ase, N phase power. Not one of you "experts" could do it. I did, very simply:
N Phase Power - A power delivery system that uses N related voltage sources , that are periodic waveforms of the same frequency, differing only in phase.
It fits:
one phase two phase 90 deg two pahse 179 deg two phase 180 deg three phase five phase N phase
And I note you can't answer the simple questions a student would ask a teacher:
The old two phase power was 90 deg over four wires. If it was instead two phases over 3 wires, a shared neutral, would there still be two phases present?
If yes, then how about if the phase angle was changed to 179 deg, or
181 deg, would there still be two phases there?
How about 180 deg? Two phases, yes or no?
And if it's suddenly no, then why?
The reason neither of you will address it is because you can't. There is no rational explanation and it leaves you grasping for straws.
Or how about the other scenarios I gave Fretwell. You have a black box that generates 5 sine waves coming out of it, one at 120 deg, one at 150, one at 180, one at 210. Fretwell would have you believe you need to analyze an entire system to be able to determine how many phases there are. I say the fact that there are five power sources coming out, defined by their phase differences is all we need to know that there are 5 phases there. Where are you on that? Are there five or not? And if there are 5, why does the one at 180 deg count there, but not coming into a house?
If there are not two phases, then I should be able to parallel any two 120V receptacles in the house. Can I do that? No, because some are 180 deg out of PHASE with the others. Everthing is explained with basic electricity 101. I have all the questions raised here covered explained. And it all fits with the IEEE Fellow's paper, 100%. You two are left grasping at straws with evolving explanations that make no sense. And once again, neither of you will respond to the simple questions in the scenarios I put forth. I address all of yours.
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. 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
the Electric Utility Management Program until his retirement in 2002. He is currently a consultant for Milsoft Utility Solutions. He is also a partner in WH Power Consultants, Las Cruces, NM.
All that shows is this guy spends too much time in theory and not enough time in the real world. There are plenty of well credentialed people who write gibberish.
It is not 2 phases, it is just one and the reason you can't parallel 2 phases is exactly because it is ONE phase. You are taking the second half of the sine wave and trying to lay it down over the other side.
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. 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
the Electric Utility Management Program until his retirement in 2002. He is currently a consultant for Milsoft Utility Solutions. He is also a partner in WH Power Consultants, Las Cruces, NM.
The reason you can't parallel these two "in phase" sources is that it is connected in series. You can't simultaneously connect anything in series and parallel at the same time. If you want to parallel those two circuits, all you have to do is break the connection at the center tap, making 2 windings. Then you can connect them in parallel. If it was truly 180 out of phase the voltage would be zero but since they are in phase you would have 120v with the ability to handle twice the current.
Wow, you really are confused. Two 120 volt AC sources that are 180 deg out of phase sharing a common neutral produce 240V between them.
You are just looking at the 2 halves of a 240v
I suppose the prof of electrical engineering, who presented to his peers at a power industry conference is confused too. Funny, he's saying EXACTLY what I said. And he goes through many pages of analysis of it as two phases.
"Distribution engineers have treated the standard "singlephase" distributio n transformer connection as single phase because from the primary side of t he transformer these connections are single phase and in the case of standa rd 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. Whi ch now brings into focus the reality that standard 120/240 secondary system s 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 secon dary phases are separated by 180 degrees instead of three phases separated by 120 degrees. What all of this means is that analysis software and method s must now deal with an electrical system requiring a different set of algo rithms than those used to model and analyze the primary system. This paper will describe the modeling and analysis of the single-phase center tap tran sformer serving 120 Volt and 240 Volt single-phase loads from a three-wire secondary."
Why is it that if you're so smart and I;m the one confused that you can't answer the simple questions I posed?
Put two windings on the same shaft at the generator and feed it to the house over three wires, shared neutral, with a 90 deg phase difference between the two coils. Would there then be two phases entering the homeowner;s house?
Yes or no?
Would there still be two phases there if I rotate one generator coil so that it's 179 deg phase difference instead of 90?
Yes or no?
If it's 180 phase difference, then what? Is that still two phases?
So I run that into a house as 240/120, how many phases now?
If phase is so simple and you understand it, why can't you answer those questions?
And if that is still two phases, then it's electrically identical to what's coming into the house from the center tapped transformer. Electrons and engineering don't care how it was created, only what is actually there. As I said before, from an engineering perspective, let's say I have a black box that has five phases coming out of it, at 120,
150, 180, 210, 240. They are electronically synthesized as you would in a uninterruptable power supply. Do you need to know what power source it uses? Why does it matter if it's powered by a DC battery, single phase or 3 phase? Is the 180 one not a legitimate phase, just because it's at 180?
The other poster raised another good point. If there are not two phases present, then I should be able to take any two receptacles in a house and parallel them. Fact is you can't, because they are 180 deg out of PHASE with each other.
That would be two phases just the same as it is two phases by center tapping the transformer. If we did it with a separate winding, how would you tell from the house that it was one vs the other? You can't. Because there are two phases either way.
No idea what your talking about now. And again, why can't you answer the simple questions one at a time? Go back to the step by step generator example. You claimed you have to analyze a whole system. I gave you one in that example, so answer the simple questions.
Anything else irrelevant that you'd like to toss in to try to avoid answering those simple questions in sequence?
le phase service as 2-phase service. If you call the power company an d ask to have 180° 2-phase electric service installed, they'll tell yo u they only offer single and three
l in operation. Furthermore, if you connect a dual trace scope up a certain way, it will look like you have two phases. While that's a nice parl or trick that might make a slow student
ransformer secondary.
what we're talking about
ion transformer connection as single phase because from the primary side of the transformer these connections are single phase and in the case of stan dard rural distribution single phase line to ground. However, with the adve nt of detailed circuit modeling we
d past the transformer to the secondary. Which now brings into focus the re ality 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
in that the secondary phases are separated by 180 degrees instead of three phases separated by 120 degrees. What all of this means is that analysis s oftware and methods must now deal with an electrical system requiring a dif ferent set of algorithms than those
deling and analysis of the single-phase center tap transformer serving 120 Volt and 240 Volt single-phase loads from a three-wire secondary.
He received the BSEE degree from New Mexico State University, Las Cruces, and the MSEE degree from Illinois Institute of Technology. He joined the fa culty at New Mexico State University in 1962 and served as Professor of Ele ctrical Engineering and Director of
is currently a consultant for Milsoft Utility Solutions. He is also a partn er in WH Power Consultants, Las Cruces, NM.
I see, so prof of elec engineering, who wrote a paper, presented it to peers at a power industry conference, had it published by the IEEE, has 40 years of experience, consults for utilities, writes "jibberish". I bet he can define N phase power too.
Do you realize how whacko what you just posted is? It's precisely because the two hots in half the receptacles in a house are on opposite phases, that explains why you can't parallel them. If I take two 9 volt batteries, I can parallel them if I connect positive to positive. I get the capacity of both batteries at 9 volts. If I take two batteries and connect them positive to negative, then they are connected in OPPOSITE POLARITY and they explode. Opposite polarity in the AC world IS THE SAME THING AS 180 deg out of phase and it's why you can't randomly try to parallel any two receptacles. If they were on the same hot, (phase) coming from the panel, then you could parallel them.
I have a transformer with two 120v secondaries. Assume the taps are A & B on each. If they are wound around the core in the same direction from A to B, do you agree each would be in phase if they are measured A to B. Now if I connect them in series A to B do you agree the current is going in the same direction in both windings so they are still in phase? You will see 240v from the A to B on each end. If they were connected A to A in series they would be 180 degrees out of phase the voltage would be zero. In fact they have to be in phase to add. Otherwise they buck.
Now look at your pole pig outside your house and tell me which one it most closely resembles.
You are confusing the halves of one sine wave with two sine waves. I don't know what the professor has to rationalize to teach this simple thing to the snowflakes in his class.
Ignoring the voltage/current zero crossings and assuming a pure resistive load,
at any time t, the current on the secondary winding is either flowing from end L1 toward end L2 or end L2 toward end L1.
Also, at that same time t, the voltage is either rising or falling at all points along the entire length of the wire at the same rate.
The rise and fall of the voltage at L1 and L2 are in sync, obviously because there is only one phase on the single continuous piece of wire that forms the secondary coil.
The rise and fall on the secondary coil is in sync with the rise and fall on the primary coil. Since the primary coil is single phase, so is the secondary.
Clearly single phase, anything else is a parlor trick.
Are you in marketing? I ask because I don't see how your "180° 2-phase" has any useful advantage over standard residential single phase service? Seems like pure marketing fluff.
le phase service as 2-phase service. If you call the power company an d ask to have 180° 2-phase electric service installed, they'll tell yo u they only offer single and three
l in operation. Furthermore, if you connect a dual trace scope up a certain way, it will look like you have two phases. While that's a nice parl or trick that might make a slow student
ransformer secondary.
what we're talking about
ion transformer connection as single phase because from the primary side of the transformer these connections are single phase and in the case of stan dard rural distribution single phase line to ground. However, with the adve nt of detailed circuit modeling we
d past the transformer to the secondary. Which now brings into focus the re ality 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
in that the secondary phases are separated by 180 degrees instead of three phases separated by 120 degrees. What all of this means is that analysis s oftware and methods must now deal with an electrical system requiring a dif ferent set of algorithms than those
deling and analysis of the single-phase center tap transformer serving 120 Volt and 240 Volt single-phase loads from a three-wire secondary.
He received the BSEE degree from New Mexico State University, Las Cruces, and the MSEE degree from Illinois Institute of Technology. He joined the fa culty at New Mexico State University in 1962 and served as Professor of Ele ctrical Engineering and Director of
is currently a consultant for Milsoft Utility Solutions. He is also a partn er in WH Power Consultants, Las Cruces, NM.
More bizarre wandering in the wilderness. All one needs to know is that I have a box, coming out of it are two hots, each 120v, one 180 deg out of phase with the other, with a shared neutral. End of story. No series, parallel, doesn't matter if it was generated from a generator with two coils, from a center tap transformer, or purely synthesized electronically like a UPS would. That "box" is what the supply coming into your house looks like. And the two hots,
120V each, shared neutral, 180 deg out of phase, completely describes it.
And again, I note that you still refuse to answer the simple step by step questions that a beginning student would ask a teacher. Questions that go to the heart of the issue. I can answer them and have, why can't you? Here it is again:
Problem #1:
You say the old 90 deg two phase was over 4 wires. If I instead put it over three wires, with a shared neutral, would there still be two phases ?
Put two 120V windings on the same shaft at the generator and feed it to the house over three wires, shared neutral, with a 90 deg phase difference between the two coils. Would there then be two phases entering the homeowner;s house?
Yes or no?
Would there still be two phases there if I rotate one generator coil so that it's 179 deg phase difference instead of 90?
Yes or no?
If it's 180 phase difference, then what? Isn't that still two phases?
And if that is still two phases, then it's electrically identical to what's coming into the house from the center tapped transformer. Electrons and engineering don't care how it was created, only what is actually there.
Problem #2
I have a black box that has five phases coming out of it, at 120,
150, 180, 210, 240. They are electronically synthesized as you would in a uninterruptable power supply. Do you need to know what drives it for there to be 6 phases there? If the 180 phase doesn't count as a phase, then why not? I can see all five on a scope. Does it matter that the black box is driven by one phase, 3 phases, a transformer, a generator or a battery?
I don't have to reconnect anything. What's going on inside the house is completely explained by there being two phases present that are each 120V, out of phase with each other by 180 deg. It's exactly what the electrical engineering prof said and did in his multi-page complex analysis of how to correctly model it. My definition of N phase, phases, covers it all. It consistently addresses every case we've gone through. And it's odd that I had to define it for you pros, after giving you a couple days to come up with your definition of N phase power. You still have no definition.
Go ahead, keep disparaging the professor of electrical engineering with 40 years of experience, who presented the paper I cited at a power industry conference to his peers. I'm sure they are all dumb snowflakes. Did you look at the math, where he did the analysis? This coming from the guy who still can't give a definition of what N phase power even means. I gave you two or three days, then I gave you the simple definition that cover it all. One that doesn't rely on transformers, generators, it's a complete, general definition.
You're hung up on transformers, components when it doesn't matter how what's delivered over those 3 wires originates. As I've said many times now, it could be from a center tapped transformer, a generator with two windings sharing a neutral, or a black box with electronics that synthesizes it electronically.
N Phase Power - A power delivery system that uses N related voltage sources, that are periodic waveforms of the same frequency, differing only in phase.
Where is your definition? How can you argue about what something is or isn't when you can't give the definition?
And again I note that neither you nor your new sidekick will answer the simple two problems I laid out, ones that any beginning elect engineer who took his first course in circuits could easily answer. Here they are again. I can keep posting them at least as long as you can refuse to answer:
Put two windings on the same shaft at the generator and feed it to the house over three wires, shared neutral, with a 90 deg phase difference between the two coils. Would there then be two phases entering the homeowner;s house?
Yes or no?
Would there still be two phases there if I rotate one generator coil so that it's 179 deg phase difference instead of 90?
Yes or no?
If it's 180 phase difference, then what? Is that still two phases?
So I run that into a house as 240/120, how many phases now?
If phase is so simple and you understand it, why can't you answer those questions?
And if that is still two phases, then it's electrically identical to what's coming into the house from the center tapped transformer. Electrons and engineering don't care how it was created, only what is actually there.
As I said before, from an engineering perspective, let's say I have a black box that has five phases coming out of it, at 120,
150, 180, 210, 240. They are electronically synthesized as you would in a uninterruptable power supply. Do you need to know what power source it uses? Why does it matter if it's powered by a DC battery, single phase or 3 phase? Is the 180 one not a legitimate phase, just because it's at 180?
Here;s another way of looking at it. Let's say you're an engineering student. I put you in a house with 240/120 service, give you whatever instruments and test gear you want, tell you to analyze the 3 wire service. You don't know where it's coming from, how it's generated. Describe it and how you would model it.
I can give you my answer. You have two 120V 60 hz sinusoidal voltage sources that are 180 deg out of phase with each other that share a common neutral. And that's how you'd model it, you need TWO ideal voltage sources that are 180 deg out of phase with each other. Or of opposite polarity if you like, which is exactly the same thing. Note that I didn't need to reference transformers, synthesizers, generators, or how many phases came from the power company. It's completely defined by the electrons coming and going on those 3 wires, without regard to how or where they were generated.
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