So lets take the UK system in Andrew's post - 230V, 2 wires, hot and neutral. It is clearly single phase. Connect it to a phase-converter and you have 3-phase. One-phase becomes 3-phase.
Your argument doesn't work. The phase-converter creates the 3rd phase relative to the single phase source.
It is like open delta, where a single transformer adds the 3rd phase. You could do a corner grounded open delta - you have 2 clearly single phase transformers that give you 3-phase.
Any supply with two voltages which are not in phase can be considered 2 phase (3 or 4 wires). "Balanced" 2 phase, mathematically speaking (where for equal loads on each phase such that the sum of the currents is 0), will have a phase difference of 180 degrees - as in the 3 wire
120/240V system. This is not generally called 2 phase in North America where it is commonly used. "2 phase" generally refers to the 2 phase 90 degree shift system (sum of currents will not be 0) which, for motors, has the advantage that, as for 3 phase, a rotating field with ideally no pulsations is produced. Such motors are not common-no advantage in general with respect to 3 phase motors. They have been used as control motors in the 40's-80's.With regard to comparative practices in distribution-this is a kettle of fish with pros and cons either way which were determined by (sometimes poor) choices made over 100 years ago. Practice depends on the past as well as factors such as housing styles, lot sizes, peak and average demands, price of copper, etc with compatibility with the past being a major factor. While, in many places 3 phases are run down each street, in many areas only a single phase is used. In my district a single HV phase is run underground supplying several pad mounted transformers- each feeding a few houses. Heavy air conditioning loads are not a concern.
I can't figure out whether you're a moron or a troll.
Thank you. That's consistent with what I've been saying. It's also what the paper delivered at the IEEE conference on power engineering that I've cited says. The only part I would disagree with is that there is no reqt that it be balanced. If it's not balanced, you still have two phases,, 180 deg off, you also have current flowing in the neutral.
This is not generally called 2 phase in North America
I agree with that too. I've said from the beginning that the
240/120V is commonly referred to as split-phase."2 phase" generally refers to the 2 phase
Those arguing the other side of this, accept the two phase system that was used 100 years ago for awhile as being two phase. I've presented a simple learning exercise that no one will address. With that two phase distribution system, we had two phases, A and B and a neutral. B phase is 90 deg off from A. Everyone I believe here agrees that two phases are present. So, let's change the phase to being off by 120 deg. Still two phases? I think we agree the answer is yes. Make it 280 deg off, it's still two phase? So, if we now make it 180 deg off, how many phases are there? I think you and I agree there are still two, unless some magic happens. And if the power source voltages are 120V, then at that point what you have is identical to 240/120V split phase at the panel. You could not tell them apart. Neither can the electrons. That is what is there, no matter what anyone calls it.
Agree with that too.
Thank you. There are now at least 3 of us here that agree.
ference of power engineers, where the author/speaker, says there is a 180 d eg phase relationship, that you do have two phases. He's the author
y systems are not single phase line to ground systems, instead they are thr ee 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 t he secondary phases are separated by 180 degrees instead of three phases se parated by 120 degrees."
It's isn't a question of viewpoint. It's very basic electrical engineering. He clearly says that you have two phases present and that is how it needs to be correctly analyzed using electrical engineering. He doesn't say, "There really aren't two phases present, but let's pretend there are". He's saying there are two and that is how it needs to be modeled, analyzed, etc., which he does in the paper.
The fact that it's called split-phase, single phase whatever doesn't change electrical engineering. Which is why I've asked a dozen times now for your definition of the electrical engineering term "phase".
Which source is that? I don't see a cite.
Good grief. Did you even look at it? The first diagram is a 2 wire circuit. That's what you're looking at? The second diagram is split-phase 240/120V, which is what we're talking about. It shows 3 wires: PHASE A, PHASE B, and a neutral. It states:
"The two legs represented by PHASE A and PHASE B, are 180 deg apart."
I've given you several other sources that describe split-phase that say the same thing, ie that there are two phases present.
0900004ESigh.... I was hoping for an engineering definition, which clearly that isn't. I'm surprised you even posted that. It's kind of like saying Planters and everyone else calls peanuts a nut. Then arguing with someone who has horticulturists describing it as the legume, Arachis hypogaea L, and saying it just isn't so.
Phase in basic electrical engineering terms is simply the relationship between two periodic waveforms, expressed in degrees. One complete cycle is 360 degs.
In the case of the power company, they generate 3 phases at the generating station. They differ by 120 deg. You have 3 phases, you can see it on a scope. At your house, they take one of those
3 phases, and via a center tap transformer, create split-phase 240/120V service. It has two phases, that differ by 180 deg. You can see it on a scope. When you split something, do you know of any examples where you stil just have one thing? The industry may refer to it as single phase, because it originates from a transformer connected to just one of their primary phases, but that doesn't change what it really is.And where is the answer to the exercise in two phase power? I've asked that 6 times now too:
Those on the other side of this agree that two phase existed
100 years ago. They have no problem with it being called two phase, that was two phase according to them. So, that system had two phases, let's call them A and B and a neutral. Phase B was 90 deg off from phase A. Everyone OK so far?Now, instead of having phase B be off by 90 degrees, let's make it off by 120 deg. How many phases are there now? I say two. Let's change it again, so phase B is off by 220 degrees. How many phases do we have now? I say two. Let's change it to being off by 170 deg, how many phases do we have now? I say two. And now, let's change it to be off by 180 deg. How many phases do we have now? I say two. And if it they agree that it is indeed still two, then it is in fact electrically identical to split-phase 240/120V service, so you have two phases there too.
Note that the above view of phase is 100% consistent, from a piece of paper, to circuit analysis, to the 3 phases at the generating plant, the two phase system of old, the split-phase of today. The alternate view is apparently that something magical happens at 180 deg phase difference.
The transformer on my house is single phase in and single phase out.
The secondary may be split-voltage but it sure ain't two phase.
All we know for certain is that traitor4 is wrong. :-)
That figures. You're confused. I can figure it out in your case though.
Rules for bathroom sockets in the UK are that it must be from an isolating transformer, and restricted to (IIRC) 25W (usually restricted by a very slow acting self reset thermal fuse, or just a self-reset thermal switch on the isolating transformer). It's intended for shavers, electric toothbrushes, etc. The isolating transformer is to prevent risk of electrocution in an environment which is likely to be wet, and the person and appliance is also likely to be wet. The output is isolated and not connected to ground (which would defeat the whole object).
There's always a 120V socket and a 240V socket, simply because if you have an isolating transformer there anyway, the cost of providing an extra voltage output is negligable.
This rule has been relaxed in the latest regs to allow ordinary socket outlets providing they are at least 3 meters from a bath or shower (IIRC - haven't got the regs to hand just now). This allows for having a shower in a bedroom, for example, and having standard sockets in the rest of the bedroom.
EU has rules requiring that all member states allow free movement of people and products across borders. This prevents the UK from insisting that construction site tools must all operate on a special voltage only found in the UK, as a carpenter from, say, Italy won't have 110V tools, and thus would not be able to take up a job on a UK construction site.
In practice all UK construction sites are still 110V and all UK construction workers tools are 110V, but in theory an Italian carpenter could now turn up on site and request a 230V supply for his tools - that used to be illegal. At one point in the negotiation of this change, 110V construction site tools were to have become illegal in the UK - they were only saved because they result in far fewer construction site electrocutions than is the case in other EU countries which use 230V tools.
He says that is how he thinks it should be viewed, which is a change from how "distribution engineers" currently view it (first sentence).
Which I supplied, below.
Your IEEE cite, first sentence in the context of the abstract.
The author has a different view from "distribution engineers". Did "distribution engineers" change their view? Not in the abstract.
Third repetition.
Any english teachers around?
Of course. It has a single hot wire that is "phase A". It is a way of referring to the wire.
I supplied one, below.
But I supplied one, below.
It is kind of like your other references (not IEEE) that use Phase A... as a label for the wires.
Oh, my! Now he'll be stalking you.
onference of power engineers, where the author/speaker, says there is a 180 deg phase relationship, that you do have two phases. He's the author
ary systems are not single phase line to ground systems, instead they are t hree wire systems with two phases and one ground wires. Further, the standa rd 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 never uses the word "think". It's not an opinion piece. He says they have been "treated" as single phase because they originate from a single phase on the primary side, but in reality two phases are present.
That isn't an engineering definiton of phase by any stretch of the imagination. It's not even at a high school level.
He explains that the reason it's been viewed that way is because it originates from one phase of the primary. He then clearly explains how in fact there are two phases present. Which is why I've asked 15 times now for YOUR definition of the electrical engineering term phase. You can't give your own definition? Neither can anyone else on the other side of it. Instead you come up with one reference at an embarrasing level, from the glossary of a transformer catalog? That's your engineering? On my side I have a engineer who has written many highly technical papers that have been peer reviewed and published by the IEEE. He says there are two phases present and I'm sure if you asked him, like me, he could give you a definition.
Why are you deliberately looking at what is the wrong diagram instead of the second one which is the one that obviously is split-phase? Now you're resorting to basically lying instead of dealing with the issue.
And the above, which you did not respond to, is the section, complete with diagram, of EXACTLY what we're talking about. It says there are two phases, A and B present. Yet you keep harping back to the circuit that has nothing to do with the discussion. Unbelievable.
=TB00900004E
The fact is I have multiple references, including the IEEE. I can give you the engineering definition of phase. I don't have to go look in the glossary of a transformer catalog. Hmmm. IEEE engineer paper delivered at a power engineering conference, published by the IEEE, vs an unbelievably dumb defintion from a transformer catalog. Which one should we believe?
Do capacitor manufacturers that sell caps call them two phase? Yet the current and voltage are out of phase in a cap too. You can see it on a scope. Just like you can see two phases present on a split-phase service.
Still waiting for an answer to the question of why two phase is two phase when it was 100 years ago and delivered via two hots and a neutral, one hot 90 deg off from the other. If it were 130 deg off would it be two phase? 160 deg off, still two phase? Then explain to us why if I make it 180 deg off, suddenly there are no longer two phases present? In my world, the IEEE world, at least two others here now who agree, there are still two. And at 180 deg, that two phase service looks electrically exactly like split-phase. In your world apparently something magic happens at 180 degrees and hence it can't be explained.
Of course it is.
It is his opinion of how split-phase should be viewed. He contrasts it with the view of "distribution engineers".
That is the viewpoint of "distribution engineers".
That is his opinion He wants to change how "distribution engineers" view split-phase.
I didn't know phasors were taught in high school. [Note: these are not the same phasors that are used as weapons in the
21st century.]
The way "distribution engineers" view it.
In his opinion.
I did, 2 posts ago, and pointed that out in my last post.
That is not my definition. Perhaps if you learned to read...
In his opinion.
Still need - an english teacher for the paper, and also to tell trader I put up a definition of "phase".
Why can't you figure out if the piece says a single phase 2-wire circuit has "Phase A" it is a label.
And it is still there.
And it is still there.
Multiple references that use "phase A" as a label. And an IEEE paper that supports my view ("distribution engineers").
And two posts ago I put up a definition of phase.
I believe the "distribution engineers" in the paper. I didn't see where anyone supported the opinion of the author.
And a definition not from a transformer catalog.
Oooh... an new idea. Capacitors are 2 phase. One terminal is 90 degrees out of phase with the other?
This discussion seems to keep going on, continued from prior identical threads on other newsgroups. Each person is repeating the same thing over and over. It is clear that I'm not the only one with too much time on their hands!
Yes, everyone (should) agree with the basic idea of phase. Yes, the grids of push-pull tubes are 180 degrees apart in phase, as are the plates. Yes, the two leads of a simple transformer secondary are 180 degrees apart in phase, regardless of whether there is a center tap or not.
The argument seems to hinge on whether the power grid uses the same definition of phase. Of course it does. But then you confuse "split phase" of a 3-phase power system with the obvious fact that a center-tapped transformer secondary has each side 180 degrees apart from the other. Big deal. You are still referring to the one phase of a 3 phase power distribution system, that is split into two voltages by center-tapping a local distribution transformer.
I think this discussion is comparable to two political parties refusing to acknowledge their positions are just two ways of looking at the same thing. If they agreed, there would be no need for two parties!
Fred
conference of power engineers, where the author/speaker, says there is a 1
80 deg phase relationship, that you do have two phases. He's the authorndary systems are not single phase line to ground systems, instead they are three wire systems with two phases and one ground wires. Further, the stan dard 120/240 secondary is different from the two phase primary system in th at the secondary phases are separated by 180 degrees instead of three phase s separated by 120 degrees."
It's as much opinion as it's opinion that water is formed from
2 hydrogen, one oxygen atoms.
It's not his opinion of how it should be viewed. He clearly states that two phases are present and that is how it has to be correctly analyzed, modeled, etc. If there were not two phases present, it would be really dumb to analyze it that way to come up with a correct and meaningful answer. And it would be pretty dumb for the IEEE, the most credible of sources, to publish a technical paper as an opinion piece. This is something anyone who has taken a first course in EE knows.
He's clearly saying that while it's been called single phase, there are in fact two phases present on the secondary side. He further says that distribution engineers have treated it as single phase, BECAUSE IT's SINGLE PHASE ON THE PRIMARY SIDE OF THE TRANSFORMER. He doesn't say that distribution engineers insist that there is only one phase present at the service panel in the house.
You apparently can't understand the difference betwen engineers casually referring to something from a limited perspective with an accurate engineering analysis of a circuit. It;s like bitching because a hortoculturist calls a peanut a legume and insisting that because it's commonly called a peanut, that's all there is to it and it's just the "opinion" of the misguided hortoculturist.
It's not a viewpoint issue. You can't magically create a phase that does not exist. And that is why you can't give your own basic definition of the engineering term phase. Funny thing. Those of us on the side of the IEEE paper can define it and define it consistently.
In fact, with regard to magic, that is what is required to make your world work. I'll get back to that later.
Just as much as it's opinion that water is made of 2 atoms of hydrogen, one water.
He said no such thing. He said that for it to be correctly analyzed in electrical engineering you have to recognize that two phases are present. And he presented that paper at a room full of power systems engineers, did they toss
I was referring to the crap definition from a tranformer catalog glossary. Is that what they used to define engineering terms where you went to school?
Regarding your phasor obfuscation, who in their right mind uses "phasors" to define phase? Phase is the beginning, the origin, you need to define that before you ever get to phasors. But if you want to draw a phasor diagram of the split-phase service, repersenting the two hot legs and their phase relationship, you have two at the panel, one for each leg, 180 deg apart. At the primary side of the transformer, you have just one.
This from the guy who uses a glossary in a transformer catalog to define phase in electrical engineering terms.
Yes, just like Planters and everyone else views a peanut as a nut. It's a commmon reference. It can be explained where it came from, why it's commonly called that. But it doesn't change the fact that when in scientific terms, it's really a legume. Your argument boils down to exactly that. Because it's commonly called single phase, that's all there can be, just one phase.
On the other side, we can tell you why it's called single phase. It's because it's single phase on the PRIMARY side of the transformer. That is where the distribution system engineers stop looking, stop caring, etc. That doesn't change the fact that there are two phases present coming out of the transformer. It's defined in electrical engineering. You can see it on a scope.
It's the only source you've cited with a definition.
Phase is not a matter of opinion. And it's not this one IEEE engineer at a power conference with an IEEE published paper. I've given you references from electrical equipment manufacturers. Not a glossary definition of phase from a catalog. Actual white papers on split-phase complete with CIRCUIT DIAGRAMS. And they say the same thing, that two phases, 180 deg different, are present.
Still need any kind of teacher for bud to help him learn. I post a detailed reference and he's incapable of realizing that the second example they talk about, where they call it split-phase and say there are two phases present, is the relevant one. Instead bud covers that up and lies, pretending that the first single wire example is all that is there.
You're just losing all credibility now. Sure, the first single wire circuit is labeled as having one phase, "Phase A". So what? That is entirely consistent with everything I've said, what the IEEE engineer says, the other references I've supplied, and those in this thread that agree with me have said.
It's the SECOND circuit that shows split-phase and describes it. It says there are TWO PHASES, Phase A and Phase B and that they are 180 deg apart. Good grief. It could not be any clearer. Yet you won't acknowledge it and instead just keep going back to the single wire circuit, with one phase that is above. Split-phase is NOT a single wire circuit.
All your credibility is gone. They don't just use Phase A as a label. They use both Phase A and Phase B. All these references talk about two phases being present and that they are 180 deg apart.
Behlman:
"The two legs, represented by Phase A and Phase B are 180 deg apart." They go on to say that since they are 180 deg apart, wiring them L-N gives 120V, L-L gives 240V.
Samlexamerica:
"Phase of hot leg 2 (phase B) is in the opposite direction, ie 180 deg apart from hot leg 1 (phase A)."
It's as clear as can be to anyone that will look and learn.
No distribution engineers made any statements in that paper.
Which of course is a lie. I've given you many references, two I;ve posted, yet again, above. They all say two phases are present.
I'm curious. Do you have a degree in electrical engineering? If you do, I'd be embarrassed if I had to go to an tranformer glossary when asked to define phase.
And I'm still waiting for an answer to these simple excercises. They are very easy to answer for anyone that understands electrical engineering:
#1
Those on the other side of this agree that two phase existed
100 years ago. They have no problem with it being called two phase, that was two phase according to them. So, that system had two phases, let's call them A and B and a neutral. Phase B was 90 deg off from phase A. Everyone OK so far? Let's make the voltage from either phase to neutral 120V.Now, instead of having phase B be off by 90 degrees, let's make it off by 120 deg. How many phases are there now? I say two. Let's change it again, so phase B is off by 220 degrees. How many phases do we have now? I say two. Let's change it to being off by 170 deg, how many phases do we have now? I say two. And now, let's change it to be off by 180 deg. How many phases do we have now? I say two. And if it you agree that it is indeed still two, then it is in fact absolutely electrically identical to split-phase 240/120V servic e, so you have two phases there too.
#2
We have 3 phase power coming from a power plant. Everyone agrees that is three phases. So, you have Phase A, B, C and a neutral. Phases A,B, C differ by 120 deg. Let's make the phase to neutral voltage 120V. Now lets eliminate phase C. We have Phase A, Phase B and a neutral. How many phases now? My answer: two. Let's run that into a house panel. So, we have two phases. Instead of 120 deg apart, make them 170 deg apart, or 250 deg apart. How many phases now? My answer: two. Now make them 180 deg apart. How many phases now? If your answer is two, which is should be, then what you have is indistinguishable from split-phase 120/240v service. There is no electrical difference, no test you could perform at the panel, no difference in voltages, current flow, nada.
And if your answer is just one phase, then explain the magic that just happened.
Note that the above treatment of phase is 100% consistent, from a piece of paper, to circuit analysis, to the 3 phases at the generating plant, the two phase system of old, the split-phase of today. The alternate view is apparently that something magical happens at 180 deg phase difference or else because distribution engineers commonly call something single phase, that no further analysis that shows electrically what is going on is required or even allowed.
Yes, they should, but only a few have even tried to define it.
Not true. If a transformer has only two leads, they are *not* 180 degrees out of phase because there is just a single circuit. You can't see two waveforms on a scope, because there aren't two.
Going back to what started all this, someone just said that the two hot legs of a split-phase service are 180 deg apart. krw said that was flat out wrong, that they are just "opposites" Aside from the fact that "opposites" is not exactly an engineering term, what about your push-pull example? Is it not correct to say the output is 180 degrees apart from the input?
It's not a big deal. It's just that you then have a 3 wire circuit with two phases present that are 180 deg apart. You can see it on a scope.
Who is the you? And just because it's common to refer to something as one thing, does that make it so? If everyone calls a peanut a nut, does it make it one? My guess would be that those stuck on the other side of this call it single phase because the PRIMARY of the transformer is on a single phase. That doesn't change the physics of what is on the secondary side. Also, in your experience, can you cite an example where you split something and still have just one thing? It is called "split-phase".
If you believe the last nonsense, I can see why you're totally confused.
If the secondary winding had 9 equally spaced taps, how many phases would you have then?
You would still have two phases.
I haven't seen anyone recently write an engineering paper about what water was made from.
The IEEE paper is the authors opinion. It is not the same as the view of "distribution engineers".
Would that be like your source that shows a single-phase 2-wire circuit with the hot wire labeled "Phase A"? And then a split-phase circuit with "Phase A" and "Phase B"?
You have to label them something.
I agree.
The primary is single-phase. So is the secondary.
I did give a definition. At least 4 posts ago. It uses phasor math. It seems to have disappeared.
Did anyone agree with him.
And what is the point of what he said. I have no idea because I have not read the paper that was abstracted. Perhaps you have.
My definition used phasors. (It seems to have disappeared).
Phasors (or the math behind them) are used to analyze multi-phase circuits.
Both on the "real" axis which is trivial and does not require phasor math.
I thought Danny might be reading.
Distribution engineers are not concerned about power delivery up to the customer? News to me.
The 2-wire example shows "Phase A" is used as a label.
They said there was a "Phase A" with only 2 wires?
So I can not conclude they have been convinced by the paper.
I said (still quoted above) my definition was not from a transformer manufacturer.
I defined "phase" by use of the tool that is used to analyze multiple phases - phasors. (My definition seems to have disappeared).
What you label them may depend on context. An electrician might label three wires L1, L2 and N.
Fred
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