As previously posted, in the second half of the abstract the author suggests a _change_ from the standard practice and wants to call split-phase 2 phase. No vote on his suggestion is recorded. In the first half the author says the standard practice is to call split-phase single-phase.
The abstract does not agree with you.
I seem to remember the state of matter being called "phase". So you have two phase oil (liquid / gas).
Did not know that.
I was thinking it started out to be a fighter but there was a sudden need for the spy plane when the U2 was shot down.
No. 240/480V was only used on farms in very remote areas, and there were probably no new installations of this type since WWII (and there maybe none left by now, having all been upgraded to 3-phase).
It's not necessary elsewhere here because we run 230V 3-phase down each street, so houses which need more than 1 phase get a 3-phase 230/400V supply. (In reality, it's 240/415V for historical reasons.)
That doesn't work with the US 120/240V, because, to a first approximation, you can only carry it a quarter of the distance before the voltage regulation goes too bad (and the low power pole mount transformers actually make this much worse). This means you have to carry the high voltage supply down each street and use regularly spaced pole transformers to generate the 120/240V supplies. To keep costs down, there's usually only 1 of the 3 phases from the HV supply carried down each street, so you don't generally have access to a
3-phase supply in any one residential street.Construction sites here use a safety supply of 110V with earthed centre-tap, i.e. 55-0-55 for single phase and 65/110V for 3-phase, but the 0V connection is only grounded at the transformer and carried to tools as a protective ground conductor, and never used as a power conductor, so these are never described as 55-0-55 or 65/110V supplies, because there's no neutral connection. This is designed to prevent electrocution of construction workers if a tool gets dropped into a puddle or the cord is damaged or something similar, as the highest voltage to ground is only 55 or 65V.
This safety supply used to be mandatory on UK construction sites. It's no longer mandatory (that would be contrary to EU rules on movement of workers and products), but it's what you'll still find on all UK construction sites.
The above post and other replies indicate that knowledge is more important than jargon. In terms of poly phase jargon, think of a symmetrical 4-phase system with neutral. What we call 2-phase really is a subsystem of two adjacent phases. Two opposite phases give you an Edison system. You can get other such combinations.
In principle, as long as you have at least two phases other than completely in-phase (three or four wires) or completely out of phase, you can use transformer combinations to give you any phase combination you like. The Scott T-connection happens to be the one that converts between 3-phase and 2-phase (adjacent phases of a 4-phase) system.
We run 3-phase down most streets, too. In many places, each house has its own transformer. Three-phase makes distribution simpler but split-phase gives the flexibility that you have, using more than one phase, in a simpler manner.
Irrelevant.
Wrong. Except in rural areas, the 3-phase HV *is* distributed on each street with, at most, a few houses on each transformer. In rural areas they may only have one phase on the pole but there is a transformer there, too.
The only scales a slide rule needs are the 'C' and 'D' scales. The rest are optional and included based on the target market. ...sorta like calculators.
That must have been an abridged version. The full handbook is about the size of three encyclopedia volumes.
Sure. Three significant digits is good enough for 99% of the engineering tasks out there. Two probably covers it.
Right you are. It came from a design for an interceptor, the YF12. The original plane was intended to shoot down Soviet bombers. Ballistic missiles shot those plans down.
No, it's the liquid phase going into the furnace and the gaseous phase coming out. The furnace is a "phase converter". Coal and wood burners are the same deal.
Though you have a point. Perhaps an LP fired furnace is a better example.
Propane furnaces use both liquid and a gas propane.
But doesn't a phase converter manufacture just the third phase? So how would three phase motors run off of it if single phase is actually just one phase? There must actually be two incoming phases. That's why it makes sense to me that the term single phase is a misnomer at least on the secondary side of the utility transformer. Other misnomers if you're really bored:
Depending on how you look at it. In any case, how do you think it "manufactures" that third phase. The induction motor becomes a motor-generator.
Nope. Only one.
Words mean things. You're wrong.
Except "single phase" is *not* a misnomer.
You are in fact exactly correct.
If you have three distinct conductors that are not connected to each other, it is defined as a 2 phase system.
Between any two conductors there is just one phase. Hence if any one of the three conductors is labeled as "Neutral", the other two are Phase 1 and Phase 2. (If there are 40 conductors, there are 39 phases.)
The magic about 180 degree phase shift is not really magic. No matter what the phase relationship is, there is a single phase between any two conductors. Of course with a two phase system the voltage between the two non-neutral conductors will be greatest if the phase relationships to neutral are 180 degrees different. It will be minimum of course if the phase relationships are 0 degrees.
The same significance for a three phase system occurs of course with 120 degree phase relationships.
No, that is most certainly *not* what the discussion was ever about. I never said it was commonly called two phase. No one else ever said it was called that either. Like the IEEE engineer that delivered the paper at the power engineering conference, I simply said that in fact from an electrical engineering perspective, there are two phases present. The references I've cited from electrical eqpt manufacturers, etc, say the same thing. They explicitly talk about two phases being present. Are they all nuts too?
I'd also point out that this whole thing started when a poster pointed out that one hot on a split-phase service is 180 deg out of phase with the other. That is what krw said was wrong, that they are not 180 deg out of phase, they are "opposites". That is about as dumb a thing as one can imagine. I've given probably 10 references now, including about as credible a refernce as you can get, a paper delivered at an IEEE c 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 of a whole bunch of very technical papers on power engineering, all published by the IEEE, a peer reviewed group. Is he and the IEEE nuts too?
"Which now brings into focus the reality that standard 120/240 secondary sy stems are not single phase line to ground systems, instead they are three w ire 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 s econdary phases are separated by 180 degrees instead of three phases separa ted by 120 degrees."
Page 2: Explicitly talks about split-phase consisteing of two phases, A and B and that they are 180 deg opposite each other.
Says the same thing.
And I'd also note that none of those references say it's called two phase either. Just that there are in fact two phases present.
It's properly called "split-phase", everyone agrees on that. When you spli t something, can you give us an example of a case where you still have just one of those things? In quantum physics I guess, but not in the everyday world. The argument that because it's commonly referred to as single phase doesn't change what's there. It's like saying that because you call something Kleenex, it's not also correct that when you analyze it, it's a soft paper tissue. Or that because water is called water, when you correctly analyze it, it's not H20, made up of hydrogen and oxygen. From the power company's perspective, split-phase originates from one of their 3 primary phases. So, I'm guessing, that is the historical reason that it's frequently just called single phase service, to distinguish it from the other common power source, 3 phase.
And I'm still waiting for someone on the other side of this to provide their definition of the engineering term "phase". How can people make post after post, yet no one can define a very basic term? Good grief. Or to address the simple excercise in phase, where I go from what you all say is a true two phase service to split-phase, just by changing the phase difference? Split-phase either has two phases present, or else something magical happens at 180 deg, as you slowly change the phase from 90, to 120, to 179, to finally 180. How can there be two phases at every other possible phase angle, but not at 180?
You mean the centertap that is tied to the neutral and earthed? The zero potential point for all 120V loads? THAT reference point? It's the most logical reference point when analyzing the system in question. It's not like someone is talking about using Mars as a system reference point.
No confusion here.
Not much to go on there. But depending on the number of conductors, and how it's tied together, if at all, whether the generators are running in synch or not, then sure it makes a big difference in how many phases are present.
The IEEE says you're wrong. From an IEEE paper delivered at a conference of power engineers and published by the IEEE. It directly addresses the specific issue:
"Which now brings into focus the reality that standard 120/240 secondary sy stems are not single phase line to ground systems, instead they are three w ire 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 s econdary phases are separated by 180 degrees instead of three phases separa ted by 120 degrees. "
Check out the author's credentials, all the highly technical papers he's had published by the IEEE.
Your response..... crickets and name calling.
Still waiting for your answer to the simple question asked a dozen times now. What is your definition of the electrical engineering term "phase"? How can you keep posting about something, yet you can't even define it?
Still waiting for an answer to the simple exercise I presented. We have what I believe you acknowledge is a two phase system used to deliver power in the past. It had two phases and a neutral. One phase was 90 deg off from the other. That had two phases, right?
OK, so now I change the phase relationship so they differ by 120 deg. How many phases now? Still two? I make it 220 deg. Still two? I make it 175 deg. Still two? I make them differ by 180, how many phases do I have now? And if the latter is still two phase, it's electrically indistinguishable from what you have on a 240/120V split phase service.
All simple questions, that even a high school student could answer, but we have no answers, just crickets and insults.
You keep proving that you're illiterate. You really are getting as bad as Malformed.
It is what I attempted to convey it too few words.
If I remember right, there are bathroom outlets that are connected the same.
How does the EU get involved.
As I have responded twice already, the author is suggesting a change from how "distribution engineers" view this - that is in the first (missing) sentence. The author suggest a change to view split-phase as two phases. Where did anyone agree with him?
This source ("distribution engineers") supports my view.
Maybe we need an english teacher, not an engineer.
Thats the one with a 2-wire circuit, hot and neutral, with the hot labeled "Phase A"
For my amusement I looked at a major transformer manufacturer.
Eaton defines "Phase: Type of AC electrical circuit; usually single-phase two- or three-wire, or three-phase three- or four-wire".
I would define a meaningful use of "phase" as using the "imaginary" axis in a phasor representation. Split-phase uses just the "real" axis.
Eaton has no single phase transformers with 2 phases on the secondary.
The specific question is whether in US distribution, split phase
240/120V has "2 phases", phase A and phase B? Is the centertapped secondary "single phase"? When "phase B" is negative "phase A" does it make sense to talk about 2 phases?Relatively small 480/277V to 208/120V wye transformers sometimes use 2 transformers with a Scott connection. The transformers operate at true
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