Why is residential wiring known as single phase?

[mivey]

"energy in the wire"

"energy in the wire"

On energy flowing in a wire:
I'll address energy flow one more time even though I haven't heard but one member say that energy is not carried in the electromagnetic fields. The idea that energy is carried in the wire by the electrons acting like coal cars is just pure ignorance of how electricity works. The electrons do not scoop up energy and drop it off at the load as they pass by. I do not believe any competent electrical engineer on this forum thinks that way; but it would not be my first surprise.

The simple analogy of an electron picking up a measure of energy and transporting it through a medium to the load at the other end is just wrong. Simple coal-car type analogies are sometimes used at a very elementary level to talk about electricity but really only create a stumbling block for those that go on to learn more in the future. There is some energy in the wire that is dissipated in ohmic losses but the energy to the load is carried in the electromagnetic field surrounding the wire. The energy in a coaxial cable travels in the field between the outer and inner conductor.

Energy travels towards the load, not necessarily in the direction of current. Current is charge flow and is not the same thing as energy flow. Current (charge flow) moves very slow as compared to energy which flows at near light speed. Current and energy flow can be in opposite directions.

Whether the ignorance about how electricity works is a result of a bad student or a bad teacher does not really matter at this point. What matters is that if someone does not understand that energy is carried in the electromagnetic wave, it is time they got their education up to date. I'll be glad to help someone who really wants to learn, but there is little help for someone who has no desire to learn.



If anyone here has this "energy in the wire" misconception or may have been confused by some mis-informed posts by those lacking sufficient knowledge, let me give you some food for thought before you speak without thinking:

What causes EMF problems if the energy is contained in the wires? Why does the EMF problem decrease as the wires are brought together?

What causes inductive heating if the energy is contained in the wire? Why does keeping the wires together fix this problem?

Electrons do not jump the gap in a capacitor neither do they jump the gap in a transformer, but the energy still gets through.

If an electron is carrying energy to the load as it flows from the source to the load, then a different electron would take energy from the load as it flows from the load to the source and the load would get a net zero delivery of energy.

 

[rbalex]

On"not in-phase" waveforms having the same phase:
The truth of the matter is for phase-opposed waves, you can invert one of thewaveforms and the inverted waveform will have the same phase points as theother waveform. In other words, the inverse of one wave is in phase with theother wave. Nothing new, and we all know this.

Thanks for the confirmation.

But to say both original waveforms have the same phase is incorrect. Our industry does not agree with that, reference texts do not agree with that,….

IEEE Std. 100 agrees with it

…, textbooks do not agree with that…

rattus’textbook agrees with it. see Post 1493

… and our universities do not teach that.

I have no idea what your school failed to teach, but my school was tired of ex-military technicians who had "Jungle Fever" coming in like they knew something no one else in the class including the professors did. Most were cured. There were a few addicts.

… Anyone who says both original waveforms have the same phase is simply misinterpreting the definition of phase because that interpretation conflicts with the way the rest of our industry interprets the definition of phase...

Are you saying the “Oscilloscope Jungle” represents the “rest of the industry”? Sorry there's obviously a significant part that doesn't agree with you.

…The phase constant is defined by the initial conditions of the waveform...

YES – thanks for explaining that to rattus.

… It is silly to say that there is a phase constant plus some other adder that can be removed because it only results in a negative sign...

Adder no - operation yes. Does that mean you don’t understand trig identities any more than rattus?

… Anyone familiar with the physicsof oscillating systems and the accompanying math knows that is the same as saying two springs moving in opposite directions is the same as two springs moving in the same direction. It just ain't so, and you will not find acredible reference that says it is the same…

If they have the same period and frequency – they have the same phase. P hase is defined in terms of the direction of time – not the direction of motion.

…
What the trig reduction says is that if we have two springs oscillating inopposite directions, and we reverse the direction of one spring, then the twosprings will oscillate in the same direction. Well duh.

Yeah– so? Seeabove.

 

[gar]

120301-1954 EST

Rick:

We are talking about two voltage supplies connected to three terminals. It matters not what the actual device or devices are if those devices produce voltages like those from the center tapped transformer.

If I have one voltage source connected to two terminals, and from this same voltage source that signal travels thru a delay line of exactly one period to a second pair of terminals. From measurements at those terminals can you identify which terminals are at the output of the delay line? Obviously we assume the output impedances and source voltages are the same at both sets of terminals.

.

 

[Rick Christopherson]

Rick:

We are talking about two voltage supplies connected to three terminals.

No we are not. We are specifically discussing a single-phase, center-tapped transformer.

It matters not what the actual device or devices are if those devices produce voltages like those from the center tapped transformer.

I am well aware that there are other means for producing the same voltage representations that may or may not be either physical inversions or physical phase shifts. Mivey's generator example is one where there is a physical phase shift and only a mathematical inversion. If someone were to claim that this inversion was not mathematical, then I would be contesting that statement with equal fervor (except it doesn't apply to the discussion).

If I have one voltage source connected to two terminals, and from this same voltage source that signal travels thru a delay line of exactly one period to a second pair of terminals.......

If that were the setup, then you wouldn't be getting an argument from me because that would be a real phase shift that could be mathematically represented as being directly in-phase (1 full period).

I am not arguing about how people want to define phase or phase shift or whatever they happen to be arguing. What I am arguing is when someone refers to a mathematical transformation as though it is a real-world transformation. For the most part, I don't recall your postings ever making this mistake. It is Rattus, Besoeker, and sometimes (but not as often) Mivey.

 

[rattus]

Yes, I've done it repeatedly. But then, I've gone through the exercise of deriving the more complex derivatives in calculus from the simple derivatives.

All right then. Show us how to use the identity to prove the impossible!

 

[mivey]

Thanks for the confirmation.

You're welcome. Not the first time I said that either.

IEEE Std. 100 agrees with it

It does not. You are misrepresenting the text.

rattus?textbook agrees with it. see Post 1493

It does not. You are misrepresenting the text.

I have no idea what your school failed to teach, but my school was tired of ex-military technicians who had "Jungle Fever" coming in like they knew something no one else in the class including the professors did. Most were cured. There were a few addicts.

I don't believe your school taught what you are saying. Rather, I think you were not paying attention and made up your own version of what was said much like you do here. However, if they did teach that, your professors were morons.

Are you saying the ?Oscilloscope Jungle? represents the ?rest of the industry?? Sorry there's obviously a significant part that doesn't agree with you.

Prove it. I have provided you with over two dozen examples of where you are wrong. You have provided nothing to support your made-up ideas other that twisting the meaning of the words around.

YES ? thanks for explaining that to rattus.

He knows that and has said the same. As usual, you only hear what you want to hear.

Adder no - operation yes. Does that mean you don?t understand trig identities any more than rattus?

It means I understand them better than you because I know the trig identities do not make the wild claims you make about "not in phase" voltages having the same phase. They are just trig identities.

If they have the same period and frequency ? they have the same phase. Phase is defined in terms of the direction of time ? not the direction of motion.

Clearly you learned at the feet of morons or just heard what you wanted to hear in class.

 

[mivey]

...What I am arguing is when someone refers to a mathematical transformation as though it is a real-world transformation...

Rick, can't you accept the idea that a reversed direction in a winding is a physical transformation as well? It may not agree with your idea of a phase shift, but with all due respect, it is not your idea of a phase shift that is the issue.

Do you not agree that in my open-wye example the X1->X2+X3->X4 results in a 0? voltage while the X2->X1+X6->X5 produces a 120? voltage? Can you not see that the winding reversal is recognized to produce an angle difference? It may not agree with your idea of a phase shift, but we are talking about what is recognized as a difference in phase in this common configuration.

I agree that it does not fit some definitions of a phase shift, but it does fit the definition as it is used in utility transformer banking.

 

[Rick Christopherson]

Rick, can't you accept the idea that a reversed direction in a winding is a physical transformation as well?

Of course. That is a physical transformation. It is an inversion. You apparently want to claim that this is a physical phase shift, instead of it being a physical inversion that mathematically equals a phase shift.

It may not agree with your idea of a phase shift, but with all due respect, it is not your idea of a phase shift that is the issue.

Well, it is at issue, for as long as you guys want to take the discussion out of the ideal/mathematical realm and claim it to be "real". You're fairly careful to say the "voltages are real" and I do not contest that. What I contest is when someone claims the phase shift is real.

 

[mivey]

Of course. That is a physical transformation. It is an inversion. You apparently want to claim that this is a physical phase shift, instead of it being a physical inversion that mathematically equals a phase shift.

Well, it is at issue, for as long as you guys want to take the discussion out of the ideal/mathematical realm and claim it to be "real". You're fairly careful to say the "voltages are real" and I do not contest that. What I contest is when someone claims the phase shift is real.

Please clarify.

How would you classify the phase angle of the V@120? voltage produced in my open-wye example that comes from X2->X1+X6->X5?

How do you differentiate it from the phase angle of the 2V@0? voltage that comes from X1->X2+X3->X4?

 

[Rick Christopherson]

Please clarify.

How would you classify the phase angle of the V@120? voltage produced in my open-wye ......

That would be a real phase shift. No argument there.

 

[mivey]

That would be a real phase shift. No argument there.

Then I'm still not following you.

Two of the pre-existing voltages (V@0? and V@240?) are made up of voltages from winding halves taken in one direction. The V@120? voltage, which you just said is a real phase shift, is made up of voltages from other winding halves taken in the opposite direction.

If voltages in opposite directions in the winding halves produce a real phase shift for both of the single-phase transformers, why do you say it does not when we just look at one of the single-phase transformers?

 

[Rick Christopherson]

Then I'm still not following you.

Frankly, I didn't bother wasting the time to figure out what example you were referring to because you never said which one you were referring to. Nor do I care. (I saw 120 degrees and wye).

Is there some reason why you can't stay on-topic? We're discussing a single-phase, center-tapped transformer.

 

[mivey]

Frankly, I didn't bother wasting the time to figure out what example you were referring to because you never said which one you were referring to. Nor do I care. (I saw 120 degrees and wye).

Is there some reason why you can't stay on-topic? We're discussing a single-phase, center-tapped transformer.

My example uses single-phase, center-tapped transformers.

 

[Rick Christopherson]

My example uses single-phase, center-tapped transformers.

For some reason you keep thinking I am contesting the mathematics. I'm not. Your example neither proves nor disproves anything I have been discussing.

 

[rattus]

Realists:

Realists:

For those of you who think the real world must be considered, let me say this:

In the OP's original question, there is no mention of currents, loading, power factor, etc. So, we replace the transformer with two ideal sources connected to provide equal voltages and opposing angles. There is no need to consider the windings, turns ratio, wire size, magnetic material, leakage reactance, or anything else about the real world. We know it's there, but we don't care. So please knock off the real world blather.

The issue at the moment is the validity of rbalex's claim that all waveforms in a split phase system exhibit the same phase. So far the only reference we have heard is a story about a college lecture--hardly satisfactory. You would think this "trick" would appear in textbooks or handbooks if it were valid.

 

[Rick Christopherson]

For those of you who think the real world must be considered, let me say this:

You claim that all you are discussing is ideal systems, which means they are mathematical. I would not be making an argument if you kept your discussions within that realm. You three are the ones that broached the boundary into a discussion of real versus mathematical phase shift.

Each of you three, has brought up the notion of the phase shift being real!

Lest you doubt that, I pulled up one example for each one of you (My emphasis will be in red):

It isn't mathematically represented. <emphasis by Besoeker>
It's what happens in real life.
It's real.

So it is a physical fact, not just a mathematical equivalent, that we have 0? voltages and 180? voltages across the windings. The difference is which reference frame you use, but both are physical realities.

In other words, we have both in-phase voltages and phase-opposed voltages at the transformer.

No, we are not saying N must be used. We are saying that it is convenient and logical to do so, then V1n and V2n are as Bes says antiphase. They don't just appear to be so, they are. After all, V1n and V2n are what is seen on the bus bars in a residential panel.

So you see, the three of you brought it from the ideal, mathematical realm and made it a real world discussion. Furthermore, even when called out on it, you continually refused to retract these assertions. I wouldn't be arguing any point if you three had simply left the discussion in the ideal/mathematical realm.

 

[mivey]

So it is a physical fact, not just a mathematical equivalent, that we have 0? voltages and 180? voltages across the windings. The difference is which reference frame you use, but both are physical realities.

In other words, we have both in-phase voltages and phase-opposed voltages at the transformer.

So you see, the three of you brought it from the ideal, mathematical realm and made it a real world discussion. Furthermore, even when called out on it, you continually refused to retract these assertions. I wouldn't be arguing any point if you three had simply left the discussion in the ideal/mathematical realm.

Why retract it when I can prove it?

 

[pfalcon]

All right then. Show us how to use the identity to prove the impossible!

Rbalex is arguing the proofs. You made the following claim. As always a presumptive dismissal of an opposing argument claiming a consensus that doesn't exist.

... BTW, I have never seen trig identities used in that manner. I doubt that anyone else has either. ...

For those of you who think the real world must be considered, let me say this:

In the OP's original question, there is no mention of currents, loading, power factor, etc. So, we replace the transformer with two ideal sources connected to provide equal voltages and opposing angles. There is no need to consider the windings, turns ratio, wire size, magnetic material, leakage reactance, or anything else about the real world. We know it's there, but we don't care. So please knock off the real world blather.

The issue at the moment is the validity of rbalex's claim that all waveforms in a split phase system exhibit the same phase. So far the only reference we have heard is a story about a college lecture--hardly satisfactory. You would think this "trick" would appear in textbooks or handbooks if it were valid.

Well, since the width of railroad tracks traces back to horses we'd probably never be able to answer your questions about railroads with those presumptions either. Questions beg for supporting evidence that is rarely contained in the question. But then the OP actually did mention windings. And the OP actually did ask it as an open ended question.

Every sparky knows he's working with 2 phases in a standard residential panel, and better not get them mixed up! If I have to be careful with tandem breakers, and not getting my multi-wire legs on the same phase etc., how does "single phase" apply?

Because they pull off opposite ends of the same utility transformer (ie. one winding)? Because they cancel out on the neutral with 240V? Or is it a misnomer. I've always been curious about this.

But then rattus, that wasn't really the point. In one post you unilaterally dismissed all other evidence other than that which you wanted to provide. Drat all those pesky real-world parts of a 120/240 system that interfere with the rattus interpretation of the system.

 

[pfalcon]

On energy flowing in a wire:
I'll address energy flow one more time even though I haven't heard but one member say that energy is not carried in the electromagnetic fields. The idea that energy is carried in the wire by the electrons acting like coal cars is just pure ignorance of how electricity works. The electrons do not scoop up energy and drop it off at the load as they pass by. I do not believe any competent electrical engineer on this forum thinks that way; but it would not be my first surprise.

You would be the member that's posted about coal cars. And when I've mentioned trains it's been about current and the induced field. So from the above you've stated that we should not consider you a competent engineer.

The simple analogy of an electron picking up a measure of energy and transporting it through a medium to the load at the other end is just wrong. Simple coal-car type analogies are sometimes used at a very elementary level to talk about electricity but really only create a stumbling block for those that go on to learn more in the future. There is some energy in the wire that is dissipated in ohmic losses but the energy to the load is carried in the electromagnetic field surrounding the wire. The energy in a coaxial cable travels in the field between the outer and inner conductor.

Yea, I think I've mentioned electrons wiggling back and forth like they were part of a train. But the coal cars, and the "picking up" and "transporting" are all you Mivey.

 

[rattus]

Where is the reference??

Where is the reference??

Where is the reference? Where is the support for this ridiculous claim? I have seen none. No one else has seen one because there is none. No not a math handbook. I have one of those. Where is the verbiage that proves you can use the identity to make a constant disappear? Until someone provides a valid reference, your position is untenable.

You cannot simply ignore the negative sign before sin(wt). It is the operator that shifts the sine by PI radians--nothing else

All this blather about the real world does nothing to prove your point.