Why is residential wiring known as single phase?

[mivey]

120302-2124 EST

I may have found an indirect definition of what rbalex is using for his argument that "same phase" implies that a center tapped transformer is single phase.

Which, as you have demonstrated, makes his argument about as solid as a bog.

Am I getting to the root of the problem?

I believe I identified the root of the problem in Post # 1626

 

[rbalex]

120302-2124 EST

I may have found an indirect definition of what rbalex is using for his argument that "same phase" implies that a center tapped transformer is single phase.
...

Sorry gar, although attempting to change references seems to be one of the Tribes most common tactics, I'm satisfied with using the definition rattus provided, and I don't intend to contend with another.

Phase: Phase is the fractional part of a period through which time or the associated time angle wt has advanced from an arbitrary reference.
[Kerchner and Corcoran, Alternating-Current Circuits, Wiley, 1951]

All relevant voltage functions for a conventional 120/240V system, however validly determined, measured from whatever reference point, line or neutral, in any direction, or not measured at all, have a mathematically identical phase; i.e., throughout any given period, assuming a common t₀, at any time t, they all have the identical, "... fractional part of a period through which time or the associated time angle wt has advanced from an arbitrary reference."

For a conventional 120/240V system, t₀ must be common for each voltage function.

While phase is an element of the definition of all sorts of phenomena, including "in phase", all sorts of phenomena, including "in phase", are not elements of the definition of phase. The only independent variable for phase as defined is time - not position, spatially or otherwise.

If you care to support your analysis with Kerchner and Corcoran's definition, feel free.

 

[jim dungar]

I think JD is playing games and pretending he did not get what you said. I'm pretty sure he gets it.

I provided the exact quote as well as its source. I am not playing games.

 

[jim dungar]

There you go again, yet you want to protest when I say 'ergo' you make claims of "real" and "not real".

Where have I said not real or fake or imaginary.

Lets try it again.

Vbn=-Vnb, Vbn=-Vnb, Vbn=-Vnb, Vbn=-Vnb, Vbn=-Vnb, Vbn=-Vnb, Vbn=-Vnb, Vbn=-Vnb, Vbn=-Vnb, Vbn=-Vnb, Vbn=-Vnb.


You need to expand your vocabulary, if you think words like arbitrary and appearance are 'first choice' technical synonyms for 'not real'.

 

[jim dungar]

Perhaps some terminal numbers will help you understand that what I drew is the same as what was said. I'll add them.

I already explained how it is your arbitray assignment of these subscript that is proving your point, not the physical connection.
It is hard to follow your refute argument. You are showing X1 and X0 for the sorce side and you mix transformer and generator. Then you proved a description of the 'right' side only.


Are you claiming the waveforms for Vleft is not 'in-phase' with Vright'? Should we ask Besoeker to post a scope tracing?

 

[rattus]

FWIW, here is a question asked on cramster.com.

"In the equation for simple harmonic motion x=Acos(ωt+δ) I know that the ωt+δ is the phase and that the δ is the phase constant...."

One would assign different values to δ, i.e., 0 and PI. Since we already have a clear definition for phase, why mess with it?

Now, that is not much of a reference, but it is better than rbalex has supplied.

 

[mivey]

I provided the exact quote as well as its source. I am not playing games.

OK then, I guess you really don't get what he is saying.

 

[mivey]

Where have I said not real or fake or imaginary.

Right here:

One is an actual physicality.
One is an actual mathematical manipulation.

Lets try it again.

Vbn=-Vnb, Vbn=-Vnb, Vbn=-Vnb, Vbn=-Vnb, Vbn=-Vnb, Vbn=-Vnb, Vbn=-Vnb, Vbn=-Vnb, Vbn=-Vnb, Vbn=-Vnb, Vbn=-Vnb.

One is not two. One is not both. If it is not both then one is excluded.
One is not two. One is not both. If it is not both then one is excluded.
One is not two. One is not both. If it is not both then one is excluded.
One is not two. One is not both. If it is not both then one is excluded.
One is not two. One is not both. If it is not both then one is excluded.
One is not two. One is not both. If it is not both then one is excluded.
One is not two. One is not both. If it is not both then one is excluded.
One is not two. One is not both. If it is not both then one is excluded.
One is not two. One is not both. If it is not both then one is excluded.
One is not two. One is not both. If it is not both then one is excluded.
One is not two. One is not both. If it is not both then one is excluded.

You need to expand your vocabulary, if you think words like arbitrary and appearance are 'first choice' technical synonyms for 'not real'.

Physical is real. The math models the real but you think it does not.
Physical is real. The math models the real but you think it does not.
Physical is real. The math models the real but you think it does not.
Physical is real. The math models the real but you think it does not.
Physical is real. The math models the real but you think it does not.
Physical is real. The math models the real but you think it does not.
Physical is real. The math models the real but you think it does not.
Physical is real. The math models the real but you think it does not.
Physical is real. The math models the real but you think it does not.
Physical is real. The math models the real but you think it does not.
Physical is real. The math models the real but you think it does not.

 

[mivey]

I already explained how it is your arbitray assignment of these subscript that is proving your point, not the physical connection.
It is hard to follow your refute argument. You are showing X1 and X0 for the sorce side and you mix transformer and generator. Then you proved a description of the 'right' side only.

It proves that both 0? and 180? are physical voltages at the same winding. It disproves that only one is physical while the other is just a math manipulation. They are both physical voltages.

Are you claiming the waveforms for Vleft is not 'in-phase' with Vright'? Should we ask Besoeker to post a scope tracing?

I am claiming the negative of on waveform is in phase with the positive of the other. To use the industry standard terminal labels, we have two things to note about the match-up at the terminals:

1) In one half of the center-tap winding we physically have the voltage from X0->X1 in phase with V@0?

2) In the other half of the center-tap winding we physically have we have the voltage from X0->X1 in phase opposition with V@0? (also the voltage from X1->X0 is in phase with V@0?).

If we consider the physical reference from the left, we have 0? and 180? voltages. If we consider the physical reference from the right, we have two 0? voltages. Both are actual physicalities. Both voltage sets physically exist in the same space between the terminals.

 

[rattus]

I already explained how it is your arbitray assignment of these subscript that is proving your point, not the physical connection.
It is hard to follow your refute argument. You are showing X1 and X0 for the sorce side and you mix transformer and generator. Then you proved a description of the 'right' side only.


Are you claiming the waveforms for Vleft is not 'in-phase' with Vright'? Should we ask Besoeker to post a scope tracing?

Jim, are you comfortable working with phasors?

 

[rattus]

Another informal defintion of phase:

Another informal defintion of phase:

"The quantity φ is called the phase constant. It is determined by the initial conditions of the motion. If at t = 0 the object has its maximum displacement in the positive x-direction, then φ = 0, if it has its maximum displacement in the negative x-direction, then φ = π. If at t = 0 the particle is moving through its equilibrium position with maximum velocity in the negative x-direction then φ = π/2. The quantity ωt + φ is called the phase."

 

[rattus]

MORE

MORE

The complete article about simple harmonic motion can be found at:

http://electron9.phys.utk.edu/phys135d/modules/m9/oscillations.htm

 

[Rick Christopherson]

It proves that both 0? and 180? are physical voltages at the same winding. It disproves that only one is physical while the other is just a math manipulation. They are both physical voltages.

You are using "Prove" and "disprove" a little too liberally there, Mivey. Your example neither proved or even demonstrated that the phase angles were real. It did demonstrate that they are mathematically equal, and no one has disputed that. Please explain how you think it proves/demonstrates that the phase angles are real and not mathematical?

The reason why it does not prove that they are real versus mathematical, is because I could re-solve that same problem and incorporate the same mathematical manipulations that you guys use in the normal 120/240 system with exactly the same results--as should be expected.

The only way you can prove that the phase angles are real and not mathematical is to use something similar to my example.

 

[mivey]

Please explain how you think it proves/demonstrates that the phase angles are real and not mathematical?

Coming from the left side of my generator, the phase-opposed voltages are the result of a real physical shift produced by rotating one generator 180?. These are voltages with a real 180? phase angle between them.

Coming from the right side, we have the series additive voltages that have a 0? displacement in one linear direction across the winding. These are voltages with a real 0? phase angle between them.

When tied together, both the in-phase voltages and the phase-opposed voltages are occupying the same space between the center-tap transformer terminals. That demonstrates that both voltages occupy the same space and both voltages with their associated phase angles are really present.

The presense or absense of the left side voltages does not suddenly make the 180? voltages appear and disappear. The physical truth is, they were really there all along but just may not have been recognized as actually being there.

The reason why it does not prove that they are real versus mathematical, is because I could re-solve that same problem and incorporate the same mathematical manipulations that you guys use in the normal 120/240 system with exactly the same results--as should be expected.

Well sure you could because the math is just modeling the physical.

The only way you can prove that the phase angles are real and not mathematical is to use something similar to my example.

Your example is related to a time shift. I agree that we do not have a time shift. A phase shift does not have to mean a time delay. Three-phase generators produce waveforms that all start at exactly the same time but are physically shifted in phase relative to each other.

 

[Rick Christopherson]

Well sure you could because the math is just modeling the physical.

Correct. It is modeling the real. You are presenting it as though it causes the real.

Your example is related to a time shift. I agree that we do not have a time shift. A phase shift does not have to mean a time delay. Three-phase generators produce waveforms that all start at exactly the same time but are physically shifted in phase relative to each other.

This is an important distinction. Mathematically a phase shift may not require a time shift, but a real one does. That is why my example clearly demonstrates that the phase shift is mathematical and not real.

 

[mivey]

Correct. It is modeling the real. You are presenting it as though it causes the real.

This is an important distinction. Mathematically a phase shift may not require a time shift, but a real one does. That is why my example clearly demonstrates that the phase shift is mathematical and not real.

Rick, in the utility industry we "shift" phases in transformer banks. They do not create a time shift like we would be concerned with in audio, but it is still recognized as a phase "shift" in the electrical world. Call it a phase displacement if it makes you happier.

The shift, displacement, difference, or whatever you want to call it that takes place by using voltages in different directions in the transformer is considered a real physical difference in phase, not just a math difference. That is what my open-wye example demonstrates.

 

[Rick Christopherson]

Rick, in the utility industry we "shift" phases in transformer banks. They do not create a time shift like we would be concerned with in audio, but it is still recognized as a phase "shift" in the electrical world. Call it a phase displacement if it makes you happier.

The shift, displacement, difference, or whatever you want to call it that takes place by using voltages in different directions in the transformer is considered a real physical difference in phase, not just a math difference. That is what my open-wye example demonstrates.

No, you are creating inversions that can be mathematically represented as phase shifts. Contrary to some of the other discussions here, I am not basing my comments on what the industry may use as "commonly recognized". Some people in the industry may call them the same because they are mathematically equivalent, but it is wrong to call them real.

 

[mivey]

No, you are creating inversions that can be mathematically represented as phase shifts. Contrary to some of the other discussions here, I am not basing my comments on what the industry may use as "commonly recognized". Some people in the industry may call them the same because they are mathematically equivalent, but it is wrong to call them real.

I understand what you are saying. And I agree with the technical "flag on the play" you threw. But it is how the inversions we are discussing are used and referenced by our industry.

 

[Rick Christopherson]

I understand what you are saying. And I agree with the technical "flag on the play" you threw. But it is how the inversions we are discussing are used and referenced by our industry.

It is probably perfectly acceptable to call them real when you are sitting around the lunch table (although I still never would), but this thread is a deeply technical discussion, where such distinctions are not trivial.

 

[Rick Christopherson]

I understand what you are saying. And I agree with the technical "flag on the play" you threw. But it is how the inversions we are discussing are used and referenced by our industry.

It is probably perfectly acceptable to call them real when you are sitting around the lunch table (although I still never would), but this thread is a deeply technical discussion, where such distinctions are not trivial.

So therein lies the answer to the Original Poster's question. It is called single phase because there is just a single, real, phase angle in the system, even though there may be 2 apparent phase angles.