Why is residential wiring known as single phase?

[rbalex]

Not a red herring. As long as you limit the discussion to voltage, Mivey wins. Because he's playing scarecrow to Dorothy. He's dropping a negative on you. But if you're gonna insist on voltage anyway, then model the equivalent DC circuits for T=90 and T=270. That should point out his inversions. He's using his neutral reference convention to measure both directions at the same time and claiming it's only one direction.

ex. If I face south the south pole is forward. If I face north the north pole is forward. Therefore both poles are "away" from me and therefore in a positive direction. Both are +(half a world away).

Would you care to post a relevant definition of phase? All the formal ones posted so far indicate that, as it applies to "Why is residential wiring known as single phase?", direction is irrelevant; it's relevant to synchronism, not phase.

Is power a vector or a scalar? If it's a vector how did you determine it? A cross (vector) product would result in no power at all when current and voltage are "in phase" since sin (0) is zero and it would be a moment anyway. If it?s the result of a scalar (dot) product, it has no direction and so is useless as a ?direction? reference. If it?s a simple scalar constant x vector quantity product, then you must assume either voltage or current has no direction. Since most would agree at least current is a vector quantity, it means voltage has no direction and is useless as a "direction" reference. How would you analyze an ?open circuit? when there is no current flow at all?

The only "references" necessary for phase as it applies to "Why is residential wiring known as single phase?" are the voltage functions' period and "when did the function effectively or equivalently start?"

 

[rbalex]

?All adhesive tapes are ?Scotch ^?? tapes.?

?No, not all tapes are cellophane; some are vinyl; some use a polyethylene backing and some are even paper backed.?

?You?re not listening; I said ?All adhesive tapes are ?Scotch ^?? tapes.?

?Oh, I misunderstood your point; but there are other brands.?

?Hmph. Well, ?Scotch ^?? is the only one we use in my shop."

 

[rattus]

Of course you don't switch probe leads. Which is EXACTLY your problem. As I stated, you need to correct your probe DIRECTIONS if you want to see it correctly. "Away" is not a valid choice of direction for establishing "Positive". "Away" is pointing in two distinctly different directions like the scarecrow in the Wizard of Oz. As to knackering your scopes, try getting a better scope with isolated probes. Stop wearing Wal-Mart shirts in a fashion show.

More nonsense! You are telling me that I have a problem? Forget the scopes. The simple fact is that we we establish a reference, the neutral in this case, and we reference all voltages to it. We can then perform loop and node analyses if we wish.

Do you accept the nonsense laid on us by rbalex? That somehow two sinusoids separated by 180 degrees are in phase?

BTW, some of the better minds on this forum agree with me

 

[pfalcon]

Would you care to post a relevant definition of phase? All the formal ones posted so far indicate that, as it applies to "Why is residential wiring known as single phase?", direction is irrelevant; it's relevant to synchronism, not phase.

Why bother with a definition of phase when the relevant part of the question is why it's single? We all know what a sinusoidal wave form looks like. It's not gonna change. You're standing on the middle of a train claiming the engine and caboose are moving in opposing directions. Nah. No matter how you phrase it the whole train of power in the circuit is always moving in concert. You just get confused cause it wiggles back and forth.

Is power a vector or a scalar? If it's a vector how did you determine it? A cross (vector) product would result in no power at all when current and voltage are "in phase" since sin (0) is zero and it would be a moment anyway. ... Since most would agree at least current is a vector quantity, it means voltage has no direction and is useless as a "direction" reference. How would you analyze an ?open circuit? when there is no current flow at all?

Yes it's a vector. It has both magnitude and direction. And talk about stating the obvious. At T=0 the instantaneous magnitude of the power is amazingly zero. Duh. At T=180 it's also zero. Duh.
Voltage has no direction?!? How did you make THAT leap of illogic. Voltage is dependant on power flow. Power has direction therefore voltage has direction. And you keep switching the direction you measure the voltage in.
As to analyzing an open circuit. Guess what. You can't measure the voltage without a leakage current either. But the math still grinds out an answer despite that reality.

The only "references" necessary for phase as it applies to "Why is residential wiring known as single phase?" are the voltage functions' period and "when did the function effectively or equivalently start?"

Sigh, but you can't establish when something starts until you establish how it starts. It starts with power flow. Power determines the instantaneous direction. Power determines the instantaneous direction of voltage. For example when T=90 power is flowing from A to N to B. That's a direction that establishes positive at A and negative at B. They're measuring AN then reversing the direction of measurement to measure BN. Effectively they're comparing AN T=90 to NB T=-90. So of course they can't resolve the equations properly. They've got to get the problem set up correctly or it'll continue to give bogus results.

More nonsense! You are telling me that I have a problem? Forget the scopes. The simple fact is that we we establish a reference, the neutral in this case, and we reference all voltages to it. We can then perform loop and node analyses if we wish.

Either way. If you refuse to measure all voltage in a uniform direction at an instantaneous point in the cycle then you'll never get the right result. Snapshot the system at a quarter cycle.

Do you accept the nonsense laid on us by rbalex? That somehow two sinusoids separated by 180 degrees are in phase?

I believe a single solitary wave form does not become out of phase with itself just because you measure two different halves in two different physical directions. It's still just ONE wave form. There isn't any other wave form to compare it against except smaller pieces of itself. Which by any decent definition cannot be anything but in phase with the whole. Any system of measurement that makes it appear out of phase with the whole is flawed. In this case it's flawed by measuring in two different directions. The train analogy is apt. "Away" is not a valid direction.

BTW, some of the better minds on this forum agree with me

BTW, some of the better minds on this forum disagree with you. Love the blustering. Adds sooo much.

 

[Besoeker]

So we're arguing over this because some people can't understand that their circuit should be modeled for each peak like a DC circuit?

The circuit wasn't modeled. That's how it is in real life.

Here's one I made earlier:

You will note that the two cathodes are connected together, just in my diagram.
It's as real as you get.

 

[mivey]

A lot of people in the industry still refer to the low lead in a typical 24VDC circuit as a neutral too. And everyone understands what they mean. But for a technical discussion - it's flat wrong.

My sources included textbooks, technical reference material, and university lecture material which is different than "a lot of people" and my sources would be what you would use in a technical discussion. "A lot of people" can say "a lot of things".

Close but not quite. With two phases at 180 the neutral is always the sum of the two circuits

Where is the neutral in a 2-wire circuit? Two wires, one voltage, one currrent: only one phase present. It can be no other way.

Two transformers would not be a single source.

Thanks for the tip Captain Obvious.

The concept never loaded the sources independantly. The loads were applied across the entire series not just one leg. And it was referred to as matched phases not single phase.

Actually, the experiments were to see if the two forces could be combined to produce one larger single force.

During the first half cycle the power flows from A to B

No. As I told you before, the power flows towards the load as if the wires were a waveguide. The energy flows along both wires towards the load. It travels in the electromagetic field surrounding the wires, not riding in the wires like a line of coal cars traveling back and forth.

If they were actually opposed then we would have a phase-to-phase short.

Connect Va to Vb and that is what you get.

 

[Besoeker]

View attachment 6493

Thank you for doing that, JD.

 

[Besoeker]

Rereading my answer, i can see where there may have been some confusion.

What did I say wrong?
One diode conducts while the current is flowing in the direction of A towards N and from N towards B.

In the circuit, which you kindly posted in #1194, the current never flows from N towards B.

My second statement related to; if your voltages are relatively in phase with your currents.

No disagreement with that.

 

[pfalcon]

The circuit wasn't modeled. That's how it is in real life.

Here's one I made earlier:

You will note that the two cathodes are connected together, just in my diagram.
It's as real as you get.

I was posting about your analysis not your circuit. We're not using glue here.

And no. I can't see your photobucket. That's why Jim posted #1004 for me.

 

[pfalcon]

A lot of people in the industry still refer to the low lead in a typical 24VDC circuit as a neutral too. And everyone understands what they mean. But for a technical discussion - it's flat wrong.

My sources included textbooks, technical reference material, and university lecture material which is different than "a lot of people" and my sources would be what you would use in a technical discussion. "A lot of people" can say "a lot of things".

And how are these two quotes related in your mind?

Close but not quite. With two phases at 180 the neutral is always the sum of the two circuits

Where is the neutral in a 2-wire circuit? Two wires, one voltage, one currrent: only one phase present. It can be no other way.

Glad to have the support for discussing an earlier circuit. Now, how about commenting on the one with two sources you attached your comment to.

Two transformers would not be a single source.

Thanks for the tip Captain Obvious.

Glad I could help. But now that I know you were thinking about a circuit in a different post that explains why your prior to comments were off.

The concept never loaded the sources independantly. The loads were applied across the entire series not just one leg. And it was referred to as matched phases not single phase.

Actually, the experiments were to see if the two forces could be combined to produce one larger single force.

Okay, now we appear to be back on track. I'm suggesting you expand the experiment.

During the first half cycle the power flows from A to B

No. As I told you before, the power flows towards the load as if the wires were a waveguide. The energy flows along both wires towards the load. It travels in the electromagetic field surrounding the wires, not riding in the wires like a line of coal cars traveling back and forth.

LoL, but a resounding NO. AC travels inside the copper to a depth determined by frequency. I get to deal with a lot of induction hardeners. If the current and power didn't flow through the metal they wouldn't heat or harden. It takes frequencies well above what we're using to become a wave guide.

If they were actually opposed then we would have a phase-to-phase short.

Connect Va to Vb and that is what you get.

Nah, Va to Vb is like connecting any of the three phase wye legs to neutral. Same phase, different ends of the coil.

 

[Besoeker]

I was posting about your analysis not your circuit.

What I posted was an actual circuit arrangement and the actual resulting waveform.
Analysis neither required nor undertaken.

 

[Besoeker]

And no. I can't see your photobucket. That's why Jim posted #1004 for me.

Maybe this will work for you:

 

[Besoeker]

It would work fine - it must, since the phase of the transformer secondary voltages of your graphic are identical.

They're not.
Were it so, the circuit in post #1004 wouldn't work.
Think about it.
Why are I_a and I_b not in phase?

 

[rbalex]

Why bother with a definition of phase when the relevant part of the question is why it's single? We all know what a sinusoidal wave form looks like. It's not gonna change. You're standing on the middle of a train claiming the engine and caboose are moving in opposing directions. Nah. No matter how you phrase it the whole train of power in the circuit is always moving in concert. You just get confused cause it wiggles back and forth...

And with that response, I will again withdraw from the "oscilloscope jungle" and allow those of you with, "Have oscilloscope, will probe" tattooed somewhere on your anatomy to continue with your guerilla war, ambushing each other; each content in the firm belief that your position is unassailable by anyone who "oscilloscope challenged"; that there is no mathematics to be applied beyond arithmetic and the only valid definition is how you apply it in your particular branch of the industry - although you can't even seem to agree on that.

One would think you would at least give some deference to:

From IEEE Std 100 The IEEE Standard Dictionary of Electrical and Electronic Terms:

phase (of a periodic phenomenon ?(t), for a particular value of t) The fractional part t/P of the period P through which ? has advanced relative to an arbitrary origin.

Note: The origin is usually taken at the last previous passage through zero from the negative to the positive direction. See also: control system, feedback; simple sine-wave quantity. (IM) [120]

After all, it did come from your branch of the industry. (?(IM) [120]? indicates the definition was extracted from IEEE Std 120-1989. IEEE Master Test Guide for Electrical Measurements in Power Circuits.) I'm sure at least some of you may even have it on your bookshelf.

 

[rbalex]

They're not.
Were it so, the circuit in post #1004 wouldn't work.
Think about it.
Why are I_a and I_b not in phase?

Because they don't need to be. The current's behavior has nothing to do with the phase of the transformer's secondary voltages.

But for my respect for you I wouldn't respond to this. See my Post above.

 

[bob]

Answer To all your questions

Answer To all your questions

http://en.wikipedia.org/wiki/Split-phase_electric_power
http://www.nfphampden.com/xftheory.pdf

 

[220/221]

Only 478 pages to go.


All I know is that phase doesn't equal leg.


Carry on.

 

[rattus]

http://en.wikipedia.org/wiki/Split-phase_electric_power
http://www.nfphampden.com/xftheory.pdf

Thank you Bob, for this ray of light in this dungeon of misinformation.

 

[bob]

Thank you Bob, for this ray of light in this dungeon of misinformation.

:lol::jawdrop:

 

[Besoeker]

Because they don't need to be.

But they are not in phase.