Why is residential wiring known as single phase?

[rbalex]

Nonsense! The phase constant CANNOT be cancelled or altered in any way because that is what determines the starting point!

rbalex himself first posted that,

phase = (wt + phi0) I certainly did - so why do you keep objecting to it when it's applied properly INSIDE A SINE FUNCTION
That is what makes V2n an inverse of V1n when the phase constants differ by PI.

Why can't you keep you applications straight?

 

[rattus]

I thought the reason you brought up your "hexiphase" system was because you wanted to know how my position applied to it. I really don't want to start over with single-phase systems again. As relevant to conventional 120/240V systems, phase stops at the transformer; how you monkey with it downstream is irrelavent.

Edit add: Maybe I should say " As relevant to this discussion, phase stops at the transformer; how you monkey with it downstream is irrelavent."

Nonsense! Every AC wave has a phase. Leading and lagging currents have phases. We can double the number of phases by center tapping the transformers, but they are still phases and all are of equal relevance.

We do however label the systems usually by the number of transformers involved. The exception is the open wye with two transformers.

 

[rattus]

Quote from rattus:
rbalex himself first posted that,

phase = (wt + phi0)

Response from rbalex:
I certainly did - so why do you keep objecting to it when it's applied properly INSIDE A SINE FUNCTION
End response.

That is what makes V2n an inverse of V1n when the phase constants differ by PI.

More response:
Why can't you keep you applications straight?

I have NO problem with using wt + phi0, and I don't know what you mean by keeping my applications straight!

 

[rbalex]

I have NO problem with using wt + phi0, and I don't know what you mean by keeping my applications straight!

If you want to insist (wt + phi0) is the definition of phase, then for a single-phase system:

“Phase 1” = Sin (wt + phi0) = - Sin (wt + phi0 + π) [valid trig]​

AND

“Phase 2” = Sin (wt + phi0 + π) = - Sin (wt + phi0) [also valid trig]​

Therefore I can define two equivalent sets each in terms of an identical phase for each of them.
Assuming a common t₀:

SET 1 is:

Sin (wt + phi0) AND - Sin (wt + phi0) [both use the same phase (wt + phi0) by your definition]​

AND

Set 2 is:

Sin (wt + phi0 + π) AND - Sin (wt + phi0 + π) [again both use the same phase (wt + phi0 + π) by your definition]​

Either set (NOT both) can be used as the basis for the periodic voltage functions of a single phase system

If trig identities work for you, then they work for me, whether you like the conclusion or not. I will not waste any more time explaining this to you.

 

[__dan]

Just talked with the smartest man I know. He says in so many words that you CANNOT use trig identities to dump the phase constant!

mmm, rattus. The phase constant 180 deg difference was dumped into the equation when you swapped the leads of the test equipment relative to the winding turn direction. The second measurement taken is of an otherwise identical in every way second winding, induced by the same uniform magnetic field. The only change is of the orientation of the test leads relatve to the winding turn direction. The transformer supplied to you by the factory for testing has two fixed matched windings that have uniform turns in the same direction.

Could you ask your smart friend if creating the 180 phase difference by reversing the leads relative to the winding turn direction is a valid second independent phase or a conventional case available from any one unique phase ?

That is, the arguement includes the facts provided by the transformer itself and not just the on paper statement, sin(wt) != sin(wt + 180).

The facts provided to you by the fixed constant of the transformer's manufacture are two identical matched windings sharing the same iron core and same magnetic field. The 180 deg phase constant difference is added by you when the leads are swapped relative to the winding turn direction. Effectively, looking from the center of the winding and turning your head 180 deg to look at one winding, then the other. Using two points of view (different by 180 deg), rather than looking at the same from one end and seeing that the factory provided two windings both wound in the same direction (seeing what is actually there).

The windings are two voltage sources added in series, the phasors are summed at the output to yield a 240 volt source.

Simply: sin(wt) + sin(wt) = 2sin(wt)

Your view is: sin(wt) + sin(wt + 180) = 0, which is not what is observed at the output.

Somehow you need to add in an extra multiplication by (-1) to cancel out the 180 deg phase shift added by you, by reversing the test leads, during the measuring process.

You are describing the underlying reality, not creating it. That is done for you by the factory and fixed. Take both phasor measurements consistent with the winding turn direction, which is the physical reality provided to you to observe, and sum the phasors because the series connection is the arrangement provided to you to observe. The windings are connected in series as matched identical voltage sources. The facts are provided to you to observe if you have any interest in the underlying physical reality.

Your arguement consistently included the statements 'subtract when I add the winding in series' and 'forget the transformer' as the facts provided by the transformer are inconvenient for you and inconsistent with your arguement. You omit that phi0 = 180 was added by you to the second measurement, by being inconsistent relative to the winding turn direction. The factory provides a second winding to you that is consistent in turn direction.

 

[readydave8]

188 pages?

more pages than most threads have posts. more posts per day than most threads get total. very little that I understand although I think I get the gist of it.

 

[rattus]

If you want to insist (wt + phi0) is the definition of phase, then for a single-phase system:

?Phase 1? = Sin (wt + phi0) = - Sin (wt + phi0 + π) [valid trig]​

AND

?Phase 2? = Sin (wt + phi0 + π) = - Sin (wt + phi0) [also valid trig]​

Therefore I can define two equivalent sets each in terms of an identical phase for each of them.
Assuming a common t₀:

SET 1 is:

Sin (wt + phi0) AND - Sin (wt + phi0) [both use the same phase (wt + phi0) by your definition]​

AND

Set 2 is:

Sin (wt + phi0 + π) AND - Sin (wt + phi0 + π) [again both use the same phase (wt + phi0 + π) by your definition]​

Either set (NOT both) can be used as the basis for the periodic voltage functions of a single phase system

If trig identities work for you, then they work for me, whether you like the conclusion or not. I will not waste any more time explaining this to you.

You are ignoring the fact that phi0 is different for the two voltages. It is set to 0 for V1n and to PI for V2n.

Then the phases are (wt) and (wt + PI).

The phase constant determines the starting point for the two waves, in this case 0 and PI. It is that simple.

There is no reason to apply trig identities, no precedent, no mention of it in any textbook, and you won't provide any reference material to support that illogical claim. Surely you know better. Very unprofessional.

Maybe you could waste some time explaining it to mivey, gar, and besoeker. Also explain why you haven't provided any references. I would think a PE would be ready with references if there were any.

 

[jim dungar]

We do however label the systems usually by the number of transformers involved. The exception is the open wye with two transformers.

Don't forget the exception of an open-delta with two transformers.
Don't forget the exception of two T connected transformers.

All those darn real world applications of transformers which are dependent on the actual windings' construction and connections.

 

[rattus]

Don't forget the exception of an open-delta with two transformers.
Don't forget the exception of two T connected transformers.

All those darn real world applications of transformers which are dependent on the actual windings' construction and connections.

Thanks Jim, I knew I would leave something out.

 

[gar]

120307-2335 EST

A device that I have built would not be able to tell me in what direction a shaft was orientated if a sine wave with a phase shift of 180 deg was the same as a phase shift of 0 deg.

In my real world it is nonsense to claim that a phase shift of 180 deg is the same as 0 deg.

.

 

[rbalex]

120307-2335 EST

A device that I have built would not be able to tell me in what direction a shaft was orientated if a sine wave with a phase shift of 180 deg was the same as a phase shift of 0 deg.

In my real world it is nonsense to claim that a phase shift of 180 deg is the same as 0 deg.

.

But we aren't talking about phase shifts, or phase angles, or "in phase" or any other phenomena that depends on phase; phase just isn't dependent on any of them. It doesn't change your designs and it certainly wouldn't change your competency to recognize phase is simply dependent on time, not position, spatially or otherwise.

 

[mivey]

Actually, perfectly relevant.

Let's let the lab assistant hold onto the positive pulse outputs and see if he thinks it is just math or physics.

Starting around the clock-o-phase, we move 60­?:
Assistant: "Hey, what was that?"
Mr. Resolver: "That was not real positive pulse but was just the inverse of the voltage we would have on the other half of the period. Don't worry about it. I extracted a negative sign to reduced the number of phases."
Assistant: "Errr. OK."

Another 60?:
Assistant: "Ouch"
Mr. Resolver: "Easy, easy. That was a real positive voltage pulse. That's to be expected at this phase."
Assistant: "Well just how many phases are there?"
Mr. Resolver: "There are only three phases."

Another 60?:
Assistant: "Owe. This is getting old. I'm sure glad I'm getting $50 per phase."
Mr. Resolver: "That was another pulse. Some try to call that a positive pulse but we who done learned our Trig know it is really just a negative of a different phase. But I removed the negative."
Assistant: "Well you must not have removed all of it 'cause that hurt. Do you have any references for what you are doing?"
Mr. Resolver: "No. But if you want to question me, I'll need some references from you."

Another 60?:
Assistant: "Hey! What's going on? I thought there were only three phases!"
Mr. Resolver: "True dat! You see, I can make six phases magically become three through trig manipulations."
Assistant: "I think I see my $50 is going to magically disappear too. Do you even know what a phase is?"
Mr. Resolver: "Sure. Your problem is you just don't understand the proper mis-application of math."
Assistant: "But I understand why none of this was in the textbook and why I could not find this in any reference material. I believe I'll leave you to experiment on your own."

 

[mivey]

Maybe you could waste some time explaining it to mivey, gar, and besoeker.

No thanks. I think gar did a nice job of explaining how the Trig was being mis-applied. Maybe he is up to hearing the noise.

 

[mivey]

All those darn real world applications of transformers which are dependent on the actual windings' construction and connections.

Along with their phase shifts.

 

[rbalex]

You are ignoring the fact that phi0 is different for the two voltages. It is set to 0 for V1n and to PI for V2n.

Then the phases are (wt) and (wt + PI).

The phase constant determines the starting point for the two waves, in this case 0 and PI. It is that simple.

There is no reason to apply trig identities, no precedent, no mention of it in any textbook, and you won't provide any reference material to support that illogical claim. Surely you know better. Very unprofessional.

Maybe you could waste some time explaining it to mivey, gar, and besoeker. Also explain why you haven't provided any references. I would think a PE would be ready with references if there were any.

No, I didn't ignore anything. For t₀= 0, sin(wt)= 0 and sin(wt+PI) = 0. Therefore phi0 = 0 for both cases and sin(wt+PI) = -sin(wt) for all values of t throughout the period; i.e., wt is still valid as the common phase.

 

[jim dungar]

Along with their phase shifts.

Which is why using the construction of the transformer (bank) is a perfectly valid reference, which provides consistency even when the arrangement does not contain a true neutral point for each winding connection (i.e with a zig-zag).

 

[pfalcon]

No, I didn't ignore anything. For t₀= 0, sin(wt)= 0 and sin(wt+PI) = 0. Therefore phi0 = 0 for both cases and sin(wt+PI) = -sin(wt) for all values of t throughout the period; i.e., wt is still valid as the common phase.

Except that rattus appears to refuse to equate sin(wt+PI) = -sin(wt) but appears to want to use sin(wt+PI) != sin(wt) instead.

 

[rattus]

In-phase and Phase:

In-phase and Phase:

To be 'in-phase', two waves must carry the same 'phase'. That is their starting points must be the same, therefore their 'phase constants' must be the same. phi1 = phi2

It follows then that to NOT be 'in-phase', their starting points must be different, that is their 'phase constants' must be different. Therefore, their phases must be different. phi1 NE ph2.

(wt + phi1) NE (wt + phi2)

in this case,

(wt + 0) NE (wt + PI)

Their phases are (wt) and (wt + PI)

They are NOT 'in-phase', nor do they carry the same 'phase'.

 

[rattus]

Except that rattus appears to refuse to equate sin(wt+PI) = -sin(wt) but appears to want to use sin(wt+PI) != sin(wt) instead.

You don't get it do you?

 

[rbalex]

To be 'in-phase', two waves must carry the same 'phase'. Yes-so? In your example they do. That is their starting points must be the same, And they do for the Sine Functions therefore their 'phase constants' must be the same. phi1 = phi2 OR their equivalent inverse.

It follows then that to NOT be 'in-phase', their starting points must be different,(But the Sine values aren't different; they both start at zero in your example) that is their 'phase constants' must be different. For "in phase" maybe But their Therefore, their phases must be different. phi1 NE ph2. Yes - so? That only applies to "in phase", not phase.

(wt + phi1) NE (wt + phi2) Not necessarily
in this case,What is phi1 and phi2?

(wt + 0) NE (wt + PI) But sin (wt) = -sin(wt + PI) = 0 at wt = 0, so they do have the same starting points. This is where you keep swapping applications.

Their phases are (wt) and (wt + PI) OR both are validly (wt) OR (wt + PI).

They are NOT 'in-phase',Maybe nor do they carry the same 'phase' false.

Quit swapping the "phases" in and out of the functions indiscriminately - That's what I mean by getting your applications straight.