Why is residential wiring known as single phase?

Status
Not open for further replies.

jim dungar

Moderator
Staff member
Location
Wisconsin
Occupation
PE (Retired) - Power Systems
I said "on paper". Most if not all simulation programs require a "ground" reference. Quite alright for simulation purposes where we can't get hurt by doing something stupid.
We need tools that allow us to measure and analyze based on what is physically there.


What is inconsistent? V1n is seen at X1, neutral is the X1-X2 tie, and V2n is seen at X4. Pretty standard stuff as I see it.
I believe I asked you to compare and actual circuit of V12 and V43, using Mivey's' subscripts (which he and I agreed commonly mean From-To, and so have been used through out this thread) the common node would be 2&4.

You know that Vx4x3 is 180 out from Vx3x4 and Vx1x2. So what is the problem?
The problem is the physical connection is actually X1-X2 (V12) joined in series to X3-X4 (V34) to create V14. Unless you physically rewire this connection, everything thing else is simply mathematical manipulations.
 

rattus

Senior Member
Are you saying the fundamental frequency of the currents in 1004 won't have the same phase as the transformer's?

Can't really talk about phase of the currents since they are positive half waves separated by PI radians, but they are produced by voltages with phases that exhibit a PI radian phase shift. It is that simple. No need for Mssr. Fourier.
 

pfalcon

Senior Member
Location
Indiana
Nonsense, the phase definition does not specify how the energy flows nor is it necessary to do so. You are just introducing extraneous arguments.
I don't know whether to put on my helmet or my poncho. Maybe I will put on both.

Phase is a description of how the energy flows. So yea, if you don't know how the energy flows then you don't know what a phase is. The definition presumes you have a basic understanding of the energy flow.

You're defending an indefensible position supporting Mivey and his wave guide theory. This is typical of the neutral reference group. Dispose of key facts that are inconvenient or not understood.

http://www.electronicsteacher.com/a...pedance-inductive/more-on-the-skin-effect.php
http://www.physicsforums.com/showthread.php?p=2763995
http://www.st-andrews.ac.uk/~www_pa/Scots_Guide/audio/skineffect/page1.html
 

rattus

Senior Member
I believe I asked you to compare and actual circuit of V12 and V43, using Mivey's' subscripts (which he and I agreed commonly mean From-To, and so have been used through out this thread) the common node would be 2&4.

The problem is the physical connection is actually X1-X2 (V12) joined in series to X3-X4 (V34) to create V14. Unless you physically rewire this connection, everything thing else is simply mathematical manipulations.
I believe we have been discussing the standard connections all along, no need to rewire anything.

Yes,
V12 + V34 = V14
and
V12 - V43 = V14

And V43 is displaced from V12 by PI. V43 is what you see in the real world, it is there on the buses, It is what Bes and others have chosen to describe the voltages in their circuits, it is more than just math. It is just as important as V12.
If V12 is the voltage on L1, then V43 is the voltage seen on L2.

I see no reason to get into a long drawn out argument about something that doesn't matter. I think the OP's question was answered in the first few posts, so why are we still yakking about the transformer connections. I am saying it doesn't matter what the source of the voltages is as long as we model them correctly.
 

rattus

Senior Member
Phase is a description of how the energy flows. So yea, if you don't know how the energy flows then you don't know what a phase is. The definition presumes you have a basic understanding of the energy flow.

What does the IEEE say about it?
 

mivey

Senior Member
...Are you gonna tell me you think the current travels OUTSIDE the copper as Mivey stated?

Right now it implies you think residential current travels through the air. If someone can't understand the current stays in the copper then they'll never understand phase.

You're defending an indefensible position supporting Mivey and his wave guide theory. This is typical of the neutral reference group. Dispose of key facts that are inconvenient or not understood.

Show me where I said the current is flowing in the air. We were discussing power. I claimed it always flowed towards the load and the energy was carried in the electromagnetic field.

The more you post, the more you demonstrate your lack of knowledge on the subject. Until you learn the difference between current and energy flow, you will continue to ramble on in confusion.
 

rattus

Senior Member
Phase is a description of how the energy flows. So yea, if you don't know how the energy flows then you don't know what a phase is. The definition presumes you have a basic understanding of the energy flow.

You're defending an indefensible position supporting Mivey and his wave guide theory. This is typical of the neutral reference group. Dispose of key facts that are inconvenient or not understood.

http://www.electronicsteacher.com/a...pedance-inductive/more-on-the-skin-effect.php
http://www.physicsforums.com/showthread.php?p=2763995
http://www.st-andrews.ac.uk/~www_pa/Scots_Guide/audio/skineffect/page1.html

A voltage can exist with zero current, therefore no energy flow.

In a nutshell, phase is the argument of the sinusoid describing the voltage or current. The argument in general is (wt + phi0).

Skin effect is minor at 60hz.

You are out of your league now. Knock off the nonsense. You are wasting bandwidth.
 

jim dungar

Moderator
Staff member
Location
Wisconsin
Occupation
PE (Retired) - Power Systems
I believe we have been discussing the standard connections all along, no need to rewire anything.
It is amazing how you selectively ignore facts. I asked about physically reconnecting a transformer - your reply is let's not.

May be I should post slowly this time?

A standard transformer is physically connected V12+V34 (X1->X2 joined to X3->X4) resulting in V14.
Any other representation of the voltages is simply a mathematical manipulation.

The transformer is absolutely not connected V12+V43 (X1->X2 joined to X4->X3), if it were, we would get an entirely different result.

I am still trying to find a source of negative volts (or negative current for that matter), so when I see Vxy=-Vyx, I figure some value in my circuit analysis is not directly representing the real world value I thought it was.
 
Last edited:

pfalcon

Senior Member
Location
Indiana
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.

Show me where I said the current is flowing in the air.

Emphasized so you can find your own words. Unless of course, you think something ELSE could possibly exist surrounding the wires. Like the insulation.

The electromagnetic field surrounding the wires in the secondary circuit is power lost. In the primary coil of a transformer we use the power lost in EMF to perform the work by inducing current in the secondary. The EMF is a liability in most circuits because it does things like ripping wires loose from terminations. Except for things like transformers, the power we use and are interested in is the charge moving through the conductor, not around it.
 

rattus

Senior Member
It is amazing how you selectively ignore facts. I asked about physically reconnecting a transformer - your reply is let's not.

May be I should post slowly this time?

A standard transformer is physically connected V12+V34 (X1->X2 joined to X3->X4) resulting in V14.
Any other representation of the voltages is simply a mathematical manipulation.

The transformer is absolutely not connected V12+V43 (X1->X2 joined to X4->X3), if it were, we would get an entirely different result.

I am still trying to find a source of negative volts (or negative current for that matter), so when I see Vxy=-Vyx, I figure some value in my circuit analysis is not directly representing the real world value I thought it was.

Jim, in order to answer the original question, we don't need to worry about the real world connections. We need only concern ourselves with the fact that, in effect, however wired, we have two legs at 120Vrms phase opposed. They are there on L1 and L2; there is no rule that we have to define them one way or the other. Do it your way if you wish. And, one can add impedances to the circuit to simulate the transformer losses.
 

Besoeker

Senior Member
Location
UK
Are you saying the fundamental frequency of the currents in 1004 won't have the same phase as the transformer's?
As a professional engineer I'm sure that you understand that frequency and phase are two quite different measurements.
 

rbalex

Moderator
Staff member
Location
Mission Viejo, CA
Occupation
Professional Electrical Engineer
As a professional engineer I'm sure that you understand that frequency and phase are two quite different measurements.

Let?s try it this way - are you claiming the currents have no characteristic function or that the characteristic function has no fundamental harmonic or that the fundamental harmonic has no phase that is the same as the voltage functions.
 

gar

Senior Member
Location
Ann Arbor, Michigan
Occupation
EE
120225-1950 EST

jim dungar:

In 1092 your statement was
Chose a direction and use it consistently is not double-talk.
If you claim that the two winding outputs are 'in phase' when they are connected in parallel then you have chosen a direction for each output, in the industry standard transformer connections I have been focussing on, the output of winding X1-X2 is in phase with the output of winding X3-X4. This is a simple fact.

This I agree with.

Then if X1 and X3 are connected together the voltage difference between X2 and X4 is zero or very near zero and there is zero phase difference between X2 and X4.

Therefore the voltage of X2-X1 is 180 degrees out of phase with X3-X4. If X2 is connected to X3, then X1 is 180 out of phase with X4, and there is a large voltage difference between X1 and X4. Do you agree? If not why not?

.
 

mivey

Senior Member
I think you need to check your circuit diagrams.
I'm pretty sure I labeled the ABCD correctly but I may have a typo. I guess you followed what I meant either way, correct?

A center-tapped/reconnectable set of windings is connected a lot more like delta than it is like a wye.

I ask for a little leeway with standard designations, and ignoring external connections.
Given three transformer coils X1-X2, X3-X4, and X5-6.
A delta connection would be X2&X3, X4&X5, and X6&X1 -an open delta could be just X2&X3
A wye connection would be X2&X4&X6 - an open wye could be just X2&X4

So an open wye is the physical connection of V12+V43, while an open delta is the physical V12+V34, giving two vastly different results.

I apologize if I missed your line of reasoning but I am very tired.

To help clarify: Wouldn't X1&X3&X5 be a valid wye also? Then we have an open wye of V43+V12?

Another question concerning this delta vs. wye line of thought:
Just from a physical standpoint, to get the series additive combo from the open delta we would have to shift one winding 120?. To get the series additive combo from the open wye we would have to shift one winding 60?. Wouldn't that make the open wye closer to the single-phase configuration?

Besoeker's rectifier does not change the physical connection of V12+V34.
I don't remember saying it did but if I did say that I did not intend to.
 

jim dungar

Moderator
Staff member
Location
Wisconsin
Occupation
PE (Retired) - Power Systems
To help clarify: Wouldn't X1&X3&X5 be a valid wye also? Then we have an open wye of V43+V12?
yes.

Another question concerning this delta vs. wye line of thought:
Just from a physical standpoint, to get the series additive combo from the open delta we would have to shift one winding 120?. To get the series additive combo from the open wye we would have to shift one winding 60?. Wouldn't that make the open wye closer to the single-phase configuration?.
in phase angle maybe.

In the case of the delta the windings are connected begining to end without changing the winding direction V43+V12. In the case of a wye, the end to end connection means one of the windings is physically rotated 180?, V43+V21.
 
Last edited:

Besoeker

Senior Member
Location
UK
Let?s try it this way - are you claiming the currents have no characteristic function or that the characteristic function has no fundamental harmonic or that the fundamental harmonic has no phase that is the same as the voltage functions.
No. I'm stating that Ia and Ib as shown is post #1004 are not in phase.
Since the load is resistive, it thus follows that the voltages, Van and Vbn, driving those currents are not in phase.
Since those voltages are not in phase there is more than one phase.
 

rattus

Senior Member
Polarity Dots:

Polarity Dots:

One could view polarity dots as indicating the start of a winding. Then the voltages appearing at those dots, relative to their respective finishes, would be in phase.

And a tap could be considered to be the junction of a start and a finish.
 

rattus

Senior Member
Hear, hear!

Hear, hear!

No. I'm stating that Ia and Ib as shown is post #1004 are not in phase.
Since the load is resistive, it thus follows that the voltages, Van and Vbn, driving those currents are not in phase.
Since those voltages are not in phase there is more than one phase.

The Brit is right. Van and Vbn are not in phase, they are separated by PI. So we have two phases according to the official definitions, but we call the service single phase because:

The service utilizes a single transformer.

Furthermore, we wish to avoid confusion with the real two phase service, and because the second phase is provided by an inversion and is of no use in driving two phase loads, namely motors.

Give it up Bob.
 

rbalex

Moderator
Staff member
Location
Mission Viejo, CA
Occupation
Professional Electrical Engineer
No. I'm stating that Ia and Ib as shown is post #1004 are not in phase.
Since the load is resistive, it thus follows that the voltages, Van and Vbn, driving those currents are not in phase.
Since those voltages are not in phase there is more than one phase.
OK, piece by piece and more direct:


Do the currents have a characteristic function?

Do the current’s characteristic functions have a fundamental harmonic?

Do the fundamental harmonics of both voltages and currents have same the period P.

Is the fraction t/P of each fundamental harmonic of both voltages and currents identical throughout the period P?

Do you plan to keep evading the obvious?​
 
Status
Not open for further replies.
Top