Split phase service--one or two?

[rattus]

Before it's too late:

Before it's too late:

Before this thread gets closed again, here are just some of the references provided by mivey. This ought to put the nail in the coffin so to speak!

Alternating Current Machines", Sheldon:

If the zero ordinates of the two curves coincide, but the positive maximum of one coincides with the negative maximum of the other, as in Fig. 11, then Φ = 180? and the curves are in opposite phase.

"M-I-C-K-E-Wye", Richard P. Bingham, Dranetz-BMI:

A "delta" circuit looks like the delta symbol, which is an equal-sided triangle. There are numerous variations of the delta circuit, such as: grounded deltas (one corner of the triangle is connected to a grounded conductor); open-leg delta (only two elements instead of three are used); or, crazy-leg (where one leg is center-tapped to produce two voltages that 180 degrees out of phase from each other).

"Navy Electricity and Electronics Training Series-Module 8?Introduction to Amplifiers-NAVEDTRA 14180 pg 1-7":

One way in which a phase splitter can be made is to use a center-tapped transformer. As you may remember from your study of transformers, when the transformer secondary winding is center-tapped, two equal amplitude signals are produced. These signals will be 180? out of phase with each other. So a transformer with a center-tapped secondary fulfills the definition of a phase splitter.

"Photovoltaic Power Systems and The National Electrical Code", Sandia National Laboratories:

In a utility connected system or with a 120/240-volt stacked pair of inverters, where the 120 /240-volt power consists of two 120-volt lines that are 180 degrees out of phase, the currents in the common neutral in the multiwire branch circuit are limited to the difference currents from any unbalanced load. If the loads on each of the separate branch circuits were equal, then the currents in the common neutral would be zero.

RF/Microwave Circuits lecture on baluns by Dr. Charles Baylis, Ph.D, of USF:

Baluns are commonly made using the center-tapped transformer below...{illustrates a X1->X2 primary winding and a X3->X4+X5->X6 center-tapped secondary winding}...The center tap (nodes 4,5) is grounded. This provides a 180-degree phase difference between nodes 3 and 6.

When observing that the four-phase system also had opposing pairs of E and -E as well as jE and -jE, C.P. Steinmetz noted that the four e.m.fs of the quadrature system were in pairs opposite to each other and:

...Hence can be produced by two coils in quadrature with each other, analogous as the two-phase system, or ordinary alternating current system, can be produced by one coil.

"Differential VNA Measurements...", James R. Andrews, Ph.D, IEEE Fellow, of SPL:

Figure 2 shows another example of a BALUN. In this case the balanced secondary consists of two identical windings that are connected as a center-tapped secondary. The center tap is usually then connected to the common ground. Coax connectors might now be used for all three terminals. Note that the black dots are polarity indicators for the various transformer windings. With the arrangement shown in Figure 2, one of the secondary outputs is "in-phase" with the input and is thus labeled as the (+), or Non- Inverting output. The other secondary output is "out-of-phase" with the input and is thus labeled as the (-), or Inverting output. There is a 180 degree phase difference between the (+) and (-) outputs.

Andrei Grebenikov in "High Frequency Electronics" on Combiners and Couplers:

The main requirements to baluns are to provide an accurate 180-degree phase shift over required frequency bandwidth, with minimum loss and equal balanced impedances.
...
A wire-wound transformer with a simplified equivalent schematic, shown in Figure 13(a), provides an excellent broadband balun covering in commercial applications frequencies from low kHz to beyond 2 GHz. They are usually realized with a center-tapped winding that provides a short circuit to even-mode (common-mode) signals while having no effect on the differential (odd-mode) signal.

 

[Rick Christopherson]

Before this thread gets closed again, here are just some of the references provided by mivey.

Not a single one of those references support Mivey's assertion. None! Mivey stated that non-mathematical phase shifts don't necessarily have a time shift. He has made this statement several times, but cannot defend it when it is challenged.

 

[pfalcon]

Before this thread gets closed again, here are just some of the references provided by mivey. This ought to put the nail in the coffin so to speak!

Alternating Current Machines", Sheldon:
If the zero ordinates of the two curves coincide, but the positive maximum of one coincides with the negative maximum of the other, as in Fig. 11, then Φ = 180? and the curves are in opposite phase.
"M-I-C-K-E-Wye", Richard P. Bingham, Dranetz-BMI:
Incomplete reference. However, if we're stuck on independent measurements then good enough.

A "delta" circuit looks like the delta symbol, which is an equal-sided triangle. There are numerous variations of the delta circuit, such as: grounded deltas (one corner of the triangle is connected to a grounded conductor); open-leg delta (only two elements instead of three are used); or, crazy-leg (where one leg is center-tapped to produce two voltages that 180 degrees out of phase from each other).
"Navy Electricity and Electronics Training Series-Module 8?Introduction to Amplifiers-NAVEDTRA 14180 pg 1-7":
Definitely treats voltages as independent measurements. So by that definition of phase is correct. Two voltages 180 out of phase.

One way in which a phase splitter can be made is to use a center-tapped transformer. As you may remember from your study of transformers, when the transformer secondary winding is center-tapped, two equal amplitude signals are produced. These signals will be 180? out of phase with each other. So a transformer with a center-tapped secondary fulfills the definition of a phase splitter.
"Photovoltaic Power Systems and The National Electrical Code", Sandia National Laboratories:
ditto

In a utility connected system or with a 120/240-volt stacked pair of inverters, where the 120 /240-volt power consists of two 120-volt lines that are 180 degrees out of phase, the currents in the common neutral in the multiwire branch circuit are limited to the difference currents from any unbalanced load. If the loads on each of the separate branch circuits were equal, then the currents in the common neutral would be zero.
RF/Microwave Circuits lecture on baluns by Dr. Charles Baylis, Ph.D, of USF:
ditto

Baluns are commonly made using the center-tapped transformer below...{illustrates a X1->X2 primary winding and a X3->X4+X5->X6 center-tapped secondary winding}...The center tap (nodes 4,5) is grounded. This provides a 180-degree phase difference between nodes 3 and 6.
When observing that the four-phase system also had opposing pairs of E and -E as well as jE and -jE, C.P. Steinmetz noted that the four e.m.fs of the quadrature system were in pairs opposite to each other and:
ditto

Repetitious in argument if nothing else. But simply put:
Voltage source measurements are referred to as phases by the industry. Hence any system measuring to a common reference may produce up to (n-1) voltage phases were is the number of tap points. Additional voltage phases can be created by using multiple reference points.

And though these industry defined phases are present, they have nothing to do with the phase of a system. Nor can any of these phases be used to prove the number of system phases present. Therefore none of these references aid in resolving the OP question. Unless of course the real question was how many voltage phases can I get from (3) taps; which would be (2) from a common reference and (6) using multiple references.

 

[pfalcon]

Not a single one of those references support Mivey's assertion. None! Mivey stated that non-mathematical phase shifts don't necessarily have a time shift. He has made this statement several times, but cannot defend it when it is challenged.

If by that we're discussing whether there's such a thing as a phase shift that isn't a time shift then there is no reference. The lead/lag between transformer coils is mathematically called a time shift.

Any cyclic function (sinusoidal, triangle, square waves) can be represented by an equation describing the curve over one cycle. The period from the beginning of the function to the end of the function is referred to as the time domain although it may represent some other intrinsic characteristic of the system. Modulo math can then be used to represent the scalar shift in values when comparing cycles. Scalar because the actual values in the time domain are magnitudes from zero though in short hand negative values may be used as -(period - shift) for example 240 degrees may be represented as -(360-240) or -120. Negative values are usually avoided when dealing with non-sinusoidal cycles.

It's also considered scalar because cyclic curves are considered to be infinite in both directions in the time domain. The most common cycle function used is the sinusoidal with a normalized period of 360 or 2*PI as these values allow easy computation using standard trig functions. It should be stressed that the angle used when modeling sinusoidals is not a direction but a convenience used to make computation easy. The same type of modelling is used for triangle and square waves with the trig functions being replaced by appropriate algebraic equations. However, in those models the circle period is normally not used, nor is the term angle but simply phase shift or time shift. When using non-sinusoidals the Modulo function is much more commonly used which makes negatives much more trouble to deal with.

In AC, the rotating portion of the phasors cancel througout leaving the static portion (due to having a common frequency). The phase angle actually represents the fraction of the cycle period of 1/60 sec. Therefore in the case of an AC circuit model - all phase angles represents real time shifts as well as being a mathematical time shift.

 

[Rick Christopherson]

If by that we're discussing whether there's such a thing as a phase shift that isn't a time shift then there is no reference.

That's correct. Mivey's assertion was that non-mathematical phase shifts can exist without time shifts, but then all of his references to support that assertion were related only to mathematical phase shifts. That makes it a circular argument.

 

[rattus]

Dead Equine:

Dead Equine:

Rick,

That horse is dead! Quit beating it!

 

[jim dungar]

This thread is closed.