We are of course speaking of ideal xfrmrs, Nit picking.
Why is residential wiring known as single phase?
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We are of course speaking of ideal xfrmrs, Nit picking.
Rick Christopherson
Senior Member
I don't give a "rattus" what the mathematical definitions are....I do not contend them! You can take that argument up with people foolish enough to follow it. I am not one of them.
When you take your mathematical transformation or representation and use it to redefine the system, that is when you are going to draw my attention....as has been stated countless times.
You don't have an answer for this contention that suits your needs, so you historically ignore it or trivialize it. In my opinion, this is extremely poor debating form. That is why I keep backing out of this discussion, because I refuse to engage in a debate where the information presented is not truly honest to the audience reading it.
You have stated that there is a physical phase shift that I contend is only mathematical. When I gave you a clear example where this is proven to be false, you chose to ignore it. I don't contend your mathematical representation, but stop telling people it is real.
The Inversion is REAL. The phase shift is Apparent!
Both of these concepts can exist peacefully next to each other, so long as you don't force one into the other. You are trying to shoehorn your apparent phase shift into a place where it is not absolute.
As I have said many times....this is NOT trivial, or you wouldn't be denying it and wouldn't keep repeating it.
Please drop the "for your elders" stuff. I bought into that when I was a kid. Now I'm an "elder" I know that most people stop learning before they reach 30.
As to this question repeatedly answered: They aren't opposed, they never were opposed. You're making the common mistake of measuring one half of the coil WITH the power flow and the other half of the coil AGAINST the power flow. The result is a display that traces one leg in the classic sine wave and the other in an inverted sine wave.
And before Mivey chimes in again. No. No one said the voltages are fake. Using the two halves of a voltage divider separately or in concert is always useful. Using one leg of the voltage divider in the reverse direction is even more useful. But it's still only a single voltage gradient with a center tap.
If we don't maybe, Mike Holt himself might give us his view on this, just don't hold your breath.
Rick Christopherson
Senior Member
No we are not! If your statements were limited to "ideal" discussions, then you would not be getting responses from me. "Ideal" systems are "mathematical", and I do not contend them. You are falsely extending your "ideal" interpretations into the real world.
If you wish to stick with "ideal" transformers and wave forms, then you will get no argument from me. But the instant you make absolute statements, you take it out of the "ideal" system and mistakenly bring it into the "real" system. That's where you will get argument from me.
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OK one last try:
Using a definition YOU proposed the phase is the same for any set of relevant voltage functions; i.e., the frequency (ωt) and the effective origin (φ0 ) are not only equal but identically equal - they must be for a single-phase residential transformer.
Both conduct in the forward direction.
Just at 180 deg displaced intervals.
That would not be possible if the voltages were in phase.
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Rick Christopherson
Senior Member
Because "Phasors" are a mathematical tool that you are mistakenly transforming into reality. The fault isn't from another member disrespecting their elders. The fault is from the elders not realizing that their mathematics are a tool that only represents a system.
I may not be old enough to have apprenticed under Nikola Tesla like you did, but I am not a newbie either.
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Afraid not:
Afraid not:
No so. The radian frequency "w" is the same, but the phase constants, phi1 and phi2 are not. Let phi1 be 0; let phi2 be 180. Those are the phasors I have drawn. We have two phases, (wt + 0) and (wt + 180). But we do not call the service two phase because there is only one generator whereas a real two phase service requires two generators and two transformers.
Furthermore, if they were in phase, we could not drive 240V loads with them. There would be zero voltage between L1 and L2 and the neutral current could possibly double.
Afraid not:
No so. The radian frequency "w" is the same, but the phase constants, phi1 and phi2 are not. Let phi1 be 0; let phi2 be 180. Those are the phasors I have drawn. We have two phases, (wt + 0) and (wt + 180). But we do not call the service two phase because there is only one generator whereas a real two phase service requires two generators and two transformers.
Furthermore, if they were in phase, we could not drive 240V loads with them. There would be zero voltage between L1 and L2 and the neutral current could possibly double.
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One diode is effectively connected Van, the other diode is effectively connected Vbn. The windings are effectively connected Van to Vnb otherwise Rattus is wrong about his winding interconnections of X2&X3.
Mathematics is an important tool for engineering.
I had a lecturer who put this very succinctly.
You have an electrical problem that requires calculation. Three stages.
Understand the problem and express it in mathematical terms.
Solve the mathematical problem.
Interpret the results.
One diode is connected Van anode to cathode in series with the load. The other diode is connected Vbn anode to cathode in series with the load.
That's how it is. No effective about it.
It requires the 180deg displacement to make it work.
Two voltages displaced by 180 deg cannot be in phase.
They are thus different phases. So, more than one phase.
LoL. I'm not suggesting any but an ideal transformer. I'm suggesting unbalanced power-factors due to loads.
Why don't you start a new thread on this subject?
Of course it's possible for them to do this and be in phase. In fact, if they were 180 out then it wouldn't work.
AC functions because power flows on coil AB from one end, let's call it A, at T=90 and the other end of the coil, let's call it B, at T=270.
So you apply your scope to AN and BN and discover !! Power flows from A at T=90 and from B at T=270 !! Wonder of wonders.
You call it "out of phase". Nonsense. At T=90 the linear voltage gradient runs from A |240| to B |0| and at T=270 from B |240| to A |0|. What? You didn't want 240 from your rectifier circuit? So you changed it to use the center-tap. Wow, gee, that's exactly what a voltage divider is supposed to do: divide the voltage. It does it because the voltage gradient is continuous across the coil. No magic, no out of phase, no real mystery. AC does exactly what it claims to do: Supply power alternately from each end of the coil.
Where do I find the schematic for said rectifier circuit? Sounds like a full wave rectifier to me.
And as all my math teachers with actual math diplomas always laughed: Most errors are because people don't test their answers correctly against the problem. If you leave something out of your presumptions you still get an answer and it still appears to work. In fact, it often works TOO well for TOO many distinctly different problems. You're getting the answers you expect because you neglect instantaneous power flow in your setup then use it in your calcs.
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- PE (Retired) - Power Systems
But the windings are physically connected Van to Vnb, using Rattus' assignment of V1=V12 and V2=V34 where 1=a, 2&3=n, and 4=b. Didn't we just have the agreement that connecting them V12 and V43 doesn't work?
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OK, Let's try this - the big hand is on ... oh yeah, you use a digital watch, you won't understand.
(I apologize right now - I don't know what came over me)Seriously, you acknowledge the frequency is the same ? that?s a start. Speaking of starting, while it may be a wild assumption, I believe you would probably agree the phasors started rotating at the same time. That means their periods are identical. It also means the characteristic phase of the voltage functions they inscribe can BOTH be written based on either (wt + 0) or (wt + 180) or (wt - 180) or (wt + 360) or (wt - 360) or, guess what, any other (ωt + Φ0) or (ωt - Φ0) you choose; i.e., the phases are also identical.
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