Just to clarify.
- Thread starter jim dungar
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I probably knew that was your point. But my point was its a cleaner problem if washed first (that would be a pun:roll: - and I would rather illustrate my point - what a suprise:roll:rattus said:
I put an arrow on the sketch to define In. Post 148, 150.rattus said:
Extra credit to you and mivey if you show your work - at least as much as I did.
carl
Rick Christopherson
Senior Member
I agree wholeheartedly. We have been trying to explain the simple error that created this entire discussion, but it has been met with resistance. There has been denial that it is an error to begin with, and that is why this discussion has gone on this long.mivey said:
As I have said many times now, this entire discussion is predicated on a missing minus sign. Once we get past this missing minus sign, the entire ballpark is open. I look forward to opening this discussion up to other areas, but we can't do that until we get this minus sign issue acknowledged. If we don't get this issue resolved, it will simply propagate into all other discussions that are based on this original discussion.
Does that make any sense?
mivey
Senior Member
my problem with it is
my problem with it is
But as for other problems, consider the following 4 analysis methods. I swapped the rattus vs coulter voltages and the rattus vs coulter loops (typos don't count). None of the methods saved me any steps. But I'm going to have to call the coulter voltages and the coulter loops the yummiest.
Now, to paraphrase Jim, "why would you"? There is no argument that both ways work. But why not simplify the analysis on the front end? I think Winnie pointed out earlier (I think he said this) that for a complex circuit, there may be advantages to using other initial conditions, but why do it for this circuit?
[edit: civility]
my problem with it is
Since you asked: I have no problems with the numbers themselves. The method is perfectly valid.rattus said:
But as for other problems, consider the following 4 analysis methods. I swapped the rattus vs coulter voltages and the rattus vs coulter loops (typos don't count). None of the methods saved me any steps. But I'm going to have to call the coulter voltages and the coulter loops the yummiest.
Now, to paraphrase Jim, "why would you"? There is no argument that both ways work. But why not simplify the analysis on the front end? I think Winnie pointed out earlier (I think he said this) that for a complex circuit, there may be advantages to using other initial conditions, but why do it for this circuit?
[edit: civility]
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mivey
Senior Member
Rick Christopherson said:
Yes. Perfectly. You will see the minus sign in the post I just made.
Rattus, do you have issues with the minus signs? Are you opposed to me using them? I admit I converted them to 180 degree angles but you will see it was part of the thought process before I wrote the actual equation.
mivey
Senior Member
Then, just as it was in your circuit, it would mean the loop currents are in a different direction from the circuit currents. I think I may have alluded to something along those lines before.rattus said:
We usually drew the current coming out of the positive terminal of voltage sources and in the same direction as current sources. If we got it backwards or forgot, it was no big deal because the analysis would indicate whether our loop currents were in the same direction as the circuit currents.
I see the loop current as a tool. The circuit currents are found by using this tool. It really doesn't matter to me if they are in the same direction, but it can look cleaner and make the final labeling of the circuit currents cleaner.
mivey
Senior Member
forensic analysis
forensic analysis
ok gang here it is. As I see it, rattus's teaser problem has made his position clear. I think it is a valid position and all of the currents and voltages work correctly.
To see if this thread might be able to reach a conclusion, we have to see if the OP has been delt with. If you will bear with me, I think a "forensic" analysis might be in order or I don't see how we are ever going to get to the end:
1) In ancient times, from #88 rattus was responding to #86 and said: "Just trying to demonstrate that V1n and V2n exhibit a phase difference of 180 degrees". Rattus has done that here. No problem. Rattus gave V2 a 180 degree phase angle but also changed the polarity so the circuit is not compromised and we have a working circuit. No problem. This is what had to be done. The polarity shift negated the 180 degree shift. No problem.
2) In ancient times, from #94 Jim did not appear to catch that what rattus meant. Rattus meant to express that he was keeping things in order by reversing the polarity on the 180 degree voltage. That was not explicitly stated back then. Rattus made it clear with the teaser circuit example here that this polarity change was on his mind. No problem.
3) In ancient times, from #96 rattus replied back to Jim. I have read this post several times. Just based on the post alone, I could not follow what rattus was saying. I don't know if it was the wording, the terminology, or just my ignorance, but I could not get it. BUT. Based on what we have learned here, it would appear rattus was trying to express the things that have been cleared up here. I see no value in trying to go back and re-state that post or interprete it, as we now clearly know what rattus's position is, based on the teaser analysis here. The circuit works fine and the voltages and currents all work out. No problem.
4) In ancient times, from #97 Jim continued to ask rattus about the currrent and voltages being out of phase. It was not clear then but it should be clear now that it was just a misunderstanding. No problem.
5) In ancient times, from #100 rattus responded to #97. I could follow the sentence but this post could not stand on its own without some clarification. It appears to say something that won't hold up. But that is the problem. Without further information, we can't analyze what is meant here. What something APPEARS to say and what the author meant can be two different things. This post needed some additional info. BUT. Since we have now learned what rattus was trying to express about the voltage and current angles, I see no value in trying to fix this old post. We are now in possession of newer, better detailed information. This new information is correct. No problem.
6) This thread started with Jim wanting clarification on what was said before. What rattus said before was not clear. From here on out, this thread has been about trying to figure out what in the world was going on. Rattus had not made himself clear and Jim was trying to figure it out.
7) If there have been any errors posted in the past, I say forget it. We now know, by the teaser problem, what rattus's position is and that it is a valid position. We also understand it was not originally clear to Jim because rattus's explanation was lacking the detail needed. Rattus has now provided that detail.
Now can we move on to something else?
[edit: typo]
forensic analysis
ok gang here it is. As I see it, rattus's teaser problem has made his position clear. I think it is a valid position and all of the currents and voltages work correctly.
To see if this thread might be able to reach a conclusion, we have to see if the OP has been delt with. If you will bear with me, I think a "forensic" analysis might be in order or I don't see how we are ever going to get to the end:
1) In ancient times, from #88 rattus was responding to #86 and said: "Just trying to demonstrate that V1n and V2n exhibit a phase difference of 180 degrees". Rattus has done that here. No problem. Rattus gave V2 a 180 degree phase angle but also changed the polarity so the circuit is not compromised and we have a working circuit. No problem. This is what had to be done. The polarity shift negated the 180 degree shift. No problem.
2) In ancient times, from #94 Jim did not appear to catch that what rattus meant. Rattus meant to express that he was keeping things in order by reversing the polarity on the 180 degree voltage. That was not explicitly stated back then. Rattus made it clear with the teaser circuit example here that this polarity change was on his mind. No problem.
3) In ancient times, from #96 rattus replied back to Jim. I have read this post several times. Just based on the post alone, I could not follow what rattus was saying. I don't know if it was the wording, the terminology, or just my ignorance, but I could not get it. BUT. Based on what we have learned here, it would appear rattus was trying to express the things that have been cleared up here. I see no value in trying to go back and re-state that post or interprete it, as we now clearly know what rattus's position is, based on the teaser analysis here. The circuit works fine and the voltages and currents all work out. No problem.
4) In ancient times, from #97 Jim continued to ask rattus about the currrent and voltages being out of phase. It was not clear then but it should be clear now that it was just a misunderstanding. No problem.
5) In ancient times, from #100 rattus responded to #97. I could follow the sentence but this post could not stand on its own without some clarification. It appears to say something that won't hold up. But that is the problem. Without further information, we can't analyze what is meant here. What something APPEARS to say and what the author meant can be two different things. This post needed some additional info. BUT. Since we have now learned what rattus was trying to express about the voltage and current angles, I see no value in trying to fix this old post. We are now in possession of newer, better detailed information. This new information is correct. No problem.
6) This thread started with Jim wanting clarification on what was said before. What rattus said before was not clear. From here on out, this thread has been about trying to figure out what in the world was going on. Rattus had not made himself clear and Jim was trying to figure it out.
7) If there have been any errors posted in the past, I say forget it. We now know, by the teaser problem, what rattus's position is and that it is a valid position. We also understand it was not originally clear to Jim because rattus's explanation was lacking the detail needed. Rattus has now provided that detail.
Now can we move on to something else?
[edit: typo]
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Rick Christopherson
Senior Member
If Rattus agrees with this summary point, then I am in absolute agreement, and the discussion is over as far as my point is concerned. I would be a happy camper! :grin:mivey said:
Rattus, Do you agree with this?
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quogueelectric
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I think we should start a mandatory drug testing program.
Rick Christopherson
Senior Member
Pay attention! Cracked wiring is not the same as being wired on crack! It's a subtle difference, but it is important. :grin:quogueelectric said:
mivey
Senior Member
I think the teaser circuit indicates it. He placed V2n@180 at the bottom of the circuit instead of at the N point. This indicates the polarity is different than the V1n voltage. We will have to wait to see what he says because we can only speculate.Rick Christopherson said:
You and me both:grin:Rick Christopherson said:
Rick Christopherson
Senior Member
Yes, but I need to hear it from Rattus, not just an assumption that we have made.mivey said:
mivey said:
If we describe the line voltages on L1 and L2 with phasors, we label them V1n and V2n. We provide magnitudes, which are always positive, and phase angles, e.g.,
Vn2 = 120Vrms @ 0
V2n = 120Vrms @ 180
Obviously these waveforms are inverses of each other. I don't like to use "polarity" here because it might be confused with the polarity marks on the transformer which do not change.
Now, if we assign an arbitrary phase angle to either voltage, the other phase angle will be shifted by 180 degrees. It is pointless to quibble about the use of the terms "phase shift", "inversion", "phase difference", etc. It is also pointless to argue about "single source". It simply does not matter. If it looks like a phase shift, then for practical purposes it is.
Simply put, I have used V2n instead of Vn2. These voltages exhibit a 180 degree phase difference, and this is perfectly valid, and it is conventional to use a common reference point where possible.
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Rick Christopherson
Senior Member
Sorry Mivey, It was a good effort on your part, but it looks like we are back to square-one.rattus said:
I do get the impression that you understood all of this, and it is now just Rattus that stands alone, but nevertheless, he is still contesting what so many of us have been saying--even you--his strongest ally.
I may be wrong, but I would have thought that when someone loses their strongest ally they would stop and take stock in their position. That is, unless you still want to support what Rattus is saying? Are you still supporting his position?
Edit: Do you agree that the minus sign is missing from Rattus' description?
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quogueelectric
Senior Member
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- new york
I am going to play lotto today. The earth is in perfect harmony.
winnie
Senior Member
- Location
- Springfield, MA, USA
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- Electric motor research
rattus said:
Rick Christopherson said:
Rick, the description that Rattus provided in post 176 is correct. Could you please point out where he missed a minus sign? As I recall, the only place where the polarity was wrong was in a very early diagram (in this thread), where the phase angles implied by the diagram were clearly at odds with the text description that Rattus gave. In the 'teaser' diagram that Mivey references, the voltage phasors have been moved to clearly indicate the nodes that they apply to.
So I am feeling clueless as to where the - sign is missing, and my opinion at this point is that Rattus is using a _different_ but _correct_ representation from you.
-Jon
Thanks:
Thanks:
Thank you Winnie for this glimmer of light. Now, I am clueless about the argument that these two voltages cannot be out of phase because they are taken from the same transformer?? The black box examples which you and I both have presented should kill that argument.
Thanks:
Thank you Winnie for this glimmer of light. Now, I am clueless about the argument that these two voltages cannot be out of phase because they are taken from the same transformer?? The black box examples which you and I both have presented should kill that argument.
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