quogueelectric
Senior Member
- Location
- new york
While he has the book open also hit SINGLE PHASE XFORMER it is inherently single phase by definitionRick Christopherson said:
Battle of the Phases
- Thread starter rattus
- Start date
- Status
Rick Christopherson said:
A real engineer would know that the neutral node is that point in a system which is equipotential from all other points. There is no such point in a delta system. Likewise, there is no such point in a 120V system either.
Real engineers are not sarcastic either.
quogueelectric said:
What does this discussion have to do with two-phase, three-phase, poly-phase, multi-phase, or the phase of the moon for that matter??
Real engineers know the difference between two-phase and phase difference. Sorry quogue, the Devil made me say it.
This must be the 99th time I have tried to get this point across.
Last edited:
Rick Christopherson
Senior Member
I alluded to this in another thread, but I did not go so far as to directly challenge what you list in your user profile, and I am not being sarcastic.rattus said:
I am now asking this as a direct question:
Did you, or did you not, graduate from an ABET Accredited University Program with a Bachelor of Science (or higher) degree in Electrical Engineering?
If you do not know if your University program was ABET accredited, then list the name of the University and the Program, and I will tell you if it is accredited or not.
quogueelectric
Senior Member
- Location
- new york
Keep trying then This post is titled the battle of the phases. Do you remember back in Reel engineering school the transformer drawing that looked like a christmas tree?? A four wire delta?? A 120/240 delta with a high leg?? page 13 in the uglys book?? Does any of this sound familiar?? Did your airbag deploy recently?? Like you would find at say a gas station which has mostly 3phase pump loads but needs some 120/240 for the lights and recepicles??rattus said:
- Location
- Wisconsin
- Occupation
- PE (Retired) - Power Systems
mivey said:
Boy it is hard not to jump back in to this.
V1 and V2 are not out of phase with each other. They can not be because they are simply two points for one measurement. If I remember geometry correctly, two points make a single straight line, it is not possible to have an angle between them.
If you want to add an arbitrary third point for reference (i.e. a neutral in a 120/240 3 wire system, or dirt, or your neighbors car battery) then you may begin to discuss angles, phases, directions, or any number of other topics. But, when making your argument remember not every circuit/system may have your reference point.
- Location
- Lockport, IL
- Occupation
- Semi-Retired Electrical Engineer
STOP IT RIGHT NOW, ALL OF YOU!
I have not read any part of that “other thread.” I don’t know if I want to. But I am beginning to suspect that the personal insults and general rudeness I am seeing here are mere carryovers from earlier exchanges. I’ll not have it.
Keep the discussion on topic, and stay away from suggestions that any other member lacks the credentials to speak about the subject.
If I see any more personal attacks or rudeness, two things will happen. First, I will close this thread, and possibly the other one as well. Secondly, the offending party will be banned from the use of this forum for a minimum of one week.
Stay professional, or stay away.
I have not read any part of that “other thread.” I don’t know if I want to. But I am beginning to suspect that the personal insults and general rudeness I am seeing here are mere carryovers from earlier exchanges. I’ll not have it.
Keep the discussion on topic, and stay away from suggestions that any other member lacks the credentials to speak about the subject.
If I see any more personal attacks or rudeness, two things will happen. First, I will close this thread, and possibly the other one as well. Secondly, the offending party will be banned from the use of this forum for a minimum of one week.
Stay professional, or stay away.
Last edited:
Rick Christopherson said:
I don't think that is a matter for this Forum. It is not your place to ask such a question. You are being condescending again.
Now, the smartest fellow I know did not finish his Freshman year, yet his knowledge puts me in the in the shade, and he has a fistful of patents.
quogueelectric said:
I think you are referring to the 120/240V subsystem which has a neutral, but the delta itself has no neutral--that is my point.
Actually "Battle of the Phases" is a misnomer because we are indeed speaking of a single-phase system. Leave the rest of the system out of it.
jim dungar said:
Jim, we ARE speaking of a 120/240 3-wire system. Furthermore V1 and V2 cannot be measured without some reference point. In this case, it is the neutral. That is we measure V1n and V2n which are negatives of each other, and that is the same as a 180 degree phase difference. Likewise for V12 and V21.
This is no different in principle from measuring a 3-phase wye where the common reference is the neutral. Van, Vbn, Vcn---V1n, V2n---same principle.
Did someone say 2-phase? 3-phase? No! The basic discussion is about a 120/240 1-phase system. Just using the wye for a comparison.
- Location
- Illinois
- Occupation
- retired electrician
We have been down this road before, but if the two conductors are out of phase with each other we cannot possibly have a single phase system. A phase cannot be out of phase with itself. There are only two choices....agree that they are not out of phase, or agree that they are and get rid of the term single phase. The two ideas are mutually exclusive.
LarryFine
Master Electrician Electric Contractor Richmond VA
- Location
- Henrico County, VA
- Occupation
- Electrical Contractor
It's amazing how far the theoretical discussions can be dragged out, and to no conclusion. It's like discussing religon or politics. Nobody is going to change anyone else's opinion merely by saying the same thing again and again.
Yes, from the neutral's aspect, the two ends of a 1-ph winding are of opposite polarity at any given moment. The poeple who refuse to call it "out of phase" aren't doing so because they haven't been convinced of this. It really is a matter of semantics.
In the old days of transistor audio amplifiers, single-ended power supplies were the norm, and the amp required a large electrolytic capacitor in series with the output to block DC, since the output modulated half of the supply voltage.
Later, bi-polar supplies came along, and the output cap was no longer necessary. There were both + and - power supply rails, relative to chassis ground. One could easily place a voltmeter's - lead on the - rail and read two positive voltages, chassis looking like a center tap.
So, is it a power supply with two positive voltages? Is it one with two negative voltages? Or is it a split supply, with one of each? Nothing changes among the readings except the placement of the test leads. It's a matter of perspective.
It's all of the above. To me, the whole discussion is a waste of time. The engineers may like magnitudes, vectors, phasors, or whatever. The electricians need to know how to hook 'em up. I'm an electrician.
Yes, from the neutral's aspect, the two ends of a 1-ph winding are of opposite polarity at any given moment. The poeple who refuse to call it "out of phase" aren't doing so because they haven't been convinced of this. It really is a matter of semantics.
In the old days of transistor audio amplifiers, single-ended power supplies were the norm, and the amp required a large electrolytic capacitor in series with the output to block DC, since the output modulated half of the supply voltage.
Later, bi-polar supplies came along, and the output cap was no longer necessary. There were both + and - power supply rails, relative to chassis ground. One could easily place a voltmeter's - lead on the - rail and read two positive voltages, chassis looking like a center tap.
So, is it a power supply with two positive voltages? Is it one with two negative voltages? Or is it a split supply, with one of each? Nothing changes among the readings except the placement of the test leads. It's a matter of perspective.
It's all of the above. To me, the whole discussion is a waste of time. The engineers may like magnitudes, vectors, phasors, or whatever. The electricians need to know how to hook 'em up. I'm an electrician.
- Location
- Wisconsin
- Occupation
- PE (Retired) - Power Systems
rattus said:
That is why my point was directed to a specific statement that said two points were out of phase without specifing that a third reference point was involved. Participants in discussions need to use a common terminology and not assume that any specific reference point is "always understood". Voltages reading should always be given in a "from and to" format.
I spend more time working with 240V corner grounded, 240V ungrounded, and 240/120V wild leg systems than I do 120/240 single phase. I have hard time problem solving when all I am given is V1 = 240V, V2 = 240V as I am left to guess what reference was being used.
dbuckley
Senior Member
- Location
- Canterbury, New Zealand
That thing where you have 120-0-120 supply, the first item in the diagram; it is without doubt a single phase system (hint - count the wires on the primary of the transformer of a typical single phase supply).
There seems to be some confusion between the terms "polarity" and "phase". For the avoidence of doubt, you have a to have a time difference between the zero cross points of the waveforms to have a phase difference between the waveforms. In a single phase system there is no time difference between the two "ends" of the supply, though they differ in polarity compared to the centre point.
There seems to be some confusion between the terms "polarity" and "phase". For the avoidence of doubt, you have a to have a time difference between the zero cross points of the waveforms to have a phase difference between the waveforms. In a single phase system there is no time difference between the two "ends" of the supply, though they differ in polarity compared to the centre point.
don_resqcapt19 said:
Now Don, I know your thoughts, but no one is claiming this to be a two phase system. It is simply a matter of the reference point. Put a scope on L1 and L2 and you see one sinusoid is the negative of the other. That does not constitute a 2-phase system. What you see is what you get--a phase difference.
V1n and V2n are NOT the same voltage even if they appear on a common, center tapped winding. In computer simulations one would model them as separate AC sources.
Rick Christopherson
Senior Member
Even though I am a newbie to this forum, and I know I risk being banned from the forum for this, but I did not ask this question in a disrespectful way. I think we all have the right to know the basis behind a person's comments.rattus said:
You questioned my credentials last week, and I responded that I registered for this forum using my full name, so my credentials are out there for everyone to see. If you Google my name, you will see that I am who I say I am, and I do have the right to call myself an Engineer. As worthless at it is, I even have an E.I.T. certification, (EIT 13889-T).
I asked a legitimate question, and I expect a legitimate answer.
All you had to do was say "Yes" or "No".
I simply want to know the caliber of the person I am communicating with.
Last edited:
- Status