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Old 07-05-2010, 08:43 PM   #46
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Quote:
Originally Posted by a7ecorsair View Post
Some more on phasing.
Phase relationships of voltage or current only have meaning when a single device makes use of them. There is no single device that requires a connection to both bus bars and the neutral to operate.
Three phase power is used to run a single device with the most common being a three phase motor and the phase relationship will determine the direction of rotation. Swap any two leads and the motor will run the other direction.
Yup!
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Old 07-05-2010, 08:51 PM   #47
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Originally Posted by nap View Post
in that particular statement, he was speaking of 3 phase power so there would be multiple phases, obviously.

as to phases in a 120/240 system; I believe it is simply a misnomer that has permeated the trade and been accepted as the term of choice. Obviously there is only 1 phase but when trying to explain, using the term phase is synonymous with leg or whatever term you happen to use. Doesn't make it the correct term, just the one that gets used.

'Tis but thy name that is my enemy;
Thou art thyself, though not a Montague.
What's Montague? it is nor hand, nor foot,
Nor arm, nor face, nor any other part
Belonging to a man. O, be some other name!
What's in a name? that which we call a rose
By any other name would smell as sweet;
So Romeo would, were he not Romeo call'd,
Retain that dear perfection which he owes
Without that title. Romeo, doff thy name,
And for that name which is no part of thee
Take all myself.
Aha! you do have a way with words, and you have precisely stated the case!
Its this misnomer that causes confusion for those who are newbies and are having a problem understanding!
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Old 07-07-2010, 07:23 PM   #48
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Do you have a connection the A7?
Nope, just a heartfelt admiration and respect for those who secure and protect my freedom.
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Old 07-07-2010, 07:36 PM   #49
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Originally Posted by Wildie View Post
TVI. if you study this link to Wikepedia ( http://en.wikipedia.org/wiki/Three-phase ) it has an excellent article about 3 phase power. The wave forms shown will never ever be seen on an oscilloscope, in a home that is single phase serviced.
WHO EVER SAID THAT IT WOULD? This discussion is not about THREE PHASE power, it is about 120/240 split phase power delivered to residential customers in the US and CANADA. You are doing a lot of arm waving and confusing the issue.

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Your diagram that you have provided, is exactly the same as the one provided to our electrical class in 1950.
It was around LONG before that, so what?

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What I am attempting to do, is make the point that the term ' PHASE' should never, ever be used in conjunction with single phase, residential service.
No you are talking yourself in circles my friend.

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The 220 volt poles in single phase services were mistakenly called phases in early years, as the term seemed to fit, but in reality, was incorrect. Sadly, many such as yourself, fail to grasp the significance, and unfortunately are continuing misinform those who are attempting to understand.
I have not misinformed anybody sir. It is you who has muddied the waters and confused people. The great thing about forums is that your words are there for everybody to read, all they have to do is scroll back a page or two.

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I'll attach a diagram of a 3 phase wave form. A wave form such as this is never to be seen in a single phased application.
We are not talking about 3-phase power and don't care what the waveform looks like. We are talking about single phase service delivered to residential customers. The service is derived from a single phase transformed by a center tapped transformer and delivered as two 120V poles that are exactly 180 degrees out of phase from each other with respect to the center tap (Neutral). Wave you arms and play word games all you want, you spoke in error.

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Hows it feel to have both your feet in your mouth!
Again, the nice thing about forums is that anybody interested can go read the context and chronology of comments. Do I have a foot in my mouth becuase YOU say so? Do you have a foot in your mouth because your put it there?

Honestly, before you dig yourself a deeper hole....
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Old 07-07-2010, 07:50 PM   #50
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Originally Posted by nap View Post
yes: phase

the problem is: there is "a phase" as we see on the scopes and then there being "in or out of phase" synonymous with the term sync.

While a single phase system has only one phase, the coexisting sine waves are out or phase with each other.
Exactly....

Each sine wave is a complete entity with respect to the center tap (neutral). As derived, they are 180 degrees out of phase with each other.

So we go back to the initial post by WILDE on the topic:

Quote:
Originally Posted by Wildie
Something else for you to think about!

How can you have 2 hots, out of phase when You only have single phase service in most residential applications.
It ain't possible!
In single phase residential service, we have have 'poles' that usually supply 220 volts A/C! The wave form of these poles is always in phase and never change!
Again: The transformer creates two sinewaves (or splits one if you prefer) that ARE OUT OF PHASE with respect to each other, 180 degrees to be exact.

Somebody help him yank those feet out of there... it looks painful!

Last edited by TheVillageIdiot; 07-07-2010 at 07:56 PM.
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Old 07-07-2010, 09:02 PM   #51
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Originally Posted by TheVillageIdiot View Post
WHO EVER SAID THAT IT WOULD? We are not talking about 3-phase power and don't care what the waveform looks like. We are talking about single phase service delivered to residential customers. The service is derived from a single phase transformed by a center tapped transformer and delivered as two 120V poles that are exactly 180 degrees out of phase from each other with respect to the center tap (Neutral). Wave you arms and play word games all you want, you spoke in error.
They are not out of phase with each other! If you must insist in using the expression 'phase' then these poles are exactly in phase with each other.
At any given moment these voltages are in absolute unison with each other.
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Old 07-07-2010, 09:09 PM   #52
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Originally Posted by Itsdanf View Post
Does this mean that the common neutral wire has a possible max load of 30A or more? If so, is this a problem, given it's 14/3 NM wiring? Or does the reverse-phasing minimize the neutral load?
You can measure the voltage drop from one end of the neutral to the other and then you will know the current in that lead.
For #14 copper it's 2.6 ohms per 1000' so 1 A in 50' of this neutral conductor will drop 0.13 vac.

It's easier to imagine if you mentally freeze the sine wave as it's crossing through the instantaneous value of 120v. Then you've got two 120vdc batteries stacked so they add to 240vdc and feeding two loads with a common return to the battery's center tap, and in this DC circuit you can see how the current cancels in the common lead.

Last edited by Yoyizit; 07-07-2010 at 09:20 PM.
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Old 07-07-2010, 09:34 PM   #53
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Originally Posted by Wildie View Post
They are not out of phase with each other! If you must insist in using the expression 'phase' then these poles are exactly in phase with each other.
At any given moment these voltages are in absolute unison with each other.
It appears that there is a language barrier here and we both speak English. You entered this discussion with a somewhat smug response based on the meaning of words, not concepts. There is no doubt that you understand how the split phase power is derived, the unfortunate part is that in your haste to correct others, you tripped over the very words that you endeavored to define. Why continue to dig your heels in when it is abundalty clear that you erred in your usage of words?

More clearly, you are using a narrow definition of a words and ignoring the context in which they are used. In this case, you made the mistake in the presence of several other well informed people and you have been backed into a [proverbial] corner.

Nobody here is saying that "2-phase" power is being generated or delivered. You are stuck on transmission phases and refuse to look at the context in which the word PHASE is being properly used to describe the relation of one wave form to another. So yes, I insist on using the term PHASE as it is the proper way to describe the relationship of waveforms.

Before you dig a deeper hole, you need to take a half a step back and understand where you are making your mistake. We are not talking about a SINGLE sine wave. Each leg of the derived service can be viewed and utilized as an independent voltage and current. That is, we have TWO sine waves, we don't care WHERE they came from. This is your error sir!

Last edited by TheVillageIdiot; 07-07-2010 at 09:40 PM.
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Old 07-07-2010, 09:42 PM   #54
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Originally Posted by TheVillageIdiot View Post
It appears that there is a language barrier here and we both speak English. You entered this discussion with a somewhat smug response based on the meaning of words, not concepts. There is no doubt that you understand how the split phase power is derived, the unfortunate part is that in your haste to correct others, you tripped over the very words that you endeavored to define. Why continue to dig your heels in when it is abundalty clear that you erred in your usage of words?

More clearly, you are using a narrow definition of a words and ignoring the context in which they are used. In this case, you made the mistake in the presence of several other well informed people and you have been backed into a [proverbial] corner.

Nobody here is saying that "2-phase" power is being generated or delivered. You are stuck on transmission phases and refuse to look at the context in which the word PHASE is being properly used to describe the relation of one wave form to another.

Before you dig a deeper hole, you need to take a half a step back and understand where you are making your mistake. We are not talking about a SINGLE sine wave. Each leg of the derived service can be viewed and utilized as an independent voltage and current. That is, we have TWO sine waves, we don't care WHERE they came from. This is your error sir!
For some reason, Sir! You seem to be obsessed with denegrating myself in an effort to further your argument.
This attitude does nothing to make a meaningful discussion for others, so I inform you that I will not take any further response to your diatribe.
I'm surprised that a stance such as yours is countenanced by the administration.
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Old 07-07-2010, 10:43 PM   #55
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For some reason, Sir! You seem to be obsessed with denegrating myself in an effort to further your argument.
This attitude does nothing to make a meaningful discussion for others, so I inform you that I will not take any further response to your diatribe.
I'm surprised that a stance such as yours is countenanced by the administration.

You were more than happy to attempt to denegrate me when you felt your position had merit. I have simply presented you with facts and pointed out where your comments are in error. Presented with those facts, you refuse to make any further response becuase you refuse to admit error. It is easier to deflect the attention and attempt to portray me as a bad, mean spirited person for correcting you, when in fact YOU are the person who set out to correct several of us.

Last edited by TheVillageIdiot; 07-07-2010 at 10:45 PM.
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