How does the typical mains power connect in the USA anyway?

Didn't have to, after the freezing rain about that time of year. But, it sure is a good idea. And hide the hammer, so they don't bust out the glass.

Reply to
Stormin Mormon
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Like that?

Reply to
Stormin Mormon

That why you're called a night crawler??

Reply to
clare

Nope. Not one sine to be seen. However, you did do a good job of feeding into Dean's post. ;-)

Reply to
krw

Here's the wave:

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Reply to
Stormin Mormon

Cute sign, but not a sine to be seen.

Reply to
krw

understand the details about how a part of a circuit gets "out of phase."

learly there is a phase relationship between part of the wire and another p art, in that ON THE SAME WIRE some part of it is 180 degrees out of phase w ith another.

amplitude of Trace A

The only problem with that is the accepted reference point for the system in question is the NEUTRAL/Ground. No one in their right mind would reference the scope to one of the hot legs.

Don't believe me about two phases, ask the IEEE ppower engineers, which is about as credible an authority on the subject as you can get:

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4520128

"Distribution engineers have treated the standard "singlephase" distributio n transformer connection as single phase because from the primary side of t he transformer these connections are single phase and in the case of standa rd rural distribution single phase line to ground. However, with the advent of detailed circuit modeling we are beginning to see distribution modeling and analysis being accomplished past the transformer to the secondary. Whi ch now brings into focus the reality that standard 120/240 secondary system s are not single phase line to ground systems, instead they are three wire systems with two phases and one ground wires. Further, the standard 120/240 secondary is different from the two phase primary system in that the secon dary phases are separated by 180 degrees instead of three phases separated by 120 degrees."

Or see the seperate discussion I started where I start out with

3 phase, and show what phases are, how you can morph that step by step into split-phase using two of the three phases. It winds up identical to a 240/120V split phase service and one of the phases doesn't disappear.

BTW, still waiting for one of you alleged experts to define the term "phase" for me.

Reply to
trader4

snipped-for-privacy@googlegroups.com...

d look like to the power plant?

He agrees with me. You say correct. And then you hurl another insult at me. You really are confused here.

Reply to
trader4

Neither will the IEEE power engineers:

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4520128

"Distribution engineers have treated the standard "singlephase" distributio n transformer connection as single phase because from the primary side of t he transformer these connections are single phase and in the case of standa rd rural distribution single phase line to ground. However, with the advent of detailed circuit modeling we are beginning to see distribution modeling and analysis being accomplished past the transformer to the secondary. Whi ch now brings into focus the reality that standard 120/240 secondary system s are not single phase line to ground systems, instead they are three wire systems with two phases and one ground wires. Further, the standard 120/240 secondary is different from the two phase primary system in that the secon dary phases are separated by 180 degrees instead of three phases separated by 120 degrees."

Are the IEEE trolls too? You just hurl insults but refuse to address the above that clearly shows the IEEE power engineers agree with me.

BTW, still waiting for you to give your definition of "phase". If you know so much, why can't you do that?

Reply to
trader4

l flow along the neutral wire.

ndary for a second.

s a zero reference.

The poster never said "no center tap" or "no neutral". What he said was not having the NEUTRAL BONDED TO GROUND. But you'd rather hurl insults instead of reading what people actually write.

Here is what the poster said:

"The ground IS a parallel path for return, but most of the current will flo w along the neutral wire. The center tap of that transformer is bonded to ground. That gives us a ze ro reference. But that technically is not necessary. Your house would wor k fine without it. Your oven would still "see" 240 volts and your lights 1

  1. The problem is you might have a voltage difference between some of you r equipment and ground."

Again, he never said there is no center tap, no neutral. Only what would happen if the neutral was not bonded to ground.

Read and learn. He's right, you're wrong, yet again.

You mean asinine drivel like the IEEE power engineers agreeing

100% with me?

Or me asking for you to simply give us your definition of the term "phase"?

Are you as sure about all this as you were about it being illegal for employers to help pay for their employees Obamacare? Remember when you hurled insults and profanities at me and others here about that and you were dead wrong? How about when you argued about how a 4 wire vs 3 wire appliance connection works? You had Bud, RBM, me telling you that you had it wrong. You as sure about this as you were about those earlier embarrasments?

Reply to
trader4

I used to install power-plant generators, yes. Not utility generators. These private plants fed the grid and were under the ultimate control of the utility, meaning that the utility could kick them off-line, at will. Most of the plants were not stand-alone. If the grid went down, they went down. The gas-turbine plants were stand-alone, and some city service generation facilities were, also.

Per generator:

A Wye system only has the standard voltage/amperage/frequency/ ground-fault protective systems. Each phase has one bus, two detection transformers (CT and PT), and the neutral is grounded through a current transformer. The neutral does not go out of the plant. The ground fault and generator detection trans- formers are installed on the generator side of the 52G breaker.

The utility only has one set of detection devices in the plant, right after the service entry switch. This set-up provides the best user safety for power generation.

Delta systems are set up primarily the same way with the exception that they usually do not have a grounded leg, hence, no reference to ground. To get a reference to ground requires a complicated and costly system that is separately derived from the direct gener- ation process. These things take up a lot of space. There is no way to have these units inside the control room as with the Wye set- up. Each phase of each generator will have a transformer 1/3 the size of a standard pole pig. This is quite a footprint. My memory of the exact set-up is rather vague, but I do recall a set-up that only sensed the outgoing feed to the step up transformer. That took up a roughly 8' dia. area of ground. I might try to pull up a picture via Google maps.

In industrial/commercial building(s)/complex(s), the service is brought into a distribution panel. This service is 1200 amps and up. The distribution panel feeds other distribution panels directly (building), via meters (complex--separate business'), or a combination of the two. The primary distribution panel uses large form factor circuit breakers that have adjustable magnetic trip settings and are sized, amperage wise, for the load anticipated, either via load calc, or other means. Say, a 400 amp feed to what will be a production facility that uses large machinery and other devices that draw heavy current loads. A 200 amp feed to another section that does not have a purpose at the time of installation and so on until all of the spaces in the dist. panel are used up, or only the immediate (known) service sourcing is to be powered. Why waste the money before the use for the space is known?

(I have to step out for a bit, so I will not be able to finish at this time)

Reply to
Nightcrawler®

Um, that was a joke. A pin-hole in one of the hots will slowly erode the messenger cable. A slow blow fusible link?

Reply to
Nightcrawler®

LOL! Sure, why not. :-)

Reply to
Nightcrawler®

That's an entirely different kettle. Of course they're Wye connected because that's what the customer sees. the POWER COMPANY'S generators

*are* delta connected, as is the transmission system.

At the customer end, OK, but that has nothing to do with the power company.

Huh? Delta has no neutral.

You're talking about an *entirely* different issue and irrelevant to the discussion.

Reply to
krw

Not obvious what the author has in mind in the minimal summary of his paper.

He clearly says the standard way of looking at split-phase, 3-wire supplies is they are single phase. Everyone here but you (that has provided an opinion) agrees with that.

The author suggests a departure where the 2 hot wires are considered separate phases for "modeling". And for modeling, if you are looking at the *currents* in the 3 wires, you have to consider them separate phases because the currents will be 180 degrees out of phase only if the loads are resistive. Not obvious what the author is saying beyond that.

But, alas, I don't see where the author's suggestion has been accepted.

The paper confirms what the rest of us have been saying.

My service panel is "single phase". If I replaced it, the only panels manufacturers have are "single phase". The 2-pole breakers for them are "single phase".

I propose we resolve this by using L1, in my L1-N-L2 service, as the reference. L1-N and L1-L2 are in phase.

The standard real 2-phase supplies have 2 transformers 90 degrees apart with the centertaps connected. Does this then have 4 phases?

In a 3-phase wye system are there 6 phases at the transformers (each transformer has 2 ends)?

Reply to
bud--

ution transformer

rmer these connections

phase line to ground.

to see distribution

condary. Which now

re not single phase

ases and one ground

o phase primary system

ree phases separated

It's clear to me:

"Which now brings into focus the reality that standard 120/240 secondary sy stems are not single phase line to ground systems, instead they are three w ire systems with two phases and one ground wires. Further, the standard 120 /240 secondary is different from the two phase primary system in that the s econdary phases are separated by 180 degrees instead of three phases separa ted by 120 degrees. "

He's saying that in fact you have two phases and that's how you have to analyze it.

He didn't say that at all.

Everyone here but you (that has

He did not say it's just for modeling.

And for modeling, if you are looking at

So, how can you consider them separate phases if they are really not separate phases?

How about these white papers from electrical eqpt manufactuers that clearly talk about two phases being present:

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Are they wrong too?

No because the logical reference point to look at phases is from the neutral common point. You have 3 phases, differing by 120 degr ees. Similarly, the logical reference point in a split-phase service is the neutral common point. From that perspective, you have two phases present. Since you brought up 3 phase, what about the other thread I started where I used 3 phase to show how you can get to split-phase and how it looks like two phases? A lot of people looked at that post, but no one wants to comment? Here it is again:

Let's start with a 3 phase wye power source. For anyone not familiar, here's a diagram of it, it's fairly straightforward:

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It's the first diagram that shows a 3 phase wye power source. Let's assign Phase A as the reference point and make it 0 deg. Phase B is 120 deg off from Phase A. Phase C is 240 deg off from Phase A. You can see those 3 waveforms on a 3 input scope, one input attached to each phase, the scope reference point tied to the neutral. I believe everyone here is in 100% agreement that you have 3 phases present there. Let's put that power source inside a box and I run those 4 wires out of the box, I have 3 phases. For convenience, let's assign each of the 3 voltage sources in the box to be 120V. So, we have 3 phases emerging from the box, with 120V between any phase and neutral. All this I hope we agree is still 3 phase.

OK, so now, lets just leave everything as it is, but only run Phase A and B and the neutral out of the box. How many phases do I have now? I would hope that you would agree that I have two phases, Phase A at 0 deg, Phase B at 120 deg. Again, I can see exactly that on a scope.

Now, lets change the source for phase B so it's at 90 deg. How many phases do I have coming out of the box? My answer: two. Change B to

175 deg. How many phases do I have? My answer: two. Change B to 185 deg, how many phases do I have? My answer: two. Now change Phase B to 180 deg and how many phases do I have? My answer: two.

And if I have two there, how exactly is what's coming out of that box any different than the 3 wires coming into a split-phase

240/120V service? You have a neutral and two phases 180 deg apart coming out of the box. Between Phase A and neutral you have 120V. Between Phase B and neutral you have 120V. Between phase A and Phase B you have 240V. What's coming out of that box is identical in every way to what's delivered with a 240/120V split-phase service. If I hooked either the box or the 240/120V split-phase service up to your house, there is absolutely nothing different in terms of current flow, voltage, etc that is going on at the panel. You could not tell the difference.

Another way of looking at it. I could replace the power source in the box with a center-tap transformer that delivers 240/120V split-phase and you could not tell the difference. The electrical charecteristics on the 3 wires coming out would be EXACTLY the same.

My position is clear. The 180 deg phase relationship is just one special case of the various possibilities. You can still view it as two phases, treat it that way from an engineering analysis basis, etc. The opposing view is apparently that something magical happens at 180 deg, so that it can no longer be referred to as 180 deg out of phase, it must only be called "opposite" or some other imprecise non-engineering term. In fact, no one who says I'm confused has yet given their definition of "phase", though I've asked 10 times now. How can you even talk about something, when no one will define it?

Reply to
trader4

He is proposing that you consider them 2 phases to analyze it.

And says that is a change from how "distribution engineers" view split-phase.

"Distribution engineers have treated the standard "singlephase" distribution transformer connection as single phase because from the primary side of the transformer these connections are single phase and in the case of standard rural distribution single phase line to ground."

He is suggesting a change from that view.

It is not really clear what he is saying when all we have is a summary of the paper.

But he says he is proposing a change from how split-phase is viewed by "distribution engineers".

The currents are not necessarily 180 degrees out of phase even though the voltages are. That is not something new. I have analyzed currents in a split phase system without considering the voltages are different "phases".

The summary does not indicate if he is talking about more than that.

It is a way of referring to the wires. And a way that is consistent through the piece with 3-phase diagrams.

A single 120V circuit has a "Phase A" wire? What is the point of that?

Also uses "Hot Leg L1 and L2".

Find me a 2 phase panel.

Other opinions here all disagree with you. Some of us are involved in power distribution. Your IEEE paper agrees with us. You can call it whatever you want to. IMHO calling the legs "phases" adds to confusion.

But I don't really care.

Reply to
bud--

After shuffling across the carpet in your slippers, a spark is created when you touch a doorknob.

Following the flawed concept of "return" as a circuit concept, the spark goes where? It travels thru a wooden door, it's hinges, the door frame, building structure etc, to earth ground?

Or, is the spark injected into the human, from a resulting high ground potential? Ground, (often mistakenly understood as having zero/no potential) is lurking in doorknobs waiting to zap some unsuspecting doofus.

Reply to
Wild_Bill

ibution transformer

former these connections

e phase line to ground.

g to see distribution

secondary. Which now

are not single phase

phases and one ground

two phase primary system

three phases separated

y systems are not single phase line to ground systems, instead they are thr ee wire systems with two phases and one ground wires. Further, the standard 120/240 secondary is different from the two phase primary system in that t he secondary phases are separated by 180 degrees instead of three phases se parated by 120 degrees."

You can analyze them any way you want. It doesn't change what is there.

What more does he need to talk about:

"Which now brings into focus the reality that standard 120/240 secondary sy stems are not single phase line to ground systems, instead they are three w ire systems with two phases and one ground wires. Further, the standard 120 /240 secondary is different from the two phase primary system in that the s econdary phases are separated by 180 degrees instead of three phases separa ted by 120 degrees."

It's as clear as can be. He doesn't say, that there really are not two phases present, but we can pretend there are. He says the

*reality* is there are two phases.

And a way that says you have two phases, Phase A and B, and that they are 180 deg out of phase with each other.

We're not looking at just a single 120V circuit. We're looking at a 3 wire circuit.

Sure. I have no problem with that. But why skip the elephant in the room:

"The primary side of the Distribution Transformer is connected between Grou nd and one of the 2400V, 7.2 kV, 12.47 kV, 13.2 kV or 13.8 kV phases of the utility company's 3-Phase Distribution Network. The secondary of the Distribution Transformer has a grounded center tap and is wound in a manner that supplies two 120 VAC phases which are 180° out of phase with each other (Split Phases)

The center-tapped configuration of the secondary side of the Distribution T ransformer provides following voltages to the Service Entrance Panel: ? 120 VAC between the Hot Leg L1 (Phase A, Red wire) and the grounded, ce nter tapped Neutral (White wire). The oscilloscope trace of the voltage waveform between the Hot Leg L1 and Neutral shows the voltage risin g in the Positive direction at the start of the waveform ? 120 VAC between the Hot Leg L2 (Phase B, Black wire) and the grounded, center tapped Neutral (White wire). Please note that the corresponding oscilloscope trace of the voltage waveform between the Hot Le g L2 and Neutral shows the voltage rising in the Negative direction at the start of the waveform. This indicates that the two 120 VAC voltages are 180 degrees out of phase ? 240 VAC between the Hot Leg L1 (Phase A, Red wire) and the Hot Leg L2 ( Phase B, Black wire)"

What something is commonly called doesn't change physics or electrical engineering. It's like saying because you call something Kleenex, it isn't actually a piece of soft tissue paper.

That isn't true either. We had one poster describing how transformers are used to create phases in farm pump applications that agreed with me. I also believe nightcrawler said he agreed with me.

Some of us are involved in

It agrees only with what it's been *called* by the power industry and clearly says that while it's called single phase, in reality you have two phases and that is how you need to model it. That is what the paper is about.

You must, because you're still posting. And I'm still waiting for a answer to the simple question of your definition of the term "phase". Why is it that despite me having asked 12 times now, not one of those arguing against me can even define it? How can you talk about something you won't define?

And why no response to my detailed example of going from 3 phase, to two phases that then looks just like a split-phase service? Here's another example. People here have brought up the 100 year old two phase system where the phases were 90 deg apart. OK, I'll play that game. So we have two phase wires, A and B and a neutral. Phase B is 90 deg apart from Phase A. Everyone here seems to agree that two phases are present, right?

So, now let's make phase B 120 deg apart. Still two phase? Let's make it 280 deg apart. Still two phase? Let's make it 170 deg. Still two phase? Let's make it 180 deg apart, still two phase? And if it's suddenly no longer two phase, why not and by what definition of the term "phase"? And if it is two phase, then it's also electrically indistinguishable from split-phase 240/120 coming into your house from the service. That is the reality and that is exactly what the IEEE author is saying. A phase difference of 180 deg is just one special case of a phase relationship.

Reply to
trader4

I haven't been in a rural enough area in years to even look for one. The fact that it isn't common doesn't mean that it doesn't still exist. Some farms were 20 miles from the nearest highway, on a private dirt or clay road. They were electrified by either a co-op or the TVA and 20 miles of copper wire was expensive.

Reply to
Michael A. Terrell

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