May I ask a question about the single vs two phase stuff

[ggunn]

It can. Whether it means anything is another matter.

I'm pretty sure that if you plot y = sin(omega t) and y = -sin(omega t) on the same timeline it will look like split phase. Forgive me if my math lacks rigor; I have been out of school a very long time.

 

[Besoeker]

I'm pretty sure that if you plot y = sin(omega t) and y = -sin(omega t) on the same timeline it will look like split phase. Forgive me if my math lacks rigor; I have been out of school a very long time.

Or Vsin(ωt+π)?

 

[RumRunner]

I truely do not like the term split phase.

How can one “split” a phase?

That is a tough call. If you don't like it, then perhaps you need to write a book.

A claptrap on top of a drivel. . . which is outside the profession's accepted norm or convention for decades.

“The word phase which is used in AC terminology, refers basically to time. When two alternating currents are in phase, they reach their corresponding zero, maximum, and intermediate values at exactly the same instants.

If currents or voltages are not in phase, they reach corresponding values at different instants of time. Since electrical degrees are proportional to time, it is standard practice to state the out-of-phase relation of two quantities in electrical degrees.”

Recall the: ELI the ICE man--which I have mentioned in previous thread.

Split phase term has been extensively used in the Handbook of Electrical Engineers (Fink and Beaty) and the electricians' bible (sort of) American Electricians' Handbook (Watt and Summers)

The use of this apothegm has been sanctioned, written and taught to both electricians and electrical engineers. This is not a play on semantics. . . science is not debated based on rhetorics as others had claimed.

I used both of these handbooks during my active days and still do-- each is comprised of close to 2000 pages.

I'm open to opinions if anyone feels he needs to assert in favor of the contrary.

Have a good day, all.

 

[jumper]

That is a tough call. If you don't like it, then perhaps you need to write a book.

A claptrap on top of a drivel. . . which is outside the profession's accepted norm or convention for decades.

“The word phase which is used in AC terminology, refers basically to time. When two alternating currents are in phase, they reach their corresponding zero, maximum, and intermediate values at exactly the same instants.

If currents or voltages are not in phase, they reach corresponding values at different instants of time. Since electrical degrees are proportional to time, it is standard practice to state the out-of-phase relation of two quantities in electrical degrees.”

Recall the: ELI the ICE man--which I have mentioned in previous thread.

Split phase term has been extensively used in the Handbook of Electrical Engineers (Fink and Beaty) and the electricians' bible (sort of) American Electricians' Handbook (Watt and Summers)

The use of this apothegm has been sanctioned, written and taught to both electricians and electrical engineers. This is not a play on semantics. . . science is not debated based on rhetorics as others had claimed.

I used both of these handbooks during my active days and still do-- each is comprised of close to 2000 pages.

I'm open to opinions if anyone feels he needs to assert in favor of the contrary.

Have a good day, all.

I have a book too, no need for me to write one, it is called the NEC or NFPA 70. Seems that nowhere in it do I find “split phase” .

I understand the usage of the term, but I certainly do not have to like it nor use it. Single Phase works just fine for me.

 

[Carultch]

Single Phase works just fine for me.

The problem I have with just calling it "single phase", is that it is ambiguous. Split-phase is more specific. Your standard 120V circuit is also called single phase. At least the term split phase contrasts it from this, and gives the idea that there are more than just the single live and neutral conductors.

 

[RumRunner]

I have a book too, no need for me to write one, it is called the NEC or NFPA 70. Seems that nowhere in it do I find “split phase” .

I understand the usage of the term, but I certainly do not have to like it nor use it. Single Phase works just fine for me.

That's where the weakness is rearing it's ugly head.

NEC or NFPA don't delve deeply into the fundamentals of engineering. They're basically rote learning akin to memory work. Just memorize the articles and you're good to go.

 

[jumper]

The problem I have with just calling it "single phase", is that it is ambiguous. Split-phase is more specific. Your standard 120V circuit is also called single phase. At least the term split phase contrasts it from this, and gives the idea that there are more than just the single live and neutral conductors.

I see your point.

I have no real problem with people using the term as a teaching tool, like some of the analogies we use at times, but at some point, a certain level of understanding makes the term silly IMO.

I accept the usage, I just do not need for myself. I use the term network for 120/208V in explaining the supply. It is just a term to help explain the set up.

For myself, I need only the designated expressions like 120/240V and 120/208V.

“Split phase” to me sounds like there is a sword wielding mini electrical ninja hidden in the tranny “splitting” the phase in half.

 

[jumper]

That's where the weakness is rearing it's ugly head.

NEC or NFPA don't delve deeply into the fundamentals of engineering. They're basically rote learning akin to memory work. Just memorize the articles and you're good to go.

Bit of advice, never assume that you know the educational/experience of someone.

I may not be an EE, but I spent a few hours in college also......

 

[Adamjamma]

So I wonder if Boesecker or one of the others here in UK would suggest I use split phase or just call it single phase?lol

 

[jumper]

So I wonder if Boesecker or one of the others here in UK would suggest I use split phase or just call it single phase?lol

Bes will answer according to how a Brit would define our 120/240V supply, which is fine.

The problem is how those of us on this side of the pond define the supply.

 

[RumRunner]

Bit of advice, never assume that you know the educational/experience of someone.

I may not be an EE, but I spent a few hours in college also......

I'm not assuming anything...please don't put words in my mouth.

I solicit advice when I need one. And I do seek advice from right people from the right places.

I'm a pragmatist.

 

[jumper]

I'm not assuming anything...please don't put words in my mouth.

Your words sir:

“That is a tough call. If you don't like it, then perhaps you need to write a book.

A claptrap on top of a drivel. . . which is outside the profession's accepted norm or convention for decades.”

Kinda feels a bit condescending towards me.

The term split phase is a common convention and I understand why.

I simply do not need things dummied down for me.

I can reconcile common usage, NEC/IEEE terms, and physics just fine.

 

[ggunn]

The problem I have with just calling it "single phase", is that it is ambiguous. Split-phase is more specific. Your standard 120V circuit is also called single phase. At least the term split phase contrasts it from this, and gives the idea that there are more than just the single live and neutral conductors.

I don't at all care what we call it as long as we know what it means.

 

[jumper]

I don't at all care what we call it as long as we know what it means.

Amen and pass the popcorn please.:thumbsup:

 

[Russs57]

Well there are times where we do use a center tapped transformer to “split phases”. We are looking to have, on one secondary winding, the original waveform, and on the other one the same exact waveform with polarity inversion. We certainly don’t want something displaced in time by 180 degrees. Doesn’t matter that this isn’t electrical distribution as transformers don’t know and obey the same laws regardless.

Sometimes we do it the other way a round, a center tapped primary, AC grounded by cap with high voltage DC on it to feed two AC generators. It follows the “AC generators” are driven by previous center tapped transformer and operating in anti-phase/polarity. Under ideal conditions no AC is returned thorough the cap on center tap and DC currents are equal and opposite so core isn’t saturated.

Now what happens if one AC generator is “cut off”? What impedance does the remaining AC generator now see? Assume this generator is current limited and its transfer function is highly load dependent.

Now moving back to the discussion at hand, what impedance does the source see if we only have a L1 load on our residential electrical service? Would it be different if said supply was 120/208 secondary?

I will admit to not thinking my own thought experiment through before posting. Long day and a few too many beers. Just thought some of the later posts were getting a little personal and wanted to shift focus.

And yes, a little surprised in lack of interest in how 180 shifted versus-1 would behave with distorted waveforms.

 

[Adamjamma]

Bes will answer according to how a Brit would define our 120/240V supply, which is fine.

The problem is how those of us on this side of the pond define the supply.

But, since I am going to take tests in London eventually... must learn the language, which is hard because the guys I hang out with are always going to smoke some fags and never get arrested..lol...

 

[jumper]

But, since I am going to take tests in London eventually... must learn the language, which is hard because the guys I hang out with are always going to smoke some fags and never get arrested..lol...

If you are taking a British test define the secondary of a 120/240V as a Brit would.

If you wish to define it in the USA, pick your point of view.

All are valid.

 

[jumper]

Well there are times where we do use a center tapped transformer to “split phases”. We are looking to have, on one secondary winding, the original waveform, and on the other one the same exact waveform with polarity inversion. We certainly don’t want something displaced in time by 180 degrees. Doesn’t matter that this isn’t electrical distribution as transformers don’t know and obey the same laws regardless.

Sometimes we do it the other way a round, a center tapped primary, AC grounded by cap with high voltage DC on it to feed two AC generators. It follows the “AC generators” are driven by previous center tapped transformer and operating in anti-phase/polarity. Under ideal conditions no AC is returned thorough the cap on center tap and DC currents are equal and opposite so core isn’t saturated.

Now what happens if one AC generator is “cut off”? What impedance does the remaining AC generator now see? Assume this generator is current limited and its transfer function is highly load dependent.

Now moving back to the discussion at hand, what impedance does the source see if we only have a L1 load on our residential electrical service? Would it be different if said supply was 120/208 secondary?

I will admit to not thinking my own thought experiment through before posting. Long day and a few too many beers. Just thought some of the later posts were getting a little personal and wanted to shift focus.

And yes, a little surprised in lack of interest in how 180 shifted versus-1 would behave with distorted waveforms.

FYI, just because you started this thread, any chance of steering it into a simple direction is gone.

 

[Besoeker]

We certainly don’t want something displaced in time by 180 degrees. .

But that's what you've got with 120-0-120

 

[jumper]

But that's what you've got with 120-0-120

And what do we Yanks designate that system per NEC/IEEE?