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

[jumper]

That's what I'm trying to get you engineers to do! Seems it's not simple, no one can just quote a book.



Seems like it's a concept that emerges from some math and some other stuff, and it's genuinely fuzzy around the edges.

Defining phase here is like playing with a live grenade...

One must be careful. Lemme think about it.

 

[jumper]

And if there's no neutral?

Then we have simply series connected the secondary with two 120V sources and generated a 240V signal without access to those 120V signals.

 

[GoldDigger]

And if there's no neutral?

Then you arbitrarily pick one phase and phase conductor as the reference.
"Corner phase" instead of corner ground.

 

[Besoeker]

Then we have simply series connected the secondary with two 120V sources and generated a 240V signal without access to those 120V signals.

I'll say it again.
You have the dot notation. Polarity signs are irrelevant/meaningless on alternating quantities.

 

[jumper]

I'll say it again.
You have the dot notation. Polarity signs are irrelevant/meaningless on alternating quantities.

Those polarity signs are fine, merely reference.

Dots and signs in the pic make sense to me.

 

[Besoeker]

Those polarity signs are fine, merely reference.

Dots and signs in the pic make sense to me.

OK.
How do you assign a polarity to an alternating waveform that goes from positive to negative over a cycle every cycle?

 

[Carultch]

OK.
How do you assign a polarity to an alternating waveform that goes from positive to negative over a cycle every cycle?

Pick a particular instant in time when both waveforms are at equal and opposite peaks. Then assign polarities based on that.

 

[jumper]

OK.
How do you assign a polarity to an alternating waveform that goes from positive to negative over a cycle every cycle?

How do I measure signals without an assigned reference? I chose that polarity for continuity of my analysis.

Like “current” flow, conventional or electron? Choose one direction and stick with it. Just gotta understand that the other guy may be using the other. Both work.

 

[ggunn]

OK.
How do you assign a polarity to an alternating waveform that goes from positive to negative over a cycle every cycle?

I would assign the + to the waveform which is at its maximum at the same time as the voltage on the primary and the - to the other one, which is what I believe has been used in this thread, but it's arbitrary. It's all just convention, anyway; I mean, what has phase angle to do intrinsically with AC waveforms?

 

[jumper]

I would assign the + to the waveform which is at its maximum at the same time as the voltage on the primary and the - to the other one, which is what I believe has been used in this thread, but it's arbitrary. It's all just convention, anyway; I mean, what has phase angle to do intrinsically with AC wave forms?

I was good till last sentence. Please clarify.

 

[Besoeker]

Pick a particular instant in time when both waveforms are at equal and opposite peaks. Then assign polarities based on that.

It's a continuously time varying signal. On what basis would you pick a particular instant in time? The dots tell you all you need to know.

 

[ggunn]

I was good till last sentence. Please clarify.

I mean what's electricity got to do with geometry? Nothing, other than the convention we have invented to tie them together.

 

[ggunn]

It's a continuously time varying signal. On what basis would you pick a particular instant in time? The dots tell you all you need to know.

Call one of them George and the other one Elmo. It's just convention.

 

[Besoeker]

Call one of them George and the other one Elmo. It's just convention.

Or L1 and L2.

 

[K8MHZ]

Or L1 and L2.

But not Phase 1 and Phase 2.

 

[jumper]

I mean what's electricity got to do with geometry? Nothing, other than the convention we have invented to tie them together.

I will buy that. No problem.

 

[Besoeker]

But not Phase 1 and Phase 2.

But would that actually be incorrect even not the common/usual/NEC description?

 

[K8MHZ]

But would that actually be incorrect even not the common/usual/NEC description?

To me it's incorrect. Where in the NEC does it say that one conductor can be a phase?

 

[jumper]

To me it's incorrect. Where in the NEC does it say that one conductor can be a phase?

One conductor is not a phase.

Two conductors is not a phase either.

Phase is a mathematical expression used to define a relationship between two points.

You pick the points, you define the relationship, and there is your phase.

 

[jumper]

That's what I'm trying to get you engineers to do! Seems it's not simple, no one can just quote a book

Wait! I ain’t a train driver, I is a lab rat.

Problem is that it kinda depends on which and what type of book you quote.

Seems like it's a concept that emerges from some math and some other stuff, and it's genuinely fuzzy around the edges.

Fuzzy is an understatement.