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

[Sahib]

It only resembles an offset in time; it's an opposition in instantaneous polarity.

If you were to change the frequency but maintain what you perceive as the "timing offset" between the two waves, the opposing peaks would no longer occur at the same time.

Both halves have the same frequency and amplitude but their values are opposite with respect to time. So some argue there are two phases in 240/120V system. But functionally it is a single phase system because, for example, it can not run a two phase motor by itself. So I dialectically combined the two concepts into one in my last post to resolve the issue for both parties here.

 

[Besoeker]

It only resembles an offset in time;

Doesn't that describe exactly what a phase shift is?

Whether that time offset is 5.55 ms (120°) or 8.33 ms (180°), it is still an offset.

 

[ggunn]

Doesn't that describe exactly what a phase shift is?

Whether that time offset is 5.55 ms (120°) or 8.33 ms (180°), it is still an offset.

Maybe he should have put resembles in italics. He said that is only resembles an offset in time, not that it is one. It's not. It's a waveform inversion masquerading as a phase shift. I agree that as long as things remain unperturbed the waveforms look just as if they were phase shifted, but when the slightest perturbation occurs to the transformer input waveform it is immediately obvious that it's an inversion, not a phase shift. The perturbations appear simultaneously on both output waveforms.

 

[Besoeker]

Maybe he should have put resembles in italics. He said that is only resembles an offset in time, not that it is one. It's not. It's a waveform inversion masquerading as a phase shift.

Don't they reach their positive peaks at different times?
Why is that not an offset in time?

 

[wwhitney]

You made my case. Very eloquently.

So now you agree it is a negation, not a phase shift? Because that is what the math you responded to shows.

Cheers, Wayne

 

[Sahib]

Don't they reach their positive peaks at different times?
Why is that not an offset in time?

ggunn proposed another practical criterion to identify a single phase system. However your argument holds good mathematically. Here again dialectics at work. We all have to agree on both opposing concepts combined dialectically as I did before.

 

[ggunn]

Don't they reach their positive peaks at different times?
Why is that not an offset in time?

It's an inversion, not an offset. When you look in a mirror everything looks backwards ("180 degrees out" from where they are on your face) but there is no way to produce that image from rotating the primary.

 

[Besoeker]

It's an inversion, not an offset. When you look in a mirror everything looks backwards ("180 degrees out" from where they are on your face) but there is no way to produce that image from rotating the primary.

We are talking about the time varying electrical wave forms here. Not reflections.
The positive peak for L1-N occurs at a different instant in time to the positive peak for L2-N.

Your reflection in the mirror doesn't reverse sixty times a second. Not a valid analogy.

 

[jaggedben]

From post #8:

... Otherwise, mathematically sin=-sin(n+180), and thus it's a bit pointless to argue over which is a 'better' mathematical representation of what you read with your meter. ...

:roll::slaphead::lol:

 

[GoldDigger]

We are talking about the time varying electrical wave forms here. Not reflections.
The positive peak for L1-N occurs at a different instant in time to the positive peak for L2-N.

Your reflection in the mirror doesn't reverse sixty times a second. Not a valid analogy.

The positive peak occurs at a fixed offset later, but if we look at the possibility of assymetry in the waveform or one time perturbations, we see that shifting one waveform on the scope by 180 degrees will not cause them to overlay perfectly. The underlying mechanism that produces the second waveform is in fact an inversion rather than a time shift. But usually the results are hard to distinguish.

Sent from my XT1585 using Tapatalk

 

[mivey]

Time shifting may have a different meaning as well. We did not time shift N-L2 to get L2-N. We just did not use N-L2 in the first place.

L1-N starts going positive at the same time L2-N starts going negative. This occurs with a center-tap transformer winding or with two 180 degree displaced windings on a generator shaft.

 

[Sahib]

Actually the issue whether 240/120V system is single phase or two phase is resolved philosophically because the 240/120V system has attributes of both. Such a situation is not uncommon in science. Take for example electron. It has the properties of particle and wave i.e it may be at one place (particle nature) or it may be at all places (wave nature) depending on experimental set up to detect it. So the electron has wave particle duality. Similarly the 240/120V is single phase system with two phase attributes.

 

[ggunn]

We are talking about the time varying electrical wave forms here. Not reflections.
The positive peak for L1-N occurs at a different instant in time to the positive peak for L2-N.

Your reflection in the mirror doesn't reverse sixty times a second. Not a valid analogy.

I get it; it's invalid because it doesn't support your thesis.

 

[Besoeker3]

I get it; it's invalid because it doesn't support your thesis.

Invalid because it isn't two time varying waveforms.
Your reflection doesn't reverse 60 times a second.

 

[ggunn]

Invalid because it isn't two time varying waveforms.
Your reflection doesn't reverse 60 times a second.

Which has nothing whatsoever to do with the analogy I was posing.

 

[Besoeker3]

Which has nothing whatsoever to do with the analogy I was posing.

Well, OK.
I could respond that the reflection has nothing to do with the 180deg phase difference between the two time varying AC supply voltages.

 

[Besoeker3]

I get it; it's invalid because it doesn't support your thesis.

No thesis about it. The two voltages are 180deg apart.
What you make of that is your interpretation.

 

[ggunn]

Well, OK.
I could respond that the reflection has nothing to do with the 180deg phase difference between the two time varying AC supply voltages.

But of course it does. The L2 voltage is a reflection about the X axis of the L1 voltage. It's the general case that covers any and all waveforms, and it illustrates how the two waveforms in question are actually created. L2 is most definitely not created by delaying (phase shifting) L1.

 

[ggunn]

No thesis about it. The two voltages are 180deg apart.
What you make of that is your interpretation.

And right back atcha.

 

[LarryFine]

180 degrees in direction, as in polarity, yes; 180 degrees in timing, no. There is no timing differential.