240 split phase. Are you correct or not?

Nobodybusiness · Dec 17, 2022

This is just to throw out to see what people say.

WITHOUT looking at anything is American split phase power 2 120V 180degree out of phase sine-waves OR 2 In Phase 120 V sine waves?

I know this will tweek people.

Mattb4 · Dec 17, 2022

Neither. Each leg is 1/2 of a output side of a transformer with a 240v single phase input. 120v, N, 120v They are 180 degrees out of phase due to this but strictly speaking they are still just one phase and not two. Which is why we call it split phase.

peakbagger · Dec 17, 2022

If you really want to have your mind blown, the old papermill I worked at still had some 2 phase electrical equipment and generation. The phases are 90 degrees apart. Another old mill I worked in still had a 40 cycle power system in parts of the plant.

Supervstech · Dec 17, 2022

Nobodybusiness said:
This is just to throw out to see what people say.

WITHOUT looking at anything is American split phase power 2 120V 180degree out of phase sine-waves OR 2 In Phase 120 V sine waves?

I know this will tweek people.

It depends on where you connect the probes on the scope...
It can be thought of as a single 240V phase with a midpoint connection to connect 120V items for a series 240V load...
It can be mimicked with a pair of 120V phases generated by inverters 180degrees out of phase, and IF measured from the neutral and each hot, the scope will see two waveforms 120V RMA ...
There is a good video showing the phenomenon

timselectric · Dec 17, 2022

It's a pointless discussion.
Those who know, know.
And Those who don't, never will. lol

time2roll · Dec 17, 2022

Depends on your definition of "phase"

Nobodybusiness · Dec 17, 2022

Supervstech said:
It depends on where you connect the probes on the scope...
It can be thought of as a single 240V phase with a midpoint connection to connect 120V items for a series 240V load...
It can be mimicked with a pair of 120V phases generated by inverters 180degrees out of phase, and IF measured from the neutral and each hot, the scope will see two waveforms 120V RMA ...
There is a good video showing the phenomenon

Exactly correct. Just wanted to see folks argue over it. Have seen folks go round and round over this.

Supervstech · Dec 17, 2022

Nobodybusiness said:
Exactly correct. Just wanted to see folks argue over it. Have seen folks go round and round over this.

So, you seem to be poking the sleeping bear...

45North · Dec 17, 2022

The facts have spoken.
It's not a matter of opinion.

Nobodybusiness · Dec 17, 2022

Mattb4 said:
Neither. Each leg is 1/2 of a output side of a transformer with a 240v single phase input. 120v, N, 120v They are 180 degrees out of phase due to this but strictly speaking they are still just one phase and not two. Which is why we call it split phase.

It depends on how you measure it.
One ways shows out of phase and other ways shows in phase.

timselectric · Dec 17, 2022

It is what it is.
How you measure it, or how you look at it. Doesn't change what it is.
I'll give you a hint. The answer is in its name.

Nobodybusiness · Dec 17, 2022

Supervstech said:
So, you seem to be poking the sleeping bear...

Yea. Was bored and just like to see people going at it over something superfluous. ?

Supervstech · Dec 17, 2022

timselectric said:
It is what it is.
How you measure it, or how you look at it. Doesn't change what it is.
I'll give you a hint. The answer is in its name.

Well...
What it IS is a specification to power circuits in N.American homes...
How it is implemented by some power companies or generators, or inverters is rarely the same... so, how it is measured is important to determining what it is.

Spunky · Dec 17, 2022

Most single phase distribution transformers have three windings, one primary and two secondaries.

timselectric · Dec 17, 2022

Supervstech said:
Well...
What it IS is a specification to power circuits in N.American homes...
How it is implemented by some power companies or generators, or inverters is rarely the same... so, how it is measured is important to determining what it is.

But switching the test leads around, doesn't change what it is.
Split-phase is a single phase that is split in half.
No matter how it's generated, it's still a single phase.
Otherwise, it couldn't produce 240v.

Mike 134 · Dec 17, 2022

Spunky said:
Most single phase distribution transformers have three windings, one primary and two secondaries.
View attachment 125128

you'll notice the secondary winding can be connected either in series or parallel giving you either 240 or 120. the center tap on the lower right allows you to obtain either 120 or 240 from that wiring configuration.

tigerwillow1 · Dec 17, 2022

Nobodybusiness said:
I know this will tweek people.

Understatement!
If you're the power company, it looks like single phase. If you're the consumer, it looks like 2-phase. I believe that it would have been called 2-phase had that name not had been already used for the 90 degree service mentioned in an earlier post. For those who want to dare argue against calling it 2-phase, I point out that 6-phase service is exactly analogous to 3-phase as what we also call split phase is analogous to single phase. After a rebuttal I just forget about it and go on. Under the circumstances I think that everybody calling it split phase is a reasonable compromise to avoid war over it.

timselectric · Dec 17, 2022

If it looks like 2-phase to you, you don't understand what you are looking at. There's only a single phase.
This comes from the misunderstanding of 3-phase.
Some people are under the impression that each of the 3 wires are a phase. When it's actually the combination of 2 legs that make a phase.
3-phase
1 & 2 = phase A
2 & 3 = phase B
3 & 1 = phase C

Single phase
1 & 2 = one phase

Split-phase
1 & 1.5 & 2 = one phase , split in half.

timselectric · Dec 17, 2022

THE END

Nobodybusiness · Dec 17, 2022

timselectric said:
THE END

Lol . I knew this would be interesting..

240 split phase. Are you correct or not?

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