240 split phase. Are you correct or not?

[Nobodybusiness]

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]

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]

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]

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]

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

 

[time2roll]

Depends on your definition of "phase"

 

[Nobodybusiness]

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]

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]

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

 

[Nobodybusiness]

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]

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]

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]

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]

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

 

[timselectric]

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]

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]

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]

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]

THE END

 

[Nobodybusiness]

THE END

Lol . I knew this would be interesting..

 

[timselectric]

Not really.
It's fairly simple, once you see it.
My work is done, here.
I believe, with enough time to think about it.
Everyone can eventually understand.

 

[tigerwillow1]

My work is done, here.

Sigh, if your work wasn't done I would have asked why it's wrong to call split-phase power 2-phase, and yet call 6-phase power 6-phase. Maybe somebody else with a greater understanding than I can explain it. For starters here are some random Internet excuses to not call it 2 phase:

- This is called split phase because there is more than one voltage from a single transformer.
- Since the two phasors do not define a unique direction of rotation for a revolving magnetic field, a split single-phase is not a two-phase system.
- It’s a religious phenomenon.
- Single phase means that the AC power is delivered by one pair of wires.
- Even if you have a disturbance on the “high tension” line…. you still get a mirror image on the L1 and L2 split-phase.
- A two phase motor is used for servos.
- Two phase is where the two phases are 45 degrees apart if my memory serves me well.
- The only two phase system I have come across was 120°.
- Our utility references the 120v/240v service coming to the residence as a single phase service.
- The term “split-phase” merely refers to the split-voltage supply in such a system.

But then I still can't figure out why a 6-phase feed isn't called something like triple split phase instead .

 

[Spunky]

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.

That is probably true where it is being generated (a Delta system), but if the substation is supplying through Wye transformers, it would be a phase to ground voltage.
So, again... it's relative to your perspective. LOL

 

[timselectric]

That is probably true where it is being generated (a Delta system), but if the substation is supplying through Wye transformers, it would be a phase to ground voltage.
So, again... it's relative to your perspective. LOL

This is part of the misconception. It's not a phase to ground. It's a single leg to ground. A leg, that is common to two different phases. But, just a leg.

 

[Spunky]

This is part of the misconception. It's not a phase to ground. It's a single leg to ground. A leg, that is common to two different phases. But, just a leg.

So, a lone inverter can not by it's self make a phase?