On Wed, 25 Jul 2018 08:39:37 -0700 (PDT), trader_4
wrote:

On Tuesday, July 24, 2018 at 12:53:33 PM UTC-4, wrote:
On Tue, 24 Jul 2018 06:53:13 -0700 (PDT), trader_4
wrote:

On Tuesday, July 24, 2018 at 7:43:54 AM UTC-4, Bubba wrote:
On 7/24/2018 5:45 AM, trader_4 wrote:
How you generate it doesn't matter. When this came up last time, I
even gave you a presentation made by a power engineer at a power industry
conference, about how split-phase service needs to be analyzed as a
two phase system, because that is actually what it is. I believe it
was also published, because I found it online. I don't think he got
laughed out of the room, but at the very least it was a power industry
source that said exactly what I'm saying. I just looked for it again,
couldn't find it. I'll look again later.

Grab a dual-trace oscilloscope.

Connect the Scope Common lead to transformer L1

Connect Scope Trace 1 lead to the transformer center tap

Connect Scope Trace 2 lead to transformer L2


You'll observe two screen traces in perfect sync that vary only in amplitude.Â* Only a Hillary voter would mistake it for two-phase.

Did you read the link I posted to the discussion on that other forum?

https://forum.allaboutcircuits.com/t...-phase.105861/

The group moderator, Wbahn posted this:

Take two generators built on a single shaft (the same way that three-phase generators are built on a single shaft) so that you get two 120VAC outputs that are 180 degrees out of phase. Would it be reasonable to call this two-phase power?

Bubba, what's your answer?



Now run them to a house and tie them together so that you have 120VAC between the common and either of the other lines and 240VAC between the two lines. Would it still be reasonable to call this two-phase power?

Bubba?



Could you tell the difference between that situation and the one in which the wires coming to the house are from a center-tapped transformer?

Bubba?


If not, then wouldn't it be reasonable to use the same name for either?
(that was Wbahns final question)

Bubba?


And what he described would still show exactly the same thing on the scope
as the test you described. In all the above, if we changed the phase
difference to 90, would it then be two phase? How about to 179 deg?
In engineering we don't make it up case by case, we analyze the general
case. 180 is just one special case, where it's easy to generate two
voltage sources that are 180 deg out of phase with each other. Or go
take a look at the MIT electrical engineering course in power systems
where they show the mathematics of what
they call two phase power. There are simply two voltage sources
driving two loads. They do the analysis for a 90 deg phase difference,
but you could just as well do the same analysis for a difference of 70
degrees or 180 degrees. The same analysis, the same math applies,
because to the system, it is the same thing.

It's like Wbahn says, it's a matter of semantics and convention.

If you feel differently, then give us your definition of two phase,
3 phase, and N phase power and show us why split-phase is not also
two phases? The only way I see it's not would be to rule that special case
out by *definition*, which is back to the semantics. In that case,
if you can site the electrical body, authority, organization that
has done that, I'm sure we'd all like to see it.

From your discussion group
"So I would put forward the argument that the secondary is a center
tapped transformer providing 120v each side of the center(with center
hard wired to "earth"and providing the "neutral connection") and 220v
across the whole winding. This does NOT constitute a "2 phase" system"

I didn't say there were not others there arguing the other side.
Funny thing though, none of these "professionals" are able to define
what single phase, two phase, three phase, N phase power means.





Don't let electronIC engineers confuse the terminology used by
electricAL professionals. We use specific terminology to avoid
confusion and perhaps save lives. Homeowners and electronics geeks can
call things whatever they want but they only sound stupid when they
talk to the people who do this stuff for a living.



Are you sure you want to now resort to disparaging electronic engineers
as not professional and stupid? Funny I didn't see you ripping into
this alleged "professional", Ed's Electric that posted:

"No, professionals call it single-phase. Unless you want people to think you voted for Hillary, you should use the proper terminology."

You gave him a wink. I guess that was before you saw the links I provided
to Siemens, Square D, that show they call their panels single phase.
That;s what they call them in the product catalog, in the index, etc.
Doh!



Your reference to the panel descriptions confirm what we say.
There are no "split phase" panels, nor are they calling any of them "2
phase". They sell single phase panels and 3 phase panels.

As for electronic engineers, they simply use different terminology.
They look at things from a different perspective. You will also find
the voltage drop charts they use are different too. It doesn't mean
they use different copper or wire sizes. They just apply different
conditions when they rate the wire. Electronics people generally make
lousy electricians. I have lived in both worlds and there is a vast
cultural divide between them,.

I have defined single phase to you several times but let's try it
again. It is a system derived from a single secondary winding of a
transformer. (or a single rotating field in a generator/alternator
stator). The fact that you ground the center tap of that secondary
does not change a thing as far as the number of phases in concerned.
There is still one sine wave generated (a single phase) and that does
not change no matter where you stand to look at it.

3 phase is derived from 3 separate secondary windings (although you
can delete one and it still works) with three distinct sine waves, 120
degrees out of phase with each other. It is necessary to start with a
3 phase primary too. That can be grounded at the center tap of one
transformer in a delta configuration, at the end tap of two adjacent
transformers of a delta configuration or at the end tap of all three
in a wye configuration.
You can even leave that ungrounded, typically as a delta.
It is still always going to be 3 phase.
Anything derived from a single secondary winding will be single phase,
center tapped or not.

2 phase is derived from 2 windings, 90 degrees out of phase with each
other.
Your 2 generators is a red herring but if you must, when you tie them
together, they are in phase with each other and that is still a single
phase. In fact when you do tie generators together, they will sync up,
if they don't burn each other out before they do. The grid does that
every day.