amplitude. Only a Hillary voter would mistake it for two-phase.
phase generators are built on a single shaft) so that you get two 120VAC ou tputs that are 180 degrees out of phase. Would it be reasonable to call thi s two-phase power?
C between the common and either of the other lines and 240VAC between the t wo lines. Would it still be reasonable to call this two-phase power?
hich the wires coming to the house are from a center-tapped transformer?
k you voted for Hillary, you should use the proper terminology."
Who;s the "we". Ed's Electric posted that no professional would ever call it single phase. And you appeared to agree with him, you gave him a wink.
Again, in my very first post, I said I would not call them two phase either. But what they are called and what is there, what you see, how you analyze it are not one and the same.
Here, I found the presentation I referred to. It was made by a power system engineeing professor with a career going back to the 60's. He consults on power system, the presentation was made at a power engineeri ng conference and it's published by the IEEE. He last worked for Milsoft Utility Solutions, that does work for power utilities. He doesn't sound like a stupid guy or a homeowner.
Abstract: Distribution engineers have treated the standard "singlephase" distribution transformer connection as single phase because from the primary side of th e transformer these connections are single phase and in the case of standar d rural distribution single phase line to ground. However, with the advent of detailed circuit modeling we are beginning to see distribution modeling and analysis being accomplished past the transformer to the secondary. Whic h now brings into focus the reality that standard 120/240 secondary systems are not single phase line to ground systems, instead they are three wire s ystems with two phases and one ground wires. Further, the standard 120/240 secondary is different from the two phase primary system in that the second ary phases are separated by 180 degrees instead of three phases separated b y 120 degrees. What all of this means is that analysis software and methods must now deal with an electrical system requiring a different set of algor ithms than those used to model and analyze the primary system. This paper w ill describe the modeling and analysis of the single-phase center tap trans former serving 120 Volt and 240 Volt single-phase loads from a three-wire s econdary.
W. H. Kersting Milsoft Utility Solutions, USA W. H. Kersting (SM'64, F'89, Life Fellow 2003) was born in Santa Fe, NM. He received the BSEE degree from New Mexico State University, Las Cruces, and the MSEE degree from Illinois Institute of Technology. He joined the facul ty at New Mexico State University in 1962 and served as Professor of Electr ical Engineering and Director of the Electric Utility Management Program un til his retirement in 2002. He is currently a consultant for Milsoft Utilit y Solutions. He is also a partner in WH Power Consultants, Las Cruces, NM.
And he's saying pretty much what I'm saying, that yes it's derived from a single phase, center tapped transformer, but to correctly analyze it, model it, you treat it as having two phases. Note, he didn't say to call it two phase power, neither did I.
So, if I create the generator example where I use two windings in the generator 180 out of phase on a single shaft, share a common neutral, that's not single phase because it has two secondary windings? I don't see the number of windings being the issue.
The fact that you ground the center tap of that secondary
I agree that there is only one sine wave generated. What I don't get and what you haven't explained is why if coming out of the generator you had two hots 90 deg out of phase, that's two phase. I asked, but never got answered from anyone here, supposed it's 170 deg instead? Is that still two phase? If it's 190 deg is it two phase? Why if it's 180 is it suddenly not? That's the problem. Science and engineering likes rules, laws, explanations that fit the general case. And 180 would just seem to me to be one case of all the possible two phase possibilities. And how exactly you generate it doesn't matter to the box it's entering or how you analyze it. You can see that in the MIT example two, they just used two ideal voltage sources, that in their case were 90 degrees out. But you could use the same model, same math to *analyze* 120 deg, or (oh no), 180 couldn't you?
I agree after looking more at those panel makers, that they do use the term single phase, but other power system component manufacturers also call it split-phase, including other divisions of the same power system component manufacturer, eg Siemens
But again, that's not what we're talking about. That is the historical case of what it once was. I think you will admit they didn't have to make it 90, suppose it was 100 or 70? Would that still be two phase? So, what's so special, so different that 180 suddenly can't be analyzed, looked at as consisting of two phases? Yes it's a trivial case, but if
179 or 181 can be called two phase, then why not 180?