120/208, 1Ph, 3 Wire

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NEC calls it a multiwire circuit, at least any branch circuit that would utilize all three supply conductors.
 
jumper said:
Noooooo, do not mention 2 phase. That is a whole different system here.

This is called single phase derived from 2 poles of a three phase system.

Why?

It just is, trust me. Confusing but true.
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The way I explain it is "how many different ways can you get pole-to-pole?

Single phase therefore requires two of the poles.
Three-phase requires all three.

I did research the old "two-phase" systems. They used 4 conductors and were basically two separate single phase circuits created out of phase with each other if I'm describing that in a way that didn't make things worse.
 
MAC702 said:
The way I explain it is "how many different ways can you get pole-to-pole?

Single phase therefore requires two of the poles.
Three-phase requires all three.

I did research the old "two-phase" systems. They used 4 conductors and were basically two separate single phase circuits created out of phase with each other if I'm describing that in a way that didn't make things worse.
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2 phase can be 3, 4 or 5 wires. Still two separate single phases 90 degrees out of phase from one another, but 3 and 5 wire versions have a "common" that ties each coil together. 3 wire common is at one end of each coil, 5 wire midpoint of each coil is tied together.
 
kwired said:
2 phase can be 3, 4 or 5 wires. Still two separate single phases 90 degrees out of phase from one another, but 3 and 5 wire versions have a "common" that ties each coil together. 3 wire common is at one end of each coil, 5 wire midpoint of each coil is tied together.
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I've decided that 2 phase does not truly exist.

Y'all made it up just to drive me bonkers.

Not very nice IMO.

:)
 
electrofelon said:
No, that is the correct designation. I know you don't like it. How about go for a walk with that handsome dog of yours and forget all about it :)
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It isn't about liking it or not liking it. One voltage is line to line, the other line to neutral. The two voltages are not in phase. But, call it 1PH if you wish.
And, yes I did walk the dog.......:)
 
kwired said:
2 phase can be 3, 4 or 5 wires. Still two separate single phases 90 degrees out of phase from one another, but 3 and 5 wire versions have a "common" that ties each coil together. 3 wire common is at one end of each coil, 5 wire midpoint of each coil is tied together.
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That actually makes perfect sense.
 
Besoeker said:
It isn't about liking it or not liking it. One voltage is line to line, the other line to neutral. The two voltages are not in phase. But, call it 1PH if you wish.
And, yes I did walk the dog.......:)
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There is a difference between phase shift and phase inversion.
 
jumper said:
I've decided that 2 phase does not truly exist.

Y'all made it up just to drive me bonkers.

Not very nice IMO.

:)
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I have yet to see a real two phase system myself - and probably won't unless I go east.

Philly area is where you are most likely to run into them from my understanding.

That said single phase induction motors are pretty much "two phase" design, with the phase shift happening at the motor and not at the source.
 
Tony S said:
A bit late. We did and still do use 2Ph.
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Chapter 8 of the J&P goes into the Scott and Le Blanc connections in some detail.
So yes, obviously they obviously exist. But, I think, not very common. I don't think I've ever come across either and certainly never used one on any of the projects we designed.
 
Besoeker said:
Not sure what point you are making WRT to line to line and line to neutral voltages?
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This comes up a lot in audio; many folks call the complementary lines of a balanced circuit "180 degrees out of phase" but if that's what it was the shift in time for every frequency would have to be different. In "pure" 60Hz the difference isn't as significant, although for L1 and L2 to be 180 out a spike on one line would not be seen on the other until 1/120 sec later. Inversion is not the same as phase shift.
 
ggunn said:
This comes up a lot in audio; many folks call the complementary lines of a balanced circuit "180 degrees out of phase" but if that's what it was the shift in time for every frequency would have to be different. In "pure" 60Hz the difference isn't as significant, although for L1 and L2 to be 180 out a spike on one line would not be seen on the other until 1/120 sec later. Inversion is not the same as phase shift.
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Different topic. A 180 shift doesn't apply.
 
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