Both ends cannot be positive at the same instance on a single secondary winding transformer. Grounding the center tap does not change that. Yes, it's easy to depict these as out-of-phase voltages on paper. But how are you going to depict concurrent L1-L2, L1-N, and L2-N current flow with arrows when both Lines are positive?
Single Phase Question?
- Thread starter EEC
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I admit it is somewhat unintuitive, but you can draw two arrows pointing up to represent conventional current flow at one point in time.
IMHO it comes down to how comfortable (and consistent) you are at working with phasors.
For AC the plus and minus indications only represent a shorthand for how you connect your measuring equipment, not positive and negative at some arbitrary moment in time.
I suspect this is why a simple dotted end notation is used for transformer diagrams. There is no true + and - in the way that there is with DC.
as a 180 deg phase delta
Correct
+ and - are references for math operations
not an indication both are positive and in phase at the same time
doesn't matter as long as consistent
makes more sense to me to common the - at the grounded point
Typical. I see the talk but don't see the walk. IOW, where's the diagram? Let's see how easy it is for you two to make it appear easy.
I figured this pursuit would turn into nothing more than the previously- and much-debated in-phase, out-of-phase condition for a single winding output.
:lol:
diagram is in my previous post and copied below
120/0
120/180
(polarities are opposite around the loop)
120 + 0j
-(-120 + 0j)
= 240 + 0j = 240/0
Tony S
Senior Member
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- Resting under the Major Oak UK
Sorry, UK voltages
Neither of the diagrams have current flow indication. If I wanted equations, I wouldn't be asking for a diagram.
You're too funny. :rotflmao:
FionaZuppa
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- Part Time Electrician (semi retired, old) - EE retired.
its rather simple.
the generator has 3 generating coils separated by 120 degrees (3x120=360), someone said it was 90 degree separation which is not correct.
and what does + and - really mean? in math its usually convention to establish reference, but in physics it has to do with actual stuff. as example, we would not expect electrons coming out of the + (pos) terminal, etc. in AC the terminals swap positions in some mathematical way (Hz, sinusoidal, sawtooth, etc).
post #26 is not accurate. a single pole (phase) 240 with CT, no matter how you connect to it all the power at any given point in time is the exact same phase, there is no 180 phase shift on the scope, both signals as seen on the scope are in phase with each other and occur at the same time, you just see the inverse of the other due to the CT being the reference for "zero", etc.
the generator has 3 generating coils separated by 120 degrees (3x120=360), someone said it was 90 degree separation which is not correct.
and what does + and - really mean? in math its usually convention to establish reference, but in physics it has to do with actual stuff. as example, we would not expect electrons coming out of the + (pos) terminal, etc. in AC the terminals swap positions in some mathematical way (Hz, sinusoidal, sawtooth, etc).
post #26 is not accurate. a single pole (phase) 240 with CT, no matter how you connect to it all the power at any given point in time is the exact same phase, there is no 180 phase shift on the scope, both signals as seen on the scope are in phase with each other and occur at the same time, you just see the inverse of the other due to the CT being the reference for "zero", etc.
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