buffalonymann
Senior Member
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- NC
Connect the scope properly and then your readings will harmonize with electrical theory.
May I ask a question about the single vs two phase stuff
- Thread starter Russs57
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Connect the scope properly and then your readings will harmonize with electrical theory.
winnie
Senior Member
- Location
- Springfield, MA, USA
- Occupation
- Electric motor research
Motors and rotating fields are deeply relevant to this discussion because they show how a 180 degree phase difference is qualitatively different from other values of phase difference.
With a three terminal source giving a phase difference of 120 degrees, using suitable transformers but no delay elements, I can construct any other phase difference I wish. I can take two legs (plus neutral) from a three phase system and use transformers to construct the third leg. I can convert from 2 phase to 3 phase. I can generate 'hexaphase'. Etc.
The same can be said for a three terminal source with _any_ phase difference _except_ 180 degrees. Without delay elements I can't convert a three terminal single phase system to a three phase system.
So while I agree that inversion causes a phase difference, that phase difference is in a very important way different from the phase difference seen in a true '2 phase' system.
-Jon
With a three terminal source giving a phase difference of 120 degrees, using suitable transformers but no delay elements, I can construct any other phase difference I wish. I can take two legs (plus neutral) from a three phase system and use transformers to construct the third leg. I can convert from 2 phase to 3 phase. I can generate 'hexaphase'. Etc.
The same can be said for a three terminal source with _any_ phase difference _except_ 180 degrees. Without delay elements I can't convert a three terminal single phase system to a three phase system.
So while I agree that inversion causes a phase difference, that phase difference is in a very important way different from the phase difference seen in a true '2 phase' system.
-Jon
Yes. It will show that, on a 120-0-120, the two 120V legs are 180° apart.
buffalonymann
Senior Member
- Location
- NC
Would you just try to think of what current actually is; its clearly the work that's being performed. I assume you are now backing off of your assertion that currents cancel?
buffalonymann
Senior Member
- Location
- NC
What I don't understand is why they don't apply theory and derive conclusions from that perspective.
buffalonymann
Senior Member
- Location
- NC
You're mistaken. Look, you have only (1) Primary coil creating the energy in the secondary coil. There is only one voltage and current sine wave within the secondary coil across L1 and L2. If you pick any point between L1 and L2 you will be tapping that one sine wave. If you're seeing a 180 degree phase difference, then you haven't connected your scope correctly.
mivey
Senior Member
Yes, they are aligned but still different. Different but still existent.
Two phases with a 120d difference produce positive pulses at different times. Sames for a 121d difference, 122d, 123d, ... 178d, 179d, AND 180d. One degree does not negate the phase difference and they still produce positive pulses at different times.
Most of the time we do not make use of this 180d difference and just use the individual phases alone as single-phase sources. Either the smaller phases or the larger phase.
A case where we do make use of the 180d difference producing positive pulses at different times is the 2-diode full-wave rectifier circuit using a center-tapped transformer.
Other cases include using the 180d positive pulses in a multi-phase inverter.
Just because the phases align does not negate the relationship.
if I have 3 phases
and I measure across 2 I have single phase
exactly the same as 120/240/1 except angle, 120 vs 180
winnie
Senior Member
- Location
- Springfield, MA, USA
- Occupation
- Electric motor research
Must of us understand the theory. This is all about what we call what the theory predicts.
Inversion is a perfectly acceptable way to look at things.
In some ways it is the most sensible way to look at us 'split phase' services.
When you do an inversion you clearly see a 180 degree phase difference.
Now we are arguing about how to _name_ that clearly seen phase difference.
-Jon
Nope.
If you have the same load across each of the L-N 120V legs the current in the neutral will be zero.
yep
if in phase, or of single phase, you would not get 240 across lines
120/0 = 120 + 0j
120/0 = 120 + 0j
120 + 0j + [(-) (120 + 0j)] = 0
winnie
Senior Member
- Location
- Springfield, MA, USA
- Occupation
- Electric motor research
These threads keep getting closed because we simply start calling each other names. I'd like to suggest we can remain polite and focus on the issues.
IMHO buffalonymann is appealing to logic and reason ('electrical theory') and ignoring the fact that logical reasoning depends upon the premises one uses.
Included in those premises are the language definitions one uses.
I am beginning to like 'hemiphase' more and more to describe how an inversion gives a 180 degree phase difference without requiring a time delay.
-Jon
IMHO buffalonymann is appealing to logic and reason ('electrical theory') and ignoring the fact that logical reasoning depends upon the premises one uses.
Included in those premises are the language definitions one uses.
I am beginning to like 'hemiphase' more and more to describe how an inversion gives a 180 degree phase difference without requiring a time delay.
-Jon
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no one is saying this is a 2 phase power system
only that split phase can be resolved into 2 phases
one is a 90 deg shift, the other 180
if the shift was 170 is that 2 ph? 179? 181?
current is charge/time, not work
it takes force (emf) to move mass (electron) over time, result: work/energy
i is not work
I'd like that we were.
jaggedben
Senior Member
- Location
- Northern California
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- Solar and Energy Storage Installer
Define 'phase'.
jaggedben
Senior Member
- Location
- Northern California
- Occupation
- Solar and Energy Storage Installer
To repeat what's been said...
Only if you use N as common reference, which is a choice.
Define 'phase'.
of the moon? :lol:
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