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Thread: May I ask a question about the single vs two phase stuff

  1. #1161
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    Quote Originally Posted by Carultch View Post
    Because V1-to-N is a sine wave, and V2-to-N is a sine wave.
    But out of phase so they can't be the same phase. Ergo, you have more than one phase.
    Si hoc legere scis nimium eruditionis habes.

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    Quote Originally Posted by Carultch View Post
    Because V1-to-N is a sine wave, and V2-to-N is a sine wave.
    Therein lies the crux of the debate. I would say it as "V1-to-N" and "N-to-V2" instead. You're "artificially creating the inversion" when you keep one theoretical probe on the neutral while moving the other theoretical probe to both, or opposite, sides of it.

    The essential difference between the voltage functions, can be seen as a shift in time. A shift in time between periodic functions, is called a phase shift. That's why one might see it as two phases, even though it is instead generated by mirroring the first sine wave around the V=0 axis, instead of shifting it by 180 degrees along the time axis.
    Meaning that, for this one instance, what is a polarity phenomenon merely resembles a phase shift
    Code references based on 2005 NEC
    Larry B. Fine
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    Richmond, VA

  3. #1163
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    Quote Originally Posted by Besoeker View Post
    But out of phase so they can't be the same phase. Ergo, you have more than one phase.
    But, they're not out of phase. They couldn't possibly come from a single transformer if they were. Every winding on a single transformer core is in phase with all of the others.

    Like batteries, you must get the polarity correct when combining them. That it's AC doesn't change this, since they all swap polarity in sync twice per cycle; instantaneous polarity.

    The same reason a universal motor works on AC or DC.
    Code references based on 2005 NEC
    Larry B. Fine
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    Quote Originally Posted by LarryFine View Post
    Therein lies the crux of the debate.
    This isn't a debate, it's a silly argument that will not change anyone's mind. Pass the popcorn.

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    Quote Originally Posted by LarryFine View Post
    But, they're not out of phase.
    They are 180 deg out of phase.
    Call it anything you want but it doesn't negate that point.
    Si hoc legere scis nimium eruditionis habes.

  6. #1166
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    Quote Originally Posted by Besoeker View Post
    They are 180 deg out of phase.
    For a pure sine wave. Add any even harmonic, and they are no longer 180 degrees out of phase. But they would still be negatives of each other.

    Cheers, Wayne

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    Quote Originally Posted by ggunn View Post
    This isn't a debate, it's a silly argument that will not change anyone's mind. Pass the popcorn.
    What is on your mind? Popcorn?

  8. #1168
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    Code references based on 2005 NEC
    Larry B. Fine
    Master Electrician
    Electrical Contractor
    Richmond, VA

  9. #1169
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    Quote Originally Posted by wwhitney View Post
    For a pure sine wave. Add any even harmonic, and they are no longer 180 degrees out of phase. But they would still be negatives of each other.
    Because they are 180 degrees out of phase.
    Si hoc legere scis nimium eruditionis habes.

  10. #1170
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    Quote Originally Posted by LarryFine View Post
    But, they're not out of phase. They couldn't possibly come from a single transformer if they were. Every winding on a single transformer core is in phase with all of the others.

    Like batteries, you must get the polarity correct when combining them. That it's AC doesn't change this, since they all swap polarity in sync twice per cycle; instantaneous polarity.

    The same reason a universal motor works on AC or DC.
    under this thought, you cannot create a three phase power supply from a single phase...
    The windings of the core is what creates the phases... the sine waves are proof of the phases. I mean, I may not understand all the math you guys are quoting... Even for AM/FM Phase shifting radio theory I did not get into some of these calculations, but I know that proper windings on a transformer can create phasing that is of various shift patterns form the original phase. This is how some of the transposing ciphers were created in the later part of WW2 and are used in military communications in some parts of the world even now.
    The standard transformers form three phase to single phase, or even the so called Center Tap transformer are all used to create phases.
    Student of electrical codes. Please Take others advice first.

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