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Thread: Volts leaking to ground rod

  1. #76
    Jack of all trades DonL's Avatar
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    Two AC signals with the same amplitude and same frequency 180 Degrees out of phase = 0 V

    Because they cancel each other out.

    The Zero Cross over point is the important thing when working with AC at any frequency.


    Are we confused yet ?
    Last edited by DonL; 02-23-2014 at 10:14 AM.
    Theory only works perfect in a vacuum.

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  2. #77
    Electrical Contractor/Instructor jwelectric's Avatar
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    nice day today what do you think
    Last edited by jwelectric; 02-23-2014 at 10:20 AM.

  3. #78
    DIY Senior Member Reach4's Avatar
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    Quote Originally Posted by jwelectric View Post
    What the scope is showing is a vector that is referenced from half way through a 240 bolt winding. As can be clearly seen is that while channel A is positive channel B is negative which means they are in phase not 180 degrees out of phase.
    In order to be 180 degrees out of phase then both ends would have the same polarity.
    Methinks your use of words here is out of phase with the norm.
    "When I use a word,it means just what I choose it to mean — neither more nor less."
    Last edited by Reach4; 02-23-2014 at 10:30 AM.

  4. #79
    Jack of all trades DonL's Avatar
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    Quote Originally Posted by jwelectric View Post
    nice day today what do you think

    I like it.

    The Daytona 500 just started.


    Have a Great day.
    Theory only works perfect in a vacuum.

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  5. #80
    Electrical Contractor/Instructor jwelectric's Avatar
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    Quote Originally Posted by Reach4 View Post
    Methinks your use of words here is out of phase with the norm.
    It doesn’t matter about my words the fact remains the same about the scope and the 180 degrees out of phase. The laws of physics remain true and there is no way possible that the two ends of a single phase winding to be 180 degrees out of phase with each other.

    It doesn’t matter what one tries to prove using the picture of a scope especially if they don’t understand vector math, the fact remains that the two ends of a single phase winding are in phase with each other.

    It doesn’t matter what someone has read or been told all that matters is the laws of physics which prove the fact that using a scope to look at the sine wave of a center tap winding shows that the winding is in fact in phase with each other and there is no way possible that the two 120 volt sine waves are 180 degrees out of phase with each other.

  6. #81
    DIY Senior Member bluebinky's Avatar
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    Quote Originally Posted by jwelectric View Post
    No they are not 180 degrees out of phase they are referenced from a mid point. There is no way they could be 180 degrees out of phase with each other as there is only one winding that has a center tap unless there has been something new invented that will somehow let one winding be 180 degrees away from itself.

    What the scope is showing is a vector that is referenced from half way through a 240 bolt winding. As can be clearly seen is that while channel A is positive channel B is negative which means they are in phase not 180 degrees out of phase.
    In order to be 180 degrees out of phase then both ends would have the same polarity.

    Ever hear the old saying to believe nothing you hear and only half of what you see? Well that applies here until you take a course in vector math.
    With all due respect, the signals being shown are 180 degrees out of phase.

    Forget about which way the windings go, center tapping, or whatever -- look at the two signals. Vector math? Better hit the books again before trying that one.
    Last edited by bluebinky; 02-23-2014 at 11:21 AM.

  7. #82
    DIY Senior Member Reach4's Avatar
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    Quote Originally Posted by jwelectric View Post
    It doesn’t matter about my words the fact remains the same about the scope and the 180 degrees out of phase. The laws of physics remain true and there is no way possible that the two ends of a single phase winding to be 180 degrees out of phase with each other.

    It doesn’t matter what one tries to prove using the picture of a scope especially if they don’t understand vector math, the fact remains that the two ends of a single phase winding are in phase with each other.
    If you cannot agree that this picture of an oscilloscope shows channel A being 180 degrees out of phase with channel B, then your use of words differs from the norm.
    Quote Originally Posted by jwelectric View Post


    It doesn’t matter what someone has read or been told all that matters is the laws of physics which prove the fact that using a scope to look at the sine wave of a center tap winding shows that the winding is in fact in phase with each other
    I am confident that we both know how the voltages on the two hot legs on a 120/240 AC breaker box relate to each other and the ground/neutral. There is no argument on the underlying physics.
    Quote Originally Posted by jwelectric View Post

    and there is no way possible that the two 120 volt sine waves are 180 degrees out of phase with each other.
    It's a terminology thing. Do you don't seem buy into the normal terminology.

    Here is a list of statements. Which is the first in the list that you disagree with?

    1. A voltage is measured at one point with respect to another point.

    2. Measuring the vector, complex, time-domain or frequency domain voltages on 120 VAC hot lines with respect to the grounded wires is the common way. (sorry about the long drawn out wording, but wanted to avoid ambiguities)

    3. That way is reasonable.

    4. Two sine waves that have their most positive instantaneous voltage occur at the same time can be said to be in phase.

    5. Presuming the same frequency for both and presuming a common reference point, a sine wave observed on one wire that has its most positive instantaneous voltages occur at the same time as the most negative instantaneous voltages occur on a different wire , the voltages would be described as out of phase with each other.

    6. The oscilloscope picture shown shows two out of phase (180 degrees out of phase) sine waves.
    Last edited by Reach4; 02-23-2014 at 11:23 AM.

  8. #83
    DIY Senior Member bluebinky's Avatar
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    JW, try this thought experiment...

    Remove the transformer core and set it on the ground. Then from the tap point follow the winding on one leg to its terminal. Now go back to the tap and follow the other one. If you don't move anything or change your view angle or whatever, you will notice that you were following (something like) a spiral. However, one leg was going clockwise, and the other counter-clockwise. On the other hand, if you went end to end, the direction would not change as you passed the tap.

  9. #84
    Electrical Contractor/Instructor jwelectric's Avatar
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    Quote Originally Posted by bluebinky View Post
    JW, try this thought experiment...

    Remove the transformer core and set it on the ground. Then from the tap point follow the winding on one leg to its terminal. Now go back to the tap and follow the other one. If you don't move anything or change your view angle or whatever, you will notice that you were following (something like) a spiral. However, one leg was going clockwise, and the other counter-clockwise. On the other hand, if you went end to end, the direction would not change as you passed the tap.
    Hence my mention of vector math. What you are trying to do is start in the middle of the winding and add 120 to 120 which would be N to A plus N to B. This math will result in the same answer should you add the 120 from A to N and then N to B which will be the manner in which the electrons flow through the winding.

    What can’t happen is to have electrons flowing from N to A at the same time that electrons are flowing from N to B. This type of configuration would indeed be two 120 volt windings that are 180 degrees out of phase with each other.

    The fact that the electrons are entering at one end of the winding and exiting from the other end of the winding and reversing this process 60 times a second is more than enough to prove that the two 120 volt sine waves are indeed in phase with each other and could not in any way be 180 degrees out of phase with each other.

    What is 180 degrees out of phase is the method in which you are viewing the two sine waves, not the sine waves their self.

  10. #85
    DIY Senior Member bluebinky's Avatar
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    Two (sinusoidal) signals which are the same amplitude and phase are in fact the same signal and measuring between them will result in no information (power/voltage/whatever). An analogy would be a battery with two positive terminals.

    Lets try something even simpler...

    The two terminals of a single 120V leg are 180 degrees out of phase -- no matter how you measure them and no matter what reference you use. Does anyone besides JW disagree?
    Last edited by bluebinky; 02-23-2014 at 12:01 PM.

  11. #86
    DIY Senior Member BobL43's Avatar
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    Quote Originally Posted by jwelectric View Post
    It doesn’t matter about my words the fact remains the same about the scope and the 180 degrees out of phase. The laws of physics remain true and there is no way possible that the two ends of a single phase winding to be 180 degrees out of phase with each other.

    It doesn’t matter what one tries to prove using the picture of a scope especially if they don’t understand vector math, the fact remains that the two ends of a single phase winding are in phase with each other.

    It doesn’t matter what someone has read or been told all that matters is the laws of physics which prove the fact that using a scope to look at the sine wave of a center tap winding shows that the winding is in fact in phase with each other and there is no way possible that the two 120 volt sine waves are 180 degrees out of phase with each other.
    Even Newton knew the law of physics with the apple thing, but when he discovered figs, he sold a product to Nabisco. As to this sine wave issue, I'm going to remain Neutral. Too much talk; I'm so confused.
    I am definitely not a pro plumber, but I am a pro crastinator

  12. #87
    Electrical Contractor/Instructor jwelectric's Avatar
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    Quote Originally Posted by bluebinky View Post
    Two (sinusoidal) signals which are the same amplitude and phase are in fact the same signal and measuring between them will result in no information (power/voltage/whatever).
    Two different signals can have the same sinusoidal and amplitude and originate from two different channels and be different such as in a “SINGLE” phase transformer

    Quote Originally Posted by bluebinky View Post
    An analogy would be a battery with two positive terminals.
    the battery you mention is an analogy of two different sources that are in fact 180 degrees out of whack. Take the two cell flashlight and reverse on battery or should I say turn it 180 degrees and this is just what you have, a battery that has the same polarity on both ends.

    Quote Originally Posted by bluebinky View Post
    Lets try something even simpler...The two terminals of a single 120V leg are 180 degrees out of phase -- no matter how you measure them and no matter what reference you use. Does anyone besides JW disagree?
    The scope at which you are looking at to see what you assume means to be 180 degrees out of phase is looking from the middle at both ends at the same time.

    This is more than enough to prove that while one end is positive the other is negative or the two signals are in phase with each other. If you are going to look at the scope at least try to understand what you are seeing. Channel A is positive then Channel B is negative meaning that there is one 240 volt signal that you are looking at the two halves of at the same time. They are in phase with each other not opposing each other.

  13. #88
    Electrical Contractor/Instructor jwelectric's Avatar
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    Quote Originally Posted by bluebinky View Post
    Two (sinusoidal) signals which are the same amplitude and phase are in fact the same signal and measuring between them will result in no information (power/voltage/whatever).
    Two different signals can have the same sinusoidal and amplitude and originate from two different channels and be different such as in a “SINGLE” phase transformer

    Quote Originally Posted by bluebinky View Post
    An analogy would be a battery with two positive terminals.
    the battery you mention is an analogy of two different sources that are in fact 180 degrees out of whack. Take the two cell flashlight and reverse on battery or should I say turn it 180 degrees and this is just what you have, a battery that has the same polarity on both ends.

    Quote Originally Posted by bluebinky View Post
    Lets try something even simpler...The two terminals of a single 120V leg are 180 degrees out of phase -- no matter how you measure them and no matter what reference you use. Does anyone besides JW disagree?
    The scope at which you are looking at to see what you assume means to be 180 degrees out of phase is looking from the middle at both ends at the same time.

    This is more than enough to prove that while one end is positive the other is negative or the two signals are in phase with each other. If you are going to look at the scope at least try to understand what you are seeing. Channel A is positive then Channel B is negative meaning that there is one 240 volt signal that you are looking at the two halves of at the same time. They are in phase with each other not opposing each other.

  14. #89
    DIY Senior Member bluebinky's Avatar
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    The same rules apply to DC as AC (except that detailed analysis of AC requires higher math). Voltage by definition is a potential difference (as is subtracting) between two points -- not the addition of two potentials.

    For DC (say two car batteries in series with each end measured against the middle): 12.6V - (-12.6V) ==> 25.2V

    For AC (say residential wiring with each leg measured against the neutral): 120V@0deg - 120V@180deg ==> 240V (out of phase by definition)

    notice that 120V@0deg - 120V@0deg ==> 0V (in phase by definition)
    Last edited by bluebinky; 02-23-2014 at 01:43 PM.

  15. #90
    DIY Senior Member Homeownerinburb's Avatar
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    Quote Originally Posted by DonL View Post
    When you get the message "Do you want to leave this page" after clicking Post Reply Click No, do not click Post Reply again.

    That should put your post on the server.

    Then close the page, you may get "Do you want to leave this page" again, Click Yes.

    It works something like that but is hard for me to splain.


    Good Luck.
    I appreciate it. I do hate to clutter the place up.

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