User Tag List

Page 118 of 125 FirstFirst ... 18 68 108 116 117 118 119 120 ... LastLast
Results 1,171 to 1,180 of 1247

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

  1. #1171
    Join Date
    Oct 2009
    Location
    Austin, TX, USA
    Posts
    10,445
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by Besoeker View Post
    Because they are 180 degrees out of phase.
    A transformer that creates a balanced audio signal from an unbalanced one works exactly the same way as a transformer that creates 120V - 0V - 120V from a single phase of power. Its output is the signal and the inverted signal, and they are colloquially called "180 degrees out of phase" but they aren't because every frequency is inverted. No amount of phase shift can do that.

    But I said that nearly 1200 posts ago, didn't I?

  2. #1172
    Join Date
    Apr 2007
    Location
    Berkeley, CA
    Posts
    1,796
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by Besoeker View Post
    Because they are 180 degrees out of phase.
    No.

    Suppose due to harmonics the L1-N voltage is of the form sin(x) + a*sin(2x) [for some constant a and where I've set other constants to 1 for simplicity]. What's the L2-N voltage for an idealized center-tapped transformer secondary:

    1) sin(x + pi) + a*sin(2(x + pi)).
    2) - sin(x) - a*sin(2x)

    In this case the two answers differ. And (2) is correct, (1) is incorrect.

    Cheers, Wayne

  3. #1173
    Join Date
    Sep 2008
    Location
    UK
    Posts
    12,703
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by wwhitney View Post
    No.

    Suppose due to harmonics the L1-N voltage is of the form sin(x) + a*sin(2x) [for some constant a and where I've set other constants to 1 for simplicity]. What's the L2-N voltage for an idealized center-tapped transformer secondary:

    1) sin(x + pi) + a*sin(2(x + pi)).
    2) - sin(x) - a*sin(2x)

    In this case the two answers differ. And (2) is correct, (1) is incorrect.

    Cheers, Wayne
    You made my case. Very eloquently.
    Si hoc legere scis nimium eruditionis habes.

  4. #1174
    Join Date
    May 2011
    Posts
    4,866
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by ggunn View Post
    A transformer that creates a balanced audio signal from an unbalanced one works exactly the same way as a transformer that creates 120V - 0V - 120V from a single phase of power. Its output is the signal and the inverted signal, and they are colloquially called "180 degrees out of phase" but they aren't because every frequency is inverted. No amount of phase shift can do that.

    But I said that nearly 1200 posts ago, didn't I?
    I don't know, seems to me that 1149 is a few short of 'nearly 1200'. Stop exaggerating.

    You also said it (or made closely related points) in posts 45, 258, 268, 336, 439, 504, ... I'm sure there were a couple more. Sorry I got bored of searching.

  5. #1175
    Join Date
    May 2011
    Posts
    4,866
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by Besoeker View Post
    You made my case. Very eloquently.
    He debunked your case, very eloquently.
    Just going for post count now?

  6. #1176
    Join Date
    Feb 2016
    Location
    Illinois
    Posts
    1,214
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Am I the only one who looks at the title of this thread and thinks...”Wouldn’t it have been best to simply answer NO!”?


  7. #1177
    Join Date
    Sep 2008
    Location
    UK
    Posts
    12,703
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by jaggedben View Post
    He debunked your case, very eloquently.
    Just going for post count now?
    Are they 180 degrees apart?
    That's just yes or no.
    Si hoc legere scis nimium eruditionis habes.

  8. #1178
    Join Date
    May 2011
    Posts
    4,866
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by Besoeker View Post
    Are they 180 degrees apart?
    That's just yes or no.
    NO.

    And (2) is correct, (1) is incorrect.

  9. #1179
    Join Date
    Feb 2013
    Location
    India
    Posts
    2,550
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by Besoeker View Post
    Are they 180 degrees apart?
    That's just yes or no.
    Yes. Two phases (with respect to time) in a single phase(with respect to function) system. GLAD I AM ABLE TO COMBINE TWO CONTRADICTORY COCEPTS INTO ONE! That is dialectics of development.

  10. #1180
    Join Date
    May 2005
    Location
    Richmond, Virginia
    Posts
    24,256
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by Sahib View Post
    Yes. Two phases (with respect to time) in a single phase(with respect to function) system.
    It only resembles an offset in time; it's an opposition in instantaneous polarity.

    If you were to change the frequency but maintain what you perceive as the "timing offset" between the two waves, the opposing peaks would no longer occur at the same time.
    Code references based on 2005 NEC
    Larry B. Fine
    Master Electrician
    Electrical Contractor
    Richmond, VA

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •