Tech Square

• Re: cable testing - jneutron 05:57:27 10/28/03 (5)
  In Reply to: cable testing posted by biggerdog on October 28, 2003 at 05:39:06:

  Thanks..

  My equip is half in a basement, half in my office..in the middle of a move, so the wires will wait..

  Right now, I'm workin up some code for e/m field analysis. Skin stuff, trying to model the slew rate vs inductance issue which is skin effect. We have two really strong e/m packages at work, but I won't ask the guys to use them for skin current profile until I've gotten mine working; I will be including in my package the ability to add layers to the wire, to allow superconductors in the middle. That will provide justification to use work materials, otherwise I can't do that..Uncle sam's quarter, so to speak. But I'll be posting theory pics at diy as my code progresses, so that the guys can pick my work apart..unfortunately, I can only work code for now, I don't even know where my soldering iron is..

  Peltier will have to wait, I'm up to my ears right now..Including a minivan that refuses to shift out of second gear...but, the others have engaged enough to understand what to look for in testing and effects and caveats..IMHO..

  biggerdog ""some real science is sorely needed around here""

  There actually is a lot of that here. But, you're right..some of the speculations and unsupported theories need to be attacked with rigorous methodology.

  Cheers, John

  
  
  

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  • Re: cable testing - john curl 16:01:17 10/29/03 (4)
    In Reply to: Re: cable testing posted by jneutron on October 28, 2003 at 05:57:27:

    Oh sure.
    
    

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    • Your posts always make me chuckle John - jneutron 18:10:30 10/29/03 (3)
      In Reply to: Re: cable testing posted by john curl on October 29, 2003 at 16:01:17:

      I clicked on your subject line hoping for technical dialogue..

      You always like to keep em guessing, I guess.

      Check out the e/m analysis pics I did over at diy..

      The scans showing the flux profile inside and outside the wire were exactly as predicted by maxwell..go figure..

      Next, I'll code in integral inductance scans, and auto-ranging magnitude software..

      Then, the real fun...Flux integration to determine inductance profiles, first static scans, then try for some dynamic scans..

      It was really neat to see how the current shell flux profile dropped so fast on the way into the conductor..way cool..

      First, I'll code in mu for the conductor, to show how a mu of 100 really causes the inductance to skyrocket..

      Look forward to some technical talk John..I'm patient..

      Cheers, John

      
      
      

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      • Re: Your posts always make me chuckle John - john curl 16:05:26 10/30/03 (2)
        In Reply to: Your posts always make me chuckle John posted by jneutron on October 29, 2003 at 18:10:30:

        Oh sure.
        
        

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        • You seem to be stuck, there John.. - jneutron 16:20:05 10/30/03 (1)
          In Reply to: Re: Your posts always make me chuckle John posted by john curl on October 30, 2003 at 16:05:26:

          I hope the troubles in So Cal aren't near you..

          If you have difficulties with the e/m theory or analysis or visualizations or equations, let me know..I'll provide the relevant references..

          It's surprising how easy it was to do the math for that field code..and so far, the results are matching the canned software the guys here use for analysis..

          I don't think I'll be including the conductivity and mu variations copper and steel have as they go to 4.5 Kelvin..I'll just use the endpoint numbers when I'm ready to model supers..

          Till now, I'll just be happy to model room temperature.

          Making some really cool 3-d plots of flux magnitude and radial/azimuthal fields..unfortunately, the code assumes a rotation reference that doesn't coincide with a wire center, so they are skewed..but at least that doesn't affect the point to point magnitude calculations..the normalization and scaling code seem to work now also..the 3-d plots are color mapped with height, like a relief map..

          Given that this is a "tech" forum, I was hoping you'd be willing to discuss the technical aspects of inductance mapping vs current slew rate....and how they apply to wires...

          I await..

          Cheers, John

          PS...you asked " what are we here for". is your purpose here merely to say "oh sure"?
          
          

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          • whoa, jeebus... - yessir 03:45:00 12/21/03 (0)
            In Reply to: You seem to be stuck, there John.. posted by jneutron on October 30, 2003 at 16:20:05:

            I thought I knew something. I understood slew rate but read through the rest of these posts slackjawed. I'm tempted to become a luddite at this point.

            Need to hit the books...
            

            • Why I didn't become an engineer...   (Open in New Window)

            
            

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