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How is this possible? What is voltage? 7.2 KV going through this small wire?

  1. Oct 13, 2009 #1

    foo

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    I finally got to see the inside of a voltage transformer as one happened to blow up and I got to view a part of it. The wild thing was that since it was a 7200 volt transformer I thought that there would be some thick wire in there. Well, the top portion of it has one little itty bitty wire traveling through it and it blew my mind that it could carry such high voltage without difficulty, well, unless somehow a high current load is drawn through it causing it to blow. Heh

    Here is the pic of what I'm talking about:
    http://foo.gearsector.com/foo/images/PTa_mini.jpg [Broken]
    http://foo.gearsector.com/foo/images/PT_mini.jpg [Broken]

    Ok, so then what is voltage? I have read many times about how it's what pushes current. But what the heck is "THIS", the this that's pushing? I get the idea that current is the atoms moving through something. Current I can imagine. But voltage? I can't imagine what voltage is. How can something push when it's not anything at all?

    What gives????

    Thanks in advance!

    P.S. And why can so much voltage transfer through such a small wire? It's weird how the wire connecting to the top is so thick....
     
    Last edited by a moderator: May 4, 2017
  2. jcsd
  3. Oct 13, 2009 #2

    mgb_phys

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    That looks more like an insulator - designed to hold high voltage wires away from the tower.
    http://upload.wikimedia.org/wikipedia/en/thumb/3/33/Pylon.detail.arp.750pix.jpg/250px-Pylon.detail.arp.750pix.jpg [Broken]
    Not sure why it would have a wire running through it unless that was a fragment of cable that became embedded when the equipment failed.


    Anyway - voltage and current are different.
    You can think of voltage as the pressure difference to push electrical current through a circuit. You can have very high voltages with very little current - the spark when you wear polyester clothes can be 100,000V but there is very little current.
     
    Last edited by a moderator: May 4, 2017
  4. Oct 13, 2009 #3

    foo

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    It's just the top part of the transformer that blew off. I will take another picture tomorrow of a whole x-former to show. Sorry to confuse.

    Also, the top picture is upside down. There is a connector not shown. Like I wrote, I'll post another pic tomorrow.
     
  5. Oct 13, 2009 #4
    That was my first take, mgb. It could be an insulator that is mounted on top of the transformer.

    13_09_8---High-voltage-transformer--Newcastle-upon-Tyne_web.jpg


    Why is the conductor running so far off-center? And did this cause the failure, or is this the usual quality of workmanship for these insulators?
     
    Last edited: Oct 13, 2009
  6. Oct 14, 2009 #5

    mgb_phys

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    There wouldn't be a conductor running through the middle of this.
    My guess is that it's a bit of slag from the power cable / mounting hardware that got melted by the fire.
     
  7. Oct 14, 2009 #6

    foo

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    http://foo.gearsector.com/foo/images/x-former_mini.jpg [Broken]
     
    Last edited by a moderator: May 4, 2017
  8. Oct 14, 2009 #7

    dlgoff

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    The proper term for these insulators are http://en.wikipedia.org/wiki/Bushing_%28electrical%29" [Broken].
    http://en.wikipedia.org/wiki/File:DIN_52NF1000.jpg
     
    Last edited by a moderator: May 4, 2017
  9. Oct 14, 2009 #8

    foo

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    Last edited by a moderator: May 4, 2017
  10. Oct 15, 2009 #9
    You can compare it to water flowing through a pipe.
    The current is the amount of water that flows through per second.
    And the voltage corresponds to the pressure i.e. how strongly the pump pushes the water into the pipe.
     
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