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DC Generator: Equations & Graphs

  1. Jul 25, 2012 #1
    Hello everyone,

    I found on this website http://spiff.rit.edu/classes/phys213/lectures/lenz/lenz_long.html a very good explanation for AC generators. Particularly I am considering these two images:

    attachment.php?attachmentid=49307&stc=1&d=1343211095.jpg
    And attachment.php?attachmentid=49308&stc=1&d=1343211095.jpg

    I found those equations and graphs are quite interesting and wish to make a "change" so that they are valid for DC generators.

    My thinking is that: For the sine graph, I have to flip the negative part to make it positive. It will look something like this:

    attachment.php?attachmentid=49309&stc=1&d=1343211561.jpg
    Also, the equations for magnetic flux, the current and also the voltage basically stay the same but should be taken as the absolute value.

    Can anyone please correct me if I wrong?

    Many thanks,
    LovePhys
     

    Attached Files:

    Last edited: Jul 25, 2012
  2. jcsd
  3. Jul 25, 2012 #2
    You are on the right track. The main difference between an AC and a DC generator is the means of making connections to the coil.
    In an AC machine 'Slip rings' are used to preserve the AC voltage and current. In a DC machine a 'commutator' is used to make the voltage and current in one direction, just as you have drawn in your last diagram.
     
  4. Jul 26, 2012 #3
    Thank you very much truesearch!
     
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