Notices
Results 1 to 4 of 4

Thread: Electromagnet

  1. #1 Electromagnet 
    Dan
    Dan is offline
    New Member
    Join Date
    Oct 2008
    Posts
    2
    I want to build a flat electromagnet that reacts as if it has opposite poles on either side and to be able to switch polarities.


    Reply With Quote  
     

  2.  
     

  3. #2  
    Suspended
    Join Date
    Apr 2007
    Location
    Pennsylvania
    Posts
    8,795
    Any electromagnet will switch polarities if you reverse the direction of the current through it. How flat does it have to be?


    Reply With Quote  
     

  4. #3  
    New Member
    Join Date
    Dec 2008
    Posts
    3
    speaking of which, sorry to digress, I stumbled across a remarkable phenomenon at NASA's APL. It involved dropping a magnet on a copper plate. Once the magnet is dropped from an average height of 1ft, about 4-5inches prior to collision, the magnet visibly slows it's rate of fall till it hits the copper plate. What causes this phenomena? difference in potential?
    Reply With Quote  
     

  5. #4  
    Suspended
    Join Date
    Apr 2007
    Location
    Pennsylvania
    Posts
    8,795
    Quote Originally Posted by koboko
    speaking of which, sorry to digress, I stumbled across a remarkable phenomenon at NASA's APL. It involved dropping a magnet on a copper plate. Once the magnet is dropped from an average height of 1ft, about 4-5inches prior to collision, the magnet visibly slows it's rate of fall till it hits the copper plate. What causes this phenomena? difference in potential?
    It is due to eddy currents induced in the copper plate by the changing magnetic field. This effect has been used for braking.

    http://en.wikipedia.org/wiki/Eddy_current_brake
    Reply With Quote  
     

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