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Re: corona (fwd)



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In a message dated 97-03-04 20:03:31 EST, you write:

<< In a message dated 97-03-03 23:49:25 EST, you write:
 
 << I recently took some photos of my coil in operation.  When I got the
  photos back I noticed that all the pictures show a blue ring of corona
  on the ground ring around the primary and comming down from the top of
  the secondary.  I have not noticed this while running the coil but it
  shows up on all of my photos. 
  
   I understand that the corona from the top may be from having the
  torroid too high.  Does any one have any ideas what may cause the corona
  on the ground ring? (It looks cool in the pictures but I doubt if it's a
  good thing)
  
  My coil configuration is as follows:
  
  2 15kva neons
  2 air wound and 2 ferrite core chokes
  copper tube vacuum quenched spark gap (8 tubes, .030 spacing)
  Primary -1/4" copper pipe with 3/8" spacing 12 turns
  Secondary - 6" acrylic wound with 22" of 24ga magnet wire
  Torroid - 4" dryer duct around a 24" pizza pan
  ground - very heavy welding cable (1/2" dia) connected to 1 8' copper
  plated ground rod
   >>
 
 Dave,
 
 Your coil sounds similar in size to mine.  What you are seeing is the
intense field coupling the primary energy to the secondary.  I have seen this
on mine as a perfect blue christmas tree formed from the outside of the
primary up to the top of the secondary.  This is most evident just before the
toroid breaks out, in a dark room.  You have good coupling and you will
probably find it too tight if you try to raise the input power levels.  As I
increased power, the blue field increased in intensity and finally started to
breakdown with discharges along its total length.  Then I raised the
secondary up about three inches to loosen the coupling.
 
 Ed Sonderman >>






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