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Re: corona (fwd)



richard hull wrote:
> 
> At 09:32 PM 3/3/97 -0700, you wrote:
> >
> >
> >---------- Forwarded message ----------
> >Date: Mon, 03 Mar 1997 15:01:47 -0700
> >From: Dave Burman <dburman-at-ix-dot-netcom-dot-com>
> >To: Tesla List <tesla-at-poodle.pupman-dot-com>
> >Subject: corona
> >
> >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,
> 
> The corona is just a form of high field emmision and thus loss.  It is,
> however, helping to create a nice uniform potential gradientin the area of
> the primary.  As with all things, there is good news and bad news.
> 
> If it really bothers you try using 1" diameter copper pipe for the ring and
> the corona should disappear. (larger radius of curvature)  This assumes you
> are not willing to re-engineer the whole system.
> 
> Richard Hull