Re: First Light Great, Second Time Not So Great...

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: Esondrmn@xxxxxxx 

In a message dated 5/22/05 9:45:44 PM Pacific Daylight Time, 
tesla@xxxxxxxxxx writes:
Original poster: "Daniel Koll" <dk_spl_audio@xxxxxxxxxxx>

I finally finished my first coil.  It is a 12/30  16" X 3.5" coil.  I ran
it on Friday and it was great, I just guessed on the tunning by looking at
the spark output.  Then on Saturday I was going to run it for some friends
and family.  I plugged it in beforehand and something happened.  It started
arcing from the middle of the secondary (24 AWG coated many times with
polyurethane) to the bottom of the secondary (didn't arc to primary
though).  Also, streamers were coming out of the top winding on the
secondary, not just the toroid (6" steel ball).  I tried lowering the top
load but it didn't help.  It was more humid on Saturday than Friday, not
sure if that matters.  Any ideas?  Thanks

Daniel,

It sounds like the coupling is too tight or it is not tuned 
properly.  Start with the bottom winding of the secondary just even or 
slightly above the top plane of the primary.  Is this a flat primary?  You 
should run some calculations and find out approximately how many turns on 
the primary are needed for correct tuning and start there.  Running at 
about one half power, place a grounded wire a few inches away from the 
toroid, so the sparks just hit it.  Now move the primary tap wire on the 
primary in one turn and see if the sparks get longer, or hotter.  Now go 
out one turn, etc.  Once you find the best spot, then try different 
positions on that same turn of the primary, moving the tap 1/4 turn at a 
time.  About the toroid, that is why we use a toroid instead of a ball.  A 
ball does not provide much field control for the top of the secondary.  A 
toroid shape is necessary.  Go to a hobby shop and buy a few foam donut 
shaped parts - maybe they are for making wreaths?  Not sure but they 
usually have lots of them and they are cheap.  Maybe 8 to 10" in diameter 
by 2" high.  Cut out some plastic or cardboard for the center and cover the 
whole thing in aluminum foil tape.  Mount an inch or two above the top 
winding of the secondary.  If the lowest you can mount it is 4" just try 
that, it may work fine.



Good luck,

Ed Sonderman