Outside testing

cc: tesla-at-grendel.objinc-dot-com


I set the coil up outside last night and did some more testing.  This is the
second time I have ran it outside.  I did go talk to most of my neighbors
first.  The closest is about 1/4 mile away.  He said he couldn't hear it in
his house but could hear it clearly outside.

Last week when I ran it outside for the first time, I had many discharges
that would hit the strike shield above the primary.  You know what these are
like, massive white hot bolts.  This time, I raised the toroid up 2.0 " more.
 At that point it was mounted 11.0" above the top of the secondary coil form.
 The windings start 1.25" below that.  I fired it up at about one half power
and did some tuning.  I had a wire laying on the toroid to direct the
discharges and I had a ground rod set up a few feet away.  Tuning for best
spark length got me back to 12.75 turns - where it has been tuned since I got
my commercial .025 mfd capacitor.  At this point I increased the power to 30
A primary current (should be about 7kva) and moved the ground rod back to
about 73" away from the wire on the toroid.  I do get strikes to hit at this
distance.  This is good, I can demonstrate 6.0 foot strikes which has been my

I am still getting loud pops coming from the rotary.  My controls are located
about 30 feet from the coil and you can easily hear these pops over the noise
of the secondary discharges.  I don't know how else to describe them and I
sure would like to get rid of them.  It doesn't sound healthy.  They occur
maybe one or two every couple of seconds.  Is this maybe some kind of
kickback problem?

Then I took the wire off the top of the toroid and fired the coil up again -
still at 7 kva.  Running outside is different than running in the basement.
 The wind actually blows the discharge breakout point around on the toroid.
 That looks cool.  I had only been running maybe 15 to 20 seconds and all of
a sudden I got a massive discharge from the top of the secondary (under the
toroid) to the primary strike rail.  I immediately shut the power down.  I
tried to refire it and got the same thing.  I inspected the top of the
secondary and did not see any damage.  Guessing that I now had the toroid too
high, I changed back to the shorter spacer that I had been running with in
the basement.  It is 2" shorter, the toroid is now 9.0" above the top of the
secondary.  I fired it again and everything was ok for a short while, I was
still getting strikes from the toroid to the primary strike shield, not
continuous but often.  All of a sudden a massive bolt broke out from the
center of the secondary to the primary strike shield.  I turned the power off
and refired it.  It is difficult to get it to run without breakouts happening
from the coil itself.  I even had the safety gap fire once.

What is happening here?  Too much power?  I have had the power higher in the
basement.  Toroid too large?  Toroid too high?  If I lower the toroid,  the
strike shield above the primary will be it's favorite target.  The grass was
wet and the humidity was certainly higher than it ever was in the bsement but
the equipment was dry, no condensation on anything.  As long as I put
something on the toroid to direct the dishcharges, it runs ok.  Even then it
hits the primary strike shield sometimes.  With a smooth toroid now the
discharges want to break out from the secondary coil itself.

Ed Sonderman