Re: Tesla Coil - Internal Arcing on Secondary

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: Esondrmn@xxxxxxx 

Is the secondary arcing at the bottom?  ie through the form to the 
primary?  If so, you either need more clearance inside between the 
windings or maybe add some insulation between them.  Or, move the 
primary to the outside.  The secondary wire itself should not be 
arcing to the form.  There is no reason for this to happen.  Maybe a 
shorted turn?

Ed Sonderman

In a message dated 8/15/05 12:12:27 PM Pacific Daylight Time, 
tesla@xxxxxxxxxx writes:
I've just finished a 1 kw 1/4 wave tesla coil, off a 7 stage marx
generator off of a microwave oven transformer. 3J pulses in PP snubber
caps. Far too much work - I removed the secondary on some signal
transformers for inductive separation between stages, and it took a
couple tries to figure out a workable spark gap system. I ended up using
concrete bolts with wire wrapped around the threading and vise-d
together. Problem is, now the secondary is arcing. The secondary is ~700
turns of 22 awg wire on a 6 in diameter acrylic tube, spacewound at the
top and the bottom, with 3 spray coats and 1 brush coat of polyurethane
on it after winding. The topload is 25.75 pf (calculated) and the
secondary is 21.3mh (experimental) for resonance at ~215kHz. The winding
is about 19 inches, spacewound above and below that.The primary is
inside the secondary, on a 3 inch diameter tube. The arcing seems to
happen at a consistent place. The arcing is clearly between the
secondary's wire and the acrylic form; it is so bright it shines through
the enamel clearly, making a cool looking lightning pattern just under
the wire. Any ideas on how to stop the arcing? I can draw off maybe 6
inches of spark, but I should get 6-8 times that according to my
figuring.