RE: Tesla Coil - Internal Arcing on Secondary

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "Mccauley, Daniel H" <daniel.h.mccauley@xxxxxxxx>


I'm confused to what the 7 stage marx generator is doing???

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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.