I've just finished a 1/4 wave 1kw tesla coil off a 7 stage marx generator with polypropylene capacitors off of a microwave oven transformer. It was far too much work. The secondary coil is ~700 turns on a 3 in diameter acrylic tube, with 3 spray coats and 1 brush coat of polyurethane. The primary fits inside the secondary, with the wires to the primary running through holes in the secondary. The problem is, when I run it, it arcs along the inside of the winding, between the tube and the wire. I can see white flashes in the space wound areas of the tube, and the secondary has this cool looking branching lightning that's red because the light is coming through the enamel. Obviously, this shorts part of the coil, changing the inductance, and thus de-tuning the system. The topload is ~25 pf (calculated) and the secondary is 20.1 mh (measured) with resonance at like 230kHz, I can't remember the exact numbers right now. I can draw off about 6 inches to ground, but I should be getting 8 times that. Any ideas on how to fix this?
- posted
18 years ago