Original poster: "D.C. Cox" <resonance@xxxxxxxxxx>We also use a 1/8 inch thick plastic shield between the stationary holder and the motor --- if not flashovers will occur. We bend these shields at 90 degrees with a hotwire so that they fit under the fastener for the stationary sparkgap and extend up the side of the motor approx 7 inches.
Dr. Resonance
Here is an old photo, before I upgraded it, but it gives you an idea of what Dr. Resonance was talking about: http://www.hot-streamer.com/adam/bigass_coil/srsg.jpg