Novel pin placement for enhanced triggered spark gap performance and ease of assembly

Triggered spark gaps are essential to a wide variety of applications but generally require expensive, fast risetime high voltage trigger generators to achieve reliable performance. In this effort, the specific case of a field distortion spark gap with an off-axis pin electrode that commutates via cascade breakdown was studied. A solid-state driven ignition coil with a peak open circuit voltage of 40.5 kV and risetime of 5.1 µs is used throughout the evaluation. The intent of the investigation is to determine if a change in pin geometry can enhance the switching characteristics with a slow trigger pulse. The conventional trigger pin has two design parameters–the field enhancement at the tip and its position relative to the gap. Two field enhancements and two pin positions are investigated and compared to the proposed geometry where the pin is inserted through the center of the gap. This eliminates the uncertainty in the pin parameters by fixing the position and yields similar switching jitter as the highly enhanced pin and a voltage operating range down to 50% self-breakdown but with a significant increase in the delay time. This modification has advantages for reliable manufacturing, ease of assembly, and long lifetime over the current technology.