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Spark Gaps

5E) Spark Gaps.

Spark gaps are one of the most important components in a TC in terms of their effect on efficiency and spark length. Common TC spark gaps are: single static gap (SSG) and multi gap static gaps, rotary gaps and the new kid on the block, triggered spark gaps (TSG). Spark gaps are an area of intense TC experimentation, as they represent the single biggest power loss in the system and consequently overall efficiency and spark length.

1) Static gaps. These come in many flavors and levels of sophistication. They range from a couple of bolts or washers (single static gap) to air cooled multi segmented gaps, like the famous RQ or TCBOR gap. (Note: I'm really not sure if the Tesla Coilers of Richmond originated this style or Richard Quick did).

2) Rotary gaps. These have been the "big kid's" spark gap for a long time, and there are many in service. They come in two basic flavors, synchronous and asynchronous. Essentially, they are a spinning spark gap. They have a number of advantages, like being able to dictate break rate with assurance, good quenching characteristics and uniform performance. They have some serious disadvantages too. They are complicated to make, involve heavy things spinning pretty fast and the disc itself must be finely balanced. As well, if a rotary gap fails to fire on time, it can cause a condition know as "ring up" which causes a massive voltage build up in the system. If the safety gaps are incorrectly set, blown caps and transformers can be the result. As such, these really aren't the new coilers best choice. There is also talk that these may join the plate and rolled caps in the obsolete folder with the arrival of the triggered spark gap. I have never built a rotary gap.

2) Triggered Spark gaps. These, like the MMC seem like the way of the future. These are relatively easy and inexpensive to build, which puts them in range of all coilers, although I don't recommend one for a first coil. They are still very much under development, but a number of respected coilers are getting good results from them. I attempted to build one in the infancy of the technology and had mediocre results. This was because not only did the schematic I used have a typo that caused me to blow a number of components, but that the schematic was not fully developed. My newest coil will incorporate a triggered gap, but it will probably be added after I get it up and running with a static gap.

Overall, I think a static gap is the way to go for beginners. Air cooling becomes necessary at OBIT power levels and above. I have achieved good results with a vacuum cooled static gap modeled after Gary Lau's. Click HERE for more information, pictures and construction details about spark gaps.

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