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Re: Static Gaps vs Rotary Spark Gaps

Original poster: Jim Lux <jimlux@xxxxxxxxxxxxx>

At 08:54 AM 3/30/2005, you wrote:
Original poster: "Medina, Benjamin (UMR-Student)" <bamxbb@xxxxxxx>

Hello Folks. I originally was going for an ARSG (Asynchronous Rotary Spark Gap) but got a lot of responses from the TCML saying that it's not friendly with the NST, that it might fry it, and that I had to stay at 24o BPS (at least) to be safe. Therefore, I've changed plans and am thinking about using a SG (Static Gap).

Using a 15kV/30mA NST, in terms of efficiency and performance, how does a SG compare to a RSG? Is there any rule of thumb as to the # of gaps in series? Does a RSG guarantee longer sparks vs. a SG?

I am doing a school project, so we have budget and time constraints. Which of the following Static Gaps setups would you suggest I should go with? Or anything similar to images below. Bottom line, I want something that is reliable, easy to build, and efficient. Gary Lau suggested, http://www.hot-streamer.com/TeslaCoils/Misc/terrygap.jpg

The tradeoff is that there is a fixed voltage drop "per gap", so stringing together many small gaps has more loss than a single gap. However, multiple gaps have better "quenching" performance (that is, when the voltage across the gap drops lower as the energy is transferred out of the primary into the secondary), the gap shuts off more consistently.

Your comments and advice will be very much appreciated.

Thanks again,

Ben Medina
Rolla, MO.

http://hot-streamer.com/temp/BenMedina/f73d20a6.jpg (How is the connection done here? Essentially, where is the gap?)

The gaps are between the tubes. You hook the wires to the end tubes of the set)


(Maybe two parallel wood pieces. I am guessing I connect one end of the screw/bolt to one end of the secondary side of the NST and the other end of the other screw/bolt to the other end of the secondary side of the NST)?

You got it. However, the bolt end gap has a lot of practical problems. The end of the bolt gets real hot, real fast, and that leads to bad gap performance. A bolt gap with compressed air blowing through it (at fairly high speeds) will alleviate some of these issues. I've had very, very poor luck with simple unblown bolt gaps. They're finicky, seem to change performance from second to second, etc. If you have an air compressor that can blow a stream of air through the gap, it can work better.

The RQ/TCBOR gap in your first picture has the advantage of a large electrode area over which the sparks form, being made of copper (a good thermal conductor) and lots of heat sink area. This leads to stable performance.