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Re: rotary gap question
In a message dated 4/12/99 2:49:15 AM Pacific Daylight Time, tesla-at-pupman-dot-com
writes:
>
> Chris, all,
>
> That's a good question. A non-sync rotary is not always better than
> a static gap. In a small coil, or using an NST, a static gap may give
> better results. A rotary can be best for an NST system, but it has to
> be a sync rotary.
>
> In very high powered systems, a static gap may overheat, and fail to
> quench, or it may fire too often. The rotary is a timed switch, it sets
> the firing rate as needed or desired. It may also help to quell some of
> the chaotic firing characteristics of static gaps.
>
> Another distinct advantage of the rotary, is that it permits somewhat
> independent control over the firing voltage and break rate. This can
> be achieved with a static gap, but requires an adjustment of the gap
> spacings for each change. This may be one of the greatest
> advantages of a rotary gap.
>
> John Freau
>
Chris, John,
In addition, a rotary gap must be used once the primary supply current gets
much over 150 ma. I used a cylindrical static gap with a 12 kv 120 ma neon
sign transformer supply and it performed well. With a 5 kva 14.4 kv
distribution transformer, the static gap would not quench (as in go out)
regardless how much ballast I tried in the primary control circuit. I then
built an asynchronous rotary gap and it worked fine. I have read comments
from others that the upper limits of a static gap are around 1.5 kva to 2.0
kva. Comprssed air or vacuum quenched static gaps should take this limit to
some higher number but I have no direct experience with those.
Ed Sonderman