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Re: Question regarding synchronous gap driven coils
At 10:25 PM 1/30/97 -0700, you wrote:
>Subscriber: sgreiner-at-mail.wwnet-dot-com Thu Jan 30 22:23:48 1997
>Date: Thu, 30 Jan 1997 13:48:42 -0800
>From: Skip Greiner <sgreiner-at-mail.wwnet-dot-com>
>To: tesla list <tesla-at-pupman-dot-com>
>Subject: Question regarding synchronous gap driven coils
>
>Hi everyone
>
>I address this post mostly to those of you who run synchronous rotary
>gaps but will certainly appreciate responses from anyone.
>
snip
>
>In reading various posts it appears that those of you running static
>gaps and non-synchronous gaps obtain very definite peaking when tuning
>the primary. My question is: do those running synchronous gaps see the
>same sharp tuning or do you see the much broader peaks which I
>encounter. Also is it possible that the broader tuning is due to the
>fairly large diameter primaries and secondaries which I use or is it due
>to the synchronous gap.
>
>Skip
>
>
Skip,
It is a combination of things none of which involve the gap. As larger
diameter primaries are used, there is naturally more inductance per turn.
This is especially true with the archemedian spiral. Thus, as we tap
outward more inductance per turn is added or subtracted. With coils which
use few turns or in coils with vertical, cylindrical primaries, this
inductance is not added as quickly as very large primaries with many turns
tapped way out to the tenth turn. In this manner, smaller primaries are
less sensitive to tune per turn than larger ones. Ultra small primaries
with 2-3 turns are again very sensitive to tune as the tune range from
shorted to max L is just 2 turns or less. With a medium sprial of 5-7 turns
and operating at lower frequencies below 300 KHZ the tune seems a bit sloppy.
Also, a running Tesla coil's resonator has a very low Q and the sensitivity
to tune is low comapared to a normal Hi Q radio circuit.
Richard Hull, TCBOR