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Re: Question regarding synchronous gap driven coils
Tesla List 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.
>
> Here is a quick description of my latest creation although the question
> also applies to my previous smaller TCs.
>
> Secondary:240 turns #14 ga wire on a 14" x 30" skeleton acrylic frame
>
> Primary:6 turns 3/8" copper tubing spaced 3/8" apart solenoid wound on
> 18" diameter acrylic skeleton frame tapped at 5 turns
>
> Neon:15kv -at- 120ma
>
> Toroid:8" x 18" mounted 2" above top turn of secondary
>
> Primary top turn is even with lowest turn of sec giving k=.25(about)
>
> Rotary synchronous break -at- 1800rpm giving 1 break per half cycle of the
> mains at about peak of the sine wave
>
> Discharge length over 60" point to point limited by room dimensions
>
> Although the discharges maximize at the fifth turn tap, a variation of
> +/- 1/2 turn has very little effect on the discharge length although
> changing to the sixth of fourth turn has more effect. The connecting
> wires between the gap, cap and primary are from 6" to 12" max.
>
> 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,
Any idea how long your gap is actually firing (true dwell)? If you're
able to actually quench before the secondary can begin transferring
power back into the primary, the primary frequency current spectrum will
be quite broad, and will still very effectively couple to the secondary
- even if the low power primary center frequency is significantly
different than the secondary center frequency.
However, this will be mostly a function of how your rotary is
constructed, and the resulting dwell time. What diameter, electrode
size, are the electrodes offset, simple or series, and are you running
any static series gaps in addition to the rotary?
-- Bert --