RE: [TCML] RE: Need assistance in diagnosing poor performance

["Lau, Gary" <Gary.Lau@xxxxxx>]

I disagree with a couple of the points made below.

In comparing operation between static and SRSG's, the bang size with a static gap is actually more consistent with varying mains voltage, as the gap breakdown voltage is governed by the gap geometry and is not significantly affected by mains voltage.  In a rotary gap, the bang size is directly related to mains voltage.  Bang RATE is certainly more constant with a SRSG.  But for both gaps types, streamer power and length (and secondary detuning) will BOTH equally be a function of input voltage.

If the goal is to keep things simple, a static gap seems more in line.  My static gaps all worked right off, but it took me several attempts and a couple years before I got SRSG's right.  Tweaking the phase and getting the cap size optimized was not trivial and definitely more complex that using a static gap.

I agree that streamers can significantly affect tuning, but as Steve's streamers are only 3" at this point, I don't think it is at all significant.

Regards, Gary Lau
MA, USA



> -----Original Message-----
> From: tesla-bounces@xxxxxxxxxx [mailto:tesla-bounces@xxxxxxxxxx] On
> Behalf Of Chris Swinson
> Sent: Wednesday, July 30, 2008 11:50 AM
> To: Tesla Coil Mailing List
> Subject: Re: [TCML] RE: Need assistance in diagnosing poor performance
>
> Steve,
>
> The problem is , its not as easy as you many think. For example, if you tune
> at low power, when you crank up to high power, the sparks add to the topload
> of the coil (act as a larger toroid) and lower your frequency. So even if
> you tune 100% correctly, the sparks will change whatever you set the
> frequency at anyway. With my coil 250watts I was at something like tap 4,
> and at 500W I had to retune to like tap 7, just on the basis that the longer
> sparks lowered the frequency of the secondary and then caused me to tap out
> a few tunes.
>
> In actual fact the problem becomes pretty complex. If the sparks are short ,
> say 10", then the frequency could be 100khz, then as the sparks grow in
> length the frequency could go down to 80khz, so then your primary is
> detuned. As it goes off tune, energy will drop and you are back to the
> 100khz 10" sparks again... tuning becomes a general "suck it and see" kind
> of affair. The coil is going in and out of tune constantly and tuning
> manually is the only way to find the best overall tap.
>
> It complicates things further if you are using a none-sync spark gap. Where
> the AC voltage varies and this also will effect the bang size and then the
> spark length, which again effects coil tuning. If you play around for long
> enough, you could have a coil which will "cough and splutter" then blast out
> 100" spark as it hits the top of the AC cycle and hits the ideal tuned
> frequency.
>
> Its why I think sync gaps are much better overall, it makes life easier I
> think overall aswell. Its enough that the sparks can de-tune the coil,
> without adding in another factor of varying input energy.. Its getting back
> to onto RSG spark gap types, one vs. the other.. and that's a topic in
> itself.
>
> I like to keep things as simple as possible. A constant bang size is a good
> start, at least in theory once the coil is turned at full power, then the
> coil will always deliver full power and always be in tune. Though sparks do
> vary in length all the time and so does the tuning. You could retune your
> coil just from environmental effects.. the list is endless..
>
> Sorry it does not help with your problem as such..... Though I hope it gives
> you a little bit more insight to tuning coils..
>
> Chris

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