Re: Sync-TC, latest results

To: "'Tesla List'" <tesla-at-poodle.pupman-dot-com>
Subject: Re: Sync-TC, latest results
From: Tesla List <tesla-at-stic-dot-net>
Date: Wed, 29 Oct 1997 19:15:31 -0600
Approved: tesla-at-stic-dot-net

From: 	Malcolm Watts[SMTP:MALCOLM-at-directorate.wnp.ac.nz]
Sent: 	Wednesday, October 29, 1997 2:56 PM
To: 	Tesla List
Subject: 	Re: Sync-TC, latest results

Hi John,
 
> From:   FutureT-at-aol-dot-com[SMTP:FutureT-at-aol-dot-com]
> Sent:   Tuesday, October 28, 1997 4:55 AM
> To:     tesla-at-pupman-dot-com
> Subject:    Re: Sync-TC, latest results
> 
> In a message dated 97-10-28 04:14:49 EST, tesla-at-pupman-dot-com writes:
> >snip>
> > Output was extremely intermittent as outlined in another post but the 
> > discharges were real fierce whn it did go. Definitely a coil for a 
> > sync gap with pretty close electrode presentation. I think you could
> > do far better behaviour-wise with same energy but a much smaller cap 
> > and much higher primary inductance. Peak discharges around 5 feet.
>  
> > Malcolm
>   >>
> 
> Hi Malcolm,
> 
> Thanks for this info, actually I find it amazing.  I'm using a
> much smaller cap (.007uF),higher voltage (32kV peak on cap),
> and higher primary inductance (350uH?),  120BPS.
> yet my results are much poorer; 42" sparks with 430 watts being
> provided by the caps.  My secondary Q is probably lower since
> I'm using #28 wire, but I wouldn't expect that to make the
> tremendous difference being seen here, then again, maybe it does.
> Your top load (the 22" by 16" one) is monster-sized compared to
> mine, at least in thickness, I don't know if that is the key.
> There's a mystery here, and I don't know the answer.  This has me
> completely baffled.  Would you care to speculate why my coil
> might be weaker than I would expect based on your results, and
> observations?  I assume you have the specs for my coil but I'll 
> resend them to you if you'd like.  Any comments will be 
> appreciated.

Here goes some speculation:
I think secondary Q does make a significant difference. You might 
view the secondary as a holding pen for the energy between primary 
maximums. To get a good discharge, the energy has to be maintained at 
the highest level while oscillating in the secondary. That secondary 
of mine showed itself to be over 2x better than one with a measured Q 
around 80 - 90 in terms of final output. Sshot measurement showed
first beat Vout to be a bit less but not that much different. 
Repetitive performance showed the lower Q one to be a total loser. Fr 
was the same. Mind you, k was lower as well so that would factor in 
the mix. I have always obtained better outputs from larger coils, all 
else being equal. Higher Csec appears to be a significant factor. The 
thing can only just break out with Ctot of about 30pF with around 3J 
Ep and needs several gap fires to do so which I attribute to 
leader/ion formation. I also think the beat frequency is a 
significant factor in getting a good output. I can think of no other 
reason why low k's can do so well.
    In view of all this I will scope the coil later to double-check 
the gap rep rate. I can't see it being 4xfmains because the thing is
so touchy to adjust to get it to fire at all. Will post.
    The discharges with the smaller topload were spectacular but 
those with the larger one were awesome. I estimate the output was 
twice as loud. My normal hearing protection went from safe to 
borderline. There is certainly a real reservoir of current available.
     BTW, this coil was the first large one I built and it is still 
the best. Pure beginner's luck. What I learnt through experimenting 
with and measuring this led to a magazine article.
     If I think of anything else I'll post.

Cheers,
Malcolm