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Output Voltage vs. Firing Rate (fwd)




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From:  Malcolm Watts [SMTP:MALCOLM-at-directorate.wnp.ac.nz]
Sent:  Sunday, August 09, 1998 5:04 PM
To:  Tesla List
Subject:  Re: Output Voltage vs. Firing Rate (fwd)

Hello John, Greg,
                    I conducted some experiments last night amongst 
which I noticed something I wasn't looking for which may be of 
considerable help:

> Date: Fri, 7 Aug 1998 11:01:19 EDT
> From: FutureT-at-aol-dot-com
> To: tesla-at-pupman-dot-com
> Subject: Re: Output Voltage vs. Firing Rate (fwd)
> 
> In a message dated 98-08-07 04:59:00 EDT, you write:
> 
> << 
> > This magic break rate occurs at the point where the ion lifetimes
> > can start to enhance the longevity of the arc, resulting in one 
> > or two 'dominant' arcs instead of a brush discharge.
>  
> > The gap speed where the brushy streamers coalesce into 
> >a single dominant channel also seems to depend upon the 
> > physical size of the coil.  I had thought that the ion
> > lifetimes were more or less independent of the coil action,
> > but larger coils seem to exhibit noticably longer ion lifetimes.
>  
> > My old coil 'coalesces' at around 1500RPM, or 150BPS.  However
> > the Electrum coil does so much earlier, around 110 to 120BPS.
>  
> > Perhaps this is due to a squared/cubed relationship in the 
> > surrounding ion cloud, or in the arc itself, where doubling the
> > scale increases the surface area by 4, but the volume by 8.
> > This would slow the dissipation of both the ion cloud and arc.
>  
> > This is good news if true, for it would increase the upper limit
> > on the maximum practical size of a Tesla Coil.
>  -- 

I agree - see below.
  
> > -GL >>
> 
> Greg,
> 
> I think there may be other factors involved such as the voltage and
> the relative radius of curvature of the toroid (ROC), etc.  My TC stays 
> coalesced at 60 BPS and loses coalescence somewhere between
> 30 and 60 BPS.  I would guess that if you used a different ROC
> toroid, the coalescence would occur at a different break rate.  I think
> if your main tank capacitor was of a different size, this too might
> affect the coalescent break rate.  Larger ROC toroids, for a given
> toroid voltage, or bang size, may enhance the coalescense process.
> The smoothness or texture of the toroid surface may also affect the
> coalescense...but this is pure speculation on my part.  

I agree with both things said in the first sentence. I noticed that a 
system run just above breakout voltage gives a single strong streamer
(root) but the higher the output voltage from then on, the more 
streamers formed simultaneously. I took it from that that at whatever 
power level you wish to run, always adjust top ROC so that the 
system just breaks out. If the top emits multiple streamers, only an 
increase in breakrate can make them coalesce. This would explain the 
differences between Greg's two coils.
    I remember the sshot tests of Electrum showed the same thing - a 
single rooted streamer formed just above breakout voltage. I'll 
report more fully on these experiments later today. Hopefully there 
is some information of use to list members in there.

Regards,
Malcolm