[Prev][Next][Index][Thread]

Re: How do sparks propagate, anyway? (toroid)



Subject:      Re: How do sparks propagate, anyway? (toroid)
       Date:  Mon, 12 May 1997 09:23:00 +1200
       From:  "Malcolm Watts" <MALCOLM-at-directorate.wnp.ac.nz>
Organization: Wellington Polytechnic, NZ
         To:  tesla-at-pupman-dot-com


John, Bert, Greg, all,

>   From: FutureT-at-aol-dot-com
>     To: tesla-at-pupman-dot-com
> 
> 
> In a message dated 97-05-08 23:57:54 EDT, you write:
> >snip
> <<  Why do many coilers  report that a larger toroid increases 
> >the striking distance of their  coils,  given that increasing
> > Coutput always decreases the output voltage? 
> > (I am assuming that the striking range is increased by more
> >than just  the  increase in toroid radius.)
>  > 
>  > -GL
>  
> > Greg,
>  
> >An interesting question for sure! I'm assuming you're refering to cases
> >where the tank C, gap breakdown voltage, and incoming power levels
> > are not changed. I suspect that part of the reason has to do with the
> >enhanced capability of a larger toroid to provide minimal voltage drop
> > while supplying high-amplitude current peaks that occur during
> > propagation/growth of the streamers. A larger "chunk" of toroid
> > capacitance would permit a greater reserve of charge to be available to
> > support further propagation. Although the larger C would also reduce
> > maximum voltage, I suspect this is of secondary importance AS LONG
> >AS the voltage is high enough to initiate and maintain streamer
> > production. This may be why lower Z ( or relatively higher self-C) coils
> >may see reduced benefits from oversized toroids.
>  
> >Have to think about this a bit more...
>  
> >-- Bert H --
>   >>
>  
> Bert, Greg, All,
> 
> Here's some other musings and observations: I've noticed also, that
> if a larger toroid is installed, and if power is rather limited
> (but kept the same as it was), the sparks lose their nice
> blue-white "thin" nature, and take on a purplish, fluffy look when
> the larger toroid is installed.  In spite of this, the sparks tend
> to be a little longer.  For instance, the sparks may increase from
> 45" (small toroid) to 49" with the larger toroid.   Of course if
> plenty of power is available, then the sparks using the larger
> toroid may become even brighter and whiter than with the small
> toroid.
> 
> If power input is higher, then the larger toroid seems to give
> more of a benefit.  It seems very hard to push long sparks out of a
> small toroid. I wonder if PART of the reason could be because more
> streamers tend to be produced when the toroid is small.  Multiple
> streamers definitely seems to reduce spark length esp. when power is
> limited.   It may be for this reason that some coilers seem to
> benefit from using a very long "rod type" take off point on their
> toroid, which forces it to produce only one streamer. They may be
> "compensating" to a degree for a too-small toroid.
> 
> Another thing I noticed is that in many cases, the spark length is
> equal to about 2 to 3.5 times the toroid diameter.  It seems
> difficult to go beyond this ratio.  It would seem that very large,
> high powered coils CAN go beyond this ratio; consider for instance
> Golka's impressive coil output with NO toroid.  Maybe as you said
> Bert, these large coils have so much self C, that they perform as if
> they had a built in toroid more or less. (At least I think this is
> what you're saying, correct me if I misunderstand.)

Being a copy of Tesla's design, it incorporates his original rule of
large ROC. It also has a fairly high Cself in excess of 100pF.

> Another thing to consider is that larger toroids working with
> LIMITED power inputs, tend to degrade the quenching which would
> tend to REDUCE the spark length (maybe if the quench wasn't
> degraded under these conditions, spark length gains would be 
> even better?) 

The degraded quenching is symptomatic of energy not being easily 
released from the system in my opinion.

Malcolm
<snip>