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

Re: Arc length vs pwr



Tesla List wrote:
> 
> >From MALCOLM-at-directorate.wnp.ac.nzWed Oct 16 22:23:39 1996
> Date: Wed, 16 Oct 1996 09:37:39 +1200
> From: Malcolm Watts <MALCOLM-at-directorate.wnp.ac.nz>
> To: tesla-at-pupman-dot-com
> Subject: Re: Arc length vs pwr
> 
> A quick comment on this:
>       I think arc length would have to obey a square law at least as
> far as upping power is concerned. The longer the spark, the more
> power dissipated along it both in maintaining ionization (width) and
> length (series resistance). I think one further order of power loss
> occurs in the gap when upping power levels. I do think though that
> primary things can be tailored to reduce this loss - it will be
> different for different gap systems in my opinion.
> 
>      On the lumped vs distributed thing for the secondary: the more
> top-C you have, the more lumped it gets as the secondary current
> becomes uniform and hence 0.5LI^2 applies. That measure of magnetic
> energy cannot apply in a distributed circuit as the current is not
> uniform along the length of the coil. There would be (in my opinion)
> an optimum top-C for a given secondary and bang size because several
> things happen while increasing terminal capacitance: (1) the
> secondary inductance is becoming more effective (Q increases), (2)
> voltage holdoff is increasing (assuming more C = greater radius of
> curvature (ain't necessarily so), and (3) output will eventually
> decrease due to energy limitation. It would be jolly nice to quantify
> this optimum R.O.C. and size.
> 
>      On tuning: there is one subtlety I have used where Lp and Cp are
> more-or-less fixed: raising and lowering the top terminal can
> dramatically alter secondary fr.
> 
> fwiw,
> Malcolm

Malcolm and all

My measurements show that raising and lowering the top terminal not only
changes fr but sometimes dramatically alters the Q.

Skip