Re: space winding

["Malcolm Watts" <M.J.Watts-at-massey.ac.nz> (by way of Terry Fritz <twftesla-at-uswest-dot-net>)]

Hi Robin,

On 9 Aug 00, at 12:04, Tesla list wrote:

> Original poster: "Robin Copini" <rcopini-at-merlin-dot-net.au> 
> 
> 
> Hi all,
> 
>  I have a question as to this 'proximity effect'?
> 
>  As I understand it, the effect comes about due to the field generated
> by the wire affecting the adjacent wire. Now, considering that the
> high current carrying part of the coil is the lower, say third, of the
> secondary, would there be any advantage in spacewinding the lowest
> quarter, or third of the secondary and then going closewound for the
> rest. I assume someone would have done this, is there any quantitative,
> (qualitative - bigger/brighter sparks :-)  ), results to this method?

It would be tricky to wind a graded winding but I believe it 
has been done by Dr Rzsesotarski or Terry. It would tend to 
change the voltage profile of a bare resonator to something 
more linear.
 
>  As for turn-to-turn arcing, I too had some problem with this but it was
> eliminated after carefully fine tuning the coil. While I was doing this I
> noticed that when out of tune, I suffered turn to turn arcs near the lowest
> part of the coil and racing arcs from near the top - as one would expect,
> here's the intersting part, as I varied the tuning, (higher/lower FrP)
> the distance from the top and bottom of the secondary where these problems
> would
> occur varied also. It seemed to me, correct me if I'm wrong, that as I
> decreased
> FrP, the burn/breakout effect would move towards the ends of the coil. If I
> went
> too far, the effect would appear near the center of the coil, and I would
> have to
> go 'back' with my primary tap.  I have a mental idea/image why this is but am
> asking the list if there is a definitive reason for this effect?

It would seem that there is a significantly distorted voltage 
profile due to spurious resonances. I can't say I've ever 
managed to get a turn-turn flashover. Just a partial flashover 
covering a number of turns. Sorry to hear about the smoked 
coil.

Regards,
Malcolm