Re: CW coil top terminals?

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "by way of Terry Fritz <twftesla-at-uswest-dot-net>" <FutureT-at-aol-dot-com>

In a message dated 1/28/01 5:59:23 PM Eastern Standard Time, tesla-at-pupman-dot-com 
writes:

Terry,

I'd say it depends on the effect you want.  I always put a sharp
point on top of my tube coils and let the sparks emit from it.
If the sparks emit from a small ball, they will be thicker and
raspier (using raw AC), but probably no longer.  The ball seems
to cause kickback into the tube and components.

I find that for a 20" spark, I gain about one extra inch if I use a small
toroid (6" overall), on top of the coil.  But I then install a sharp
steel point that extends about 3" above the toroid at the center
and points upwards.  The sparks emit from this point or electrode.

If your coil is running on DC, then the tungsten is a good idea
for handling the high current.  I've never built a solid state CW
coil, so I don't know quite how they compare with tube coils
regarding toroid behavior, needs, etc.

John Freau
--


> Original poster: "Terry Fritz" <twftesla-at-uswest-dot-net>
>  
>  Hi All,
>  
>  I am working on my CW coil and I was wondering what people are using for a
>  top terminal on CW coils?  
>  
>  I guess it should be fairly small but I was wondering what would take heat
>  well.  It is a 900 watt (delivered to the arec) coil and I hope to get it
>  doing the staccato stuff soon.  Would like a small brass drawer pull be ok
>  or is the something better?  The coil will melt a pretty good diameter bare
>  wire.  I may need cooling fins under the terminal since the top of the coil
>  is PVC or I could add a ceramic standoff insulator if I can find one.  I
>  could also have a tungsten needle point if that would be best.
>  
>  Any thoughts are welcome here.  I hope to soon get this coil running from
>  an arbitrary waveform generator.  It is 350kHz but the generator can
>  control the power level and I can play with any power envelope I want then 
:-
> ))
>  
>  Cheers,
>  
>   Terry