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Re: Top Toroid


>Subscriber: rhull-at-richmond.infi-dot-net Sat Feb  1 21:37:42 1997
>Date: Sat, 1 Feb 1997 09:05:08 -0500 (EST)
>From: richard hull <rhull-at-richmond.infi-dot-net>
>To: tesla-at-pupman-dot-com
>Subject: Re: Top Toroid

>>Any suggestions for a toroid major and minor diameters for this?

>Jim,
>
>You are in the ball park of normal operation of one 60 ma transformer!  It
>sounds like you are breaking out too soon.  Probably due to a short radius
>of curvature on the 3" minor axis toroid!  That's a big secondary for for
>that one little neon xfrmer!  The .016ufd cap is also a bit big for the
>transformer.  It sounds more like early breakout though with multiple 2
>footers.  Try a smaller diameter, fatter toroid.
>
Richard,
	Thank you. Friday night I built a 7" by 20" toroid. At first I
would not break out, just christmas tree corona down to the strike
rail, I raised the toroid higher above the secondary, then I had
direct strikes to the strike rail and secondary flash over. I then
reduced the coupling, retuned and achieved no breakout. I put a 1/2"
ball 1" above the toroid edge to act as a breakout bump and have a
single blue-purple 2.5' (eye guesstimate) air discharge.


Size wise, I'm waiting to get a variac for my pig before using it
again and I don't want to use a single cap at that power level.

Bert,
>Use a toroid diameter of at least 2/3 to 1X the diameter of your coil.
>An 8" coil, driven fairly agressively, should support a 6" ROC toroid.
>If you err on the large side, you can still always force it to break out
>by using one or more small foil duct-tape "bumps" to disrupt the e-field
>and instigate corona (where you want it - :^)). It sounds like your
>system is prematurely breaking out and could use a bigger ROC toroid.

A 7" ROC did it.

Skip,
>Did you wipe off the dirt and dust from the toroid? This can be a major
>cause of premature breakout.

Yes, with my hand. I discovered that during the last 6 months of
moving it in and out of my garage (door replacement) that the outer
edge has been dinged up and is full of places where the aluminum tape
has been gouged and formed sharp points.  This explains why the sparks
were sticking to each spot.

Robert,
>Congratulations for getting sparks out of the top this time. ; ) 
>I think the many simultaneous streamers is an indication that your ROC 
>is too small.

Yes

>I've seen the effect you describe on coils when they first start up, 
>but then as one dials in more power, one of those streamers will 
>mature and hog all the power, eliminating all the other little 
>imature starter streamers.  Could be you just don't have enough power 
>for your toroid.

I don't have a variac for my pig and don't want to run a single 0.12"
poly cap at pig power levels with a rotary gap. For now I'll just have
to start scrounging for another neon.


	Thank you all,

	jim