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Re: Top Toroid


>Date: Sun, 26 Jan 1997 13:18:27 -0700
>From: Jeff Detweiler <jd231825-at-engr.colostate.edu>
>To: tesla-at-pupman-dot-com
>Subject: Top Toroid
>
>Dear all,
>
>I am in the process of building my secondary coil, and I'm at the point
>where I need to make a toroid for the top. Although I remember seeing
>something about this on the list some time ago, would somebody please tell
>me how I should determine the proper dimensions for my toroid, and would
>the experienced coilers please share some of their clever ideas of how they
>made their toroids?
Jeff,
	I'll not try to quantify the minor diameter of a toroid vs
output voltage.

>As an aside, would somebody please remind me why a toroid is more ideal
>than a sphere and such? (Was it that the self-capacitance is larger or is
>there a better voltage gradient or something?)

Please visualize a 2' sphere sitting ontop of your coil. Now,
visualize a 2' flat plate sitting ontop of your coil. Which has the
larger shielding effect between your coil and the "rest-of-the-world"
?    The flat sheet, because it's in the same plane as the top turn of
your coil ( and at the same voltage (potential)).

Next problem;)  Oops, that flat sheet has sharp edges! Can you say
Corona? So let's shield that "sharp" edge. Round it. ... Soon you have
transformed that flat sheet into the intermediary between a disc and a
sphere.  The flat portion of the toroid provides the shielding (it's
close) and the rounded edge provides the corona hold off.
>
>I understand that in general, the larger the toroid, the more energy is
>needed to build up in the secondary before corona discharge happens. So am
>I shooting for the largest possible toroid where I still get a discharge?
>
I'm going to skip the conservation of energy transforms tonight. Maybe
Malcolm ( morning for him;) would like to take over;) He has a fine
explanation.

>Also, what effect does mounting the toroid closer or further away from the
>secondary have? (I've not seen anything definitive on this yet).
>
ditto.

	cheers,

	jim