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Re: Results of Paper & Poly & Oil



---------- Forwarded message ----------
Date: Tue, 30 Sep 1997 19:47:57 +0500
From: "Alfred A. Skrocki" <alfred.skrocki-at-cybernetworking-dot-com>
To: Tesla List <tesla-at-pupman-dot-com>
Subject: Re: Results of Paper & Poly & Oil 

Mon, 29 Sep 1997 14:22:04 -0400
Thomas McGahee <tom_mcgahee-at-sigmais-dot-com>

> Alfred,
>
> My flat plate capacitor "ends" refer to the section of the capacitor
> plate that is furthest away from the plate connection point. A
> diagram may help clarify. Here is a side view of the plate positions:
> 
> ______________________
> |  ______________________
> |_____________________  |
> |  _____________________|
> |_____________________  |
>    _____________________|
> 
>   ^                  ^
>   |                  |
>   |                  |
>    These are the "end"
>    points mentioned in
>    my original post.

OK, now it all makes sense! You have a geater electrostatic field at 
the "end"s because of the close proximity of opposite plate edges.

> The corona problem here is much greater than anywhere else along the
> periphery of the plates. What surprised me was how MUCH greater it
> was! I believe that because the opposite plate extends underneath the
> poly and past these "ends" that the corona is thereby extended much
> more than it is around the outside edges. The corona is sort of drawn
> across the poly surface because of the proximity of the opposite
> plate. 

Yes, if you could map out the electrostatic field you would see it is 
much more intense in this area.

> By the way, the *corners* did not show any appreciable increase in
> corona over the ends. That initially surprised me, as I thought the
> sharp edge there would have created an even greater e-field. But it
> seems that it is not so much the sharp edge that is creating the
> corona, but the extension of the opposite plate beneath the poly.
> This has implications for the way we build our caps, whether they are
> flat or rolled. The "ends" need to have MUCH more linear insulation
> distance than the outer edges. My guess is that something like three
> times the distance required on the outer edges.

I agree with your conclusions!


                               Sincerely

                                \\\|///
                              \\  ~ ~  //
                               (  -at- -at-  )
                        -----o00o-(_)-o00o-----
                           Alfred A. Skrocki
                   Alfred.Skrocki-at-CyberNetworking-dot-com
                             .ooo0   0ooo.
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