Re: Filling caps with oil

From: 	David Huffman[SMTP:huffman-at-FNAL.GOV]
Sent: 	Wednesday, December 03, 1997 9:04 AM
To: 	Tesla List
Subject: 	Re: Filling caps with oil

Hello All,

Here is some additional information. This is a different twist on the rolled
capacitor design. My caps started out flat. I used 15 layers of dielectric
at ~30mils thick. The sheets were 20" square and the foil was 20"x18". The
foil extended 1-3/4" past the edge for connection purposes. The foil is
positioned 1" from the edge and 1-3/4" from the opposing foil side. The
capacitance measures 82nF/unit and three units will be used in series. After
completing the layers I clamped the ends where the foil extends and placed
two dowel rods on either side of center held with a cable-tie. Then I held
the dowels and rolled the unit around them. This keeps the foil ends
somewhat even and both end up on the outside. I used flashing folded over
the foil for the connection to the outside of the PVC pipe. I will take some
pictures of the procedure should anyone care to try it.
Dave Huffman

>From: David Huffman[SMTP:huffman-at-FNAL.GOV]
>Sent: Monday, December 01, 1997 3:21 PM
>To: Tesla List
>Subject: Filling caps with oil
>Hello All,
>I finish 2 of the 3 caps this weekend and had a couple of questions for
>those who have been there before.  I added the oil and pumped on the cap
>with a refrigerator compressor. The oil foamed quite a bit and I had to
>pumping a few times to let it settle down. The Kraft paper seems to hold
>in small spaces and generated tiny bubbles (foam). The trapped air seems to
>be diminishing and I hope to use the caps soon. How much pumping should I
>do? One problem is the terminals through the sides of the PVC pipe leak so
>have to continually pump to keep a vacuum. I haven't figured a way to seal
>them although they don't leak oil. By the way 25 in-Hg seems to be the
>limit, does that sound about right? I will hall them into work tomorrow to
>check the capacitance on our fancy C-meter.
>More to come...
>Dave Huffman