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Re: Halloween night, CP cap {con,de}struction

Hi Chip,
    A well designed RF capacitor should take hot spotting into the design
consideration.  I am beginning to wonder about that company.  My capacitors
are 0.01 uF at 30 kV DC, BD300-103B, made by Plastic Capacitors Inc.  I
ordered these 20 years ago.  I asked for polypropylene in oil with extended
foil construction.  The salesman suggested RF induction heater capacitors.
He said that they run all day for an 8 hour shift at 300 kHz in induction
heaters.  I have never run them above 10 kV.  In one run I ran for about
1/2 hour making 5 foot streamers until the 1/8 inch tungsten rods in the
rotary burned down past the firing distance.  The capacitors were cold as
ice water.  They are in a metal can with one insulated electrode coming out.  

Barry

-----Original Message-----
From: Tesla List +ADw-tesla+AEA-pupman-dot-com+AD4-
To: tesla+AEA-pupman-dot-com +ADw-tesla+AEA-pupman-dot-com+AD4-
Date: Sunday, November 01, 1998 7:51 PM
Subject: Re: Halloween night, CP cap +AHs-con,de+AH0-struction


Original Poster: Chip Atkinson +ADw-chip+AEA-pupman-dot-com+AD4- 

Barry,

The safety gap is set at about 1/2+ACI-,  1/32+ACI-.  I had the voltage turned
up just to where it wasn't firing at all, probably around 11KV.  

Personally I suspect that the problem was due to +ACI-hot spots+ACI-
developing in
the caps.  Once the cap shorts out, it's all over because there is very
little room for expansion of the contents.

Chip


On Sun, 1 Nov 1998, Tesla List wrote:

+AD4- Original Poster: +ACI-B+ACoAKg-2+ACI- +ADw-bensonbd+AEA-erols-dot-com+AD4- 
+AD4- 
+AD4- Hi Chip,
+AD4-     Sorry to hear about the demise of your capacitors.  Did the
safety gap
+AD4- across the capacitors ever fire during any of these runs?
+AD4- 
+AD4- Barry
+AD4- 
+AD4- -----Original Message-----
+AD4- From: Tesla List +ADw-tesla+AEA-pupman-dot-com+AD4-
+AD4- To: tesla+AEA-pupman-dot-com +ADw-tesla+AEA-pupman-dot-com+AD4-
+AD4- Date: Sunday, November 01, 1998 1:29 AM
+AD4- Subject: Halloween night, CP cap +AHs-con,de+AH0-struction
+ADw-SNIP+AD4-