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



Hi Chip,
    Sorry to hear about the demise of your capacitors.  Did the safety gap
across the capacitors ever fire during any of these runs?

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 1:29 AM
Subject: Halloween night, CP cap +AHs-con,de+AH0-struction


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

Greetings all,


Tonight was both the best and most expensive coiling night I've ever had. 
I finished a 10+ACI- diameter coil a few weeks ago and got it running well
enough that I can start to tinker with it.  In other words, it isn't going
to self destruct in a few seconds.  

I put the coil and cap/gap box on top of my garage so that everyone could
see it tonight.  After a minor hiccup, I was able to get the thing running
well.  I even got some runs about as long as you see Richard Hull getting
on his tapes.  After a particularly long run, I got that strange sound of
the rotary gap firing but no output.  In about as much time as it takes to
notice and wonder what's going on, I hear a loud BOOM and flames shoot out
the sides of the box.  I shut down and climbed up to see what happened.

My Condenser Products 0.025uF/20,000V tesla coil cap blew up+ACE-  I'm glad it
was on the roof because it could have really hurt someone.  

Luckily, I had another CP cap and decided to try it too, since the coil
was going well and perhaps it was a fluke that it blew up.  Nope+ACE-  The
second one blew, and even more violently than before.  

I disected the remains of the caps and it was very interesting.  They
consist of four rolls of plastic and aluminum foil.  The ends of the plate
stick out so that the ends of the roll has a sort of +ACI-fuzzy+ACI- look
to it.
The aluminum foil is very thin, much thinner than you can buy for food
use.  The dielectric is probably polypropylene, but it is only plastic, no
kraft paper.  The rolls were also interesting in that they were basically
two caps in one.  They had two layers of plastic and three pieces of foil:

  +++++++++++++++++++++++++- 
    +AD0APQA9AD0APQA9AD0APQA9AD0APQA9AD0APQA9AD0APQA9AD0APQA9-
  +++++++++++++++++++++++++-
+AD0APQA9AD0APQA9AD0APQA9AD0-     +AD0APQA9AD0APQA9AD0APQA9AD0APQA9AD0APQ-

The +AD0-'s are foil, and the 's are plastic.  Note how the ends of the lower
part of the foil sticks out past the edge.  This is basically two caps in
series.  Very interesting.  Also interesting is how there is nothing
between the gap on the bottom plates.

In conclusion, the excitement of having the coil work well for once and
for a long time has outweighed the loss of the caps.  I'm going to expand
the under coil box to accomodate four home made rolled caps and am pretty
well through with commercial caps.

BTW, I estimate that I was running at about 500 breaks/sec (6 electrodes
turning at about 5000rpm, and somewhere between 10,500 and 11,500 volts,
based on the variac settings.  (Didn't get to check on the voltage meter
because of the excitement. :-)

Chip
+AD0--+AD0--+AD0--+AD0--+AD0--+AD0--+AD0--+AD0--+AD0--+AD0--+AD0--+AD0--+AD0
--+AD0--+AD0--+AD0--+AD0--+AD0--+AD0--+AD0--+AD0--+AD0--+AD0--+AD0--+AD0--+A
D0--+AD0--+AD0--+AD0--+AD0--+AD0--+AD0--+AD0--+AD0--+AD0--+AD0--
Chip Atkinson 
http://www.pupman-dot-com 
--- If I can't fix it, I can fix it so it can't be fixed --
+AD0--+AD0--+AD0--+AD0--+AD0--+AD0--+AD0--+AD0--+AD0--+AD0--+AD0--+AD0--+AD0
--+AD0--+AD0--+AD0--+AD0--+AD0--+AD0--+AD0--+AD0--+AD0--+AD0--+AD0--+AD0--+A
D0--+AD0--+AD0--+AD0--+AD0--+AD0--+AD0--+AD0--+AD0--+AD0--+AD0--