Re: Why do my caps keep blowing?

At 19:04 26/01/99 -0700, Jeff Corr wrote:

>>I am making them from 1mm thick poly (10layers of 100um)
>First off thats only 10 layers of 1mil thick poly, or 10 mils.  Each mil
>is good for around 300 volts, so your capacitors are only rated at
>3000 volts.  Thats why they die.

Hang-on chaps !  We have metric/imperial confusion ......

1mm = approx 40 mil

Now at 300V/mil we then get 12kV, but using 10 layers I would have thought
you would get a little more

I use total 1.5mm or 60 mil in 6 layers.  60 mil is the absolute MINIMUM
recommended in most of the archive stuff I have read, however my caps have
survived no problems at 15 kV.

Don't know why you are getting failures.

1.  Where did you get the PE from?  Is it really PE, or is it some other
plastic?  How pure & what quality?

2.  Do you use safety gaps for the caps?  how wide is your gap set?

As original post stated holes in middle, I assume it is not an edge
clearance problem.



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