Re: Cap break down voltages

        Re: Cap break down voltages
        Thu, 3 Apr 1997 18:44:22 -0500 (EST)
        richard hull <rhull-at-richmond.infi-dot-net>
        Tesla List <tesla-at-pupman-dot-com>

At 11:21 AM 4/3/97 -0600, you wrote:
>           Cap break down voltages
>      Date: 
>           Thu, 03 Apr 1997 15:02:20 -0500
>      From: 
>           Julian Green <julian-at-glosilk.demon.co.uk>
>        To: 
>           tesla-at-pupman-dot-com
>           1
>I am about to start capacitor building again and want to know a good
>working voltage to choose.   I currently have
>3 home made poly/foil caps 0.03uF -at-10KV.   These caps have
>40mils of good quality poly between the plates.
>Some time ago I remember Richard Hull posting about chemical breakdown
>of the dielectric where voltages exceed 10KV.   
>If this is the case then I see little point adding to the thickness of
>the poly for a higher voltage rating.   I will simply build more of my
>0.03uF 10KV caps and wire them in series.

>Julian Green

This latter idea is best, Julian.  At 10KV RMS input to a coil, over
peak might easily appear across working caps.  Even in oil, a small RF
corona can appear at this level and the oil is slowly worked chemically
until it fails in the long run.  I set the limit for single unit
caps at an arbitrary 10KV RMS applied.  I try to never exceed 8KV on
homemade caps.  R. Hull