Re: Capacitor check (fwd)

---------- Forwarded message ----------
Date: Tue, 28 Apr 1998 08:46:42 +1200
From: Malcolm Watts <MALCOLM-at-directorate.wnp.ac.nz>
To: Tesla List <tesla-at-pupman-dot-com>
Subject: Re: Capacitor check (fwd)

Hi Sulaiman,

> From:  Sulaiman Abdullah [SMTP:sulabd-at-hotmail-dot-com]
> Sent:  Monday, April 27, 1998 11:23 AM
> To:  tesla-at-pupman-dot-com
> Subject:  Re: Capacitor check (fwd)
> >From: Malcolm Watts <MALCOLM-at-directorate.wnp.ac.nz>
> >To: Tesla List <tesla-at-pupman-dot-com>
> >Subject: Re: Capacitor check (fwd)
> <snip>
> >No plastic overlap at the ends?  Can't say I've ever done that. I 
> >don't think two inches of creepage distance is nearly enough for the 
> >voltages Sulamain is talking about.
> >
> >Malcolm
> >
> AAAAHHH! this is what I want....2" creepage distance is enough
> for how many kV? ..... please?
> Sulaiman

I just did a quick check with a piece of acrylic and 12kV in air. The 
atmosphere is rather damp here but I noted corona tracking at over an 
inch and actual sparks about 2/3".  I would say no more than 18kV or 
so before corona would be a significant problem for 2" in air. In 
oil, 25kV is a guestimate. Something to be measured and a table made 
up for sure. The real problem is a lack of radius of curvature for 
the plate edges. Corona starts at rather low voltages and will deal 
to the plastic long before sparks do.