Re: Blown Cap

Malcolm wrote:
> Hi David and others,
>                      You asked...
> > Obvously the way to use homemade rolled caps is to build four and
> > wire two in series and parrallel them for double the voltage rating.
> > But at around $80 US per cap it is probibly wiser to just buy a
> > commercial cap. Has anybody had any problems with the Condencer
> > Products caps at 15KV?
> Unfortunately, one of mine suddenly lost about 4nF during a run with
> a particularly nice secondary on Saturday night. The sudden detune
> caused the secondary to smoke at the base. On the surface it looks as
> though one of the internal units has gone open circuit. I'll be
> double-checking this tonight but there is little doubt. I replaced it
> with my second unit and things were away again. I checked it with a
> known inductance (8mH) to determine what it was. Bizarre in a way. I
> wouldn't expect caps made for this kind of service to go open circuit
> (or short for that matter, although that is how I would expect one
> to fail).
>     This seems to be an isolated incident at this stage. I was using
> it with a 12kV 60mA neon and the total gap length (two series gaps)
> was 1/4" max.
> Malcolm

Hello Malcolm,
Just quick question: what were the ratings of the 'Condencer Products' Cap that you 
think has had the internal short? I'll be opperating in the 15KV region and just need to 
know what specs I need to shoot for? Thanks.

David Trimmell <dwt-at-efn-dot-org>