[Prev][Next][Index][Thread]

Re: A new cap failure mode?



to: Terry, Mike, et al

The setting of the primary spark gap controls the potential to which the HV
capacitor is charged.  Safety gaps and resistors are not at all necessary
if your capacitor is of good design and your primary gap setting is not
excessive.  One area many cap constructors get into serious problems is
that they handle the foils and dielectric materials with their bare hands
and deposit their hand oils (with conductive sodium chloride).  If not
removed before assembly these oils lead to "tracking" along the edges of
the dielectric and foils which is the major cause of breakdown in in high
voltage RF caps.  

With a proper design for the cap and care in assembly these extra measures
are not necessary.  If you are not sure of your cap then just keep your
primary gap small -- it will control the potential the cap can charge to. 
Additional gaps and resistors are not necessary.

Regards,

Dr.Resonance-at-next-wave-dot-net


----------
> From: Tesla List <tesla-at-pupman-dot-com>
> To: tesla-at-pupman-dot-com
> Subject: Re: A new cap failure mode?
> Date: Friday, February 05, 1999 9:38 PM
> 
> Original Poster: Hollmike-at-aol-dot-com 
> 
> In a message dated 2/5/99 6:26:21 AM Mountain Standard Time,
tesla-at-pupman-dot-com
> writes:
> 
> > The suggestion comes up that perhaps a safety gap placed directly
across a
> >  primary cap needs a little resistance in the circuit to keep this
current
> >  to a "safe" level.  
> >  
> >  Comments or suggestions are welcome...
> >  
> >  	Terry
> >  
> Terry,
>    Would a transorb (or MOV) work for this?
> Mike
>