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Re: Cap Failure

I shipped back the pieces of the failed Condenser Products cap today, after 
shooting some film of the same.  The pictures will be back from the processor
tomorrow, so I'll try to get them posted on my WWW site later in the day.
Those interested should check the following URL around or after 4:00 PM CDT.

	http://homepage.interaccess-dot-com/~dfroula/tesla/tesla.html

After reading a few suggestions that carbon tracking through the PVC wall 
might be the cause, I performed a careful examination of the tube before
shooting the photos.  I saw no evidence of through the wall or internal
carbonization.

The cap could probably be salvaged, but I doubt Condenser Products will return
the damaged pieces if they end up replacing the cap.  The engineer I spoke to
stated that the operating conditions under which the cap failed were far below
the design limits of the device.  He was very eager to have a look, as none
of the earlier cap failures had been returned for examination. After
mucking with the smelly, burned transformer oil-soaked pieces for an hour or
so, I think I can understand why!

Hopefully, we'll get a definitive reason for the failures.

Don


> 
> >From bert.hickman-at-aquila-dot-comTue Oct 15 22:07:56 1996
> Date: Mon, 14 Oct 1996 23:58:08 -0700
> From: Bert Hickman <bert.hickman-at-aquila-dot-com>
> To: tesla-at-pupman-dot-com
> Subject: Re: Cap Failure
> 
> Tesla List wrote:
> > 
> > >From MALCOLM-at-directorate.wnp.ac.nzMon Oct 14 21:29:04 1996
> > Date: Tue, 15 Oct 1996 09:00:46 +1200
> > From: Malcolm Watts <MALCOLM-at-directorate.wnp.ac.nz>
> > To: tesla-at-pupman-dot-com
> > Subject: Re: Cap Failure
> > 
> > Hello all,
> >            I take it from this post there has been another CP cap
> > failure....
> > 
> > > >During the next run, power was adjusted to about 80% (about 112
> > > >volts) on the 15 KV 120 MA neon tansformer source, with good coil
> > > >output, when after about 20 seconds one end of the capacitor was
> > > >suddenly and explosively blown off with no prior warning. A loud "pop"
> > > >and a yellowish colored flash were heard and seen, and capacitor oil
> > > >was ejected in the immediate area.
> > 
> > and that the failure is caused by carbon tracking inside the case?
> > Would somebody please fill me in on the details.
> > 
> > Thanks,
> > Malcolm
> > <Major snip>
> 
> Malcolm,
> 
> Welcome Back!
> 
> Probably not carbon tracking _thru_ the case in the latest failure,
> since the cap was resting on a thick HDPE sheet. In Richard Wall's case,
> thru-wall carbon tracking may have been a contributing factor.  I've
> asked him if he had the cap resting on a conductive surface while
> operating the coil. 
> 
> In the latest failure, no obvious cause was apparent, but clearly
> something caused significant pressure rise in the cap. Closer
> examination will be done, and the capacitor will hopefully be
> salvageable.
> 
> -- Bert --
>