Re: Maxwell cap filler plugs & oil

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Edward Wingate by way of Terry Fritz <twftesla-at-uswest-dot-net>" <ewing7-at-rochester.rr-dot-com>

Tesla list wrote:
> 
> Original poster: "Lau, Gary by way of Terry Fritz <twftesla-at-uswest-dot-net>"
<Gary.Lau-at-compaq-dot-com>
> 
> I've been meaning to ask this.  I found several Maxwell caps at a flea
> market  last year.  One of them is silent when shaken and I've been
> using this with great results.  The others all "slosh" when shaken.
> I've not yet used them and they appear to be unused.  They all have a
> plastic screw that can be removed, presumably to fill or drain the oil.
> Is it castor oil that is used in these?  Where can this be found?
> Anything else I should know about topping them off?
> 
> Thanks, Gary Lau
> MA, USA
> 
> >When purchasing Maxwells, (I have 3), you never know their prior
> >history, ergo you never know their remaining life expectancy. It is
> finite.
> >Some have a plastic screw as a "filler plug"  these occasionally
> >leak during shipping or they leaked before shipping and weren't topped
> up.
> 

Gary,

Most of the (considerable) number of Maxwells that I have obtained will
"slosh" when shaken. The airspace is there to allow for expansion of the
oil when the capacitor heats up when subjected to continuous use,
something which doesn't happen in Tesla service (normally). I would
definately check the silent one to be sure that it is silent because it
is full of oil, not empty!

I wouldn't worry about some "slosh" from airspace. I have torn several
Maxwell pulse caps apart and the internal construction is such that each
of the separate "packs" is individually wrapped with a 1/8" thick layer
of very porous cardboard that "wicks" up the oil inside the capacitor
into the "packs" so that they could never really run dry unless most of
the oil had leaked out. Maxwell builds capacitors right and when you
look inside one, you can understand why they cost as much as they do.

If it makes you feel better to top them off, by all means, do so. Any of
the ones that I have had were filled with mineral oil/capacitor
dielectric oil and to top off I used oil drained from other dissasembled
capacitors. Mineral oil should work just fine though.

I have bought and sold 50 or 60 USED Maxwell pulse caps over the last 5
years or so and I am not aware of even one of them blowing up and I know
for a fact that Bill Emery and Bert Pool of the TCBOT have punished some
of them unmercifully!

Ed Wingate RATCB