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Re: Vacuum pump for capacitor pumpdown
If you are worried about oil foaming you can let it into a seperate container
slowly as a fine spray with the vacuum pump running. This will allow it to
outgas. This method is used for the oil in underground high voltage lines.
Tony
Tesla List wrote:
> Original Poster: "D.C. Cox" <DR.RESONANCE-at-next-wave-dot-net>
>
> to: Gary
>
> You get a much better vacuum if you have at least one stage with a storage
> tank to pump into rather than pump directly. Both the Bell Jar and the
> "Scientific American Book of Projects for the Amateur Scientist", C.L.
> Stong, circa 1969, provide excellent information in this area. 500-1,000
> microns works ok for a cap pump.
>
> DR.RESONANCE-at-next-wave-dot-net
>
> ----------
> > From: Tesla List <tesla-at-pupman-dot-com>
> > To: tesla-at-pupman-dot-com
> > Subject: Re: Vacuum pump for capacitor pumpdown
> > Date: Saturday, August 29, 1998 1:00 PM
> >
> > Original Poster: "Justin Hennigan" <justinh-at-interlaced-dot-net>
> >
> > If I had time, I'd tell more.
> > But go here, it's the best source of vacuum information you're gonna
> find.
> > http://www.tiac-dot-net/users/shansen/belljar/
> > It's The Bell Jar. enjoy.
> >
> > -----Original Message-----
> > From: Tesla List <tesla-at-pupman-dot-com>
> > To: tesla-at-pupman-dot-com <tesla-at-pupman-dot-com>
> > Date: Friday, August 28, 1998 7:44 PM
> > Subject: Vacuum pump for capacitor pumpdown
> >
> >
> > >Original Poster: Gary Lau 28-Aug-1998 0833 <lau-at-hdecad.ENET.dec-dot-com>
> > >
> > >Hi All:
> > >
> > >I'm slowly progressing with the construction of my new extended foil,
> > >rolled poly caps. The rolling is done, I now just have to complete the
> > >enclosure. My problem is how to draw the vacuum before backfilling with
> > >oil. I have a vacuum pump that I can borrow, a rotary vane unit. The
> > >specs say it should be able to pull a 26" Hg vacuum, although the gauge
> > >only reads 22-23", could be that the fittings just need to be tightened.
> > >
> > >Is there a consensus on what degree of vacuum is required for cap
> pumpdown
> > >prior to oil filling? Also, I've read descriptions of the pumpdown/fill
> > >procedure, describing how the oil will foam or boil as it is introduced.
> > >Could this be minimized by either heating the oil in a pot on a stove,
> or
> > >by storing the oil in an evacuated container for some time, to cause
> > >outgassing prior to use?
> > >
> > >Regards, Gary Lau
> > >Waltham, MA USA
> > >
> > >
> > >
> >