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Re: Which oils..Capacitor oils




From: 	Bert Hickman[SMTP:bert.hickman-at-aquila-dot-com]
Reply To: 	bert.hickman-at-aquila-dot-com
Sent: 	Friday, November 28, 1997 10:29 PM
To: 	Tesla List
Subject: 	Re: Which oils..Capacitor oils

Tesla List wrote:
> 
> From:   Alfred A. Skrocki[SMTP:alfred.skrocki-at-cybernetworking-dot-com]
> Sent:   Thursday, November 27, 1997 10:42 AM
> To:     Tesla List
> Subject:        Re: Which oils..Capacitor oils
> 
> On Thursday, November 27, 1997 2:07 AM Bert Hickman
> [SMTP:bert.hickman-at-aquila-dot-com] wrote;
> 
> > Matt,
> >
> > Preferably go with either the Shell or Mobil Transformer Oils, since
> > they have undergone refining steps which make them better suited for
> > high voltage applications. For use a cap oil, an oxidation inhibitor is
> > not necessary or desirable - use the uninhibited variety.
> 
> I have always found it interesting that the so-called transformer oils all
> have poorer dielectric charasteristics than USP mineral oil!
> 
> > Now, while the oil companies won't recommend, or guarantee, that their USP
> > (or equivalent) grade of mineral oil will work as a dielectric oil, in
> > reality, it will. However, it MAY not be as "dry" as transformer oil,
> > and thus may not have a high a breakdown voltage.
> 
> My experience has been that USP mineral oil always has a higher dielectric
> strength than any transformer oils! If your concerned about water in the
> mineral oil use a simple procedure that's used all the time in organic
> chemistry labs, add some sodium sulfite anhydrous to the mineral oil and
> stir it in well then let it set a couple of days so the hydrated sodium
> sulfite can settle to the bottom then decant off the clear oil leaving
> behind a small amount of oil with the hydrated sodium sulfite.
> 
> 
>                                Sincerely
> 
>                                 \\\|///
>                               \\  ~ ~  //
>                                (  -at- -at-  )
>                         -----o00o-(_)-o00o-----
>                            Alfred A. Skrocki
>                    Alfred.Skrocki-at-CyberNetworking-dot-com
>                              .ooo0   0ooo.
>                         -----(   )---(   )-----
>                               \ (     ) /
>                                \_)   (_/
> 

Alfred and all,

I did a bit more checking. Alfred is indeed correct - dry water white
mineral oil DOES have greater dielectric strength than standard mineral
transformer oil - as much as 20-25% better! However, BOTH are excellent
dielectric fluids, capable of withstanding over 150 KV/cm (380
volts/mil) of dielectric stress even with a small amount of dissolved
water. Use whichever you can get for the least amount of money.  

-- Bert --