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RE: New cap



Hi, I suspect that the poly has absorbed some oil and swelled-up,
increasing the distance between the plates, can you notice any swelling?
Mathematically I'd expect 50x2x30x(57-55)/57=105 mil (1/10"), you may
not
notice such a small change by eye.
Just a guess ... Sulaiman

> ----------
> From: 	Tesla List[SMTP:tesla-at-pupman-dot-com]
> Sent: 	Tuesday, September 29, 1998 6:33 PM
> To: 	tesla-at-pupman-dot-com
> Subject: 	New cap
> 
> Original Poster: RODERICK MAXWELL <tank-at-magnolia-dot-net> 
> 
> I wonder if anyone could answer this question. I just completed
> construction of a new capacitor. It is a vertical plate type cap. The
> dielectric is made of 30mil poly. There are two sheets between each
> plate with a total of 50 plates 12"x12" in size. The capacitor
> measured
> 53nf dry (without oil). After adding mineral oil (refrigerant oil) the
> capacitance went up to a peak value of 57nf. But after a couple of
> days
> soaking in oil the capacitance has gone down to 55nf! Has anyone
> noticed
> this in any of the caps they have built? The cap has not been run in a
> coil yet I plan to let it soak a couple of weeks before I give a short
> run at low power.
> 
> 
> 
>                                   Frankensteins Helper
>                                          Max
> 
>