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Re: New cap



Max,
The dielectric (poly) is soaking in the oil, thus expanding the dielectric
thickness and increasing the distance between plates causing the capacitance
to decrease. Completely normal.
Bart

Tesla List wrote:

> 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