Re: oil for caps
Sent: Friday, January 02, 1998 12:26 PM
To: Tesla List
Subject: Re: oil for caps
>> If the primary dielectric material of the cap is polyethylene with a K of 2.0
>> to 2.3, using a high dielectric constant oil will not raise it. The cap will
>> measure the same - or very close, with either type of oil.
I used the formual C = [(.224 x K x A) / d] x 2
C = pf
d = distance between plates in inches
A = area of one plate in sq. inches
K = 2.3
Plates are 10" x 108 inches with 18 layers of .006 mil poly filled with HV oil.
I don't remember K for polyethylene. I designed my capacitor to be .01 uf
not figuring the oil would make any difference in K.
After the capacitor was finished I used a capacitor tester to check it. It
checks out to be .0103 uf. I did not test it without oil.
I worked the formula backwards with C = .0103 and found K to be 2.3
I have build 7 capacators and used K = 2.3 for each. When I tested each
finished capacator each one was right.
.0015 uf tested .00146 uf
.005 uf tested .00501 uf
.01 uf tested .0103 uf