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Re: The manufacture of capacitors
>6) P.S. I also found out ( after weeks of research) that "electrical grade"
> Castor oil might actually be the ideal dielectric as it has twice the
>dielectric constant of the other oils, a breakdown voltage 850v/mil and the
>dissipation factor actually *falls* as operating frequency increases! I
>would be very interested, perhaps, in working with someone in designing such
>a cap. Any takers?
>
>-DavidF-
Just a FYI, esso sells an oil called VOLTESSO 35 which is an electrical
insulating oil. Here's the product data sheet they gave me. It costs
1.48/L ($Can), minimum 20L pail.
I'm planning on using this stuff in a rolled poly cap, but
it might be good for a oil only cap too.
A physics textbook suggests the dielectric constant of transformer
oil is 4.5. I'm not familar with relative permittivity, but at a guess it's
the same as dielectric constant ? In either case, it's the same or
better than poly. I'm guessing that the dielectric strength is 35KV/mm
which is about 900V/Mil. (wasen't sure of the units for that standard)
besides all that, it's "the only electrical insulating oil
currently manufactured in Canada." :)
This stuff isen't that expensive, (lot's cheaper per volume than poly) and
you gotta buy 20L anyway so mabey it would be better to overengineer the
voltage rating to avoid the poping&carbon Richard mentioned.
some quick calculations, if the D.constant is about the same as poly,
you'd need about 4-5L for the dielectric & about 2m^2 of steel. Mabey
use nylon spacers scattered around the plate ?
Chris
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VOLTESSO 35 Typical Propartles
General
Colour, ASTM
Density -at- 15*, kg/m3
Pour Point, UC
Specific Heat kJ/kg, *C
Thermal Conductivity, W/m.*C
Ineedacial Tension, mN/m
Air Solubility. % by vol -at- 15.6*C
Viscosity
Centistokes -at- 100*C
-at- 40*C
-at- O*C
-at- -30*C
-at- -40*C
-at- -45*C
Water Saturation Levels
ppm -at- 0C 16
10C 27
15C 35
20C 45
25C 56
Gassing Tendency
u L/min. ASTM D2300 A or B Negative
Oxidation Stability
ASTM D2440 Test 164 hrs. -at- 110C
Sludge wt. % 0.20
Neutralization No. (mg KOH/g) 0.50
24 hrs. -at- 110C
Visible Sludge Nil
Neutralization No. (mg KOH/g) 0.05
Intefacial Tension, mN/m 35
Electrical Properties
Dielectric Strength D877 KV 35(min)
Relative Permittivity 2.2
Power Factor % -at- 100C, 60 Hz 0.50(max)
Volatility
Flash Point, C, COC 150
Fire Point, C, COC 177
Distillation, C
10% 278
20% 297
50% 336
90% 390
95% 404
Vapour Pressure
-at- 40C - microns 3
100C - microns 350
150C - mm 5
200C - mm 45
Comspoahion
Water Content ppm (max.) 25
Inorganic Chlorides & Sulphates Nil
Aniline Point, C 81
Sulphur, wt. % 0.15
Total Acid No. Nil
Copper Corrosion 5 hrs. -at- 100C 1
Silica Gel Analysis
Aromatics nnd Polars, % 22
Saturates, % 78
Aromatic Carbon % 12
(by infrared spectroscopy)
Impulse Strength
ASTM D3300 KV 150(min.)
(If there's something wierd here, it's probably been messed up by OCR and
I missed it)
+--------------------------------------------------------+
|Chris Cudahy | B.SC. CS/Math - getting there|
|ccudahy-at-calumet.yorku.ca | Swim Bike Run Colapse |
|http://www-home.calumet.yorku.ca/ccudahy/www/home.htm |
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