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Form Material Info!!!
Tesla Builders from afar,
I came across this little nuggett of info that was tucked away in the
archives from 94 or 95. I forgot who the original poster was and i am away
from my personal computer. This is also a greatly condensed chart, the
original one contained the dielectric constant at different frequencies, and
the breakdown voltage at differing frequencies and listed a whole bunch of
materials including the RF specs for magnet wire coatings. For the sack of
time i shall include the dissipation factor for a few common materials.
This will put to rest any rumors and settle which plastic is best for Tesla
Coil operation. While one megahert is well above standard coil operation you
can compare it to 50 hertz to get an idea...
Dissipation Factor (x10^-3)
50Hz / 1MHz
LDPE - .15 / .08 <high denstity polyethylene>
HDPE - .24 / .20 <low density polyethylene>
PP - .40 / .50 <polypropylene>
PVC - 80 / 120 (yikes!!!) <polyvinyl chloride>
PS - .1-.4 / .05-.4 <polystyrene>
ABS - 3-8 / 2-15 <I forgot what it stands for>
PC - .70 / 10 <poly carbonate OR lexan)
PU - 120 / 70 <polyurethane>
(linear)
PU - 50 / 50 <polyurethane>
(thermoset)
PU - 30 / 60 <polyurethane>
(thermoplas)
As you can see pvc is about the worst material to use and coating it with
polyurethane doesn't improve matters much at all. however i think that the
magnet wire insulation affects dissipation much more than the secondary form
material. I don't have their numbers with me but they are all very lossy
too. Supposedly teflon coated magnet wire is the best but i do not know the
RF dissipation values for teflon. but i can tell you that if you ever manage
to find any it will be expensive.
Discharge Dan
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