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Re: Secondary Core[ esoteric materials]
>>> <Tesla-at-pupman-dot-com> 04/17/00 07:41PM >>>
Original Poster: "Charles Arruda" <carruda-at-channelseek-dot-com>
>Has anyone tried
>"unique" materials to wrap their coil on? What effect does
>having an outside covering on the coil (several layers of an
>insulative plastic? Does it help with shorting or corona?
Charles,
I have built a couples secondaries out of
UHMW-PE-POLYETHYLENE-POLYETHYLENE-POLYETHYLENE (a robust form of HDPE)
mainly because of availability (ie free) the biggest advantage of using is
zero H2O absorption and the high dielectric strength (2300v/mil) coupled
with a low dissipation factor of .0002 at 1khz
however I have pondered going to some esoteric materials.....such as a tube of
G-7 glass fabric/silicone binder--- this stuff is it! .003 dissipation
factor and 4.2 dielectric constant at 1Mhz +450*f operating
temp,flame&arc resistance.......
6"OD x 1/8w runs about $70-80/ft..........
after winding I would cover with a Fluorinated Ethylene Propylene (a type
of Teflon) shrink
tube roll cover (.02-.03 thk)after recovery dielectric strength of 500v/mil
dissipation factor
of .00005 at 1khz (!!)
yikes! expensive!!(and most likely enhanced performance will be negligible)
another high end material is cross linked polystyrene-sold under the
rexolite trade name
(also called Q200.5 years ago)
.0001-.0006 dissipation factor from 1Mhz to 10GHz dielectric constant 2.5
thru to 500GHz
low H2O absorption... the works.... cost unknown but I can guess.
ref:www.acculam-dot-com
www.rexolite-dot-com
www.portplastics-dot-com
www.interstateplastics-dot-com
regards
Robert