The Turn Of The Century Electrotherapy Museum

Protocakes:  9" Pancake Coils for
Studying Stratia, Electrical Discharges,
and Phantom Streamers

Construction Photos:

The coils were first wound and impregnated in a soft wax insulation.  This wax has the advantage of good insulating
properties, and when cooled does not distort like many other waxes.  The soft nature of the wax prevents it from fracturing
under stress or environmental changes.

The centre post of the coil is made from CPVC.  It is turned on a lathe at 1000 RPM.
First, the end is beveled to remove sharp edges...

Next, a 3/4" diameter hole is bored out for insertion of the post...

Last, a hole is drilled in the side to accept the inner-most wire of the Secondary Coil.

Upright posts are also turned on the lathe out of PVC pipe.  A brass knob is used to make  the discharge terminal.

The coil socket is cast in a mixture of hard paraffin wax, which will surround and protect the inner coil.

The finished coil has a uniform textured pattern on top of the coil to increase the surface area,
much like fins on an electrical insulator.  Data for each coil is recorded.

Each coil also has a tight-fitting non-reflective black fabric cover.  This not only keeps dust from attracting
to the surface of the coil, but also aids in studying and photographing electrical phenomena by providing a dark background.

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