The article in the 'Rho Sigma' book is somewhat ambiguous as to the
arrangement of voltage and mica disk. The suggestion is that the disk is
balanced on a point at its centre so that it may rotate freely. Exactly how
the HV DC is applied to the disk is unclear, it is possible that the static
voltage electrodes are placed near the edge of the disk, perhaps 180 deg
from one another. Whatever the arrangement the disk is supposedly free to
fly off its support, so one would imagine that an electrode is not placed
above the disk. With electrodes at either side of the disk I could imagine
that rotation might be effected by ionizing discharge between the
electrodes 'blowing' across the mica to create a reaction force. This would
be similar to blowing air across the flat disk causing it to rotate.
This does not explain why and how the disk 'flies off' its support, though.
If anyone can locate further reference to this device/experiment, yet
another little mystery in life might be resolved. Short of that it would
make for an interesting and simple experiment. Rotation of the disk is not
unexpected, but ecceleration of the disk vertically up and away from the
electrodes (against gravity) begs an answer. Is it due to electromagnetic
forces or is it due to air pressure gradients created around the rotating
charge carrying disk? If an insulated electrostatically charged disk is
rotated does a magnetic field result (charge in motion => magnetic field)?
Questions, questions...
Regards, Bill.
At 11:30 14/12/98 -0800, Jerry Wayne Decker wrote:
>Hi Bill!
>
>Thanks for posting that anecdote. It appears to be a purely
>electrostatic motor unless I am misreading it. It compares the
>magnetic propulsion of the iron disk in the presence of a rotating
>electromagnetic field to the mica disc, a dielectric, in the presence
>of a high voltage DC field.