Re: Finally a Field Mill!

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Dr. Resonance by way of Terry Fritz <teslalist-at-qwest-dot-net>" <resonance-at-jvlnet-dot-com>


They work great.  We've used our field mill meter with 18 inch dia. rotor
and a 18800 rpm synchro motor to check voltages.  It also works great on low
clouds.

You need a reliable calibration field, ie, around 200 kV DC (peak) to set
your initial calibration.

Dr. Resonance

Resonance Research Corporation
E11870 Shadylane Rd.
Baraboo   WI   53913
 >
 > One of the topics that naturally comes up on this list from time to time
is
 > the measurement of electric fields.  A couple of years ago there was a
very
 > interesting thread about using x-ray tubes for voltage measurements of a
 > running Tesla coil (I think Dr. Resonance or someone tried this....in a
 > ditch for shielding!).  One of the devices which naturally comes up in any
 > measurement discussion is the field mill or "generating voltmeter", and
 > these are devices I have always been interested in.  For those unfamiliar
 > with this device, in a nutshell it uses a series of pie-shaped sensor
 > plates that are alternately shielded and exposed by a grounded rotor.  The
 > idea is that as the plates are exposed to an electric field, induction
will
 > charge them to a certain value, current will flow from the plate to an
 > amplifier (on its way to ground), and then as the plate is shielded the
 > current will cease providing an AC signal that is directly proportional to
 > the electric field the unit is exposed to. Most mills also have a second
 > set of vanes that interrupt a beam of light so that the unit can tell the
 > orientation of the rotor and determine a negative or positive field value.