Download Felici`s generator

Principles of operation
Electrostatic generators of the «insuling carrier» type convert mechanical energy directly into
d.c. high voltage electrical energy by utilizing the charge (ion ) transfer effect in an electric field.
An electric charge placed in a field is subjected to a force. If the charge is mechanically
displaced in a direction opposite to this force, the potential of the charge will increase and the
mechanical work done will be converted into electrical energy. This energy conversion serves as
the basis of operation of all electrostatic generators.
The Felici's generator unit is comprised of three main parts :
Rotor : a hollow cylinder made of insulating material. Electric charges are deposited on the
surface of the rotor which is generally driven by an electric motor to effect the transfer of
charges in the field. This is the only moving part in the generator.
Ionizers : extremely thin metallic blades placed in dose proximity to the rotor. The charging
ionizers generate and deposit the electric charges while the discharging ionizers draw off the
charges that have been carried on the surface of the rotor.
Inductors : the purpose of the inductors is to induce a strong electric field on the sharp edge of
the ionizers. Excitation inductors hold the electric charges on the rotor whereas the extracting
inductors withdraw them. The inductors are, in fact, found « hidden » behind a slightly
conductive cylinder (made of special glass) so that the inductors can fulfill their functions
without creating local concentrations of the electric field.
The rotor passes successively opposite the charging and discharging ionizers where the rotor is
respectively charged and discharged. These operations can take place once or several times per
revolution depending upon the number of poles of the generator. The number of poles
corresponds to the number of ionizers- or the number of inductors on the other side - around the
rotor. Thus, the rotor of a two-pole generator is charged and discharged once per revolution; the
rotor of a 2n-pole generator n times per revolution.
ln the operation of electrostatic generator, an auxiliary «excitation generator» is used to apply a
sufficient potential difference between inductors and charging ionizers in order that a strong
electric field appear on the edge of the ionizer to create local ionization.
The excitation voltage of the generator unit - in order of 20 to 30 kV - is furnished by a small
auxiliary generator of very low power that provides pr
actically no current. This auxiliary generator, usually of a standard rectifier type, excites the
electrostatic generator either directly or through the intermediary of an another small auxiliary
electrostatic generator serving as an amplifier.
It is interesting to note that the mechanism of deposition and extraction of the ionic charges,
known as commutation, functions without any material contact. The cylindrical rotor, the only
moving part, rotates between the ionizers and the low-conductivity cylinder covering the
inductors, all being very close to each other - some few thousands of an inch.
Under the influence of the excitation inductors, some electric charges ( ions) arc deposited on the
rotor by the charging ionizers and will thus be driven by the rotor in a tangential electric field.
While the potential of the charges is increasing during the transfer, mechanical work is being
converted into electrical energy.
The charges, after traversing a distance equivalent to one «pole pitch», will be removed from the
rotor by the discharging ionizers in order to supply the load circuit.
An efficient structure is formed of a highly insulating cylindrical rotor running around a slightly
conductive (soft glass, 1012 ohm cm) cylindrical stator, the gap being 0.01/0.02 in.
The insulating gas is 0.9999 pure hydrogen, free from chlorinated compounds, at 10-25 atm. The
linear speed v of the rotor is 10-50 m/s. Commutation is performed by 0 - 0012 in. steel blades,
facing metallic inductors which are in good electrical contact with the glass cylinder.
Various unit, have been developed in the range of 30-3000 W, voltage 50-600 kV.
Several units can be easily associated in series as well as in parallel.
Efficiency is 0.85-0.95.
For electronic control of such generators is very easy, with high voltage low-power triodes.
Standard units have voltage stability 1 per cent and regulation 1 per cent over the whole current
range; "stabilized" units exhibit an overall voltage fluctuation less than 1 part in 105 .
Electrical hazard is absolutely negligible, unless a strong capacitor is connected to the terminals.