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PrimerThe generation of electricity is based upon principles espoused and experiments performed by Michael Faraday (1791 1867) which can be stated as follows; an electromotive force (EMF) is induced in a conductor (copper for example) whenever it cuts through magnetic lines of force. In this regard large electrical generators having field windings which surround a rotor or armature having windings. Rotation of the rotor within the field produces an electric current. All substantial forms of alternating current of the type used in homes and businesses are generated by application of this principle. There are three primary systems in existence today that are used for rotating armatures and commercially generating electricity. These primary systems comprise: (1) Water Dams Hydroelectric.
(2) Coal,
Oil or Natural Gases.
(3) Nuclear Fission
In a basic hydroelectric system, energy from stored water, which is confined in a large reservoir is channeled through a control gate that adjusts the flow rate. The flowing water passes through blades and control vanes of a reaction type turbine, which turns a shaft, which in turn is connected to a rotor inside a generator housing. Rotation of the armature then causes electrical energy to be generated (Click here) In a fossil fuel system, the fossil fuel is burned and the heat from the combustion process is concentrated around a boiler where circulating water is converted into steam. The high pressure steam is used to rotate a turbine which is connected to a shaft. This shaft is connected directly to rotor inside an electric generator and provides the necessary mechanical energy to rotate the rotor (or field).(Click here)
Nuclear fission power systems contain nuclear reactors which "burn" nuclear material whose atoms are split, causing the release of heat. The heat from the fission process is used to change circulating water into steam. The cartoon (Click here) illustrates the overall concept. First falling water causes a turbine to rotate, that is connected to a shaft that rotates, which in turn is connected to a wire loop inside a magnetic field which produces current that generates electricity to light the bulb. In a real utility plant the wire loop is referred to as a rotor or armature. |
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It important to note
that it is necessary to rotate something inside a magnetic field to generate
current. To illustrate this principle, Faraday built a
machine (Click here) that consisted of a 12 inch copper plate between the
poles of a magnet. When the disk was rotated through the magnetic field
an electric current was generated and fed through the connecting wire. Another generator was devised by Hippalyte Pixii, a French instrument maker (Click here) A magnet was set
on end like a U beneath two coils of wire. A shaft connected to
the magnet to geared wheels and to a hand crank which spun the magnet on its
axis.
The disk in Faraday's
machine and horseshoe in Pixii's machine have been replaced by a rotor
or armature in today's generators and it is the rotation of this rotor
or armature that generates electricity (in some cases the field rotates
around the rotor or armature) and analogous to Faraday's machine and
Pixxi's machine it is the
THRUST concept that uses air breathing engines to rotate the rotor or
armature.
Notice the "hand crank" in both Faradayâs machine and Pixiiâs machine that were used to rotate the magnets. The individual most recognized for the promotion of Alternating Current is NikolaTesla (Click Here) For photos of Tesla (Click Here)
In 1888, Sir Charles A Parsons developed
the first a.c. generator. Although slow speed generators had been built
for some time previously, it was not long before the high-speed generator
made its impact. Development continued until in 1922 at which increased use
of solid forging and improved techniques permitted an increase in generator
rating to 20 MW and 60 MW. Also 3000 rev/minute units were constructed during
the years immediately following the war. The changes in design at this period
were relatively small.
To see a rare photo of a rotor being installed in a water dam (Click here). Rotation is the key to generating
alternating current.
A conventional or traditional steam plant compared to the THRUST concept can be seen for comparison purposes. |
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