Download Generation of electricity

The
discovery
of
electricity
Generation of electricity
If a single wire is passed through a <magnetic field>, a small
pulse of electricity is produced. By this method, however, it
is not possible to generate enough electricity to light the tiniest
light bulb.
MAGNET
1
The discovery of electricity fact
sheets reviewed and updated with
the assistance of STAV Publishing
But if a magnet revolves inside a coil of wire, then the energy
of motion is transformed (changed in form) into electrical
energy, and an electric current flows in the wire. Electricity is
generated whether the coil of wire or the magnet is moved
relative to the other. <Michael Faraday> was the first person
to discover this, and develop an elementary method of
generating electricity by means of motion in a magnetic field.
ROTATING
MAGNET
In our power stations, a powerful <electro-magnet> (rotor) is
mounted on a shaft supported between bearings. This rotates
inside a cylindrical iron shell (stator) containing slots through
which the conductors are wound.
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Alternating current
The current produced by this type of generator flows momentarily in
one direction through the conductors and then it reverses and flows in
the opposite direction and the cycle is repeated continuously. This is
called <“alternating current”> (generally shortened to the letters AC).
2
The AC used throughout Victoria flows alternatively in each direction
50 times each second. This frequency gives some idea of the speed
the coil must turn. In technical terms, the unit of frequency is the Hertz
(i.e. 1 Hz = 1 cycle per second).
A current which continuously flows in one direction is called a “direct
current” (DC). For example, the electricity supplied by a battery flows
in one direction. Direct current is used for electroplating processes,
railway and tramway systems and other motor driven applications
where a smooth and wide range of speed control is required.
It is generally more economical to transmit and distribute electricity
in alternating current (AC) form, therefore all electricity generated at
<power stations> is AC.
The exception is for very long transmission lines connecting two
networks together where DC is often preferred, for example
<Basslink>. When DC is to be used, the electricity is converted into
direct current by means of devices called converters or rectifiers and
back into AC by devices called inverters.
STATOR
ROTOR
TURBINE
STEAM FROM BOILER
STEAM TO
CONDENSORS
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3
Why does electricity flow in a circuit?
Electrical current flows from the generators to the point where it is
used, and then it returns to the generator.
Why is a return path to the generator needed? If you pump water into
a pipe and place a secure plug in the other end of the pipe, the water
will cease to flow. Regardless of the amount of pressure you build up,
the water will not flow. However, if we construct a unit with a water
pump forcing a current of water through a closed system of pipes to
run a hydraulic motor we have made a path or circuit for the flow of
water.
A generator is like a pump. It is a machine which creates pressure
(voltage) which makes electrons move or flow in the wire. If a return
path is not available to make a complete circuit such as when a
switch is opened, the flow is stopped. Regardless of the amount
of pressure (or voltage) generated, the electrons cannot flow. In the
case of electricity, the homeowner uses the energy produced by the
movement of electrons, to do work such as running a mixer, cooking
food or heating a room.
HYDRAULIC
MOTOR
Further information
WATER
PUMP
Electricity: general
<http://www.school-for-champions.com/science.htm#Electricity>
Circuits
<http://www.energyquest.ca.gov/story/chapter04.html >
Generation of electrical power
<http://www.eia.doe.gov/cneaf/electricity/page/prim2/chapter3.html>
Alternating current
<http://www.school-for-champions.com/science/ac.htm>
<http://www.school-for-champions.com/science/actransformers.htm>
Generating electrical current
<http://www.school-for-champions.com/science/electgeneration.htm>
Electrical power
<http://www.school-for-champions.com/science/electpower.htm>
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friendly
Generation of electricity
If a single wire is passed through a
<magnetic field>, a small pulse of
electricity is produced. By this method,
however, it is not possible to generate
enough electricity to light the tiniest light
bulb.
But if a magnet revolves inside a coil
of wire, then the energy of motion
is transformed (changed in form)
into electrical energy, and an electric
current flows in the wire. Electricity is
generated whether the coil of wire or
the magnet is moved relative to the
other. <Michael Faraday> was the first
person to discover this, and develop
an elementary method of generating
electricity by means of motion in a
magnetic field.
In our power stations, a powerful
<electro-magnet> (rotor) is mounted on
a shaft supported between bearings.
This rotates inside a cylindrical iron shell
(stator) containing slots through which
the conductors are wound.
Alternating current
The current produced by this type of
generator flows momentarily in one direction
through the conductors and then it reverses
and flows in the opposite direction and the
cycle is repeated continuously. This is called
<“alternating current”> (generally shortened
to the letters AC).
The AC used throughout Victoria flows
alternatively in each direction 50 times each
second. This frequency gives some idea of
the speed the coil must turn. In technical
terms, the unit of frequency is the Hertz (i.e.
1 Hz = 1 cycle per second).
A current which continuously flows in one
direction is called a “direct current” (DC). For
example, the electricity supplied by a battery
flows in one direction. Direct current is used
for electroplating processes, railway and
tramway systems and other motor driven
applications where a smooth and wide
range of speed control is required.
It is generally more economical to transmit
and distribute electricity in alternating
current (AC) form, therefore all electricity
generated at <power stations> is AC.
The exception is for very long transmission
lines connecting two networks together
where DC is often preferred, for example
<Basslink>. When DC is to be used, the
electricity is converted into direct current
by means of devices called converters or
rectifiers and back into AC by devices called
inverters.
Why does electricity flow
in a circuit?
Electrical current flows from the generators
to the point where it is used, and then it
returns to the generator.
Why is a return path to the generator
needed? If you pump water into a pipe
and place a secure plug in the other end
of the pipe, the water will cease to flow.
Regardless of the amount of pressure you
build up, the water will not flow. However,
if we construct a unit with a water pump
forcing a current of water through a closed
system of pipes to run a hydraulic motor we
have made a path or circuit for the flow of
water.
A generator is like a pump. It is a machine
which creates pressure (voltage) which
makes electrons move or flow in the wire.
If a return path is not available to make a
complete circuit such as when a switch is
opened, the flow is stopped. Regardless
of the amount of pressure (or voltage)
generated, the electrons cannot flow. In
the case of electricity, the homeowner uses
the energy produced by the movement of
electrons, to do work such as running a
mixer, cooking food or heating a room.
Further information
Electricity: general
<http://www.school-for-champions.com/
science.htm#Electricity>
Circuits
<http://www.energyquest.ca.gov/story/
chapter04.html >
Generation of electrical power
<http://www.eia.doe.gov/cneaf/electricity/
page/prim2/chapter3.html>
Alternating current
<http://www.school-for-champions.com/
science/ac.htm>
<http://www.school-for-champions.com/
science/actransformers.htm>
Generating electrical current
<http://www.school-for-champions.com/
science/electgeneration.htm>
Electrical power
<http://www.school-for-champions.com/
science/electpower.htm>
The discovery of electricity
fact sheets reviewed and
updated with the assistance
of STAV Publishing