Transcript Electric generator

Electric generator
• An electrical generator is a
device that converts
mechanical energy to electrical
energy, generally using
electromagnetic induction.
•
The source of mechanical
energy may be a reciprocating
or turbine steam engine, water
falling through a turbine or a
waterwheel, a wind turbine, a
hand crank, or any other
source of mechanical energy.
How Does a Generator Work ?
• You already know a small electrical
motor. When you switch the motor
on it starts running. This happens
with many different home
appliances such as an electrical
whisk, an electrical train or a fan.
However, a motor can also be used
as a generator.
Fasten the motor and put the pulley
on the shaft.
Connect the two poles to a light
bulb and see what happens when
you turn the shaft.
Use a piece of string to make it
easier to turn the wheel.
WIND ENERGY
Main Shaft
• The rotor is bolted to a very
strong disc on the main
shaft of the wind turbine.
• It is important that the rotor
is firmly secured by a lot of
bolts.
The gearbox is placed at the
other end of the main shaft.
Gearbox
There is a gearbox inside the
nacelle.
There are a lot of gear wheels in
the gearbox. The wheels latch into
each other.
The rotor turns with a speed of
about 22 revolutions per minute.
This means that the rotor takes 22
complete revolutions every
minute.
• The main shaft revolves
slowly and sends a lot of
turning force into the gearbox.
The gearbox then changes the
turning force, so instead of
revolving slowly with a lot of
force in every revolution, it
now has to go faster with less
force in every revolution.
Generator
• A generator makes electricity.
There are some magnets and a
lot of copper wire inside the
generator.
The generator produces
electricity when it is running.
• If you have got a dynamo lamp on
your bicycle, you already know a
generator.
The dynamo generates electricity for
the lamps on your bicycle, when the
wheel of the bicycle makes the wheel
of the dynamo turn.
A generator also generates electricity
in a car.
See a photo of a real generator
• http://www.windpower.org/en/kids/choose/
nacelle/index.htm
Hydroelectric energy
Hydroelectric energy is Sun energy
1. The potential energy of the water will be use for electric
production.
2. When the falls on the turbine, the weight and motion makes the
turbine and the generator rotate. Potential energy transform to
kinetic energy.
3. The generator produces electricity with the frequency of 50 Hz.
4. The outflow tunnel leads the water back to the river.
5. From the generator to a transformer there it will step up to a
high voltage.
Hydroelectric dam
• A - reservoir, B - powerhouse, C - turbine, D - generator,
E - intake, F - penstock, G - long distance power lines, H
- river
Nuclear energy
Fission
Reactor