Presentation on theme: "Electric generator An electrical generator is a device that converts mechanical energy to electrical energy, generally using electromagnetic induction."— Presentation transcript:
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.
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