12. Today teacher taught in the class that the rotational speed of the wind mill is used to rotate the turbine of the power generator to generate electricity. What should be the minimum speed of wind to maintain the turbine's required speed? a. Less than 15 km/h b. More than 15 km/h c. Less than 10 km/h d. Less than 5 Km/h
Answers
Answer:
WHAT IS A WIND TURBINE?
The concept of harnessing wind energy to generate mechanical power goes back for millennia. As early as 5000 B.C., Egyptians used wind energy to propel boats along the Nile River. American colonists relied on windmills to grind grain, pump water and cut wood at sawmills. Today’s wind turbines are the windmill’s modern equivalent -- converting the kinetic energy in wind into clean, renewable electricity.
HOW DOES A WIND TURBINE WORK?
The majority of wind turbines consist of three blades mounted to a tower made from tubular steel. There are less common varieties with two blades, or with concrete or steel lattice towers. At 100 feet or more above the ground, the tower allows the turbine to take advantage of faster wind speeds found at higher altitudes.
Turbines catch the wind's energy with their propeller-like blades, which act much like an airplane wing. When the wind blows, a pocket of low-pressure air forms on one side of the blade. The low-pressure air pocket then pulls the blade toward it, causing the rotor to turn. This is called lift. The force of the lift is much stronger than the wind's force against the front side of the blade, which is called drag. The combination of lift and drag causes the rotor to spin like a propeller.
A series of gears increase the rotation of the rotor from about 18 revolutions a minute to roughly 1,800 revolutions per minute -- a speed that allows the turbine’s generator to produce AC electricity.
A streamlined enclosure called a nacelle houses key turbine components -- usually including the gears, rotor and generator -- are found within a housing called the nacelle. Sitting atop the turbine tower, some nacelles are large enough for a helicopter to land on.
Another key component is the turbine’s controller, that keeps the rotor speeds from exceeding 55 mph to avoid damage by high winds. An anemometer continuously measures wind speed and transmits the data to the controller. A brake, also housed in the nacelle, stops the rotor mechanically, electrically or hydraulically in emergencies. Explore the interactive graphic above to learn more about the mechanics of wind turbines.
TYPES OF WIND TURBINES
Answer:
WHAT IS A WIND TURBINE?
The concept of harnessing wind energy to generate mechanical power goes back for millennia. As early as 5000 B.C., Egyptians used wind energy to propel boats along the Nile River. American colonists relied on windmills to grind grain, pump water and cut wood at sawmills. Today’s wind turbines are the windmill’s modern equivalent -- converting the kinetic energy in wind into clean, renewable electricity.
HOW DOES A WIND TURBINE WORK?
The majority of wind turbines consist of three blades mounted to a tower made from tubular steel. There are less common varieties with two blades, or with concrete or steel lattice towers. At 100 feet or more above the ground, the tower allows the turbine to take advantage of faster wind speeds found at higher altitudes.
Explanation:
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