Wind Power

In an era where the use of fossil fuels has been proven to be harmful to the environment (and humans in general) alternative sources of energy and electricity are sought. One of the obvious sources is the wind to produce wind power.
Wind power means using the wind - harnessed by either a turbine, wind mill, wind pump or even sails (for ships) - to generate the desired amount of electricity to be used for home and commercial purposes. This provides an efficient power alternative that is clean, abundant and completely environmentally friendly.
Many countries have embarked on wind power ventures and have shown remarkable successes in generating power for their citizens. The drive now is to convince more people (and governments) to convert to wind power to meet their energy needs and demands. Once this has been achieved it is estimated that even more power can be generated than is currently being done making use of fossil fuels.

What is Wind Power?

Wind power means that the wind is harnessed in one of a variety of ways to generate power or energy/electricity. This means that a natural resource is used to produce clean, environmentally friendly power. The most common ways of harnessing the power of the wind is using sails to propel ships and sail boats across the water. The most desirable way of using the wind to generate electricity is by erecting wind turbines.

Types of Wind Turbines

In order to understand how wind turbines work and how they manage to produce the amounts of energy that they do, one must understand the types of turbines that are currently in use.
There are two categories of wind turbines: the horizontal axis design (HAWT) and the vertical axis design (VAWT). These are based on the Darrieus egg-beater model. Since it is the more practical and popular, the HAWT enjoys more attention than its sibling, the VAWT.
The HAWT has its main rotorshaft at the top of the column along with the electrical generator. The turbines must be pointed into the wind and is positioned favourably by either a small weathervane or a wind sensor.
The rotor shaft and gearbox of the VAWT are positioned vertically and are also installed near the ground. This makes it more accessible for maintenance and other necessary adjustments. One of the reasons why this type of wind turbine is less popular is that it can produce what is known as pulsating torque.

Wind Turbine Parts

In order to understand how these machines work, it is important to know what they consist of.
A standard wind turbine consists of sixteen main parts grouped into three main components:

• The rotor component is the first of the components of the turbine and contributes approximately 20% of the total cost of the entire turbine.
• The generator component contributes 34% of the total cost and consists of parts like the electrical generator and the gearbox.
• Contributing only 15% to the cost, the structural support component is the least expensive part of the entire turbine.
  

Making up these components, the following parts (in alphabetical order) are crucial to the proper functioning of the turbine:

• The anemometer is responsible for measuring the wind speed. It then transmits this information to the controller.
• Most turbines consist of blades. There are usually two or three blades that will start turning when the wind blows.
• In an emergency the turbine can be stopped by applying the brake. This can be done either mechanically, electrically or hydraulically.
• When the wind speed reaches 6 - 16 miles per hour (10 - 26km per hour) the controller starts the machine up. When the wind speed reaches 55 miles per hour (88 km per hour) the controller then shuts the machine off as winds speeds in excess of this speed may damage the blades.
• The gearbox works the same as the one found in a car - it is meant to control the rate at which the turbines accelerate.
• There is an off-the-shelf generator that is meant to provide the initial start-up electricity.
• The high speed shaft drives the generator, while the low speed shaft turns at 50 - 60 rotations per minute.
• On the top of the tower the nacelle houses the gearbox, the two shafts, the generator and controller as well as the brake.
• The pitch turns the blades out of the wind when necessary and in this way controls the speed of the blades.
• The rotor consists of the blades and the hub.
• The tower provides the height and support to the blades in order to catch the wind.
• Because it faces into the wind, this turbine is called the wind direction.
• Wind direction and speed is measured and communicated to the controller by the wind vane.
• The yaw drive ensures that the turbine continues to face into the wind.
• While the yaw drive controls the turbine, the yaw motor controls the yaw drive.

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