Vertical Wind Generators

Simply put, a vertical wind generator is nothing more than a rotating machine that converts kinetic energy that you find in the wind into mechanical energy. If this is used directly by machinery, the machine is commonly known as a windmill. If the mechanical energy is converted into electricity, then the machine is know as a wind turbine, wind generator, a wind energy converter or a wind power unit.

Vertical wind generators today are used in wind farms for the commercial production of electric power. They are usually three-bladed machines and they are constantly pointed into the wind using computer-controlled motors. You can find this kind of wind generator manufactured by Denmark as well as other manufacturers.

These machines have high tip speeds and can be clocked at speeds that are up to six times that of the wind speed. They are highly efficient and they have low torque ripple. All of this contributes to excellent reliability. If you happen to see one of these machines, you know that the blades are usually light gray in color so that they will blend in with the clouds.

The length of these turbines ranges from 20 to 40 meters or more. The tower can range from between 200 to 300 feet high. The blades can rotate from anywhere between 10 to 22 revolution per minute. The thing that is usually set up to ascertain the speed of the generator is a gear box. You will find that some models operate at a constant speed. All of the vertical wind generators that are produced come equipped with a high wind shut down feature which will avoid over speed damage.

A horizontal-axis wind generator has the main rotor shaft as well as the electrical generator sitting on top of a tall tower, and it has to be directly pointed in the direction of the wind.

Advantages of a horizontal-axis wind generator:

• The machine has variable blade pitch. This allows the generator’s blades to have the optimum angle of attack. This attack can be remotely adjusted so it gives greater control. The horizontal-axis wind generator is able to collect the maximum amount of wind energy geared for the specific time of day and season.
• Its tall tower base will allow access to stronger wind speeds in places that are apt to have wind shear. In some of these sites, when you increase the height by ten meters, the wind speed can increase by as much as 20% and the power output by as much as 34%.

 

Disadvantages of the horizontal-axis wind generator:

• These machines have a hard time operating in near ground winds that are turbulent.
• The very tall blades and towers are quite hard to transport.
• Transportation can now be about 20% of the equipment costs.
• Tall horizontal-axis wind generators have to have very tall towers in order to support the gearbox, the heavy blades and the generator.
• These machines are very hard to install. You have to get an expensive crane and a skilled operator for this job.
• This type of machine may affect airport radar.
• They are visibly obtrusive across large areas. This can disrupt the appearance of the landscape.
• Downward variants can often suffer from fatigue and other structural failure caused by wind turbulence.
• These machines require an additional yaw mechanism so that the blades will turn toward the wind.

 

A vertical wind generator has the primary rotor shaft arranged in a vertical fashion. The main advantage of this type of machine is that it does not have to be pointed toward the wind to be effective. This can be very advantageous on sites where the wind direction is variable. These generators can utilize winds from different directions.With a vertical wind generator, it, as well as the gearbox can be placed near ground level. Therefore, the tower does not have to support it. This generator is also more accessible for maintenance. There are some drawbacks to the vertical wind generator. Some of these designs produce pulsating torque. When the blade is rotating into the wind, drag may be created.

It is hard to mount a vertical wind generator on a tower. This means that they are usually installed closer to the base where they rest, for example, near the ground or on a building rooftop. At a lower altitude the wind speed is slower, so there is less wind energy available for any given generator.

Turbulent flow can be created by air flow close to the ground and other objects. This, in turn, introduces vibration which includes nose and bearing weight which may cause the generator to have to be serviced more or you may have to end up replacing it more often. However, when a vertical wind generator is mounted on top of a roof, the building will usually redirect the wind over the roof. Hence, this can often double the wind speed at the generator.