Vertical Axis Wind Turbine



Vertical axis wind turbine is one whose axis of rotation of blades is perpendicular to the ground. Blades of these wind turbines are attached at two points, upper point is called upper hub and lower point is called lower hub. Shaft at which blades are attached is called low speed shaft. Generator and gearbox are placed on the ground and Guy wires are needed to give spot to wind turbine 

Vertical axis wind turbine are classified into two main types
1. Lift type
2. Drag type

Lift types is one which use the lift forces produce by the moving air to produce the rotation of turbine blades and drag type wind turbine is one which use the drag force of wind to produce the rotation motion of blades


Parts of vertical axis wind turbine

1. Upper hub
2. Blades
3. Low speed shaft
4. Lower hub
5. Gear box
6. Guy wires
7. Generator
8. High speed shaft


Working of wind turbine

Like horizontal axis wind turbine kinetic energy of the wind is converted into the rotation motion of the blades and blades are attached to shaft and the shaft is attached to the generator through the gear box. So the rotation of blades result into the rotation of generator which produce the electricity


Advantages

  • They can produce electricity in any wind direction
  • Strong supporting tower in not needed because generator, gearbox and other components are placed on the ground
  • Low production cost as compared to horizontal axis wind turbine
  • As there is no need of pointing turbine in wind direction to be efficient so yaw drive and pitch mechanism is not needed
  • Easy installation as compared to other wind turbine
  • Easy to transport from one place to other
  • Low maintenance cost
  • They can be install in urban area
  • Low risk for human and birds because blades moves at relatively low speed
  • They are particularly suitable for areas with extreme weather conditions, like in the mountains where they can supply electricity to mountain huts.



Disadvantages

  • As only one blade of wind turbine work at a time so efficiency is very low
  • They need a initial push to start, this action use few of its own produce electricity
  • When compared to horizontal axis wind turbine they are very less efficient with respect to  them. this is because they have an additional drag when their blades rotates.
  • They have relative high vibration because the air flow near the ground creates turbulent flow
  • Because of vibration bearing wear increase which result in the increase of maintenance cost
  • They create noise pollution
  • Guide wires which hold up the machine, need some are to install 

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