Hi, I am back with another tutorial about the working of horizontal axis wind turbines. Hope this post will help a lot of renewable energy enthusiasts. So share it with your friends and keep reading. As you know, there are different types of wind turbines. But the most popular and widely used one is the horizontal axis wind turbine. How does a horizontal axis wind turbine work? You know what wind power is the fastest growing renewable energy source in the world. That’s why I love to talk about wind turbines and make projects.
Let’s take a look at the most important components of a wind turbine. A horizontal axis wind turbine has four important components and two controlling mechanisms. They are the Propeller, gearbox, dynamo, and the tower. Besides, there are two controlling systems called yaw mechanism and pitch control mechanisms in a wind turbine.
How does wind turbine work?
Let’s take a look at the working of wind turbines. The propeller is the most important part of a wind turbine. It is designed like an aerofoil, which means like an airplane wing. The aerodynamic cross-section of the blade is what causes the thrust on the blade to rotate when the wind blows. But this rotational speed is not enough to generate a substantial amount of electricity from the dynamo.
That’s why we use a gearbox in between propeller and dynamo; to multiply rotational speed. Higher the speed of rotation higher will be the output. This output current from the dynamo will send to the tower base where there is a step-up transformer which will step-up the dynamo output to a convenient voltage for distribution to the grid.
You’ve learned. how a horizontal axis wind turbine works. But there is a catch; wind direction and wind speed changes over time. This will dramatically affect wind turbine output. Two mechanisms are used to overcome this difficulty. Yaw mechanism and pitch control mechanism.
You may have noticed big and long tail behind horizontal axis wind turbines. The propeller should face the wind to get the maximum efficiency. So when wind direction changes this tail will adjust the propeller to face the wind. This method is known as mechanical yawing. Modern wind turbines use more advanced approach here. You can’t see a tail in modern wind turbines. But there is a tiny wind direction measuring tool similar to a tail; which will identify the wind direction and will assist the auto-adjustment circuit system to change the propeller position. Great!
Like wind direction, wind speed will also change from time to time. Changing wind speed will result in varying output. To get a uniform output we use pitch control mechanism. What is that? Pitch refers to the angle between the blade and propeller plane. There is a velocity, measuring tool on top of the turbine casing which will assist the pitch control mechanism to adjust the pitch angle automatically. When wind speed increases the PCM will increase the pitch; thereby reducing the propeller rotational speed. When wind speed decreases the PCM will reduce the pitch thereby increasing the rotational speed of the propeller.
This is how a horizontal axis wind turbine works. Why most HAWTs have three blades. That’s another topic. We will discuss it in another Post.