How to Make a Windmill?

Dhristi JEE 2022-24

What is Windmill?

A windmill is a big structure also called a mechanical device that transforms wind energy into electrical energy. It is a big structure that contains sails mounted on a rotating shaft.; these rotating sails help transform wind’s kinetic energy into electricity.


These sails make an angle so that when they rotate, the force of the wind against them is divided into the two following components:

  • One in the plane of sails, and 

  • Another imparts rotation

Windmills are prime movers that have replaced humans as a source of power and in this article, you will learn to make this device.


How to make a Windmill?

Building a model of a windmill is a great craft project for students.  Vedantu has provided here a stepwise method to create a Windmill. Once students have got your windmill assembled, they must observe how the spinning blades of the windmill convert wind into energy.


Materials used to Build Working Windmill

Materials used in this method are shown below to build a windmill working model at home by taking the help of your parents.

  • 8*8 inch square piece of paper

  • Scissor

  • Pins

  • Thermocol ball

  • Soft pencil

  • Scale

  • Blade

  • Fevicol or glue


The Steps to Build a Paper Windmill are as follows

  • Take an 8 inch by 8-inch square piece of paper.

  • Wrap it corner-to-corner, do the same thing for the other two corners.


          (Image will be uploaded  soon)  

                  

  • Now, after folding a square paper, take a midpoint on it and cut from both ends, and do the same thing on the other side.

  • Since there are two corners after cutting around each corner of a square, now pierce along each alternative corner with the help of a pin. Do the same in the centre of the square also.

  • Now, fold these pierced corners and leave the unpierced ones as such. We get tilted and folded blades, as shown in the image below: 


       (Image will be uploaded soon)


  • Put a thermocol ball on the pointed end of the pin at the backside of this folded arrangement.

  • Now, attach a straw through this thermocol ball or we can pin a soft pencil to this ball.

  • Bring these windmills in the open air, as the wind blows, these blades will start rotating. 


What is a Windmill and How does it Work?

Windmills have been a useful source of power for the last many years. Even during World War-I, windmills manufacturers produced 10,000 farm windmills each year for water pumping. 


At present, windmills are used for electricity generation, and this electricity generation is possible because of the blades that are constructed by the concept of aerodynamic analysis and other performance-enhancing equipment. 


Working Principle of a Windmill

A windmill is a big structure containing sails that are attached by a fixed rotating shaft, as you can see in the image below. The rotating shaft rotates these blades that help convert the kinetic energy of wind into electricity. 


Now, let’s understand its basic working:

When a blowing wind forces the blades, these rotating blades generate electricity because of the generator attached to the windmill. Do you know how blowing wind turns a wing?


If we closely look at the cross-section of the blade, it has a lot of airfoils on the surface. The concept of an airfoil is simple. Whenever there is a pressure difference between the two surfaces, an upward force acts on the blade, which is a dynamic lift. Since all the blades have airfoils, in this way, a lift generates in all the three blades, which makes these wind turbine blades turn, as we encounter with the windmills in the farm.


Types of Wind Turbines

  • Horizontal axis

  • Vertical axis

  • Ducted Wind Turbines


How much Electricity can a Wind Turbine Produce?

Wind strength largely influences Electricity production. According to a study, a typical wind turbine has a 2-3 MW (megawatts) capacity and can produce over 6 million kWh (kilowatt-hours) electricity per year, which is enough to power around 1500 average households. The wind turbine has on average 30% to 45% efficiency reaching 50% in the best possible scenarios. That may seem low but at 100% efficiency, it can be assumed that all wind would be absorbed by the wind turbines.


The faster the wind, the more power the wind turbine generates. 8 times more electricity is generated when the speed of the wind doubles. However, there is a cap and wind turbines need to be stopped if the wind is too strong or they risk being damaged.


Relative Velocity of Wind Turbines

Just like moving trains,  wind turbines also experience the wind relatively. So the relative velocity of the wind is given by the following formula:

V RELATIVE = VWIND - VBLADE

So, the relative velocity is the difference between the velocity of the wind and that of a blade. So that’s why blades are tilted in such a way that they align to the relative wind speed.


Now, as the blade velocity increases to the tip, the relative velocity becomes more inclined towards the tip, which means a continuous twist is given to the blade from the root to tip. 


Since due to low mechanical strength and wind noise, the blades don’t rotate and give high rpm with a generator. So, how to gain maximum speed?


How to gain Maximum Speed in a Windmill?

Now, what we do is, we connect a gearbox before the generator, which helps achieve a high-speed ratio of 1: 90 (cut-off speed of 80 kmph). A brake is also fitted in a nacelle that helps tackle the wind arrest during windy conditions. 


Consecutively, the electricity generated is transferred to the transformer filled at the base of the windmill. 

This is how a windmill works. Now, we will learn about the types of windmills.


History of Windmills

Using windmill power for rotation of objects  has been used since the 1st century in Greece. Windmills have been used to lift things up and down, mainly water from the ground, to power machines that crush grain and process food, and recently to power motors to generate electricity. windmills are the best example of wheel-and-axle machines. 


Types of Windmills

There are various types of windmills, so let’s understand their types one-by-one:

  • Post mill

  • Smock mill

  • Fan mill

  • Tower mill


Uses of Windmill

Windmills have a  mounted wind turbine that captures most energy and performs various tasks that have replaced human beings as a source of power. They are used in the following places:

  • They are used for pumping water,

  • For grinding grains, and

  • Generating electricity. 


Components of Windmill

Following are the components of windmill:

  • Rotor: Rotor is also known as a propeller.

  • Blades: Blades are one of the essential components of the windmill as they control the functioning of rotor speed.

  • Anemometer: This component is used for measuring the wind speed.

  • Tower: This is the support system holding the blades and propeller together.

FAQs on How to Make a Windmill?

1. What is a windmill and how does it work?

A windmill has a simple principle: instead of using fans or motors, the wind turbines mounted at the back of the blades help capture wind energy and convert it into electrical energy, which we use for pumping water, grinding grains, etc. The blades are required to be pointed into the wind, so in large scale wind turbines, there are wind detection systems and computers that turn the windmill to be facing the wind. The amount of electricity a wind turbine generates depends on the size of the turbine, also known as the power rating, and how fast the wind is travelling at the turbine’s location. 

2. Write the advantages of windmills.

The main advantage of wind energy is that harnessing it doesn’t disrupt natural processes or harm the environment, unlike a lot of other energy sources. This source of energy has tremendous potential to generate energy on a large scale, and like solar energy and hydropower, wind power taps a natural physical resource. The following are the key advantages of windmills.


Advantages of windmills are as follows:

  • Cost-effectiveness

  • Clean fuel source

  • Domestic source of energy

  • Increases US industry growth

  • Creates jobs

  • Doesn’t pollute environment

  • steady supply of electricity

3. Write about the disadvantages of windmills.

The disadvantages of windmills are as follows:

  • The wind is not consistent

  • May decrease the local bird population:

(As per the latest survey, a minimum of 20,000 - 573, 300 birds got killed by the windmills in the US)

  • Installation takes up a lot of land area.

  • Windmills can be a safety hazard.

  • The average efficiency of wind turbine is very less

  • Maintenance cost of wind turbines is high

  • Noise pollution problem is associated

  • Unreliable energy source as winds are uncertain

  • Requires expensive storage during peak production time

4. When was the first windmill invented? Which country is known as the city of windmills?

The first windmill was invented in 1854 by Daniel Halladay in his Connecticut machine shop. Halladay produced an ingenious self-regulating windmill with a fixed vane and four solid blades mounted on a main shaft. The rigid vane kept the wheel of blades facing the wind at an angle to produce the greatest amount of power. As wind velocities increased and the wheel spun faster, a centrifugal governor changed the pitch of the blades to present less of their surface to the wind, thus controlling their speed. When winds were high, or when the mill was turned off, the blades pivoted into a position parallel with the wind and the wheel stopped turning altogether. The Netherlands is known as the city of windmills. However, it produces very little power, i.e., Quartz.

5. Why do wind turbines fail?

Regular maintenance and inspections of wind turbines create challenges due to the remote locations of wind farms and the size and height of the turbines. During regularly scheduled maintenance, it can be difficult to access the massive rotor blades and evaluate the blade materials and the complex surface areas. Wind turbines fail because of the following reasons:

  • Damage or power regulator failure

  • Lightning strikes

  • A poor architecture

  • Blades require costly repairs and revenue lost

  • Generator Failure

  • Blade Failure

  • Gearbox Failure

6. How can I download reading material from Vedantu?

Accessing material from Vedantu is extremely easy and student-friendly. Students have to simply visit the website of  Vedantu and create an account. Once you have created the account you can simply explore the subjects and chapters that you are looking for. Click on the download button available on the website on Vedantu to download the reading material in PDF format. You can also access all the resources by downloading the Vedantu app from the play store. 

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