Introduction: Renewable Energy Windmill Project Science Fair/Stem Project
I made a small windmill to teach about renewable energy, and how easy it is to make it. This project is made in such a way that almost anyone with basic tools should be able to make it. Also, no welding is required!
Supplies
Thin aluminum sheet (1'x1'x1-1.5mm)
Jb weld
old 2"x4" piece
Step 1: Mark the First Steps on the Metal
Take the aluminum sheet, find and mark the center, and using a compass, or any tool you like, make the biggest circle possible. You will also want to make a circle with about a 1.5-inch radius at the center of the metal circle.
(For best results use a Sharpie or another permanent marking method.)
Step 2: Cut Aluminum Sheet Into Circle
Use whatever tools you have at hand, and also get creative! I used a wooden 4"x4" scrap, and put a nail through the center of the aluminum. Then I secured it to the bench and used a tool to remove material while rotating the metal. It is important to note that nothing about this project has to be perfect as long as the weight distribution is similar on both sides, the windmill should work.
This step should be the hardest and most time-consuming step in the process.
Always use tools for their intended purpose and wear proper safety gear when using any power tools. Also beware of air circulation and the sharp edges many cutting methods create.
Step 3: Flattening & Marking
You may notice a warping to the metal after cutting, which is normal considering you just heated the outside of a circular shape, causing it to expand and contract, while the inside did not. Although flattening is not strictly necessary, it makes marking much easier. You can use a combination of a hammer, malate, and vise to get it flattened out. it will never be perfect, so once it is good enough just move on.
The marking is simple. Use a wood/metalworking square, and draw a line across the entire circle that intersects with the hole/mark in the metal. Next, use the right angle on your square to make a line at a right angle to the first one that also intersects with the middle point. Extend that line to both sides of the circle. After you are satisfied with these lines, use the 45-degree angle on the square to make a line that cuts two of the sections in half. After that is done, simply do it to the last two larger sections, and you are done with this step!
Step 4: Cutting Fan Blades
Cut along the lines you made in the last step with a tool of your choice. I found that an angle grinder with a cut-off wheel was the best. Do not cut all the way through. Instead, cut only to the circle that is about 1.5 inches in radius from the center point. Make sure to have the windmill clamped down well for this step.
Step 5: Bending
Using your hands, bend each blade into roughly the same position at a slight angle so that as wind blows on it, the fan moves. Each blade will have a slight curve to it and will naturally not be perfect. As you can see in the picture above, my windmill has a slight curve into the wind also, which I think greatly affects the performance. You will most likely find that this curve comes naturally as you bend the metal.
Step 6: Drilling & Fitting
You must now drill a hole in the middle that is big enough for the top of the pinion gear to fit through. You do not want the actual gear part, however, to slip through because where the gear gets wider is where you will put the JB weld.
After you drill the hole, try to sand/file down the back so that the aluminum fan fits flat on the gear. Remember that you want the concave side facing the wind like a cup, so it is the convex side that should be up against the gear. I also roughed up the gear for better bonding.
Step 7: Finishing Steps
Now you can attach the pinion gear to the generator and attach the fan to that, using JB weld. After this, read and follow the directions on the JB weld. Be sure to mix the JB weld extremely thoroughly for the best results. I let mine dry for about 18 hours, which seemed like a perfect amount of time.
Step 8: LED Output
Plug LED into two outputs from the mini generator to create a simple circuit which will give you a vague idea of the electrical output.
Step 9: Finished Windmill Images
Step 10: Facts for Science Fair
This project is a great example of harnessing renewable energy sources. This one harnesses the wind currents, which is ultimately caused by the sun warming the air which makes the hot air rise and the cold air fall. It might seem like this is making energy out of thin air and although it is, (get it?) it is not actually MAKING the energy.
As the sun is burning, it turns its chemical potential energy into thermal energy, which then heats the air, making wind kinetic energy, which is then transformed into mechanical energy in the form of the blades turning. The generator then turns that into electrical energy.
The most notable simple machine in this project is the axle that is used to transfer rotation over a distance without converting it into linear motion. As the magnets around the outside of the generator turn, it creates an electromagnetic field, and through electromagnetic induction, this is made into an electromagnetic current that we can use in our everyday lives. This can be wired as either a series or parallel circuit; I wired it as a series.
Ohm's law states that voltage is equal to current x resistance [V=IR], so if the goal were to get more voltage, either the resistance of the wires could be lowered, or the generator could simply be spun faster, resulting in more current, and thus more voltage.
Step 11: Troubleshooting
- One common problem is that metal shavings/dust will get drawn into the generator because of the magnets. If you feel a grinding as you try to turn the generator, this is most likely the problem. I recommend using compressed air to blow out the obstructions.
- If you have an easy time getting the generator to turn initially, but the speed does not increase, it might be because the blades are at too steep of an angle. If this is the case, I recommend bending the blades back incrementally towards being flatter.
- If you follow the above steps and it is still not working, it might simply not be windy enough. The higher up on a hill without trees you go, the better. You could also just wait for a windier day!
Step 12: Bibliography
(n.d.). Wind Powers Africa. Cleantechnica.com. https://cleantechnica.com/2023/06/24/wind-powers-africa/#:~:text=In%20a%20continent%20where%20600,needed%20power%20from%20the%20wind.
(n.d.). Circuit characteristics. Workforce.Lebritexts.org. https://workforce.libretexts.org/Bookshelves/Electronics_Technology/Book%3A_Electrical_Fundamentals_Competency_(Industry_Training_Authority_of_BC)/02%3A_Unit_II-_Common_Circuit_Components_and_Their_Symbols/07%3A_Common_Circuit_Characteristics
