A Single Blade Wind Turbine! SP_Energia_Prototype.

A single blade wind turbine. In the field of renewable energy, wind is one of the most valuable resource. Hence tapping this resource can help to a great extent to level the spike of carbon emissions. Wind turbines have in general 3 blades. The 3 bladed design is easy to scale, is sweet spot between stability, economical value and power output. A single bladed turbine however is not that easy to scale, but it is almost half the cost or even lesser, has faster tip speed(speed of blade tip) and can be easily mass produced in small scales(380-600kw) in places that is hard to reach or difficult to plop a huge turbine(160 meters+). My small scale design of my turbine will be 1.83 meters tall(tower height) and the blade will be 96~98cms long. It has a power output of 1000~6000w. I designed it using fusion 360.

In fusion 360, I opened a new 'Design' and start my work. First i create the circular hub of the blade(which connects to the axial) I am using 'SERI' series of air foil to design my blade. I create sketch by adjusting the plane to 14.66cms and add a canvas (SERI) at the origin. I adjust the canvas and draw out the outline of the air foil near the root of the blade(S811). then I offset the plane at 57.83cms and repeat the same(This time S807). finally for the tip I use S806.

I use sheet metal to loft it. In all this process I made sure to create an offset of each sketch so that when i loft it, I will get a inner sheet metal blade and an outer sheet metal blade. Then i used the boundary fill tool to get the thickness of the blade done! The sheet metals are discarded.

The blade design is complete.

The axial cover T-joint structure. The cover is there to hold the counter weight, the blade, the pitch gear and the main Axial together. It also makes it look appealing to cover up the mechanics. The 2 identical openings are 46 and 45.93 mm wide. (further dimensions are linked above!). Larger one holds the counter weight. The counter weight will be made after the blade is 3d printed to get the final weight. I used the extrude tool the most and a few sketches that match the face to extrude it out. I made 2 separate pipes and merged them after I got the required shape.

The axial cover & axial design is complete.

The counter weight is a simple cylindrical structure. I just drew a circle and extruded it to form this shape(with a bit of modification to get that shape). The counter weight's weight will be decided only when the blade is done making.

The counterweight design is complete.

now i assemble this using the 'move' tool and align it with the origin for the next step.

This an Important step. Here I first calculated the required gear ratio to be 6x6 = 36(1:36). For all gears in the gear box, module is 0.875 and a 30-degree helix angle. I am using helical gear as it is less noisy. To prepare the planetary gear I first make a 15 teeth sun gear. then i make a 75 teeth helical gear then i overlap it with a 9.66 cm dia cylinder with equal thickness and then i use the combine tool and select 'cut' to get the ring gear. Placing the sun gear in the centre I create 3 helical gears each having 30 teeth. I align them carefully to make sure that the planet is at equal distances from each other. now I reinforce it using a triangular planet holder. Now I repeat the same process to create a 2 stage planetary gear system for a combined gear ratio of 36(as mentioned above). After aligning all the gears, I Make a cover for the gearbox, where I made a few sketches and mostly use the mov, extrude, hole commands. I used a helical gear add-in script.

The Gearbox-Half Design is complete.

Thia too is an important step, After all this is the source of POWER!!! The Generator half encompasses the generator and the generator axial. The generator has 3 main parts; the core(where i will be using 10mm x 65mm x 5mm neodymium magnets) with a total of 16 magnets; the coils which is made up of copper coils of 0.8mm thickness(total 12 coils) and the generator axial. I just made the coils here a simple cylindrical hollow block of copper as designing the coils individually will be almost impossible. I used the extrude command after I drew the face profile of the core and coils. I added a cooling fan behind the core so that the generator will operate at optimum temperature. The fan, and the core shall be 3d printed.

The Generator-Half designs is complete.

The Nacelle is Designed based on the gear-generator box. It has a nice rounded behind... and an air intake to help the cooling fan to circulate airflow throughout the interior of the nacelle. I used a series of sketches to create the nacelle shape. Mostly using the existing gearbox and generator cross sections and using the 'loft' command. The nacelle shall also be 3d printed for simplicity. I first thought of a simple box design... but that would be too simple, after all the nacelle gives the turbine some decent looks!

The Nacelle Design is Completed.

The tower is a steel pipe that is 1.83 meters long and 8 cm diameter. I will most probably use a pipe from the storage than literally building it.

The Tower Design is completed.

The base plate is the structure that holds the gearbox cum generator, supports the pitch mechanism and supports the whole thing on the tower and the yaw bearing. It acts like the 'ground' for the components of the turbine. This part is made of thicker metal(steel 1cm) to support the weight and the dynamic loads under normal working conditions. I used 2 profile sketches and the extrude tool to make the base plate. 1st profile for the lower part then the 2nd profile for the higher one.

The Base Plate design is completed.

This controls the pitching of the blade when the wind speed changes. It consists of the pitch bearing, which will be attached to the blade and to the axial cover so that the blade turns a few degrees( full pitch: 0 degrees i.e. the blade edge faces the wind directly giving no lift and 90 degrees where the underside of the blade is facing the wind and that gives no lift and a lot of drag. Basically the blade stops spinning at these positions.). The pitch mechanism consists of a few rods that connect to 2 couplers that move in such a way that when the slider bearing is pulled the pitch mechanism is activated.

The pitch control system design is complete.

For the yaw control I use a spur gear with 83 teeth and use 1 smaller spur gear with 10 teeth. I used the spur gear script for this. the 83 teeth gear is fixed to the tower and inside it sits snugly (connected by welding) a bearing of outer diameter 10cm and inner diameter of 6cm. this bearing supports the nacelle. The nacelle rotates on this bearing. The smaller gear is fixed to the nacelle and will be controlled by an Arduino uno with a 12v motor. I will put the codes and workings ahead.

The Yaw control design is completed.

I will be using a RS485 sensor SEN0482 to get the wind direction and an 'Arduino uno R3 smd' to code the controls. The sensor gives direction, the arduino receives the data and directs the motors in which direction it needs to turn through a motor driver. the codes are attached below.

!!!OR!!!

If it is not available or if it will take too much time to get it delivered or if it is too expensive... I will use a remote controlled Arduino Yaw system to demonstrate it instead. ( Where I live RS485 sensor SEN0482 is not available so I have to order it from a different country which will take time and money.)

This slip ring system connects the generator output(power!) to the output wire connection that can be used to power stuff. Since the nacelle is rotating, we cannot directly connect the wire or it will twist. Hence I will be using a slip ring system. Here it is a simple copper ring that is in contact with carbon contact which is softer than the copper ring. When the nacelle turn, the contact rubs on the copper ring which still ensures the circuit to be complete. I could use an encoder to count the turn and de-twist the wires, but that is for large turbines and is more complicated. Here there are springs attached to the carbon contact so that when the carbon gets grounded by the copper ring (since copper is a harder material) the springs make sure that the carbon contact is still in contact with the ring by applying pressure to it. The insulating rubber cylinder(in white) makes sure that the whole turbine does not go live wire. The insulator and the copper coil is fixed to the tower. The spring cover, springs and the carbon contact is fixed to the base plate. Wires will be connected to the carbon contact and a separate set of wires to the coil.

I unfortunately could not start building as we are having lab exams and the end sem exams coming soon...