Hybrid Darrieus Helix Rotor

thingiverse

This is a Darrieus Wind Generator, which can optionally be extended with Savonius blades to create a hybrid rotor. The Savonius extension is highly useful since the Darrieus rotor has difficulty starting. Be cautious when using vertical wind turbines as they require protection during strong winds. Rotor: The rotor consists of three NACA 0015 airfoils, which are extruded into a helix with four parts each and an overall height of 80 cm. Each of the middle three parts of the helix blade requires the "helix blade" and "helix blade 2" parts to be joined together using a strong adhesive like two-component adhesive that hardens in five minutes. This is necessary because it can be challenging to hold these pieces together for an extended period. The blades are then attached to the blade holder using aluminum tubes with a length of 222 mm each. A drill tool helps to accurately drill holes at the correct distance. Print two drill tools and place them over the tube, ensuring the hole centers are at 20 mm on one side and 17 mm on the other. A collar secures the two blade holders together using a 20 mm shaft. Use two-component adhesive to attach the collar to the blade holder, making sure that the headless screw of the collar fits into the small hole in the blade holder. The blades are printed with PETG material and have an infill of 15% to keep them as lightweight as possible. The settings used for printing include five top- and bottom layers and a layer height of 0.2 mm. Support is necessary for the pickups, and PLA can also be used as a printing material. There are two versions of the helix blade available: mid and large. It's recommended to use the mid version due to its lower weight and reduced filament usage. **Update Feb. 12 2018** A new blade has been added to increase the radius of the rotor by 100 mm, resulting in an increased length of aluminum tubes to 322 mm. This modification allows for a reduction in overall weight using two modifiers. The blades are printed with a perimeter setting of two and an infill density of five percent. The modifiers have an infill density of 20%. With these adjustments, the weight of the blade part is reduced below 150 grams. Learn more about using modifiers by visiting this blog: http://slic3r.org/blog/modifier-meshes The "blade_end_mid" part can also be used for this blade. Generator: The air-coil generator utilizes a Halbach array to achieve optimal performance. The principles of the Halbach array can be found on Wikipedia at https://en.wikipedia.org/wiki/Halbach_array For the stator coils, copper wire with a diameter of 0.75 mm was used, resulting in 35 turns per coil. Each phase has eight coils connected in series. Use the coil tool to maintain clearance around the holes in the middle of the coil. After coiling up all parts, use two-component adhesive to attach the rotor to the collar. Ensure that the headless screw fits into the hole on the rotor. All parts of the generator are printed with PETG material and have an infill of 25%. **Update Apr. 29 2018** A new part called "nipple" has been added to protect the generator from water intrusion by attaching it on top of the upper cover. **Update March 15 2019** It appears that the step-up converter generates a high load even at 3V, preventing the rotor from reaching an efficient operation point. To avoid this issue, insert a threshold switch (around 6V) into the input line of the step-up converter or use a voltage doubler as shown here https://www.mikrocontroller.net/attachment/93313/Verdreifacher_3-Phasig.png Alternatively, consider using a wind MPTT charge controller with boost function. Rod: A 40 x 3 mm aluminum rod was initially used but resulted in oscillation until the rotor reached a certain speed. It's recommended to use a 40 x 5 mm rod instead. Here are some videos showing the performance of this Darrieus Wind Generator: * Moderate wind: https://youtu.be/QC80Ev-aL6k * Stronger wind: https://youtu.be/cp6HL0YoWEE * 350mm radius: https://youtu.be/cXBZ0u_D9mc