How to make a wind generator yourself; description of a wind turbine. How to make a vertical wind generator Wiring diagram for a wind generator

Power homemade wind generator will be enough to charge batteries various equipment, lighting and, in general, the operation of household electrical appliances. By installing a wind generator, you will save yourself from energy costs. If desired, the unit in question can be assembled with your own hands. You just need to decide on the basic parameters of the wind generator and do everything in accordance with the instructions.

The design of a wind generator includes several blades that rotate under the influence of wind currents. As a result of this impact, rotational energy is created. The generated energy is fed through the rotor to the multiplier, which in turn transmits the energy to the electric generator.

There are also designs of wind generators without multipliers. The absence of a multiplier makes it possible to significantly increase the productivity of the installation.

Wind generators can be installed either individually or in groups combined into a wind farm. Wind turbines can also be combined with diesel generators, which will save fuel and ensure the most efficient operation of the home's electrical system.

What do you need to know before starting to assemble a wind generator?

Before you start assembling a wind generator, you need to decide on a number of basic points.

First step. Select the appropriate type of wind turbine design. Installation can be vertical or horizontal. In the case of self-assembly, it is better to choose vertical models, because they are easier to manufacture and balance.

Second step. Determine the appropriate power. At this point, everything is individual - focus on your own needs. For getting more power it is necessary to increase the diameter and weight of the impeller.

Increasing these characteristics will lead to certain difficulties at the stage of securing and balancing the wind generator wheel. Take this moment into account and objectively assess your capabilities. If you are a beginner, consider installing several medium-power wind generators instead of one very efficient unit.

Third step. Consider whether you can make all the elements of the wind generator yourself. Each detail must be accurately calculated and made in full accordance with factory analogues. If you do not have the necessary skills, it is better to buy ready-made elements.

Fourth step. Select suitable batteries. It is better to refuse car batteries, because... they are short-lived, explosive and demanding to care for and maintain.

Sealed batteries are a better option. They cost a couple of times more, but they last several times longer and generally have better performance.

Pay special attention to choosing the appropriate number of blades. The most popular are wind generators with 2 and 3 blades. However, such installations have a number of disadvantages.

When a generator with 2 or 3 blades operates, powerful centrifugal and gyroscopic forces occur. Under the influence of the mentioned forces, the load on the main elements of the wind generator increases significantly. Moreover, at some moments the forces act in opposition to each other.

To level out the incoming loads and maintain the integrity of the wind generator structure, you need to perform competent aerodynamic calculation of the blades and manufacture them in exact accordance with the calculated data. Even minimal errors reduce the efficiency of the installation several times and increase the likelihood of an early breakdown of the wind generator.

When high-speed wind turbines operate, a lot of noise is created, especially when it comes to home-made installations. The larger the blades, the louder the noise will be. This point imposes a number of restrictions. For example, it will no longer be possible to install such a noisy structure on the roof of a house, unless, of course, the owner likes the feeling of living in an airfield.

Keep in mind that as the number of blades increases, the level of vibration generated during operation of the wind generator will increase. Two-blade units are more difficult to balance, especially for an inexperienced user. Consequently, there will be a lot of noise and vibration from windmills with two blades.

Give your choice to a wind generator with 5-6 blades. Practice shows that such models are the most optimal for self-production and use at home.

It is recommended to make the screw with a diameter of about 2 m. Almost anyone can handle the work of assembling and balancing it. Once you gain experience, you can try to assemble and install a wheel with 12 blades. Assembling such a unit will require more effort. Material consumption and time costs will also increase. However, 12 blades will allow you to receive power at the level of 450-500 W even with a light wind of 6-8 m/s.

Keep in mind that with 12 blades the wheel will be quite slow, and this can lead to various problems. For example, you will have to assemble a special gearbox, which is more complex and expensive to manufacture.

Thus, the best option for a novice home craftsman is a wind generator with a wheel with a diameter of 200 cm, equipped with 6 blades of medium length.

Assembly components and tools

Assembling a windmill will require many different components and additional accessories. Gather and buy everything you need in advance so you don't have to worry about it in the future.

Depending on the conditions of a particular situation, a list necessary tools may vary a little. At this point, you will independently navigate the progress of the work.

Step-by-step guide to assembling a wind generator

The assembly and installation of a homemade wind generator is carried out in several stages.

First stage. Prepare three-point concrete base. Determine the depth and overall thickness of the foundation in accordance with the type of soil and climatic conditions at the construction site. Allow the concrete to harden for 1-2 weeks and install the mast. To do this, bury the support mast approximately 50-60 cm into the ground and secure it with guy wires.

Second phase. Prepare the rotor and pulley. The pulley is a friction wheel. There is a groove or rim around the circumference of such a wheel. When choosing the rotor diameter, you need to focus on the average annual wind speed. So, at an average speed of 6-8 m/s, a rotor with a diameter of 5 m will be more efficient than a rotor with a diameter of 4 m.

Third stage. Make the blades of the future wind generator. To do this, take a barrel and divide it into several equal parts in accordance with the selected number of blades. Mark the blades with a marker and then cut out the elements. A grinder is perfect for cutting; you can also use metal scissors.

Fourth stage. Attach the bottom of the barrel to the generator pulley. Use bolts for fastening. After this, you need to bend the blades on the barrel. Do not overdo it, otherwise the finished installation will be unstable. Set the appropriate rotation speed of the wind generator by changing the bends of the blades.

Fifth stage. Connect the wires to the generator and assemble them into a circuit in a dose. Attach the generator to the mast. Connect the wires to the generator and mast. Assemble the generator into a circuit. Also connect the battery to the circuit. Consider the fact that the maximum permissible length wires in the case of such an installation is 100 cm. Connect the load using wires.

It takes an average of 3-6 hours to assemble one generator, depending on the skills available and the overall efficiency of the craftsman.

The wind generator requires regular care and maintenance.

1. 2-3 weeks after installing a new generator you need dismantle the device and make sure that the existing fastenings are secure. For your own safety, check the mounts only in light wind conditions.
2. Lubricate bearings at least once every 6 months. When the first signs of wheel imbalance appear, immediately remove it and eliminate any problems. The most common sign of imbalance is uncharacteristic shaking of the blades.
3. Check the pantograph brushes at least once every 6 months. Every 2-6 years paint metal elements installations. Regular painting will protect the metal from destruction due to corrosion.
4. Monitor the condition of the generator. Regularly check that the generator is not overheating during operation. If the surface of the unit becomes so hot that it becomes very difficult to hold your hand on it, take the generator to a workshop.
5. Monitor the condition of the collector. Any contamination must be removed from the contacts as soon as possible, because... they significantly reduce the efficiency of the installation. Keep an eye on the mechanical condition of the contacts. Overheating of the unit, burnt windings and other similar defects - all this must be eliminated immediately.

Thus, there is nothing complicated in assembling a wind generator. It is enough just to prepare all the necessary elements, assemble the installation according to the instructions and connect the finished unit to the electrical network. Right assembled wind generator for the home will become a reliable source of free electricity. Follow the instructions you received and everything will work out.

Good luck!

Video - Do-it-yourself wind generators for home

Russia occupies a dual position with regard to wind energy resources. On the one hand, thanks to the huge total area and due to the abundance of flat areas, there is generally a lot of wind, and it is mostly even. On the other hand, our winds are predominantly low-potential and slow, see Fig. On the third, in sparsely populated areas the winds are violent. Based on this, the task of installing a wind generator on the farm is quite relevant. But in order to decide whether to buy a fairly expensive device or make it yourself, you need to think carefully about which type (and there are a lot of them) to choose for what purpose.

Basic Concepts

1. KIEV – wind energy utilization coefficient. If a mechanistic flat wind model is used for calculations (see below), it is equal to the efficiency of the rotor of a wind power plant (WPU).
2. Efficiency – end-to-end efficiency of the APU, from the oncoming wind to the terminals of the electric generator, or to the amount of water pumped into the tank.
3. Minimum operating wind speed (MRS) is the speed at which the windmill begins to supply current to the load.
4. The maximum permissible wind speed (MAS) is the speed at which energy production stops: the automation either turns off the generator, or puts the rotor in a weather vane, or folds it and hides it, or the rotor itself stops, or the APU is simply destroyed.
5. Starting wind speed (SW) - at this speed, the rotor is able to turn without load, spin up and enter operating mode, after which the generator can be turned on.
6. Negative starting speed (OSS) - this means that the APU (or wind turbine - wind power unit, or WEA, wind power unit) to start at any wind speed requires mandatory spin-up from an external energy source.
7. Starting (initial) torque is the ability of a rotor, forcibly braked in the air flow, to create torque on the shaft.
8. Wind turbine (WM) is part of the APU from the rotor to the shaft of the generator or pump, or other energy consumer.
9. Rotary wind generator - an APU in which wind energy is converted into torque on the power take-off shaft by rotating the rotor in the air flow.
10. The range of rotor operating speeds is the difference between MMF and MRS when operating at rated load.
11. Low-speed windmill - in it the linear speed of the rotor parts in the flow does not significantly exceed the wind speed or is lower than it. The dynamic pressure of the flow is directly converted into blade thrust.
12. High-speed windmill - the linear speed of the blades is significantly (up to 20 or more times) higher than the wind speed, and the rotor forms its own air circulation. The cycle of converting flow energy into thrust is complex.

Notes:

1. Low-speed APUs, as a rule, have a KIEV lower than high-speed ones, but have a starting torque sufficient to spin up the generator without disconnecting the load and zero TAC, i.e. Absolutely self-starting and usable in the lightest winds.
2. Slowness and speed are relative concepts. A household windmill at 300 rpm can be low-speed, but powerful APUs of the EuroWind type, from which the fields of wind power plants and wind farms are assembled (see figure) and whose rotors make about 10 rpm, are high-speed, because with such a diameter, the linear speed of the blades and their aerodynamics over most of the span are quite “airplane-like”, see below.

What kind of generator do you need?

An electric generator for a domestic windmill must generate electricity over a wide range of rotation speeds and be able to self-start without automation or external power sources. In the case of using APU with OSS (spin-up wind turbines), which, as a rule, have high KIEV and efficiency, it must also be reversible, i.e. be able to work as an engine. At powers up to 5 kW, this condition is satisfied by electric machines with permanent magnets based on niobium (supermagnets); on steel or ferrite magnets you can count on no more than 0.5-0.7 kW.

Note: asynchronous generators alternating current or collector ones with a non-magnetized stator are completely unsuitable. When the wind force decreases, they will “go out” long before its speed drops to MPC, and then they will not start themselves.

The excellent “heart” of the APU with a power from 0.3 to 1-2 kW is obtained from an alternating current self-generator with a built-in rectifier; these are the majority now. First, they maintain an output voltage of 11.6-14.7 V over a fairly wide speed range without external electronic stabilizers. Secondly, the silicon valves open when the voltage on the winding reaches approximately 1.4 V, and before that the generator “does not see” the load. To do this, the generator needs to be spun up quite decently.

In most cases, a self-generator can be directly connected, without a gear or belt drive, to the shaft of a high-speed high-pressure engine, selecting the speed by selecting the number of blades, see below. “High-speed trains” have a small or zero starting torque, but the rotor, even without disconnecting the load, will have time to spin sufficiently before the valves open and the generator produces current.

Choosing according to the wind

Before deciding what type of wind generator to make, let’s decide on the local aerology. In gray-greenish(windless) areas of the wind map, only a sailing wind engine will be of any use(We’ll talk about them later). If you need a constant power supply, you will have to add a booster (rectifier with voltage stabilizer), charger, powerful battery, inverter 12/24/36/48 V DC to 220/380 V 50 Hz AC. Such a facility will cost no less than $20,000, and it is unlikely that it will be possible to remove long-term power of more than 3-4 kW. In general, with an unwavering desire for alternative energy, it is better to look for another source.

In yellow-green, low-wind places, with a need for electricity of up to 2-3 kW, you can take on a low-speed one yourself vertical wind generator . There are countless of them developed, and there are designs that are almost as good as industrially manufactured “blade blades” in terms of KIEV and efficiency.

If you plan to buy a wind turbine for your home, then it is better to focus on a wind turbine with a sail rotor. There are many controversies, and in theory everything is not yet clear, but they work. In the Russian Federation, “sailboats” are produced in Taganrog with a power of 1-100 kW.

In red, windy regions, the choice depends on the required power. In the range of 0.5-1.5 kW, homemade “verticals” are justified; 1.5-5 kW – purchased “sailboats”. “Vertical” can also be purchased, but will cost more than a horizontal APU. And finally, if you need a wind turbine with a power of 5 kW or more, then you need to choose between horizontal purchased “blades” or “sailboats”.

Note: Many manufacturers, especially the second tier, offer kits of parts from which you can assemble a wind generator with a power of up to 10 kW yourself. Such a kit will cost 20-50% less than a ready-made kit with installation. But before purchasing, you need to carefully study the aerology of the intended installation location, and then select the appropriate type and model according to the specifications.

About security

The parts of a wind turbine for household use in operation can have a linear speed exceeding 120 and even 150 m/s, and a piece of any solid material weighing 20 g, flying at a speed of 100 m/s, with a “successful” hit, will kill a healthy man outright. A steel or hard plastic plate 2 mm thick, moving at a speed of 20 m/s, cuts it in half.

In addition, most wind turbines with a power of more than 100 W are quite noisy. Many generate air pressure fluctuations of ultra-low (less than 16 Hz) frequencies - infrasounds. Infrasounds are inaudible, but are harmful to health and travel very far.

Note: in the late 80s there was a scandal in the United States - the largest wind farm in the country at that time had to be closed. Indians from a reservation 200 km from the field of its wind farm proved in court that their health disorders, which sharply increased after the wind farm was put into operation, were caused by its infrasounds.

Due to the above reasons, installation of APUs is allowed at a distance of at least 5 of their heights from the nearest residential buildings. In the courtyards of private households, it is possible to install industrially manufactured windmills that are appropriately certified. It is generally impossible to install APUs on roofs - during their operation, even low-power ones, alternating mechanical loads arise that can cause resonance building structure and its destruction.

Note: The height of the APU is considered to be the highest point of the swept disk (for bladed rotors) or geometric figure (for vertical APUs with a rotor on the shaft). If the APU mast or the rotor axis protrude even higher, the height is calculated by their top - the top.

Wind, aerodynamics, KIEV

A homemade wind generator obeys the same laws of nature as a factory one, calculated on a computer. And the do-it-yourselfer needs to understand the basics of his work very well - most often he does not have expensive, state-of-the-art materials and technological equipment at his disposal. The aerodynamics of the APU are oh so difficult...

Wind and KIEV

To calculate serial factory APUs, the so-called. flat mechanistic model of wind. It is based on the following assumptions:

• Wind speed and direction are constant within the effective rotor surface.
• Air is a continuous medium.
• The effective surface of the rotor is equal to the swept area.
• The energy of the air flow is purely kinetic.

Under such conditions, the maximum energy per unit volume of air is calculated using the school formula, assuming the air density at normal conditions 1.29 kg*cub. m. At a wind speed of 10 m/s, one cube of air carries 65 J, and from one square of the effective surface of the rotor, with 100% efficiency of the entire APU, 650 W can be removed. This is a very simplified approach - everyone knows that the wind is never perfectly even. But this has to be done to ensure repeatability of products - a common thing in technology.

The flat model should not be ignored, it gives a clear minimum of available wind energy. But air, firstly, is compressible, and secondly, it is very fluid (dynamic viscosity is only 17.2 μPa * s). This means that the flow can flow around the swept area, reducing the effective surface and KIEV, which is most often observed. But in principle, the opposite situation is also possible: the wind flows towards the rotor and the effective surface area will then be greater than the swept one, and the KIEV will be greater than 1 relative to it for a flat wind.

Let's give two examples. The first is a pleasure yacht, quite heavy; the yacht can sail not only against the wind, but also faster than it. Wind means external; the apparent wind must still be faster, otherwise how will it pull the ship?

The second is a classic of aviation history. During tests of the MIG-19, it turned out that the interceptor, which was a ton heavier than the front-line fighter, accelerates faster in speed. With the same engines in the same airframe.

The theorists did not know what to think, and seriously doubted the law of conservation of energy. In the end, it turned out that the problem was the cone of the radar radome protruding from the air intake. From its toe to the shell, an air compaction arose, as if raking it from the sides to the engine compressors. Since then, shock waves have become firmly established in theory as useful, and the fantastic flight performance of modern aircraft is due in no small part to their skillful use.

Aerodynamics

The development of aerodynamics is usually divided into two eras - before N. G. Zhukovsky and after. His report “On Attached Vortexes” dated November 15, 1905 marked the beginning of a new era in aviation.

Before Zhukovsky, they flew with flat sails: it was assumed that the particles of the oncoming flow gave all their momentum to the leading edge of the wing. This made it possible to immediately get rid of the vector quantity - angular momentum - which gave rise to tooth-breaking and most often non-analytical mathematics, move to much more convenient scalar purely energy relations, and ultimately obtain a calculated pressure field on the load-bearing plane, more or less similar to the real one.

This mechanistic approach made it possible to create devices that could, at the very least, take to the air and fly from one place to another, without necessarily crashing to the ground somewhere along the way. But the desire to increase speed, load capacity and other flight qualities increasingly revealed the imperfections of the original aerodynamic theory.

Zhukovsky's idea was this: the air travels a different path along the upper and lower surfaces of the wing. From the condition of continuity of the medium (vacuum bubbles by themselves do not form in the air) it follows that the velocities of the upper and lower flows descending from the trailing edge should be different. Due to the small but finite viscosity of the air, a vortex should form there due to the difference in speeds.

The vortex rotates, and the law of conservation of momentum, just as immutable as the law of conservation of energy, is also valid for vector quantities, i.e. must also take into account the direction of movement. Therefore, right there, on the trailing edge, a counter-rotating vortex with the same torque should form. Due to what? Due to the energy generated by the engine.

For aviation practice, this meant a revolution: by choosing the appropriate wing profile, it was possible to send an attached vortex around the wing in the form of a circulation G, increasing its lift. That is, by spending part, and for high speeds and loads on the wing – most of the motor power, you can create an air flow around the device, allowing you to achieve better flight qualities.

This made aviation aviation, and not part of aeronautics: now the aircraft could create for itself the environment necessary for flight and no longer be a toy of air currents. All you need is a more powerful engine, and more and more powerful...

KIEV again

But the windmill does not have a motor. On the contrary, it must take energy from the wind and give it to consumers. And here it turns out - his legs were pulled out, his tail got stuck. We used too little wind energy for the rotor’s own circulation - it will be weak, the thrust of the blades will be low, and the KIEV and power will be low. We will give a lot to the circulation - the rotor will be on Idling spinning like crazy, but consumers again get little: they barely applied the load, the rotor slowed down, the wind blew away the circulation, and the rotor stopped.

The law of conservation of energy gives the “golden mean” right in the middle: we give 50% of the energy to the load, and for the remaining 50% we turn up the flow to the optimum. Practice confirms the assumptions: if the efficiency of a good pulling propeller is 75-80%, then the efficiency of a bladed rotor that is also carefully calculated and blown in a wind tunnel reaches 38-40%, i.e. up to half of what can be achieved with excess energy.

Modernity

Nowadays, aerodynamics, armed with modern mathematics and computers, is increasingly moving away from inevitably simplifying models towards an accurate description of the behavior of a real body in a real flow. And here, in addition to the general line - power, power, and once again power! – side paths are discovered, but promising precisely when the amount of energy entering the system is limited.

The famous alternative aviator Paul McCready created an airplane back in the 80s with two chainsaw motors with a power of 16 hp. showing 360 km/h. Moreover, its chassis was tricycle, non-retractable, and its wheels were without fairings. None of McCready's devices went online or went on combat duty, but two - one with piston engines and propellers, and the other a jet - for the first time in history flew around the globe without landing at the same gas station.

The development of the theory also affected the sails that gave birth to the original wing quite significantly. “Live” aerodynamics allowed the yachts to operate in winds of 8 knots. stand on hydrofoils (see figure); to accelerate such a monster to the required speed with a propeller, an engine of at least 100 hp is required. Racing catamarans sail at a speed of about 30 knots in the same wind. (55 km/h).

There are also finds that are completely non-trivial. Fans of the rarest and most extreme sport - base jumping - wearing a special wing suit, wingsuit, fly without a motor, maneuvering at a speed of more than 200 km/h (picture on the right), and then smoothly land in a pre-selected place. In which fairy tale do people fly on their own?

Many mysteries of nature were also resolved; in particular, the flight of a beetle. According to classical aerodynamics, it is not capable of flying. Just like the founder of the stealth aircraft, the F-117, with its diamond-shaped wing, is also unable to take off. And the MIG-29 and Su-27, which can fly tail first for some time, do not fit into any idea at all.

And why then, when working on wind turbines, not a fun thing and not a tool for destroying their own kind, but a source of a vital resource, do you need to dance away from the theory of weak flows with its flat wind model? Is there really no way to move forward?

What to expect from the classics?

However, one should not abandon the classics under any circumstances. It provides a foundation without which one cannot rise higher without relying on it. Just as set theory does not abolish the multiplication table, and quantum chromodynamics will not make apples fly up from the trees.

So, what can you expect when classical approach? Let's look at the picture. On the left are types of rotors; they are depicted conditionally. 1 – vertical carousel, 2 – vertical orthogonal ( wind turbine); 2-5 – bladed rotors with different numbers of blades with optimized profiles.

On the right along the horizontal axis is the relative speed of the rotor, i.e., the ratio of the linear speed of the blade to the wind speed. Vertical up - KIEV. And down - again, relative torque. A single (100%) torque is considered to be that which is created by a rotor forcibly braked in the flow with 100% KIEV, i.e. when all the flow energy is converted into rotating force.

This approach allows us to draw far-reaching conclusions. For example, the number of blades must be selected not only and not so much according to the desired rotation speed: 3- and 4-blades immediately lose a lot in terms of KIEV and torque compared to 2- and 6-blades that work well in approximately the same speed range. And the outwardly similar carousel and orthogonal have fundamentally different properties.

In general, preference should be given to bladed rotors, except in cases where extreme low cost, simplicity, maintenance-free self-starting without automation are required, and lifting onto a mast is impossible.

Note: Let's talk about sailing rotors in particular - they don't seem to fit into the classics.

Verticals

APUs with a vertical axis of rotation have an undeniable advantage for everyday life: their components requiring maintenance are concentrated at the bottom and no lifting is required. There remains, and even then not always, a thrust-support self-aligning bearing, but it is strong and durable. Therefore, when designing a simple wind generator, the selection of options should begin with verticals. Their main types are presented in Fig.

Sun

In the first position is the simplest one, most often called the Savonius rotor. In fact, it was invented in 1924 in the USSR by J. A. and A. A. Voronin, and the Finnish industrialist Sigurd Savonius shamelessly appropriated the invention, ignoring the Soviet copyright certificate, and began serial production. But the introduction of an invention in the future means a lot, so in order not to stir up the past and not disturb the ashes of the deceased, we will call this windmill a Voronin-Savonius rotor, or for short, VS.

The aircraft is good for the home-made man, except for the “locomotive” KIEV at 10-18%. However, in the USSR they worked a lot on it, and there are developments. Below we will look at an improved design, not much more complex, but according to KIEV, it gives bladers a head start.

Note: the two-blade aircraft does not spin, but jerks jerkily; The 4-blade is only slightly smoother, but loses a lot in KIEV. To improve, 4-trough blades are most often divided into two floors - a pair of blades below, and another pair, rotated 90 degrees horizontally, above them. KIEV is preserved, and the lateral loads on the mechanics weaken, but the bending loads increase somewhat, and with a wind of more than 25 m/s such an APU is on the shaft, i.e. without a bearing stretched by cables above the rotor, it “tears down the tower.”

Daria

Next is the Daria rotor; KIEV – up to 20%. It is even simpler: the blades are made of a simple elastic tape without any profile. The theory of the Darrieus rotor is not yet sufficiently developed. It is only clear that it begins to unwind due to the difference in the aerodynamic resistance of the hump and the tape pocket, and then it becomes sort of high-speed, forming its own circulation.

The torque is small, and in the starting positions of the rotor parallel and perpendicular to the wind it is completely absent, so self-spin is possible only with an odd number of blades (wings?) In any case, the load from the generator must be disconnected during spin-up.

The Daria rotor has two more bad qualities. Firstly, when rotating, the thrust vector of the blade describes a full rotation relative to its aerodynamic focus, and not smoothly, but jerkily. Therefore, the Darrieus rotor quickly breaks down its mechanics even in a steady wind.

Secondly, Daria not only makes noise, but screams and squeals, to the point that the tape breaks. This happens due to its vibration. And the more blades, the stronger the roar. So if they make Daria, they do it with two blades, from expensive high-strength ones. sound-absorbing materials(carbon, mylar), and for unwinding in the middle of the mast-pole a small aircraft is adapted.

Orthogonal

At pos. 3 – orthogonal vertical rotor with profiled blades. Orthogonal because the wings stick out vertically. The transition from BC to orthogonal is illustrated in Fig. left.

The angle of installation of the blades relative to the tangent to the circle touching the aerodynamic foci of the wings can be either positive (in the figure) or negative, depending on the wind force. Sometimes the blades are made rotating and weather vanes are placed on them, automatically holding the “alpha”, but such structures often break.

The central body (blue in the figure) allows you to increase the KIEV to almost 50%. In a three-blade orthogonal, it should have the shape of a triangle in cross-section with slightly convex sides and rounded corners, and with a larger number of blades, a simple cylinder is sufficient. But the theory for the orthogonal gives an unambiguous optimal number of blades: there should be exactly 3 of them.

Orthogonal refers to high-speed wind turbines with OSS, i.e. necessarily requires promotion during commissioning and after calm. According to the orthogonal scheme, serial maintenance-free APUs with a power of up to 20 kW are produced.

Helicoid

Helicoidal rotor, or Gorlov rotor (item 4) is a type of orthogonal that ensures uniform rotation; an orthogonal with straight wings “tears” only slightly weaker than a two-bladed aircraft. Bending the blades along a helicoid allows one to avoid losses of CIEV due to their curvature. Although the curved blade rejects part of the flow without using it, it also scoops part into the zone of highest linear speed, compensating for losses. Helicoids are used less often than other wind turbines, because Due to the complexity of manufacturing, they are more expensive than their counterparts of equal quality.

Barrel raking

For 5 pos. – BC type rotor surrounded by a guide vane; its diagram is shown in Fig. on right. It is rarely found in industrial applications, because expensive land acquisition does not compensate for the increase in capacity, and the material consumption and complexity of production are high. But a do-it-yourselfer who is afraid of work is no longer a master, but a consumer, and if you need no more than 0.5-1.5 kW, then for him a “barrel-raking” is a tidbit:

• A rotor of this type is absolutely safe, silent, does not create vibrations and can be installed anywhere, even on a playground.
• Bending a galvanized “trough” and welding a frame of pipes is nonsense work.
• Rotation is absolutely uniform, mechanical parts can be taken from the cheapest or from the trash.
• Not afraid of hurricanes - too strong a wind cannot push into the “barrel”; a streamlined vortex cocoon appears around it (we will encounter this effect later).
• And the most important thing is that since the surface of the “barrel” is several times larger than that of the rotor inside, the KIEV can be over-unit, and the rotational moment already at 3 m/s for a “barrel” of three-meter diameter is such that a 1 kW generator with a maximum load of They say it’s better not to twitch.

Video: Lenz wind generator

In the 60s in the USSR, E. S. Biryukov patented a carousel APU with a KIEV of 46%. A little later, V. Blinov achieved 58% KIEV from a design based on the same principle, but there is no data on its testing. And full-scale tests of Biryukov’s APU were carried out by employees of the magazine “Inventor and Innovator”. A two-story rotor with a diameter of 0.75 m and a height of 2 m was spun at full power asynchronous generator 1.2 kW and withstood 30 m/s without breakdown. Drawings of Biryukov's APU are shown in Fig.

1. rotor made of galvanized roofing;
2. self-aligning double row ball bearing;
3. shrouds – 5 mm steel cable;
4. axis-shaft – steel pipe with a wall thickness of 1.5-2.5 mm;
5. aerodynamic speed control levers;
6. speed control blades – 3-4 mm plywood or sheet plastic;
7. speed control rods;
8. speed controller load, its weight determines the rotation speed;
9. drive pulley - a bicycle wheel without a tire with a tube;
10. thrust bearing - thrust bearing;
11. driven pulley – standard generator pulley;
12. generator.

Biryukov received several copyright certificates for his APU. First, pay attention to the cut of the rotor. When accelerating, it works like an aircraft, creating a large starting torque. As it spins, a vortex cushion is created in the outer pockets of the blades. From the wind's point of view, the blades become profiled and the rotor becomes a high-speed orthogonal, with the virtual profile changing according to the wind strength.

Secondly, the profiled channel between the blades acts as a central body in the operating speed range. If the wind intensifies, then a vortex cushion is also created in it, extending beyond the rotor. The same vortex cocoon appears as around the APU with a guide vane. The energy for its creation is taken from the wind, and it is no longer enough to break the windmill.

Thirdly, the speed controller is intended primarily for the turbine. It keeps its speed optimal from the KIEV point of view. And the optimum generator rotation speed is ensured by the choice of mechanical transmission ratio.

Note: after publications in the IR for 1965, the Armed Forces of Ukraine Biryukova sank into oblivion. The author never received a response from the authorities. The fate of many Soviet inventions. They say that some Japanese became a billionaire by regularly reading Soviet popular-technical magazines and patenting everything worthy of attention.

Lopastniki

As stated, according to the classics, a horizontal wind generator with a bladed rotor is the best. But, firstly, it needs a stable wind of at least medium strength. Secondly, the design for the DIYer is fraught with many pitfalls, which is why the fruit of long hard work in best case scenario illuminates the toilet, hallway or porch, or even turns out to be only able to promote itself.

According to the diagrams in Fig. Let's take a closer look; positions:

• Fig. A:

1. rotor blades;
2. generator;
3. generator frame;
4. protective weather vane (hurricane shovel);
5. current collector;
6. chassis;
7. swivel unit;
8. working weather vane;
9. mast;
10. clamp for the shrouds.

• Fig. B, top view:

1. protective weather vane;
2. working weather vane;
3. protective weather vane spring tension regulator.

• Fig. G, current collector:

1. collector with copper continuous ring busbars;
2. spring-loaded copper-graphite brushes.

Note: Hurricane protection for a horizontal blade with a diameter of more than 1 m is absolutely necessary, because he is not capable of creating a vortex cocoon around himself. With smaller sizes, it is possible to achieve a rotor endurance of up to 30 m/s with propylene blades.

So, where do we stumble?

Blades

Expecting to achieve a power on the generator shaft of more than 150-200 W on blades of any size cut from a thick-walled plastic pipe, as is often advised, is the hope of a hopeless amateur. A pipe blade (unless it is so thick that it is simply used as a blank) will have a segmented profile, i.e. its top or both surfaces will be arcs of a circle.

Segmented profiles are suitable for incompressible media, such as hydrofoils or propeller blades. For gases, a blade of variable profile and pitch is needed, for an example, see Fig.; span - 2 m. This will be a complex and labor-intensive product, requiring painstaking calculations in full theory, blowing in a pipe and full-scale testing.

Generator

If the rotor is mounted directly on its shaft, the standard bearing will soon break - there is no equal load on all the blades in windmills. You need an intermediate shaft with a special support bearing and a mechanical transmission from it to the generator. For large windmills, the support bearing is a self-aligning double-row one; V best models– three-tiered, Fig. D in Fig. higher. This allows the rotor shaft not only to bend slightly, but also to move slightly from side to side or up and down.

Note: It took about 30 years to develop a support bearing for the EuroWind type APU.

Emergency weather vane

The principle of its operation is shown in Fig. B. The wind, intensifying, puts pressure on the shovel, the spring stretches, the rotor warps, its speed drops and eventually it becomes parallel to the flow. Everything seems to be fine, but it was smooth on paper...

On a windy day, try holding a boiler lid or a large saucepan by the handle parallel to the wind. Just be careful - the fidgety piece of iron can hit you in the face so hard that it breaks your nose, cuts your lip, or even knocks out your eye.

Flat wind occurs only in theoretical calculations and, with sufficient accuracy for practice, in wind tunnels. In reality, a hurricane damages windmills with a hurricane shovel more than completely defenseless ones. It’s better to change damaged blades than to do everything again. In industrial installations it is a different matter. There, the pitch of the blades, each individually, is monitored and adjusted by automation under the control of the on-board computer. And they are made from heavy-duty composites, not water pipes.

Current collector

This is a regularly serviced unit. Any power engineer knows that the commutator with brushes needs to be cleaned, lubricated, and adjusted. And the mast is made from a water pipe. If you can’t climb, once every month or two you’ll have to throw the entire windmill down to the ground and then pick it up again. How long will he last from such “prevention”?

Video: bladed wind generator + solar panel for power supply to a dacha

Mini and micro

But as the size of the paddle decreases, the difficulties fall according to the square of the wheel diameter. It is already possible to manufacture a horizontal bladed APU on your own with a power of up to 100 W. A 6-bladed one would be optimal. With more blades, the diameter of the rotor designed for the same power will be smaller, but they will be difficult to firmly attach to the hub. Rotors with less than 6 blades need not be taken into account: a 2-blade 100 W rotor needs a rotor with a diameter of 6.34 m, and a 4-blade of the same power needs 4.5 m. For a 6-blade, the power-diameter relationship is expressed as follows :

• 10 W – 1.16 m.
• 20 W – 1.64 m.
• 30 W – 2 m.
• 40 W – 2.32 m.
• 50 W – 2.6 m.
• 60 W – 2.84 m.
• 70 W – 3.08 m.
• 80 W – 3.28 m.
• 90 W – 3.48 m.
• 100 W – 3.68 m.
• 300 W – 6.34 m.

It would be optimal to count on a power of 10-20 W. Firstly, a plastic blade with a span of more than 0.8 m will not withstand winds of more than 20 m/s without additional protection measures. Secondly, with a blade span of up to the same 0.8 m, the linear speed of its ends will not exceed the wind speed by more than three times, and the requirements for profiling with twist are reduced by orders of magnitude; here a “trough” with a segmented pipe profile, pos. B in Fig. And 10-20 W will provide power to a tablet, recharge a smartphone, or illuminate a house-saving light bulb.

Next, select a generator. A Chinese motor is perfect - wheel hub for electric bicycles, pos. 1 in Fig. Its power as a motor is 200-300 W, but in generator mode it will give up to about 100 W. But will it suit us in terms of speed?

The speed index z for 6 blades is 3. The formula for calculating the rotation speed under load is N = v/l*z*60, where N is the rotation speed, 1/min, v is the wind speed, and l is the rotor circumference. With a blade span of 0.8 m and a wind of 5 m/s, we get 72 rpm; at 20 m/s – 288 rpm. A bicycle wheel also rotates at approximately the same speed, so we will take off our 10-20 W from a generator capable of producing 100. You can place the rotor directly on its shaft.

But here the following problem arises: after spending a lot of work and money, at least on a motor, we got... a toy! What is 10-20, well, 50 W? But you can’t make a bladed windmill capable of powering even a TV at home. Is it possible to buy a ready-made mini-wind generator, and wouldn’t it be cheaper? As much as possible, and as cheaply as possible, see pos. 4 and 5. In addition, it will also be mobile. Place it on a stump and use it.

The second option is if a stepper motor from an old 5- or 8-inch floppy drive is lying around somewhere, or from a paper drive or carriage of an unusable inkjet or dot matrix printer. It can work as a generator, and attach a carousel rotor to it from tin cans(pos. 6) is easier than assembling a structure like the one shown in pos. 3.

In general, the conclusion regarding “blade blades” is clear: homemade ones are more likely for tinkering to your heart’s content, but not for real long-term energy output.

Video: the simplest wind generator for lighting a dacha

Sailboats

The sailing wind generator has been known for a long time, but soft panels on its blades (see figure) began to be made with the advent of high-strength, wear-resistant synthetic fabrics and films. Multi-bladed windmills with rigid sails have spread widely around the world as a drive for low-power automatic water pumps, but their technical specifications are lower even than those of carousels.

However, a soft sail like a windmill wing, it seems, turned out to be not so simple. The point is not about wind resistance (manufacturers do not limit the maximum permissible wind speed): sailboat sailors already know that it is almost impossible for the wind to tear the panel of a Bermuda sail. Most likely, the sheet will be torn out, or the mast will be broken, or the whole vessel will make an “overkill turn.” It's about energy.

Unfortunately, exact test data cannot be found. Based on user reviews, it was possible to create “synthetic” dependencies for the installation of a Taganrog-made wind turbine-4.380/220.50 with a wind wheel diameter of 5 m, a wind head weight of 160 kg and a rotation speed of up to 40 1/min; they are presented in Fig.

Of course, there can be no guarantees for 100% reliability, but it is clear that there is no smell of a flat-mechanistic model here. There is no way a 5-meter wheel in a flat wind of 3 m/s can produce about 1 kW, at 7 m/s reach a plateau in power and then maintain it until a severe storm. Manufacturers, by the way, state that the nominal 4 kW can be obtained at 3 m/s, but when installed by forces based on the results of studies of local aerology.

There is also no quantitative theory to be found; The developers' explanations are unclear. However, since people buy Taganrog wind turbines and they work, we can only assume that the declared conical circulation and propulsive effect are not a fiction. In any case, they are possible.

Then, it turns out, IN FRONT of the rotor, according to the law of conservation of momentum, a conical vortex should also arise, but expanding and slow. And such a funnel will drive the wind towards the rotor, its effective surface will be more swept, and the KIEV will be more than unity.

Field measurements of the pressure field in front of the rotor, even with a household aneroid, could shed light on this issue. If it turns out to be higher than on the sides, then, indeed, the sailing APUs work like a beetle flies.

Homemade generator

From what has been said above, it is clear that it is better for homemade craftsmen to take on either verticals or sailboats. But both are very slow, and transmission to a high-speed generator is extra work, extra costs and losses. Is it possible to make an efficient low-speed electric generator yourself?

Yes, you can, on magnets made of niobium alloy, so-called. supermagnets. The manufacturing process of the main parts is shown in Fig. Coils - each of 55 turns of 1 mm copper wire in heat-resistant high-strength enamel insulation, PEMM, PETV, etc. The height of the windings is 9 mm.

Pay attention to the grooves for the keys in the rotor halves. They must be positioned so that the magnets (they are glued to the magnetic core with epoxy or acrylic) converge with opposite poles after assembly. “Pancakes” (magnetic cores) must be made of a soft magnetic ferromagnet; regular one will do structural steel. The thickness of the “pancakes” is at least 6 mm.

In general, it is better to buy magnets with an axial hole and tighten them with screws; supermagnets attract with terrible force. For the same reason, a cylindrical spacer 12 mm high is placed on the shaft between the “pancakes”.

The windings that make up the stator sections are connected according to the diagrams also shown in Fig. The soldered ends should not be stretched, but should form loops, otherwise the epoxy with which the stator will be filled may harden and break the wires.

The stator is poured into the mold to a thickness of 10 mm. There is no need to center or balance, the stator does not rotate. The gap between the rotor and stator is 1 mm on each side. The stator in the generator housing must be securely secured not only from displacement along the axis, but also from rotation; a strong magnetic field with current in the load will pull it along with it.

Video: DIY windmill generator

Conclusion

And what do we have in the end? The interest in “blade blades” is explained rather by their spectacular appearance than real performance qualities in a homemade version and at low power. A homemade carousel APU will provide “standby” power for charging a car battery or powering a small house.

But with sailing APUs it is worth experimenting with craftsmen with a creative streak, especially in the mini version, with a wheel 1-2 m in diameter. If the developers’ assumptions are correct, then it will be possible to remove all 200-300 W from this one, using the Chinese engine-generator described above.

Andrey said:

Thank you for your free consultation... And the prices “from companies” are not really expensive, and I think that craftsmen from the outback will be able to make generators similar to yours. And Li-po batteries can be ordered from China, inverters in Chelyabinsk make very good ones (with smooth sine). And sails, blades or rotors are another reason for the flight of thought of our handy Russian men.

Ivan said:

question:
For wind turbines with a vertical axis (position 1) and the Lenz option, it is possible to add additional detail- an impeller that points towards the wind and covers the useless side from it (going towards the wind). That is, the wind will not slow down the blade, but this “screen”. Positioning downwind with the “tail” located behind the windmill itself below and above the blades (ridges). I read the article and an idea was born.

By clicking the “Add comment” button, I agree with the site.

One of the most affordable options for using renewable energy sources is the use of wind energy. To learn how to make calculations, assemble and install a windmill yourself, read this article.

Classification of wind generators

Installations are classified based on following criteria wind turbine:

• location of the axis of rotation;
• number of blades;
• element material;
• propeller pitch.

Wind turbines, as a rule, have design with horizontal and vertical axis of rotation.

Version with a horizontal axis - a propeller design with one, two, three or more blades. This is the most common design of air power plants due to its high efficiency.

Version with a vertical axis - orthogonal and carousel designs using the example of Darrieus and Savonius rotors. The last two concepts should be clarified, since both have some significance in the design of wind generators.

Darrieus rotor is an orthogonal wind turbine design, where aerodynamic blades (two or more) are located symmetrically to each other at a certain distance and mounted on radial beams. A rather complex version of a wind turbine that requires careful aerodynamic design of the blades.

Savonius rotor is a carousel-type wind turbine design, where two semi-cylindrical blades are located one against the other, overall forming a sinusoidal shape. The efficiency of the structures is low (about 15%), but can be almost doubled if the blades are placed in the direction of the wave not horizontally, but vertically and a multi-tier design is used with the angular displacement of each pair of blades relative to the other pairs.

Advantages and disadvantages of wind turbines

The advantages of these devices are obvious, especially in relation to living conditions operation. Users of wind turbines actually have the opportunity to generate free electrical energy, not counting the small costs of construction and maintenance. However, the disadvantages of wind power plants are also obvious.

So in order to achieve efficient work installation, the conditions for stability of wind flows must be met. Man cannot create such conditions. This is purely the prerogative of nature. Another technical drawback is the low quality of generated electricity, as a result of which it is necessary to supplement the system with expensive electrical modules (multipliers, chargers, batteries, converters, stabilizers).

The advantages and disadvantages in terms of the features of each modification of wind turbines, perhaps, balance at zero. If the horizontal-axial modifications are different high value efficiency, then for stable operation they require the use of wind flow direction controllers and hurricane wind protection devices. Vertical-axis modifications have low efficiency, but work stably without a mechanism for tracking wind direction. At the same time, such wind turbines are distinguished by a low noise level, eliminate the “spreading” effect in strong winds, and are quite compact.

Homemade wind generators

Making a "windmill" with my own hands- the problem is completely solvable. Moreover, a constructive and rational approach to business will help minimize inevitable financial expenses. First of all, it’s worth sketching out the project and carrying out the necessary balancing and power calculations. These actions will be more than just collateral successful construction wind power plant, but also a guarantee of maintaining the integrity of all purchased equipment.

It is recommended to start by building a micro-windmill with a power of several tens of watts. In the future, the experience gained will help create a more powerful design. When creating a home wind generator, you should not focus on obtaining high-quality electricity (220 V, 50 Hz), since this option will require significant financial investments. It makes more sense to limit ourselves to the use of initially obtained electricity, which can be successfully used without conversion for other purposes, for example, to support heating and hot water supply systems built on electric heaters (TEH) - such devices do not require stable voltage and frequency. This makes it possible to create simple diagram, operating directly from the generator.

Most likely, no one will argue that heating and hot water supply in the house are inferior in importance to household appliances and lighting devices, for the power of which they often try to install home windmills. The installation of a wind turbine specifically for the purpose of providing a home with heat and hot water means minimal costs and simplicity of design.

Generalized design of a home wind turbine

Structurally, a home project largely replicates an industrial installation. True, household solutions are often based on vertical-axis wind turbines and are equipped with low-voltage generators direct current. Composition of household wind turbine modules, subject to high-quality electricity (220 V, 50 Hz):

• wind turbine;
• wind orientation device;
• animator;
• DC generator (12 V, 24 V);
• battery charging module;
• rechargeable batteries (lithium-ion, lithium-polymer, lead-acid);
• 12V (24V) to DC converter AC voltage 220 V.

Wind generator PIC 8-6/2.5

How it works? Just. The wind turns the wind turbine. The torque is transmitted through the multiplier to the shaft of the DC generator. The energy received at the output of the generator is accumulated in batteries through the charging module. From the battery terminals, a constant voltage of 12 V (24 V, 48 V) is supplied to the converter, where it is transformed into a voltage suitable for powering household electrical networks.

About generators for home windmills

Most domestic wind turbine designs are typically constructed using low-speed DC motors. This is the simplest generator option that does not require modernization. Optimally - electric motors with permanent magnets, designed for a supply voltage of about 60-100 volts. There is a practice of using car generators, but for this case the introduction of a multiplier is required, since car generators produce the required voltage only at high (1800-2500) speeds. One of the possible options is the reconstruction of an AC asynchronous motor, but it is also quite complex, requiring precise calculations, turning, and installation of neodymium magnets in the rotor area. There is an option for a three-phase asynchronous motor with the connection of capacitors of the same capacity between the phases. Finally, there is the possibility of making a generator from scratch with your own hands. There are a lot of instructions on this matter.

Vertical-axis homemade “windmill”

A fairly efficient and, most importantly, inexpensive wind generator can be built on the basis of a Savonius rotor. Here, as an example, a micro-energy installation is considered, the power of which does not exceed 20 W. However, this device is quite sufficient, for example, to provide electrical energy some household appliances operating on 12 volts.

Set of parts:

1. Aluminum sheet 1.5-2 mm thick.
2. Plastic pipe: diameter 125 mm, length 3000 mm.
3. Aluminum pipe: diameter 32 mm, length 500 mm.
4. DC motor (potential generator), 30-60V, 360-450 rpm, for example, electric motor model PIK8-6/2.5.
5. Voltage controller.
6. Battery.

Manufacturing of the Savonius rotor

Three “pancakes” with a diameter of 285 mm are cut out of an aluminum sheet. Holes are drilled in the center of each for a 32 mm aluminum pipe. It turns out something similar to CDs. Two pieces 150 mm long are cut from a plastic pipe and cut in half lengthwise. The result is four semicircular blades 125x150 mm. All three aluminum “CDs” are put on a 32 mm pipe and fixed at a distance of 320, 170, 20 mm from the top point strictly horizontally, forming two tiers. Blades are inserted between the disks, two per tier, and fixed strictly one against the other, forming a sinusoid. In this case, the blades of the upper tier are shifted relative to the blades of the lower tier at an angle of 90 degrees. The result is a four-bladed Savonius rotor. To fasten elements, you can use rivets, self-tapping screws, corners, or other methods.

Connection to engine and installation on mast

The shaft of DC motors with the above parameters usually has a diameter of no more than 10-12 mm. In order to connect the motor shaft to the wind turbine pipe, a brass bushing having the required internal diameter is pressed into the lower part of the pipe. A hole is drilled through the wall of the pipe and the bushing, and a thread is cut to screw in the locking screw. Next, the wind turbine pipe is put on the generator shaft, after which the connection is rigidly fixed with a locking screw.

The remaining part of the plastic pipe (2800 mm) is the mast of the wind turbine. The generator assembly with the Savonius wheel is mounted at the top of the mast - it is simply inserted into the pipe until it stops. A metal disk cover mounted on the front end of the motor, having a diameter slightly larger than the diameter of the mast, is used as a stop. Holes are drilled on the periphery of the cover for attaching guy wires. Since the motor housing diameter is smaller internal diameter pipes, spacers or stops are used to align the generator in the center. The cable from the generator is passed inside the pipe and exited through the window at the bottom. During installation, it is necessary to take into account the protection of the generator from moisture by using sealing gaskets. Again, for the purpose of protection from precipitation, an umbrella cap can be installed above the connection of the wind turbine pipe with the generator shaft.

The entire structure is installed in an open, well-ventilated area. A hole 0.5 meters deep is dug under the mast, the lower part of the pipe is lowered into the hole, the structure is leveled with guy wires, after which the hole is filled with concrete.

Voltage controller (simple charger)

A manufactured wind generator, as a rule, is not capable of producing 12 volts due to the low rotation speed. The maximum rotation speed of the wind turbine at a wind speed of 6-8 m/sec. reaches a value of 200-250 rpm. At the output it is possible to obtain a voltage of about 5-7 volts. To charge the battery, a voltage of 13.5-15 volts is required. The way out is to use a simple pulse converter voltage collected, for example, based on the LM2577ADJ voltage regulator. By supplying 5 volts of DC to the input of the converter, the output is 12-15 volts, which is quite enough to charge a car battery.

Ready-made voltage converter based on LM2577

This micro-wind generator can certainly be improved. Increase the turbine power, change the material and height of the mast, add a DC-AC converter mains voltage etc.

Horizontal-axis wind power plant

Set of parts:

1. Plastic pipe with a diameter of 150 mm, aluminum sheet 1.5-2.5 mm thick, wooden block 80x40 1 m long, plumbing: flange - 3, angle - 2, tee - 1.
2. DC electric motor (generator) 30-60 V, 300-470 rpm.
3. Wheel-pulley for an engine with a diameter of 130-150 mm (aluminum, brass, textolite, etc.).
4. Steel pipes with a diameter of 25 mm and 32 mm and a length of 35 mm and 3000 mm, respectively.
5. Charging module for batteries.
6. Batteries.
7. Voltage converter 12 V - 120 V (220 V).

Manufacturing of a horizontal-axis “windmill”

A plastic pipe is needed to make wind turbine blades. A section of such a pipe, 600 mm long, is cut lengthwise into four identical segments. A windmill requires three blades, which are made from the resulting segments by cutting part of the material diagonally along the entire length, but not exactly from corner to corner, but from bottom corner to the top corner, with a slight indentation from the last. Processing the lower part of the segments is reduced to the formation of a fastening petal on each of the three segments. To do this, a square measuring approximately 50x50 mm is cut along one edge, and the remaining part serves as a fastening petal.

The wind turbine blades are secured to the wheel-pulley using bolted connections. The pulley is mounted directly on the shaft of a DC electric motor - generator. A simple wooden block with a cross-section of 80x40 mm and a length of 1 m is used as a wind turbine chassis. The generator is installed at one end wooden block. At the other end of the bar, a “tail” made of an aluminum sheet is mounted. At the bottom of the block, a 25 mm metal pipe is attached, intended to act as the shaft of the rotating mechanism. A three-meter 32 mm metal pipe is used as a mast. The upper part of the mast is the bushing of the rotating mechanism, into which the wind turbine pipe is inserted. The mast support is made from a sheet of thick plywood. On this support, in the form of a disk with a diameter of 600 mm, a structure is assembled from plumbing parts, thanks to which the mast can be easily raised or lowered, or mounted or dismantled. Guys are used to secure the mast.

All electronics wind turbine mounted separate module, the interface of which provides for the connection of batteries and consumer load. The module includes a battery charge controller and a voltage converter. Such devices can be assembled independently if you have the appropriate experience, or purchased on the market. There are many different solutions on the market that allow you to obtain the desired output voltages and currents.

Combined wind turbines

Combined wind turbines are a serious option for a home energy module. Actually, the combination involves combining a wind generator, solar battery, diesel or gasoline power plant into a single system. You can combine in every possible way, based on your capabilities and needs. Naturally, when there is a three-in-one option, this is the most effective and reliable solution.

Also, the combination of wind turbines involves the creation of wind power plants that include two different modifications at once. For example, when a Savonius rotor and a traditional three-blade machine work in one combination. The first turbine operates at low wind speeds, and the second only at nominal ones. This preserves the efficiency of the installation, eliminates unjustified energy losses, and in the case of asynchronous generators reactive currents are compensated.

Combined systems are technically complex and expensive options for home practice.

Calculation of the power of a wind power plant

To calculate the power of a horizontal-axial wind generator, you can use the standard formula:

• N = p S V3 / 2
• N— installation power, W
• p- air density (1.2 kg/m3)
• S— blown area, m2
• V— wind flow speed, m/sec

For example, the power of an installation with a maximum blade span of 1 meter at a wind speed of 7 m/sec will be:

• N= 1.2 1 343 / 2 = 205.8 W

An approximate calculation of the power of a wind turbine created on the basis of a Savonius rotor can be calculated using the formula:

• N = p R H V3
• N— installation power, W
• R— impeller radius, m
• V— wind speed, m/sec

For example, for the design of a wind power plant with a Savonius rotor mentioned in the text, the power value at a wind speed of 7 m/sec. will be:

• N= 1.2 · 0.142 · 0.3 · 343 = 17.5 W

Often, owners of private houses have an idea to implement backup power supply systems. The simplest and most accessible method is, naturally, or a generator, but many people turn their attention to a more complex ways converting the so-called free energy (radiation, energy of flowing water or wind) into.

Each of these methods has its own advantages and disadvantages. If everything is clear with the use of water flow (mini-hydroelectric power station) - this is only available in the immediate vicinity of a fairly fast-flowing river, then sunlight or wind can be used almost everywhere. Both of these methods will have a common disadvantage - if water turbine can operate around the clock, a solar battery or wind generator is only effective for a while, which makes it necessary to include batteries in the structure of the home electrical network.

Since conditions in Russia (short daylight hours most of the year, frequent precipitation) make the use of solar panels ineffective at their current cost and efficiency, the most profitable is the design of a wind generator. Let's consider its principle of operation and possible design options.

Since none homemade device not like the other one, this one article is not step-by-step instruction , but a description of the basic principles of wind generator design.

General operating principle

The main working parts of a wind generator are the blades, which are rotated by the wind. Depending on the location of the rotation axis, wind generators are divided into horizontal and vertical:

• Horizontal wind generators most widespread. Their blades have a design similar to an airplane propeller: to a first approximation, they are plates inclined relative to the plane of rotation, which convert part of the load from wind pressure into rotation. An important feature of a horizontal wind generator is the need to ensure rotation of the blade assembly in accordance with the direction of the wind, since maximum efficiency is ensured when the wind direction is perpendicular to the plane of rotation.
• Blades vertical wind generator have a convex-concave shape. Since the streamlining of the convex side is greater than the concave side, such a wind generator always rotates in one direction, regardless of the direction of the wind, which makes the turning mechanism unnecessary, unlike horizontal wind turbines. At the same time, due to the fact that at any given time useful work performs only part of the blades, and the rest only counteract rotation, The efficiency of a vertical wind turbine is significantly lower than that of a horizontal one: if for a three-blade horizontal wind generator this figure reaches 45%, then for a vertical one it will not exceed 25%.

Since the average wind speed in Russia is low, even a large windmill will rotate quite slowly most of the time. To ensure sufficient power supply, it must be connected to the generator through a step-up gearbox, belt or gear. In a horizontal windmill, the blade-gearbox-generator assembly is mounted on a rotating head, which allows them to follow the direction of the wind. It is important to take into account that the rotating head must have a limiter that prevents it from making a full rotation, since otherwise the wiring from the generator will be broken (the option of using contact washers that allow the head to rotate freely is more complicated). To ensure rotation, the wind generator is supplemented with a working vane directed along the axis of rotation.

The most common material for blades is PVC pipes large diameter, cut lengthwise. Along the edges they are riveted with metal plates welded to the hub of the blade assembly. Drawings of this kind of blades are most widely distributed on the Internet.

The video tells about a wind generator made by yourself

Calculation of a bladed wind generator

Since we have already found out that a horizontal wind generator is much more efficient, we will consider the calculation of its design.

Wind energy can be determined by the formula
P=0.6*S*V³, where S is the area of ​​the circle described by the ends of the propeller blades (sweeping area), expressed in square meters, and V is the estimated wind speed in meters per second. You also need to take into account the efficiency of the windmill itself, which for a three-bladed horizontal circuit will average 40%, as well as the efficiency of the generator set, which at the peak of the current-speed characteristic is 80% for a generator with excitation from permanent magnets and 60% for a generator with an excitation winding. On average, another 20% of the power will be consumed by the step-up gearbox (multiplier). Thus, the final calculation of the radius of a windmill (that is, the length of its blade) for a given power of a permanent magnet generator looks like this:
R=√(P/(0.483*V³))

Example: Let's take the required power of the wind power plant to be 500 W, and the average wind speed to be 2 m/s. Then, according to our formula, we will have to use blades at least 11 meters long. As you can see, even such a small power will require the creation of a wind generator of colossal dimensions. For structures that are more or less rational in terms of making your own, with a blade length of no more than one and a half meters, the wind generator will be able to produce only 80-90 watts of power even in strong winds.

Not enough power? In fact, everything is somewhat different, since in fact the load of the wind generator is powered by batteries, while the windmill only charges them to the best of its capabilities. Consequently, the power of a wind turbine determines the frequency with which it can supply energy.

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