The air masses have inexhaustible reserves of energy that mankind used in ancient times. Basically, the force of the wind ensured the movement of ships under sails and the operation of windmills. After the invention of steam engines, this type of energy has lost its relevance.

Only in modern conditions, wind energy has again become popular as a driving force applied to electric generators. They have not yet become widespread on an industrial scale, but are becoming increasingly popular in the private sector. Sometimes it is simply impossible to connect to a power line. In such situations, many owners design and manufacture a wind generator for a private house with their own hands from improvised materials. Further they are used as the main or auxiliary sources of electricity.

Theory of the Perfect Windmill

This theory was developed at different times by scientists and specialists in the field of mechanics. It was first developed by V.P. Vetchinkin in 1914, and the theory of an ideal propeller was used as a basis. In these studies, the utilization of wind energy by an ideal windmill was first derived.

Work in this area was continued by N.E. Zhukovsky, who deduced the maximum value of this coefficient, equal to 0.593. In the later works of another professor - Sabinin G.Kh. the adjusted coefficient value was 0.687.

In accordance with the developed theories, an ideal wind wheel should have the following parameters:

• The axis of rotation of the wheel should be parallel to the speed of the wind flow.
• The number of blades is infinitely large, with a very small width.
• Zero profile wing resistance in the presence of constant circulation along the blades.
• The entire swept surface of the windmill has a constant lost airflow velocity on the wheel.
• The tendency of angular velocity to infinity.

Wind turbine selection

When choosing a wind generator model for a private house, the necessary power should be taken into account, ensuring the operation of instruments and equipment, taking into account the schedule and frequency of switching on. It is determined by monthly accounting of consumed electricity. Additionally, the power value can be determined in accordance with the technical characteristics of consumers.

It is necessary to take into account the factor that the power of all electrical appliances is not carried out directly from the wind generator, but from the inverter and the set of batteries. Thus, a 1 kW generator is capable of ensuring the normal functioning of batteries supplying a four-kilowatt inverter. As a result, household appliances with the same capacity are provided with electricity in full. Of great importance is the right choice of batteries. Particular attention should be paid to parameters such as charging current.

When choosing a wind turbine design, the following factors are considered:

• The direction of rotation of the wind wheel is vertical or horizontal.
• The shape of the fan blades can be in the form of a sail, with a straight or curved surface. In some cases, combined options are used.
• Material for the blades and the technology of their manufacture.
• Placement of fan blades with a different slope, relative to the flow of passing air.
• The number of blades included in the fan.
• The required power transmitted from the wind turbine to the generator.

In addition, it is necessary to take into account the average annual wind speed for a particular area, specified in the weather service. It is not necessary to specify the direction of the wind, since modern designs of wind generators independently rotate in the opposite direction.

For most areas of the Russian Federation, the best option would be the horizontal orientation of the axis of rotation, the surface of the blades is curved concave, which the air stream flows around at an acute angle. The amount of power taken from the wind is affected by the area of \u200b\u200bthe blade. For an ordinary house, an area of \u200b\u200b1.25 m 2 is enough.

The number of revolutions of a windmill depends on the number of blades. Wind turbines with one blade rotate the fastest. In such designs, a counterweight is used to balance. Keep in mind the fact that at low wind speeds below 3 m / s, wind turbines become incapable of taking energy. In order for the unit to perceive a weak wind, the area of \u200b\u200bits blades should be increased to at least 2 m 2.

Calculation of a wind generator

Before choosing a wind generator, it is necessary to determine the speed and direction of the wind, the most characteristic in the place of the proposed installation. It should be remembered that the rotation of the blades begins at a minimum wind speed of 2 m / s. The maximum efficiency can be achieved when this indicator reaches a value of from 9 to 12 m / s. That is, in order to provide electricity to a small country house, you will need a generator with a minimum power of 1 kW / h and wind at a speed of at least 8 m / s.

Wind speed and propeller diameter have a direct impact on the power generated by the wind turbine. It is possible to accurately calculate the operational characteristics of a particular model using the following formulas:

1. Calculations in accordance with the rotation area are performed as follows: P \u003d 0.6 x S x V 3, where S is the area perpendicular to the direction of the wind (m 2), V is the wind speed (m / s), P is the power of the generating set ( kW).
2. To calculate the electrical installation according to the diameter of the screw, the formula is used: P \u003d D 2 x V 3/7000, in which D is the diameter of the screw (m), V is the wind speed (m / s), P is the generator power (kW).
3. More complex calculations take air density into account. For these purposes, there is a formula: P \u003d ξ x π x R 2 x 0.5 x V 3 x ρ x η red x η gene, where ξ is the coefficient of use of wind energy (dimensionless value), π \u003d 3.14, R - the radius of the rotor (m), V is the air velocity (m / s), ρ is the air density (kg / m 3), η ed is the efficiency of the gearbox (%), η gene is the efficiency of the generator (%).

Thus, the electricity produced by the wind generator increases quantitatively in a cubic ratio with the increasing speed of the wind flow. For example, with a 2-fold increase in wind speed, rotor kinetic energy production will increase 8-fold.

When choosing a place for installing a wind generator, it is necessary to give preference to areas without large buildings and tall trees that create a barrier to the wind. The minimum distance from residential buildings is from 25 to 30 meters, otherwise noise during operation will create inconvenience and discomfort. The rotor of the wind turbine should be located at a height exceeding the nearest buildings by at least 3-5 m.

If you are not planning to connect a country house to the general network, in this case you can use the options for combined systems. The operation of the wind turbine will be much more effective when used in conjunction with a diesel generator or solar panel.

How to make a do-it-yourself wind generator

Regardless of the type and design of the wind generator, each device as a basis is equipped with similar elements. All models have generators, blades of various materials, lifts that provide the desired level of installation, as well as additional batteries and an electronic control system. The most simple to manufacture are rotor-type aggregates or axial structures using magnets.

Option 1. The rotor design of the wind generator.

The design of a rotary wind generator uses two, four or more blades. Such wind generators are not able to fully provide electricity to large country houses. They are used primarily as an auxiliary source of electricity.

Depending on the rated power of the windmill, the necessary materials and components are selected:

• Generator from a car at 12 volts and a car battery.
• A voltage regulator that converts alternating current from 12 to 220 volts.
• Large capacity container. An aluminum bucket or stainless steel pan is best.
• As a charger, you can use a relay removed from the car.
• You will need a 12 V switch, a charge lamp with a controller, bolts with nuts and washers, as well as metal clamps with rubberized gaskets.
• Three-core cable with a minimum cross section of 2.5 mm 2 and a conventional voltmeter, taken from any measuring device.

First of all, the rotor is prepared from an existing metal container - a pan or bucket. It is marked in four equal parts, holes are made at the ends of the lines to facilitate separation into component parts. Then the container is cut with scissors for metal or grinder. Rotor blades are cut from the resulting blanks. All measurements must be carefully checked for compliance with the dimensions, otherwise the design will not work correctly.

Next, the rotation side of the alternator pulley is determined. As a rule, it rotates clockwise, but it is better to check it. After that, the rotor part is connected to the generator. In order to avoid imbalance in the movement of the rotor, the holes for fasteners in both structures should be symmetrical.

To increase the speed of rotation of the edge of the blades should be slightly bent. With increasing bending angle, air flows will be more effectively perceived by the rotary installation. As the blades are used not only the elements of the cut capacity, but also individual parts connected to a metal billet having a circle shape.

After attaching the container to the generator, the entire structure obtained must be completely installed on the mast with the help of metal clamps. Then the wiring is mounted and assembled. Each contact must be connected to its own connector. After connecting, the wiring is attached to the mast with wire.

At the end of the assembly, the inverter, battery and load are connected. The battery is connected with a cable with a section of 3 mm 2, for all other connections, a section of 2 mm 2 is quite enough. After that, the wind generator can be operated.

Option 2. The axial design of the wind generator using magnets.

Axial windmills for the home are a structure, one of the main elements of which are neodymium magnets. In terms of their performance, they are significantly ahead of conventional rotary units.

The rotor is the main element of the entire structure of the wind generator. For its manufacture, a wheel hub complete with brake discs is best suited. The part that was in operation should be prepared - cleaned of dirt and rust, grease the bearings.

Next, you need to correctly distribute and secure the magnets. In total, they will need 20 pieces, measuring 25 x 8 mm. The magnetic field in them is located along the length. Even magnets will be poles, they are located along the entire plane of the disk, alternating through one. Then the pros and cons are determined. One magnet alternately touches the other magnets on the disc. If they are attracted, then the pole is positive.

With an increased number of poles, certain rules must be observed. In single-phase generators, the number of poles coincides with the number of magnets. In three-phase generators, a 4/3 proportion between magnets and poles is observed, as well as a 2/3 ratio between poles and coils. Magnets are installed perpendicular to the circumference of the disk. For their uniform distribution, a paper template is used. First, the magnets are fixed with strong glue, and then finally fixed with epoxy.

If we compare single-phase and three-phase generators, then the performance of the former will be slightly worse than the latter. This is due to high amplitude fluctuations in the network due to unstable current output. Therefore, in single-phase devices, vibration occurs. In three-phase designs, this drawback is compensated by current loads from one phase to another. Due to this, a constant power value is always provided in the network. Due to vibration, the life of single-phase systems is significantly lower than that of three-phase systems. In addition, three-phase models have no noise during operation.

The mast height is approximately 6-12 m. It is installed in the center of the formwork and poured with concrete. Then, the finished structure is mounted on the mast, on which the screw is mounted. The mast itself is secured with cables.

Wind turbine blades

The efficiency of wind power plants depends largely on the design of the blades. First of all, this is their number and size, as well as the material from which the blades for the wind generator will be made.

Factors affecting the design of the blades:

• Even the weakest wind can set in motion long blades. However, too long can slow down the speed of rotation of the wind wheel.
• An increase in the total number of blades makes the wind wheel more responsive. That is, the more blades, the better the rotation starts. However, power and speed will decrease, which makes such a device unsuitable for generating electricity.
• The diameter and speed of rotation of the wind wheel affects the noise level generated by the device.

The number of blades should be combined with the installation location of the entire structure. Under the most optimal conditions, correctly selected blades are able to provide maximum return to the wind generator.

First of all, you need to determine in advance the necessary power and functionality of the device. To properly manufacture a wind generator, it is necessary to study the possible designs, as well as the climatic conditions in which it will be operated.

In addition to the total power, it is recommended to determine the value of the output power, also known as peak load. It represents the total number of instruments and equipment that will be turned on simultaneously with the operation of the wind generator. If you need to increase this indicator, it is recommended to use several inverters at once.

DIY wind generator 24v - 2500w

With regard to wind energy resources, Russia has a double position. On the one hand, due to the huge total area and the abundance of flat areas, there is a lot of wind in general, and it is mostly flat. On the other hand, our winds are predominantly low-potential, slow, see fig. On the third, in sparsely populated areas, the winds are violent. Based on this, the task of starting a wind generator on the farm is quite relevant. But in order to decide whether to buy a rather expensive device, or to make it with your own hands, you need to think carefully what type (and there are a lot of them) for which purpose to choose.

Basic concepts

1. KIEV - coefficient of use of wind energy. If a plane wind is used for calculating the mechanistic model (see below), it is equal to the efficiency of the rotor of the wind power plant (APU).
2. Efficiency - the through efficiency of the APU, from the incident wind to the terminals of the electric generator, or to the amount of water pumped into the tank.
3. The minimum working wind speed (MRS) is its speed at which the windmill begins to give current to the load.
4. The maximum allowable wind speed (MDS) is its speed at which energy production stops: the automatics either turn off the generator, or put the rotor in the weather vane, or fold it and hide it, or the rotor itself stops, or the APU simply collapses.
5. Starting wind speed (CER) - at such a speed, the rotor can rotate without load, spin up and enter the operating mode, after which the generator can be turned on.
6. Negative starting speed (OSS) - this means that the APU (or wind turbine - wind turbine, or wind turbine, wind turbine) to start at any wind speed requires mandatory unwinding from an external source of energy.
7. Starting (initial) moment - the ability of the rotor, forcibly inhibited in the air flow, to create torque on the shaft.
8. Wind turbine (VD) - part of the APU from the rotor to the shaft of the generator or pump, or other energy consumer.
9. Rotary wind generator - APU, in which wind energy is converted into rotational moment on the power take-off shaft by rotating the rotor in the air stream.
10. The range of rotor operating speeds is the difference between MDS and MPC during operation at rated load.
11. Slow-moving windmill - in it the linear speed of the parts of the rotor in the stream does not significantly exceed the wind speed or below it. The dynamic flow head is directly converted to thrust of the blade.
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 traction is complex.

Notes:

1. Slow-moving APUs, as a rule, have a KIEV lower than high-speed ones, but have a starting moment sufficient to spin the generator without disconnecting the load and zero CER, i.e. absolutely self-starting and applicable in the weakest winds.
2. Slow speed and speed - relative concepts. A 300 rpm domestic windmill can be slow moving, and powerful EuroWind type APUs, from which wind fields, wind farms (see Fig.) And their rotors make about 10 rpm, are fast-moving, because with such a diameter, the linear speed of the blades and their aerodynamics on a large part of the scope are quite “airplane”, see below.

What generator is needed?

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

Note:   Asynchronous alternating current generators or collector ones with an unmagnetized stator are completely unsuitable. With a decrease in wind strength, they "go out" long before its speed drops to the MPC, and then they themselves will not start.

An excellent "heart" of the APU with power from 0.3 to 1-2 kW is obtained from an alternator with an integrated rectifier; there are most of them now. Firstly, they keep the output voltage of 11.6-14.7 V in a fairly wide speed range without external electronic stabilizers. Secondly, silicon valves open when the voltage across the winding reaches about 1.4 V, and before that the generator “does not see” the load. To do this, the generator must already pretty decently unwind.

In most cases, the oscillator can be directly connected without a gear or belt drive to the high-speed VD shaft, choosing the speed by choosing the number of blades, see below. The “speedwalks” have a small or zero starting moment, but even without turning off the load, the rotor will have enough time to spin up before the valves open and the generator gives current.

Choice downwind

Before deciding what to make a wind generator, we will decide on the local aerology. In grayish greenish   (windless) areas of the wind map, at least some sense will be only from a sailing wind turbine   (and we'll talk about them later). If you need a constant power supply, you will have to add a booster (rectifier with voltage stabilizer), a charger, a powerful battery, an inverter 12/24/36/48 V DC at 220/380 V 50 Hz AC. Such an economy will cost at least $ 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 the relentless pursuit of alternative energy, it is better to look for another source.

In yellow-green, slightly windy places, with the need for electricity up to 2-3 kW, you can take up a low-speed vertical wind generator yourself. They are designed to have few numbers, and there are designs that are almost as good as KIEV and KPI for industrial blades.

If it is supposed to buy a wind turbine for a house, then it is better to focus on a windmill with a sailing rotor. There are many disputes, and in theory, not everything is clear yet, but they work. In the Russian Federation, “sailboats” are produced in Taganrog for 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, self-made “vertical lines” are justified; 1.5-5 kW - purchased “sailboats”. "Vertical" can also be purchased, but will cost more than the APU horizontal scheme. And finally, if a wind turbine with a power of 5 kW or more is required, then you need to choose between horizontal purchased “blades” or “sailboats”.

Note: many manufacturers, especially the second tier, offer sets of parts from which you can assemble a wind generator with a capacity of up to 10 kW on your own. Such a set will cost 20-50% cheaper than the finished one with installation. But before buying, you need to carefully study the aerology of the proposed installation site, and then select the appropriate type and model according to the specifications.

About security

Details of a household wind turbine 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, kills a healthy man on the spot. 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 watts are quite noisy. Many generate fluctuations in air pressure of ultra-low (less than 16 Hz) frequencies - infrasounds. Infrasounds are inaudible, but fatal to health, and spread very far.

Note: in the late 80s there was a scandal in the USA - it was necessary to close the largest wind farm at that time in the country. The Indians from the reservation 200 km from the field of its APU proved in court that the health problems that sharply became more frequent after putting the wind farm into operation are caused by its infrasounds.

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

Note: the height of the APU is considered the highest point of the disc being thrown (for rotor blades) or a geomeric figure (for vertical APU with a rotor on the shaft). If the APU mast or rotor axis protrudes even higher, the height is calculated according to their top - top.

Wind, aerodynamics, KIEV

A homemade wind generator obeys the same laws of nature as the factory one, calculated on a computer. And the do-it-yourselfer needs to understand the basics of his work very well - most often there are no expensive ultramodern materials and technological equipment at his disposal. Aerodynamics APU oh how difficult ...

Wind and KIEV

To calculate the serial factory APU is used 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 according to the school formula, assuming an air density under normal conditions of 1.29 kg * cu. m. At a wind speed of 10 m / s, one cubic meter of air carries 65 J, and 650 watts can be removed from one square of the effective surface of the rotor, with 100% efficiency of the entire APU. This is a very simplified approach - everyone knows that the wind is not perfectly even. But this has to be done in order 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, firstly, we compress air, 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 down to the rotor and the effective surface area then turns out to be larger than swept away, and KIEV - more than 1 relative to it for a plane wind.

We give two examples. The first is a pleasure boat, rather heavy, the yacht can go not only against the wind, but also faster than it. The wind refers to the external; the pennant wind should still be faster, otherwise how will it pull the ship?

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

Theorists did not know what to think, and seriously doubted the law of conservation of energy. In the end, it turned out - the point is in the radar cone protruding from the air intake. From his sock to the side of the shell, air condensation appeared, as if raking it from the sides to the engine compressors. Since then, shock waves have firmly entered the theory as useful, and the fantastic flight data of modern aircraft is largely due to their skillful use.

Aerodynamics

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

Before Zhukovsky they flew on set sail sails: it was believed that particles of the oncoming flow give all their impulse to the leading edge of the wing. This made it possible to immediately get rid of the vector quantity - the moment of momentum - that generated the furious and most often non-analytic mathematics, go to much more convenient scalar purely energy relations, and finally get the calculated pressure field on the carrier plane, more or less similar to the present.

Such a mechanistic approach made it possible to create devices capable of somehow rising into the air and flying from one place to another, not necessarily crashing to the ground somewhere along the way. But the desire to increase speed, carrying capacity and other flying qualities increasingly revealed the imperfection of the initial aerodynamic theory.

Zhukovsky’s idea was this: along the upper and lower surfaces of the wing, air goes a different way. From the condition of continuity of the medium (vacuum bubbles by themselves do not form in air), it follows that the velocities of the upper and lower flows coming from the trailing edge should differ. Owing to the small but finite viscosity of the air, a vortex should form there because of the difference in speeds.

The vortex rotates, and the law of conservation of momentum, as immutable as the law of conservation of energy, is also valid for vector quantities, i.e. must take into account the direction of movement. Therefore, immediately on the trailing edge, an oppositely rotating vortex with the same rotational moment should form. Due to what? Due to the energy generated by the engine.

For the practice of aviation, this meant a revolution: by choosing the appropriate wing profile, the attached vortex could be launched around the wing in the form of circulation G, increasing its lifting force. That is, having spent a part, and for high speeds and wing loads - a large part, engine power, you can create an air flow around the device, which allows you to achieve the best flight qualities.

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

Again KIEV

But the windmill has no motor. On the contrary, it should take energy from the wind and give it to consumers. And here it turns out - he pulled out his legs, his tail got stuck. They put too little wind energy into their own circulation of the rotor - it will be weak, the thrust of the blades will be small, and KIEV and power will be low. Let’s give a lot of circulation - the rotor will spin like crazy at a low wind, but consumers will get little again: they just give a little load, the rotor brakes, the wind blows off the circulation, and the rotor starts.

The law of energy conservation "middle ground" gives just in the middle: we give 50% of the energy to the load, and twist the flow to the remaining 50% to the optimum. Practice confirms the assumption: if the efficiency of a good pulling propeller is 75-80%, then the KIEV of a bladed rotor as carefully calculated and blown in the 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 something and simplifying models to an accurate description of the behavior of a real body in a real flow. And here, besides the general line - power, power, and again power! - side ways are found, but promising just with a limited amount of energy entering the system.

The famous alternative aviator Paul McCready created a plane in the 80s, with two 16-hp chainsaw motors. showing 360 km / h. Moreover, its chassis was a three-support fixed gear, and the wheels were without fairings. None of the McCready devices went on line and went on combat duty, but two — one with piston engines and propellers, and the other jet — for the first time in history circled the globe without landing at one gas station.

The sails that spawned the original wing, the development of the theory also affected very significantly. “Live” aerodynamics allowed the yachts with a wind of 8 knots. stand on hydrofoils (see. Fig.); to accelerate such a whopper to the desired speed with a propeller, an engine of at least 100 hp is required Racing catamarans with the same wind go at a speed of about 30 knots. (55 km / h).

There are also completely nontrivial finds. Fans of the rarest and most extreme sports - base jumping - donning an aptial wing suit, wingsuit, fly without a motor, maneuvering at speeds of more than 200 km / h (Fig. To the right), and then smoothly land in a pre-selected location. In which fairy tale do people fly on their own?

Many mysteries of nature were resolved; in particular, the flight of a beetle. In classical aerodynamics, he is not able to fly. In the same way, the founder of the stealth F-117 with its diamond-shaped wing is also not able to fly into the air. But the MIG-29 and Su-27, which for some time can fly tail-first, do not fit into any ideas at all.

And why then, engaging in wind turbines, not fun and not an instrument for destroying their own kind, but a source of a vital resource, it is imperative to dance from the theory of weak currents with its model of plane wind? Is there really no opportunity to move forward?

What to expect from the classics?

However, the classics should not be abandoned in any case. It provides a foundation, without leaning on which you can not rise higher. In the same way as set theory does not cancel the multiplication table, apples from trees will not fly away from quantum chromodynamics.

So what can you count on with the classic approach? Let's look at the picture. On the left are the types of rotors; they are depicted conditionally. 1 - vertical carousel, 2 - vertical orthogonal (wind turbine); 2-5 - blade rotors with different number of blades with optimized profiles.

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

This approach allows us to draw far-reaching conclusions. For example, the number of blades should be chosen 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 outwardly similar carousels and orthogonal have fundamentally different properties.

In general, preference should be given to rotor blades, except when extreme low cost, simplicity, maintenance-free self-start without automation are required, and it is impossible to climb the mast.

Note:   We’ll talk about sailing rotors especially - they don’t seem to fit into the classics.

Vertical

APUs with a vertical axis of rotation have an indisputable advantage for everyday life: their nodes that require maintenance are concentrated at the bottom and do not need to go up. There remains, and not always, a self-aligning thrust bearing, but it is strong and durable. Therefore, when designing a simple wind generator, the selection of options should begin with vertical bars. Their main types are presented in Fig.

Sun

In the first position - the simplest, most often called the Savonius rotor. In fact, it was invented in the USSR in 1924 by Y. A. and A. A. Voronin, and the Finnish industrialist Sigurd Savonius unscrupulously appropriated the invention, ignoring the Soviet copyright certificate, and began serial production. But introducing the fate of an invention means a lot, therefore, in order not to tidy up the past and not disturb the ashes of the departed, we will call this wind turbine the Voronin-Savonius rotor, or for short, the sun.

The aircraft is good for the do-it-yourselfer, except for the “locomotive” KIEV of 10-18%. However, in the USSR they worked on it a lot, and there are achievements. Below we consider an improved design, not much more complex, but according to KIEV giving odds to the blades.

Note: two-bladed aircraft does not spin, but jerks; 4-lobed is only a little smoother, but it loses a lot in KIEV. For improvement, 4- “troughs” are most often spread over two floors - a pair of blades below, and the other pair, rotated 90 degrees horizontally, above them. KIEV persists, and the lateral loads on the mechanics weaken, but the flexural loads increase somewhat, and with a wind of more than 25 m / s, such an APU on the shaft, i.e. without a bearing stretched by the cables over the rotor, it “breaks the tower”.

Daria

The next is Daria’s rotor; KIEV - up to 20%. It is even simpler: the blades are made of a simple elastic tape without any profile. The Darier rotor theory is still underdeveloped. It is only clear that he begins to unwind due to the difference in aerodynamic drag of the hump and the pocket of the tape, and then it becomes kind of fast-moving, forming its own circulation.

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

The Daria rotor has two more bad qualities. First, during rotation, the thrust vector of the blade describes a complete revolution relative to its aerodynamic focus, and not smoothly, but jerkily. Therefore, the Daria rotor quickly breaks its mechanics, even with a steady wind.

Secondly, Daria is not just noisy, but screams and squeals, even to the point that the tape is torn. This happens due to its vibration. And the more blades, the stronger the roar. So Daria, if they do, is double-bladed, made of expensive high-strength sound-absorbing materials (carbon fiber, Mylar), and a small aircraft is adapted for promotion in the middle of the mast-shaft.

Orthogonal

On pos. 3 - orthogonal vertical rotor with profiled blades. Orthogonal because the wings stick out vertically. The transition from the Sun to the 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, in accordance with the strength of the wind. Sometimes the blades are made rotary and put on them weathercocks, automatically holding the "alpha", but such designs often break.

The central body (blue in Fig.) Allows you to bring KIEV to almost 50%. In a three-bladed orthogonal it should be cut in the form of a triangle with slightly convex sides and rounded corners, and with a larger number of blades a simple cylinder is enough. But the theory for the orthogonal gives the optimal number of blades unambiguously: there must 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 unattended APUs with a capacity of up to 20 kW are produced.

Helicoid

Helicoid rotor, or Gorlov's rotor (pos. 4) - a kind of orthogonal that provides uniform rotation; orthogonal with straight wings “tears” only slightly weaker than the two-bladed aircraft. The bending of the blades along the helicoid avoids the loss of KIEV due to their curvature. Although the curved blade discards part of the flow without using it, it also rakes part in the zone of the highest linear velocity, compensating for the losses. Helicoids are used less often than other windmills, because due to the complexity of manufacturing, they are more expensive than peers of equal quality.

Barrel Barrel

At 5 poses. - rotor type BC, surrounded by a guide apparatus; its scheme is presented in fig. on right. In industrial design is rare, because expensive land acquisition does not compensate for the increase in capacity, and the material consumption and complexity of production are great. But a home-made man 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-snag” is a tidbit:

• This type of rotor is absolutely safe, silent, does not create vibrations and can be installed anywhere, even on the playground.
• To bend the “troughs” of galvanization and weld the frame from pipes is nonsense.
• The rotation is absolutely uniform, the details of the mechanics can be taken from the cheapest or from the trash.
• Not afraid of hurricanes - too strong a wind cannot push into a “barrel”; a streamlined vortex cocoon appears around it (we will still encounter this effect).
• And most importantly, since the surface of the “zagrybok” is several times larger than that of the rotor inside, the KIEV can be superunit, and the rotational moment already at 3 m / s at the “barrel” of a three-meter diameter is such that the generator is 1 kW with a maximum load, such as they say it’s better not to twitch.

Video: Lenz wind generator

In the 60s in the USSR, E. S. Biryukov patented a roundabout APU with KIEV 46%. A little later V. Blinov achieved 58% of the design on the same principle of KIEV, but there are no data on its tests. And full-scale tests of the Armed Forces of Ukraine Biryukov were carried out by the staff of the journal "Inventor and Rationalizer". A two-story rotor with a diameter of 0.75 m and a height of 2 m with a fresh wind untwisted an asynchronous generator of 1.2 kW at full power and withstood 30 m / s without breaking. Drawings of the Armed Forces of Ukraine Biryukov are shown in Fig.

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

Biryukov on his APU received several copyright certificates at once. First, pay attention to the rotor cut. During acceleration, it works like a sun, creating a great starting moment. As you spin, a vortex cushion is created in the outer pockets of the blades. From the point of view of the wind, the blades become profiled, and the rotor turns into a high-speed orthogonal, and the virtual profile changes according to the strength of the wind.

Secondly, the profiled channel between the blades in the working speed range works as a central body. If the wind intensifies, then it also creates a vortex cushion that extends beyond the rotor. The same vortex cocoon arises as around the APU with a guiding apparatus. The energy for its creation is taken from the wind, and there is already not enough energy to break it.

Thirdly, the speed controller is primarily intended for the turbine. He keeps its speed optimal from the point of view of KIEV. And the optimum speed of the generator is ensured by the choice of the gear ratio of the mechanics.

Note: after publications in the Islamic Republic of Iran in 1965, the Armed Forces of Ukraine Biryukova sunk into oblivion. The author did not wait for an answer from the authorities. The fate of many Soviet inventions. They say that some Japanese has become a billionaire, regularly reading Soviet popular technical magazines and patenting everything that deserves attention.

Blades

As u said, according to the classic, a horizontal wind generator with a blade rotor is the best. But, firstly, he needs a stable, even medium-strong wind. Secondly, the design for the homemade man is fraught with a lot of pitfalls, because of which often the fruit of long hard work at best illuminates the toilet, hallway or porch, and even it can only untwist itself.

According to the schemes in Fig. consider in more detail; position:

• FIG. A:

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

• FIG. B, top view:

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

• FIG. G, current collector:

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

Note: hurricane protection for a horizontal blade more than 1 m in diameter is absolutely necessary, because he is not capable of creating a vortex cocoon around him. With smaller sizes, rotor endurance up to 30 m / s with propylene blades can be achieved.

So where are the spots waiting for us?

Blades

Expect to achieve power on the generator shaft of more than 150-200 watts on blades of any size, cut from a thick-walled plastic pipe, as is often advised - the hope of a hopeless amateur. The blade from the pipe (unless it is so thick that it is used simply as a workpiece) will have a segment profile, i.e. its upper, or both surfaces will be circular arcs.

Segment profiles are suitable for incompressible media, say, for hydrofoils or propeller blades. For gases, however, a blade of variable profile and pitch is needed, for an example see fig.; scope - 2 m. It will be a complex and time-consuming product, requiring painstaking calculation in full armor of the theory, blowing in the pipe and full-scale tests.

Generator

With the rotor nozzle directly on its shaft, the standard bearing will soon break - there is no equal load on all the blades in the windmills. We need an intermediate shaft with a special support bearing and a mechanical transmission from it to the generator. For large windmills, the thrust bearing is self-aligning double row; in the best models - three-tier, Fig. D in fig. above. This allows the rotor shaft to not only bend slightly, but also to shift slightly from side to side or up and down.

Note: the development of a support bearing for the EuroWind type APU took about 30 years.

Emergency weather vane

The principle of its operation is shown in FIG. B. The wind, growing stronger, presses on the shovel, the spring is stretched, the rotor is skewed, its speed drops and in the end it becomes parallel to the flow. Everything seems to be fine, but - it was smooth on paper ...

Try on a windy day to hold the handle of the boil-off or a large pan by the handle parallel to the wind. Only carefully - the swiveling piece of iron can sag on the physiognomy so that it will sag along the nose, cut the lip, and even knock out the eye.

A flat wind is only in theoretical calculations and, with sufficient accuracy for practice, in wind tunnels. In reality, hurricane windmills with a hurricane shovel are harder than completely defenseless. It’s better to change the distorted blades after all than to do it all over again. In industrial installations is another matter. There, the pitch of the blades, each individually, is monitored and regulated by automation controlled by the on-board computer. And they are made from heavy-duty composites, and not from water pipes.

Current collector

This is a regularly serviced site. Any power engineer knows that the collector with brushes needs to be cleaned, lubricated, adjusted. And the mast is from a water pipe. You won’t climb in, once a month or two you’ll have to throw the whole windmill to the ground and then raise it again. How much will he stretch from such a “prevention”?

Video: paddle wind generator + solar panel for powering the cottage

Mini and micro

But with a decrease in the size of the blade, difficulties fall along the square of the diameter of the wheel. Production of a horizontal blade APU on its own for power up to 100 W is already possible. The optimal is 6-lobed. With more blades, the diameter of the rotor, designed for the same power, will be smaller, but it will be difficult to firmly fix them on the hub. Rotors with less than 6 blades can not be borne in mind: a 2-blade for 100 W needs a rotor with a diameter of 6.34 m, and a 4-blade for the same power - 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 will be optimal to count on a power of 10-20 watts. Firstly, a plastic blade with a span of more than 0.8 m without additional protection measures cannot withstand wind more than 20 m / s. Secondly, with a blade span of up to the same 0.8 m, the linear speed of its ends does not exceed the wind speed by more than three times, and the requirements for profiling with a twist are reduced by orders of magnitude; here, a “trough” with a segmented profile from a pipe, pos. B in fig. And 10-20 watts will provide power to the tablet, recharge the smartphone or light up the housekeeper.

Next, select the generator. Chinese motor is perfect - wheel hub for electric bikes, pos. 1 in fig. Its power as a motor is 200-300 watts, but in generator mode it will give up to about 100 watts. But is it suitable for 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 \u003d v / l * z * 60, where N is the rotation frequency, 1 / min, v is the wind speed, and l is the circumference of the rotor. 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. The bicycle wheel also rotates at about the same speed, so we’ll remove our 10-20 W from a generator capable of producing 100. You can plant the rotor directly on its shaft.

But here the following problem arises: we, having spent a lot of work and money, at least on a motor, got ... a toy! What is 10-20, well, 50 watts? But a paddle windmill that can power even a TV can’t be done at home. Is it possible to buy a ready-made mini-wind generator, and will it cost less? As much as possible, and even cheaper, see pos. 4 and 5. In addition, it will also be mobile. Put on a stump - and use it.

The second option is if a stepper motor is lying somewhere from an old 5- or 8-inch drive, or from a paper or carriage drive for an unusable inkjet or matrix printer. It can work as a generator, and attached to it a rotary rotor from cans (pos. 6) is easier than assembling a design similar to that shown in pos. 3.

On the whole, the conclusion is clear for the “blades”: home-made ones are more likely to master the power, but not for real long-term energy efficiency.

Video: the simplest wind generator for lighting a summer house

Sailboats

A sailing wind generator has been known for a long time, but the soft panels of its blades (see. Fig.) Began to be made with the advent of high-strength wear-resistant synthetic fabrics and films. Multi-vane windmills with hard sails have spread widely around the world as a drive for low-power automatic water pumps, but their technical data is lower than that of carousels.

However, a soft sail like a wing of a windmill did not seem to be so simple. It is not a matter of wind resistance (manufacturers do not limit the maximum permissible wind speed): sailing yachtsmen already know that it is almost impossible for the wind to break the cloth of the Bermuda sail. Rather, the sheet will vomit, or break the mast, or the entire vessel will make a “twist of the overkill." The point is in the energy sector.

Unfortunately, accurate test data cannot be found. According to user reviews, it was possible to compose “synthetic” dependencies for installing a VEU-4.380 / 220.50 Taganrog plant with a wind wheel diameter of 5 m, a wind head mass of 160 kg and a rotation speed of up to 40 1 / min; they are presented in fig.

Of course, there can be no certainty for 100% certainty, but it can be seen that there is no smell of a plane-mechanistic model. No way can a 5-meter wheel in a flat wind of 3 m / s give about 1 kW, at 7 m / s reach a plateau in terms of power and then hold it until a severe storm. Manufacturers, by the way, claim that the nominal 4 kW can be obtained at 3 m / s, but when installed by forces according to the results of studies of local aerology.

A quantitative theory is also not found; developer explanations are unintelligible. However, since people buy Taganrog wind turbines and they work, it remains to be assumed that the declared conical circulation and propulsive effect are not fictitious. Anyway, possible.

Then, it turns out, BEFORE the rotor, according to the law of conservation of momentum, a conical vortex should also appear, but expanding and slow. And such a funnel will drive the wind to the rotor, its effective surface will turn out to be more swept away, and KIEV - superunit.

Full-scale measurements of the pressure field in front of the rotor, even a household aneroid, could shed light on this question. If it turns out to be higher than from the sides to the side, then, indeed, sailing APUs work like a bug flies.

Homemade generator

From what has been said above, it is clear that home-made people are better off taking up vertical lines or sailboats. But both are very slow, and transferring to a high-speed generator is unnecessary 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, the so-called. super magnets. The manufacturing process of the main parts is shown in Fig. Coils - each of 55 turns of copper 1 mm wire in heat-resistant high-strength enamel insulation, PEMM, PETV, etc. The height of the windings is 9 mm.

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

In fact, it is better to buy magnets with an axial hole and tighten them with screws; super magnets are attracted with terrible power. For the same reason, a cylindrical spacer 12 mm high is put on the shaft between the “pancakes”.

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

The stator in the mold is poured to a thickness of 10 mm. It is not necessary to center and balance, the stator does not rotate. The gap between the rotor and the stator is 1 mm on each side. The stator in the generator housing must be securely fixed not only against displacement along the axis, but also from turning; a strong magnetic field with a current in the load will pull it along.

Video: DIY generator for a windmill

Output

And what do we have in the end? The interest in the “blades” is explained more by their spectacular appearance than by their actual performance in a home-made version and at low capacities. A home-made roundabout APU will provide “standby” power for charging a car battery or powering a small house.

But with sailing APU it is worth experimenting with masters with a creative vein, especially in mini-performance, with a wheel of 1-2 m in diameter. If the assumptions of the developers are correct, then it will be possible to remove from this, through the Chinese engine generator described above, all of its 200-300 watts.

Andrey said:

Thank you for your free consultation ... And the prices “from firms” are not really expensive, and I think that skilled people from the outback can make generators like yours. Li-po batteries can be written out from China, inverters in Chelyabinsk do very good (with smooth sinus) .And sails, blades or rotors - this is another reason for the flight of thought of our handy Russian men.

Ivan said (a):

question:
For wind turbines with a vertical axis (position 1) and the “Lenz” variant, it is possible to add an additional part - an impeller, which is exposed in the wind and covers the useless side of it (going towards the wind). That is, the wind will not brake the blade, but this “screen." Staging downwind with a “tail” located behind the windmill itself below and above the blades (ridges). I read an article and an idea was born.

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Electricity is steadily rising in price. To feel comfortable outside the city in hot summer weather and on a frosty winter day, you must either thoroughly spend money, or go in search of alternative energy sources. Russia is a vast country with large flat territories. Although slow winds predominate in most regions, the sparsely populated area is blown by powerful and violent air currents. Therefore, the presence of a wind generator in the economy of the owner of suburban real estate is often justified. A suitable model is selected based on the area of \u200b\u200bapplication and the actual purpose of use.

Windmill # 1 - rotor type design

You can make a simple rotor-type windmill with your own hands. Of course, he is unlikely to be able to supply electricity to a large cottage, but to provide a modest garden house with electricity is quite within his power. With its help, you can provide light in the evening, outbuildings, illuminate garden paths and the adjoining territory.

Read more about other types of alternative energy sources in this article:

So or almost so does a do-it-yourself rotary wind generator. As you can see, there is nothing super complicated in the design of this equipment

Preparation of parts and consumables

To assemble a wind generator, the power of which will not exceed 1.5 kW, we need:

• generator from the car 12 V;
• 12 V acid or helium battery;
• converter 12V - 220V to 700 W - 1500 W;
• a large capacity of aluminum or stainless steel: a bucket or a voluminous pan;
• car battery charging relay and charge warning lamp;
• semi-hermetic button-type switch for 12 V;
• a voltmeter from any unnecessary measuring device, you can use a car;
• bolts with washers and nuts;
• wires with a cross-section of 2.5 mm 2 and 4 mm 2;
• two clamps with which the generator will be attached to the mast.

To do the work, we will need metal scissors or a grinder, tape measure, marker or construction pencil, screwdriver, keys, drill, drill, nippers.

Most owners of private homes do not recognize the use of geothermal heating, however, such a system has prospects. You can read more about the advantages and disadvantages of this complex in the following material:

Design progress

We are going to make a rotor and remake the generator pulley. To get started, we need a cylindrical metal tank. Most often, a pan or bucket is fitted for these purposes. Take a tape measure and a marker or a construction pencil and divide the capacity into four equal parts. If we cut metal with scissors, then to insert them, you must first make holes. You can also use a grinder if the bucket is not made of painted tin or galvanized steel. In these cases, the metal will inevitably overheat. We cut the blades without cutting them to the end.

In order not to be mistaken with the dimensions of the blades that we cut through in the tank, it is necessary to make careful measurements and carefully recount everything

In the bottom and in the pulley we mark and drill holes for the bolts. At this stage, it is important not to rush and to arrange the holes in compliance with symmetry, so that during rotation to avoid imbalance. The blades should be bent, but not too much. When performing this part of the work, we take into account the direction of rotation of the generator. Usually it rotates clockwise. Depending on the bending angle, the area of \u200b\u200binfluence of wind flows increases, and, hence, the speed of rotation.

This is another version of the blades. In this case, each part exists separately, and not as part of the container from which it was cut

Since each of the blades of a windmill exists separately, you need to screw each one. The advantage of this design is its increased maintainability

The bucket with the finished blades should be mounted on the pulley using bolts. Using the clamps, we install a generator on the mast, then connect the wires and assemble the circuit. It is better to rewrite the circuit, color of wires and marking of contacts in advance. The wires also need to be fixed on the mast.

To connect the battery, we use 4 mm 2 wires, the length of which should not be more than 1 meter. The load (electrical appliances and lighting) is connected using wires with a cross section of 2.5 mm 2. Do not forget to put the converter (inverter). It is connected to the contacts 7.8 with a wire of 4 mm 2.

The design of the wind turbine consists of a resistor (1), a generator starter winding (2), a generator rotor (3), a voltage regulator (4), a reverse current relay (5), an ammeter (6), a battery (7), a fuse (8) circuit breaker (9)

Advantages and disadvantages of such a model

If everything is done correctly, this wind generator will work without creating problems for you. With a 75A battery and with a 1000 W converter, it can supply street lighting, video surveillance devices, etc.

The operation diagram of the installation clearly demonstrates how exactly wind energy is converted into electricity and how it is used for its intended purpose

The advantages of this model are obvious: it is a very economical product, can be easily repaired, does not require special conditions for its functioning, it works reliably and does not violate your acoustic comfort. The disadvantages include low productivity and significant dependence on strong gusts of wind: the blades can be disrupted by air currents.

Windmill # 2 - axial magnet design

Until recently, axial windmills with ironless stators on neodymium magnets were not made in Russia because of the inaccessibility of the latter. But now they are in our country, and they cost less than initially. Therefore, our craftsmen began to produce wind generators of this type.

Over time, when the capabilities of a rotary wind generator will no longer provide all the needs of the economy, you can make an axial model of neodymium magnets

What needs to be prepared?

The axial generator needs to be based on a hub from a car with brake discs. If this part was in operation, it must be disassembled, the bearings should be checked and lubricated, and the rust cleaned. The finished generator will be painted.

To qualitatively clean the hub from rust, use a metal brush that can be mounted on an electric drill. The hub will look great again

Magnet distribution and fixing

We have to stick magnets on the rotor discs. In this case, 20 magnets 25x8mm in size are used. If you decide to make a different number of poles, then use the rule: in a single-phase generator there should be how many poles, so many magnets, and in a three-phase generator it is necessary to observe the ratio of 4/3 or 2/3 of the pole to the coils. Magnets should be placed alternating between poles. For their location to be correct, use a template with sectors printed on paper or on the disc itself.

If there is such a possibility, it is better to use rectangular magnets rather than round magnets, because for rounds the magnetic field is concentrated in the center, and for rectangular ones along their length. Opposing magnets must have different poles. In order not to confuse anything, use a marker to apply “+” or “-” on their surface. To determine the pole, take one magnet and bring others to it. On plus surfaces, put plus and minus on repulsive surfaces. On disks, poles must alternate.

The magnets are correctly positioned. Before fixing them with epoxy resin, it is necessary to make plasticine boards so that the adhesive can freeze, and not glass on the table or floor

To fix the magnets, you need to use a strong glue, after which the bonding strength is additionally strengthened with epoxy. It is filled with magnets. To prevent resin from spreading, you can make plasticine borders or simply wrap tape with tape.

Three-phase and single-phase generators

A single-phase stator is worse than a three-phase one, because it gives vibration when loaded. This is due to the difference in the amplitude of the current, which occurs due to its non-constant return for a moment in time. The three-phase model does not suffer from this drawback. The power in it is always constant, because the phases compensate each other: if in one current drops, and in the other it rises.

In the dispute of single-phase and three-phase variants, the latter comes out victorious, because additional vibration does not extend the life of the equipment and irritates hearing

As a result, the return on a three-phase model is 50% higher than the same single-phase rate. Another advantage of the absence of unnecessary vibration is the acoustic comfort when working under load: the generator does not buzz during its operation. In addition, vibration always destroys the wind generator before the end of its life.

Coil Winding Process

Any specialist will tell you that before winding coils, you need to make a careful calculation. And any practitioner will do everything intuitively. Our generator will not be too fast. We need the charging process of a 12-volt battery to start at 100-150 rpm. With such initial data, the total number of turns in all coils should be 1000-1200 pieces. It remains to divide this figure by the number of coils and find out how many turns will be in each.

To make a wind generator at low speeds more powerful, you need to increase the number of poles. In this case, the frequency of the current oscillation will increase in the coils. For winding coils, it is better to use a thick wire. This will reduce the resistance, and, therefore, the current strength will increase. It should be noted that at high voltage the current may turn out to be “eaten up” by the resistance of the winding. A simple home-made machine will help you quickly and accurately reel high-quality coils.

The stator is marked, the coils are laid in place. For their fixation, an epoxy resin is used, runoff of which is again opposed by plasticine boards

Due to the number and thickness of the magnets located on the disks, the generators can vary significantly in their operating parameters. To find out what power to expect as a result, you can wind one coil and scroll it in the generator. To determine the future power, you should measure the voltage at certain revolutions without load.

For example, at 200 rpm it turns out 30 volts with a resistance of 3 ohms. Subtract the battery voltage of 12 volts from 30 volts, and divide the resulting 18 volts by 3 ohms. The result is 6 amperes. This is the amount that goes to the battery. Although practically, of course, it comes out less due to losses on the diode bridge and in the wires.

Most often, the coils are made round, but it is better to stretch them a little. At the same time, more copper is obtained in the sector, and coil turns are straighter. The diameter of the inner hole of the coil should correspond to the size of the magnet or be slightly larger than it.

Preliminary tests of the resulting equipment are carried out, which confirm its excellent performance. Over time, this model can be improved.

When making a stator, keep in mind that its thickness should correspond to the thickness of the magnets. If the number of turns in the coils is increased and the stator is thicker, the inter-disk space will increase, and the magnetic flux will decrease. As a result, the same voltage can be generated, but less current due to the increased resistance of the coils.

Plywood is used as a form for the stator, but you can mark out sectors for coils on paper, and make borders from plasticine. The strength of the product will increase fiberglass placed on the bottom of the mold and on top of the coils. Epoxy must not adhere to the mold. To do this, it is lubricated with wax or petroleum jelly. For the same purposes, you can use a film or tape. The coils are fixed to each other motionlessly, the ends of the phases are brought out. Then all six wires are connected by a triangle or a star.

The generator assembly is tested using hand rotation. The resulting voltage is 40 volts, the current strength is approximately 10 amperes.

Final stage - mast and screw

The actual height of the finished mast was 6 meters, but it would be better to make it 10-12 meters. The base for it needs concreting. It is necessary to make such a fastening so that the pipe can be raised and lowered using a manual winch. A screw is attached to the top of the pipe.

PVC pipe - a reliable and fairly lightweight material, using which you can make a wind turbine screw with a predetermined bend

To make a screw, you need a PVC pipe with a diameter of 160 mm. A six-blade two-meter screw is to be cut from it. It makes sense to experiment with the shape of the blades in order to increase the torque at low revs. The propeller must be removed from strong winds. This function is performed using a folding tail. The generated energy is stored in batteries.

The mast must be raised and lowered using a hand winch. Additional structural stability can be imparted using tension cables

There are two options for wind generators that are most often used by summer residents and owners of suburban real estate. Each of them is effective in its own way. Especially the result of the use of such equipment is manifested in areas with strong winds. In any case, such an assistant in the household never hurts.

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

The design of the wind generator includes several blades rotating under the influence of wind flows. As a result of this effect, rotation energy is created. The generated energy through the rotor is fed to the multiplier, which in turn transfers energy to the generator.

There are also designs of wind generators without multipliers. The absence of a multiplier can significantly increase the productivity of the installation.

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

What do you need to know before assembling a wind generator?

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

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

Second step. Find the right power. In this moment, everything is individual - focus on your own needs. To get more power, you need to increase the diameter and weight of the impeller.

An increase in these characteristics will lead to certain difficulties at the stage of fixing and balancing the wheels of the wind generator. Consider this moment and objectively evaluate your capabilities. If you are a beginner, consider installing several medium power wind generators instead of one very productive unit.

Third step. Think about whether you can make all the elements of a wind generator yourself. Each detail must be accurately calculated and made in full accordance with factory analogues. In the absence of the necessary skills, it is better to buy ready-made items.

Fourth step. Select the appropriate batteries. It is better to refuse car batteries, as they are short-lived, explosive and demanding in care and maintenance.

Sealed batteries are a preferred option. They cost a couple of times more expensive, but they serve several times longer and generally have higher characteristics.

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

When the generator operates with 2 or 3 blades, powerful centrifugal and gyroscopic forces take place. Under the influence of the mentioned forces, the load on the main elements of the wind generator increases significantly. At the same time, at some points, forces act as a counterweight to each other.

In order to level the incoming loads and keep the design of the wind generator intact, you need to perform competent aerodynamic calculation of the blades and make them in strict accordance with the calculated data.   Even minimal errors reduce the installation efficiency several times and increase the likelihood of an early breakdown of the wind generator.

High-speed wind turbines generate a lot of noise, especially when it comes to improvised installations. The larger the blades, the greater the noise. This point imposes a number of limitations. For example, to install such a noisy structure on the roof of the house will not work, unless, of course, the owner does not like the feeling of life in an airfield.

Keep in mind that with an increase in the number of blades, the level of vibration generated during the operation of the wind generator will increase. Two-bladed installations 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 in favor of a wind generator with 5-6 blades.   Practice shows that such models are most optimal for self-production and use at home.

It is recommended to make a screw with a diameter of about 2 m.   Almost anyone will cope with the work of assembling and balancing it. Having gained experience, you can try to assemble and install a wheel with 12 blades. Assembling such an assembly will require more effort. Consumption of materials and time costs will also increase. However, 12 blades will allow even with a slight wind of 6-8 m / s to get power at the level of 450-500 watts.

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, more complex and expensive to manufacture.

Thus, the best option for a beginner home craftsman is a wind generator with a wheel with a diameter of 200 cm, equipped with medium-sized blades in the amount of 6 pieces.

Accessories and assembly tools

Assembling a windmill will require many different components and additional devices. Collect and buy everything you need in advance so that you do not have to be distracted by this in the future.

Depending on the conditions of a specific situation, the list of necessary tools may vary slightly. At this point, you yourself will navigate along the way.

Step-by-step guide for assembling a wind generator

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

First step. Prepare a 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. Let the concrete gain strength for 1-2 weeks and install the mast. To do this, bury the support mast in the ground by about 50-60 cm and fix it with stretch marks.

Second phase. Prepare the rotor and pulley. The pulley is a friction wheel. A circumference of such a wheel is a groove or rim. When choosing the diameter of the rotor, you need to focus on the average annual value of the 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 4 m rotor.

The third stage. Make the blades of the future wind generator. To do this, take the barrel and divide it into several identical 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.

The fourth stage. Fasten the bottom of the barrel to the alternator pulley. Use bolts for fastening. After that, you need to bend the blades on the barrel. Do not overdo it, otherwise the finished installation will work unstably. Set a suitable rotational speed of the wind generator by changing the bends of the blades.

The fifth stage. Connect the wires to the generator and assemble them in a dose circuit. Fasten the generator to the mast. Connect the wires to the generator and mast. Assemble the generator in a circuit. Also connect the battery to the circuit. Consider the fact that the maximum permissible wire length in the case of such an installation is 100 cm. Connect the load with the wires.

The assembly of one generator takes an average of 3-6 hours, depending on the skills and overall performance and the master.

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 fixtures are secure. For your own safety, only check fastenings in light winds.
2. Grease bearings   at least once every 6 months. If the first signs of a wheel balancing imbalance appear, immediately remove it and repair any malfunctions. The most common sign of imbalance is uncharacteristic jitter of the blades.
3. At least once every 6 months, check the brush of the current collector. Every 2-6 years paint metal elements installation. Regular painting will protect the metal from destruction by corrosion.
4. Monitor the status of the generator. Check regularly that the generator does not overheat during operation. If the installation surface is heated to such a state that it becomes very difficult to hold your hand on it, take the generator to the workshop.
5. Monitor collector status. Any contamination should be removed as soon as possible from the contacts, as they significantly reduce the efficiency of the installation. Keep track of the mechanical condition of the contacts.   Overheating of the unit, burned-out windings and other similar defects - all this should be immediately eliminated.

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

Have a good work!

Video - DIY wind turbines for your home

The inexhaustible energy carried by the air masses has always attracted people's attention. Our great-grandfathers learned to harness the wind in the sails and wheels of windmills, after which he wandered aimlessly over the vast expanses of the Earth for two centuries.

Today, a useful work was found for him again. A wind generator for a private house from the category of technical innovations becomes a real factor in our everyday life.

Let's take a closer look at wind farms, evaluate the conditions for their cost-effective use and consider the existing varieties. In our article, home craftsmen will receive information for reflection on the topic of self-assembly of a windmill and the devices necessary for its effective operation.

What is a wind generator?

The principle of operation of a household wind farm is simple: the air flow rotates the rotor blades mounted on the generator shaft and creates alternating current in its windings. The resulting electricity is stored in batteries and consumed as necessary by household appliances. Of course, this is a simplified scheme of a home wind turbine. In practical terms, it is supplemented by devices that convert electricity.

Right behind the generator in the energy chain is a controller. It converts three-phase alternating current into direct current and directs it to charge the batteries. Most household appliances cannot work on a “constant” basis, so another device, an inverter, is placed behind the batteries. He performs the opposite operation: converts direct current into a household alternating voltage of 220 volts. It is clear that these transformations do not pass without a trace and take away quite a decent part from the initial energy (15-20%).

If the windmill is paired with a solar battery or another generator of electricity (gasoline, diesel), then the circuit is supplemented by a circuit breaker (ATS). When the main power source is turned off, it activates the backup one.

To obtain maximum power, the wind generator should be located along the wind stream. In simple systems, the weathervane principle is implemented. To do this, a vertical blade is fixed at the opposite end of the generator, turning it towards the wind.

In more powerful installations, there is a rotary electric motor controlled by a direction sensor.

The main types of wind generators and their features

There are two types of wind generators:

1. With a horizontal arrangement of a rotor.
2. With a vertical rotor.

The first type is the most common. It is characterized by high efficiency (40-50%), but has an increased level of noise and vibration. In addition, its installation requires a large free space (100 meters) or a high mast (from 6 meters).

Generators with a vertical rotor are energetically less efficient (efficiency is almost 3 times lower than that of horizontal).

Their advantages include simple installation and reliable design. Low noise allows you to install vertical generators on the roofs of houses and even at ground level. These installations are not afraid of icing and hurricanes. They are launched from weak winds (from 1.0-2.0 m / s), while a horizontal wind turbine needs an average flow of air (3.5 m / s and above). The shape of the impeller (rotor) vertical wind generators are very diverse.

Rotor Wheels of Vertical Windmills

Due to the low rotational speed of the rotor (up to 200 rpm), the mechanical life of such plants significantly exceeds the performance of horizontal wind generators.

How to calculate and choose a wind generator?

Wind is not natural gas pumped through pipes and is not electricity that flows uninterruptedly through wires to our house. He is moody and fickle. Today, a hurricane tears down roofs and breaks trees, and tomorrow gives way to a calm calm. Therefore, before buying or making a self-made windmill, you need to evaluate the potential of air energy in your area. To do this, determine the average annual wind strength. This value can be found on the Internet at the corresponding request.

Having received such a table, we find the area of \u200b\u200bour residence and look at the intensity of its color, comparing it with the rating scale. If the average annual wind speed is less than 4.0 meters per second, then it makes no sense to put a windmill. He will not give the right amount of energy.

If the wind power is sufficient to install a wind farm, then you can go to the next step: selection of generator power.

If we are talking about an autonomous power supply at home, then the average statistical electricity consumption by 1 family is taken into account. It ranges from 100 to 300 kWh per month. In regions with low annual wind potential (5-8 m / s), such a quantity of electricity is able to generate a wind turbine with a capacity of 2-3 kW. It should be borne in mind that in winter the average wind speed is higher, therefore, energy production during this period will be greater than in summer.

The choice of a wind generator. Indicative prices

Prices for vertical domestic wind generators with a capacity of 1.5-2.0 kW are in the range from 90 to 110 thousand rubles. The package at this price includes only a generator with blades, without a mast and additional equipment (controller, inverter, cable, batteries). A complete power plant along with installation will cost 40-60% more.

The cost of more powerful wind turbines (3-5 kW) ranges from 350 to 450 thousand rubles (with additional equipment and installation work).

DIY windmill. Fun or real savings?

We will say right away that making a wind generator with your own hands full and effective is not easy. Competent calculation of the wind wheel, gear, the selection of a suitable generator for power and speed is a separate issue. We will give only brief recommendations on the main stages of this process.

Generator

Car generators and electric motors from direct-drive washing machines are not suitable for this purpose. They are able to generate energy from the wind wheel, but it will be insignificant. Auto-generators for efficient operation need very high speeds, which a windmill cannot develop.

Motors for washers have another problem. There are ferrite magnets, and for a wind generator, more productive ones are needed - niode. The process of their self-assembly and winding of current-carrying windings requires patience and high accuracy.

The power of a self-assembled device, as a rule, does not exceed 100-200 watts.

Recently, motor-wheels for bicycles and scooters have been popular among homemade manufacturers. From the standpoint of wind energy, these are powerful niode generators that are optimally suited for working with vertical wind wheels and charging batteries. Up to 1 kW of wind energy can be removed from such a generator.

Motor wheel - a ready-made generator for a makeshift wind farm

Screw

The sailing and rotor propellers are easiest made. The first consists of light curved tubes fixed to a central plate. Durable fabric blades are pulled onto each tube. A large windage of the screw requires articulation of the blades so that during a hurricane they fold and do not deform.

The rotor design of the wind wheel is used for vertical generators. It is easy to manufacture and reliable.

Homemade wind turbines with a horizontal axis of rotation are powered by a propeller. Home craftsmen collect it from PVC pipes with a diameter of 160-250 mm. The blades are mounted on a round steel plate with a bore for the generator shaft.