Make a wind generator with your own hands

Often the owners of private houses have an idea of \u200b\u200bimplementing backup power systems. The simplest and affordable way is, naturally, a gasoline or diesel generator, however, many people look at more complex ways to transform the so-called gift energy (solar radiation, the energy of flowing water or wind) into electricity.

Each of these methods has its advantages and disadvantages. If, using the flow of water (mini-hydrogery), everything is understandable - this is only available in the immediate vicinity of a fairly rapid-auction river, then sunlight or wind can be used almost everywhere. Both of these methods will have a total minus - if the water turbine can work around the clock, then or the wind generator is effective only for a while, which makes it necessary to turn the batteries into the structure of the home power grid.

Since the conditions in Russia (the small duration of the light day most of the year, frequent precipitation) make the use of solar panels ineffective at their current costs and efficiency, the most profitable becomes the construction of a wind generator. Consider its principle of operation and possible design options.

Since no self-made device does not look like another, this article - Not Step-by-step instructions, and the description of the basic basics of the design of the wind generator.

General principle of work

The main working body of the wind turbine is the blades that the wind rotates. Depending on the location of the axis of rotation, wind generators are divided into horizontal and vertical:

• Horizontal wind generators The most widespread. Their blades have a design similar to the propeller of the aircraft: in the first approximation, this is inclined relative to the plane of rotation of the plate, which convert part of the load from the wind pressure into rotation. An important feature of the horizontal wind generator is the need to ensure the rotation of the blade assembly in accordance with the wind direction, since the maximum efficiency is provided with the perpendicularity of the wind direction to the rotation plane.
• Blades vertical wind generator have a convex-concave form. Since the flow rate of the convex side is greater than concave, such a wind generator is always rotating in one direction, regardless of the direction of the wind, which makes an unnecessary swivel mechanism unlike horizontal windmills. However, due to the fact that at any time the useful work is performed only part of the blades, and the rest only counteract the rotation, The efficiency of the vertical windmill is significantly lower than horizontal: If, for a three-blade horizontal wind generator, this indicator reaches 45%, then the vertical will not exceed 25%.

Since the average wind speed in Russia is small, even a large windmill most of the time will rotate quite slowly. To ensure sufficient power supply power from the must be connected to the generator through an increase in the gearbox, belt or gear. In the horizontal windmill, the block shore-gear generator is installed on the swivel head, which gives them the opportunity to follow the direction of the wind. It is important to consider that the swivel head should have a limiter who does not give it a complete turn, since otherwise the wiring from the generator will be converted (an option using contact washers that allow the head freely rotate, more complicated). To ensure turning, the wind generator is complemented directed along the rotation axis of the workshop.

The most common material for blades is PVC pipes of large diameter, cut along. Over the edge, metal plates welded to the hub of the blade node are sticking to them. Drawings of this kind of blades are most widespread on the Internet.

The video describes the wind generator, made with their own hands.

Calculation of a blade wind generator

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

Wind energy can be determined by the formula
P \u003d 0.6 * s * v³, where s is the area of \u200b\u200bthe circle described by the ends of the screw blades (an area of \u200b\u200bomeneania), expressed in square meters, and V is the estimated wind speed in meters per second. It is also necessary to take into account the efficiency of the windmaster itself, which for a three-bladed horizontal circuit will be an average of 40%, as well as the generator set efficiency, which is at the peak of the current-speed characteristic of 80% for the generator with excitation from permanent magnets and 60% for the generator with the excitation winding. An average of 20% of the power will spend an increase in the boost (multiplier). Thus, the final calculation of the windmill radius (i.e. the lengths of its blade) for the specified power of the generator on permanent magnets looks like this:
R \u003d √ (P / (0.483 * v³))

Example: We will take the required power of the wind power station in 500 W, and the average wind speed is 2 m / s. Then in our formula we will have to use a blade with a length of at least 11 meters. As you can see, even such a small power will require the creation of a wind generator of enhancing dimensions. For more or less rational designs in the manufacture of designs with the length of the blade not more than one and a half meters, the wind generator will be able to produce only 80-90 watts of power even in a strong wind.

Not enough power? In fact, everything is somewhat different, since in fact the load of the wind generator feed batteries, the windmill only charges them in the measure of its capabilities. Consequently, the power of the wind installation determines the frequency with which it can exercise energy.

On the Internet, you can often find articles under catchy headlines like a "wind-generator for home heating." In fact, as you could already understand from the above calculations, the electric heating consuming several kilowatts can constantly maintain the network of non-one dozen homemade installations.

We offer to see another story about the wind generator and its manufacture at home

Select generator

The most logical option of the generator set for a homemade windmill seems a car generator. This solution allows you to easily comply with the installation, as the generator already has fastening points, and the pulley for the belt multiplier. Buy and the generator himself, and spare parts for it is not difficult. In addition, the built-in relay controller allows you to directly connect it to a 12-volt battery, and to it, in turn, an inverter for converting a DC to a variable voltage of 220V.

But, as already mentioned above, the efficiency of the generators with the winding of the excitation is quite low, which is very sensitive to the already low-power wind generator. The second minus is that with a discharged battery, the automobile generator will not be able to excite.

In a number of homemade structures, tractor generators G-700 and M-1000 can be found. Their efficiency is no more, only the magnetization of the rotor is useful, allowing the generator to excite even without a battery, and the low price.

Some authors in the construction of wind generators use the property of reversibility of collector electric motors - forcibly rotating their rotor, you can remove direct current from it. The stator engines of this type consists of either permanent magnets, which is more preferably for our purposes, or has a winding. To use the engine in the generator mode, it connects to the automotive relay regulator to provide the desired voltage. Consider connecting the relay controller on the example of a node from the VAZ classic (it is convenient because it is not combined into one block with a brush node):

1. One of the engine brushes to connect with the housing - it will be a negative pole of the generator. This is also securely connect the metal case of the relay controller and the "-" battery terminal.
2. Terminem 67 Relay Connect with one of the conclusions of the stator winding, the second temporarily with the case.
3. Terminem 15 Connect through a switch with a positive battery pole (the excitation current will be served on the winding). Remember the rotation in the same direction that it will provide a screw of the wind installation, and connect between the free brush and the voltmeter body. If negative potential is found on the brush, change the stator connection with the regulator and the mass relay.

The main feature of connecting the direct current generator to the battery is the need to separate their semiconductor diode, which does not allow the battery to be discharged to the rotor winding when the generator is stopped. In modern automotive generators, this feature performs a three-phase diode bridge, and we can also use it by parallel to connecting its phases to reduce the voltage drop on it.

The greatest power can be removed from the generator, the rotor of which consists of neodymium magnets. Designs based on the automotive hub with a brake disc, on the edge of which powerful magnets are fixed. At the minimum distance from them there is a stator with a single-phase or three-phase winding.

Such a generator is good for many: it is excited already at low revs even with a sex battery, does not require the maintenance of the brush node. But at the same time its output voltage cannot be adjusted, as it depends only on the speed of rotation. With the generator on neodymium magnets, it will require its connection to an additional inverter to charge the battery in a large wind velocity range. Also, this device is often called battery charge controller.

There are several different options for implementing the controller, depending on the specific solution of the generator design. Since there is a large variation of the parameters that the diagram should be considered a large variation in the general principle of the controller device, and not as a mandatory solution.

As can be seen, this scheme is designed to use as a collector electric motor as a generator. If you used alternating current, add a diode bridge to its output.

Voltage from the generator through the control unit consisting of a voltmeter and ammeter is fed to entrance of two impulse stabilizers. The battery charging is carried out by block 2, while the problem of block 1 is protection against the generator's care into the spread with a strong wind and small consuming current load: when the threshold is exceeded by the threshold voltage defined by the R3 potentiometer engine, block 1 begins to feed the voltage to the power connected to its output. Load resistor, as reported by the LED2 lighting LED.

Load that does not require accurate stabilization of voltage (for example, low-voltage incandescent lamps), connected bypassing the stabilizer to the output diode D2.

Calculation of a multiplier

The generator set has an inclined current characteristic: with increasing rotor revolutions increases the maximum power given to them. Therefore, in order to ensure the greatest efficiency of the low-speed wind generator, we will need a multiplier with a large increase in the raising coefficient.

For homemade design, the most optimal solution is a belt multiplier: it is easy to manufacture and requires a minimum of machinery. The turnover coefficient of revolutions will be equal to the ratio of the diameter of the drive pulley associated with the screw axis, to the diameter of the slave pullea of \u200b\u200bthe generator. If necessary, the gear ratio will be easily correcting the replacement of one of the pulleys.

When designing a multiplier, it is necessary to take into account both the average turnover of the blade assembly and the current characteristic of the generator. If we use the serial automobile generator, it can be easily found on the Internet, with the homemade structures, most likely, you will have to go through trial and error.

For example, take a common tractor generator, which has already been written above.

Taking the calculated power of our wind installation in 90 watts, we will find the point on the graph corresponding to the generator output to this power. At rated voltage 14, we will need a current time for at least 6.5 A - according to the schedule, this will happen when revolutions are slightly higher than 1000 rpm. Let the screw of our design rotates wind at a speed of 60 rpm (the wind of the middle strength). It means that we will need at least a twenty-time ratio of pulleys diameters - for a 70mm pulley of the Machine Pulley, the windmill should have a diameter of almost one and a half meters, which is unacceptable. This explicitly hints how small the efficacy of the wind generators of this type is - without a complex multistage gearbox, which by itself will lead to large power losses, output the automotive generator on the working mode is almost impossible.

For comparison, we will look at the characteristics of the generators used in industrial production wind generators. For example, a generator on permanent GW1000 magnets, according to the design of the same as described above the homemade from the car brake disc, in just 200 revolutions per minute outputs the power of 1 kilowatt. On the other hand, the opposite side is its significant weight (34 kg) and the price (almost 70 thousand rubles).

Mast

It not only ensures the safety of the windmill (the lower point of the circle, described by the blades, should be no closer to 2 meters to the ground), but also allows it to maximally use the wind energy, the flow of which is becoming more turbulent.

A large height leads to a low stiffness of the wind-generator mast and makes its strength calculation quite complicated not only for the amateur masters, but also for the engineer. Only highlights can be listed:

• Place the mast Perhaps further from the house and trees shadowing the air flow. In addition, with strong wind it is possible to fall the wind generator on the building or its damage to trees;
• The optimal mast design is openwork welded farm Like the power transmission, but it is complex and the road. The simplest, but a fairly effective option is a few parallel pipes with a diameter of 80-100 mm, welded with short seams and concerned to a depth of at least a meter in the ground. The design of one pipe is extremely desirable to enhance cable stretch marks, which are also attached to the supports flooded in concrete.
• To simplify the maintenance of the windmill, his mast can be made of a turning point: in this case, when weakening stretching, going in the direction of the fracture, the mast can be tilted to the ground.

Story about a very simple wind generator from home fan

Additional electrical equipment

As mentioned above, an integral part of the wind power plant is a battery that takes care of consumers. When it is elected, it must be remembered that the more its capacity, the longer it can maintain a voltage in the network, but at the same time it will be charged longer. Approximate operation can be determined as the time for which half of the battery capacity is exhausted (after this, the voltage drop will become more tangible, in addition, the deep discharge reduces the resource of lead-acid batteries).

Example: Thus, the battery with a capacity of 65 A * C will conditionally be able to give up 30-35 ampere-hour-hours of energy. Is there a lot or a little? The usual capacity of 60 watt lighting lamp will require, taking into account the presence of an inverter that converts 12 V DC to 220 V alternating and having its own efficiency within 70%, a current of 7 amps is a little more than four hours of operation. Restore the same estate energy to our windmill with a conditional power of 90 watts even at best, with constant strong wind, there will be at least five hours. As you can see, when using the wind generator solely as electricity in your home will be available only a few hours a day.

The second node of the power supply system becomes an inverter. In our case, you can use both ready-made automotive and extracted from uninterruptible power. In any case, it is important not to overload it with current consumption, given that its real operational power is 1.2-1.5 times less than the specified maximum power.

As you can see, the attractiveness of the use of gifting energy rests on numerous limitations, and even the only one effective in the middle band of Russia is the wind generator - is unable to provide long-term autonomy.

But at the same time, this idea is not bad and as a source of emergency power supply and, especially, as a design task - the pleasure of creating with your own hands the wind generator can at times exceed its power.