A simple wind generator can be made from several faulty ones hard drives and water pump from washing machine. Alternative energy is closer than it seems; there is now more than enough junk to make such necessary gizmos. This design, of course, will not power your entire house with electricity, but it is quite suitable for charging all kinds of USB gadgets.

Will need

• Automatic pump washing machine. It stands at the very bottom and serves to pump water from the drum into the sewer.
• Four hard drives, from different manufacturers.
• A pole is a long pipe for installing a windmill at a height.
• Bolts, nuts, washers.
• Wires.

A few words about the water pump

A water pump will be used as a generator that generates electricity. It consists of a movable rotor with permanent magnets and a movable stator with a U-shaped magnetic core and a coil on it.

The rotor is quite easy to pull out.

Thanks to the use permanent magnets, such a pump works perfectly as a generator, capable of delivering up to 250 V. Of course, our windmill will not give such speeds and the output voltage will be several times lower.

Wind generator manufacturing

It was decided to secure the pump with construction steel corners, bending and cutting them as needed.

It turned out like this, a kind of clamp.

A hole was made in the magnetic circuit of the pump for more reliable fixation.

Assembled unit.

Wind turbine blades

The blades are made from PVC pipe.

We cut the pipe into three even parts lengthwise.

And then we cut out our own blade from each half.

We make holes in the places where the blades are attached to the generator.

Blade attachment

To fasten the wind generator blades, two disks from the HDD were used.

The hole in which fit perfectly to the diameter of the impeller.

Let's mark it.

Let's drill.

The discs are attached to the rotor with bolts, washers and nuts.

Screw on the blades.

Swivel unit

In order for the windmill to rotate in different directions depending on the wind, it must be installed on a turntable, in the role of which an engine from hard drive, because there are very good bearings.

In the future, a disk will be placed on it on which the generator will be mounted.

We drilled a hole for the mount and sawed off the unnecessary part.

General assembly

To the HDD engine which will be used as rotating platform We fasten the corners in three places.

We cut out the tail blade from cardboard or plastic so that the wind itself directs the fan.

Now let's start assembling everything.

We take a pole and fix the power wire.

Take the swivel unit.

We insert it into the pipe and tighten the nuts and move them apart.

Basically it's holding up fine.

Biking past summer cottages, I saw a working wind generator:

The large blades rotated slowly but surely, the weather vane oriented the device in the direction of the wind.
I wanted to implement a similar design, although not capable of generating power sufficient to supply “serious” consumers, but still working and, for example, charging batteries or powering LEDs.

Stepper motors

One of the most effective options a small homemade wind generator is the use stepper motor (SD) (English) stepping (stepper, step) motor) - in such a motor, the rotation of the shaft consists of small steps. The windings of the stepper motor are combined into phases. When current is supplied to one of the phases, the shaft moves one step.
These engines are low speed and a generator with such an engine can be connected without a gearbox to a wind turbine, Stirling engine or other low-speed power source. When using a conventional (brushed) DC motor as a generator, 10-15 times higher rotation speed would be required to achieve the same results.
A feature of the stepper is a fairly high starting moment (even without an electrical load connected to the generator), reaching 40 grams of force per centimeter.
The efficiency of a generator with a stepper motor reaches 40%.

To check the operation of the stepper motor, you can connect, for example, a red LED. By rotating the motor shaft, you can observe the glow of the LED. The polarity of the LED connection does not matter since the motor produces alternating current.

Five-inch floppy drives, as well as old printers and scanners, are a treasure trove of such fairly powerful engines.

Engine 1

For example, I have a SD from an old 5.25″ floppy drive that was still part of ZX Spectrum- a compatible computer "Byte".
Such a drive contains two windings, from the ends and the middle of which conclusions are made - a total of six wires:

first winding coil 1) - blue (English) blue) and yellow (eng. yellow);
second winding coil 2) - red (English) red) and white (English) white);
brown brown) wires - leads from the midpoints of each winding (eng. center taps).

disassembled stepper motor

On the left you can see the engine rotor, on which "striped" stripes are visible. magnetic poles- northern and southern. To the right you can see the stator winding, consisting of eight coils.
The resistance of half the winding is ~70 ohms.

I used this motor in the original design of my wind turbine.

Engine 2

A less powerful stepper motor at my disposal T1319635 companies Epoch Electronics Corp. from the scanner HP Scanjet 2400 It has five outputs (unipolar motor):


first winding coil 1) - orange (English) orange) and black (English) black);
second winding coil 2) - brown (English) brown) and yellow (eng. yellow);
red (English) red) wire - terminals connected together from the midpoint of each winding (eng. center taps).

The resistance of half the winding is 58 ohms, which is indicated on the motor housing.

Engine 3

In an improved version of the wind generator, I used a stepper motor Robotron SPA 42/100-558, produced in the GDR and designed for 12 V:

Wind turbine

There are two possible options for the location of the axis of the impeller (turbine) of a wind generator - horizontal and vertical.

Advantage horizontal(most popular) location axis located in the direction of the wind is more efficient use wind energy, the disadvantage is the complexity of the design.

I chose vertical arrangement axes - VAWT (vertical axis wind turbine), which significantly simplifies the design and does not require orientation downwind . This option is more suitable for mounting on the roof; it is much more effective in conditions of rapid and frequent changes in wind direction.

I used a type of wind turbine called a Savonius wind turbine. Savonius wind turbine). It was invented in 1922 Sigurd Johannes Savonius) from Finland.

Sigurd Johannes Savonius

The operation of the Savonius wind turbine is based on the fact that resistance drag) the oncoming air flow - the wind of the concave surface of the cylinder (blade) is greater than the convex one.

Aerodynamic drag coefficients ( English drag coefficients) $C_D$

two-dimensional bodies:
concave half of the cylinder (1) - 2.30
convex half of the cylinder (2) - 1.20
flat square plate - 1.17
3D bodies:
concave hollow hemisphere (3) - 1.42
convex hollow hemisphere (4) - 0.38
sphere - 0.5
The indicated values ​​are given for Reynolds numbers. Reynolds numbers) in the range $10^4 - 10^6$. The Reynolds number characterizes the behavior of a body in a medium.

Body resistance force to air flow $(F_D) = ((1 \over 2) (C_D) S \rho (v^2) ) $, where $\rho$ is air density, $v$ is air flow speed, $S $ is the cross-sectional area of ​​the body.

Such a wind turbine rotates in the same direction, regardless of the wind direction:

A similar operating principle is used in the cup anemometer. cup anemometer)- a device for measuring wind speed:

Such an anemometer was invented in 1846 by Irish astronomer John Thomas Romney Robinson ( John Thomas Romney Robinson):

Robinson believed that the cups in his four-cup anemometer moved at one-third the speed of the wind. In reality, this value ranges from two to a little more than three.

Currently, three-cup anemometers developed by Canadian meteorologist John Patterson are used to measure wind speed. John Patterson) in 1926:

Generators based on brushed DC motors with a vertical microturbine are sold at eBay for about $5:

Such a turbine contains four blades arranged along two perpendicular axes, with an impeller diameter of 100 mm, a blade height of 60 mm, a chord length of 30 mm and a segment height of 11 mm. The impeller is mounted on the shaft of a commutator DC micromotor with markings JQ24-125H670. The rated supply voltage of such a motor is 3 ... 12 V.
The energy generated by such a generator is enough to light a “white” LED.

Savonius wind turbine rotation speed cannot exceed wind speed , but at the same time this design is characterized high torque (English) torque).

The efficiency of a wind turbine can be assessed by comparing the power generated by the wind generator with the power contained in the wind blowing through the turbine:
$P = (1\over 2) \rho S (v^3)$, where $\rho$ is the air density (about 1.225 kg/m 3 at sea level), $S$ is the swept area of ​​the turbine (eng. swept area), $v$ - wind speed.

My wind turbine

Option 1

Initially, my generator impeller used four blades in the form of segments (halves) of cylinders cut from plastic pipes:


Segment sizes -
segment length - 14 cm;
segment height - 2 cm;
segment chord length - 4 cm;

I have installed assembled structure on a fairly high (6 m 70 cm) wooden mast made of timber, attached with self-tapping screws to a metal frame:

Option 2

The disadvantage of the generator was quite high speed wind required to spin the blades. To increase the surface area I used blades cut from plastic bottles:

Segment sizes -
segment length - 18 cm;
segment height - 5 cm;
segment chord length - 7 cm;
the distance from the beginning of the segment to the center of the rotation axis is 3 cm.

Option 3

The problem turned out to be the strength of the blade holders. At first I used perforated aluminum strips from the Soviet children's construction set 1 mm thick. After several days of operation, strong gusts of wind led to the break of the slats (1). After this failure, I decided to cut the blade holders from foil PCB (2) 1.8 mm thick:

The bending strength of PCB perpendicular to the plate is 204 MPa and is comparable to the bending strength of aluminum - 275 MPa. But the elastic modulus of aluminum $E$ (70,000 MPa) is much greater than that of PCB (10,000 MPa), i.e. texolite is much more elastic than aluminum. This, in my opinion, taking into account the greater thickness of the textolite holders, will provide much greater reliability of fastening the wind generator blades.
The wind generator is mounted on a mast:

Trial operation of the new version of the wind generator showed its reliability even in strong gusts of wind.

The disadvantage of the Savonius turbine is low efficiency - only about 15% of wind energy is converted into shaft rotation energy (this is much less than can be achieved with wind turbine Daria(English) Darrieus wind turbine)), using lifting force (eng. lift). This type of wind turbine was invented by French aircraft designer Georges Darrieux. (Georges Jean Marie Darrieus) - 1931 US Patent No. 1,835,018 .

Georges Darrieux

The disadvantage of the Daria turbine is that it has very poor self-starting (to generate torque from the wind, the turbine must already be spinning up).

Converting Electricity Generated by Stepper Motor

The stepper motor leads can be connected to two bridge rectifiers made from Schottky diodes to reduce the voltage drop across the diodes.
You can use popular Schottky diodes 1N5817 with a maximum reverse voltage of 20 V, 1N5819- 40 V and a maximum direct average rectified current of 1 A. I connected the outputs of the rectifiers in series to increase the output voltage.
You can also use two midpoint rectifiers. Such a rectifier requires half as many diodes, but at the same time the output voltage is halved.
Then the ripple voltage is smoothed out using a capacitive filter - a 1000 µF capacitor at 25 V. To protect against the increased generated voltage, a 25 V zener diode is connected in parallel with the capacitor.


my wind generator diagram


electronic unit of my wind generator

Wind generator application

The voltage generated by a wind generator depends on the magnitude and constancy of the wind speed.

When the wind sways thin tree branches, the voltage reaches 2 ... 3 V.

When the wind sways the thick branches of trees, the voltage reaches 4 ... 5 V (with strong gusts - up to 7 V).

CONNECTING TO JOULE THIEF

The smoothed voltage from the wind generator capacitor can be supplied to - low voltage DC-DC converter

Resistor value R is selected experimentally (depending on the type of transistor) - it is advisable to use a 4.7 kOhm variable resistor and gradually reduce its resistance, achieving stable operation of the converter.
I assembled such a converter based on germanium pnp-transistor GT308V ( VT) and pulse transformer MIT-4V (coil L1- conclusions 2-3, L2- conclusions 5-6):

CHARGE OF IONISTERS (SUPERCAPACITORS)

Ionistor (supercapacitor, English) supercapacitor) is a hybrid of a capacitor and a chemical current source.
Ionistor - nonpolar element, but one of the terminals may be marked with an “arrow” to indicate the polarity of the residual voltage after it is charged at the manufacturer.
For initial research I used an ionistor with a capacity of 0.22 F for a voltage of 5.5 V (diameter 11.5 mm, height 3.5 mm):

I connected it via a diode to the output through a germanium diode D310.

To limit the maximum charging voltage of the ionistor, you can use a zener diode or a chain of LEDs - I use a chain of two red LEDs:

To prevent the discharge of an already charged ionistor through limiting LEDs HL1 And HL2 I added another diode - VD2.

To be continued

In this article we will consider the model powerful generator made of magnets, which is capable of generating electricity with a power of 300 watts. The frame is assembled from 10 mm thick duralumin plates. The generator consists of 3 main parts: housing, rotor, stator. The main purpose of the housing is to fix the rotor and stator in a strictly defined position. The rotating rotor should not touch the stator coils with magnets. The aluminum body is assembled from 4 parts. Corner layout provides a simple and rigid design. The body is made on a CNC machine. This is both an advantage and a disadvantage of the development, since for a high-quality repetition of the model you need to find specialists and a CNC machine. The diameter of the discs is 100 mm.

You can also take ready-made electric generator in the online store.

Rotor of the electric generator I. Belitsky

Rotor is an iron axle. There are 2 iron disks with neodymium magnets located on them. An iron bushing is pressed between the discs on the axle. Its length depends on the thickness of the stator. Its purpose is to provide minimum clearance between rotating magnets and stator coils. Each disk contains 12 neodymium magnets with a diameter of 15 and a thickness of 5 mm. Seats are made for them on the disk.

They need to be glued epoxy resin or other glue. In this case, it is necessary to strictly observe polarity. When assembled, the magnets should be positioned so that opposite each one there is another from the opposite disk. In this case, the poles must be different towards each other. As the author of the development himself (Igor Beletsky) writes: “It would be correct to have different poles, so that the lines of force would come out of one and enter the other, definitely S = N.” You can purchase neodymium magnets in a Chinese online store.

Stator device

A sheet of textolite 12 m thick was used as a base. Holes were made in the sheet for the coils and rotor bushings. The outer diameter of the iron coils that are installed in these holes is 25 mm. The inner diameter is equal to the diameter of the magnets (15 mm). The coils perform 2 tasks: the function of a magnetically conductive core and the task of reducing sticking when moving from one coil to another.

Coils are made from insulated wire 0.5 mm thick. 130 turns are wound on each coil. The winding direction is the same for all.

When creating a powerful generator from, you need to know that the higher the speed that can be provided, the higher the output voltage and current of the device will be for free energy.

We continue to recycle plastic bottles. I propose to consider the manufacture of a vertical rotary wind turbine from four bottles. The rotation unit used can become a generator of weak currents or an excellent wind speed sensor for a homemade anemometer. Photos and videos of the windmill are shown. The assembly diagram is detailed below.

How to make a windmill from PET bottles with your own hands

1. Necessary tool: heat gun, scissors, drill, knife and screwdriver. Materials used: four identical PET bottles with caps from 0.2 to 2 liters each, a hard drive motor, a plastic vitamin jar, an old sink siphon and a wooden pole of the required length.

2. Disassembling a computer hard drive is considered. To operate, you will need a motor and an overhead plate for fixing the disk plate with fasteners. Fasteners can be used with a Phillips screwdriver, but more often with an asterisk.

3. We begin the work with the most labor-intensive and important unit - installing a rotation unit in the lid of a vitamin jar. To do this, under the end of the engine, strictly symmetrically, with your own hands, cut a hole in the plastic lid of the can with a knife.

Electric motor Can lid Hole

4. We mark mounting holes along the overhead strip and drill them.

5. Install the rotation unit into the cover.

The holes are marked. The rotation unit is fixed.

6. We mark the jar into four sectors and use a well-heated hot-melt gun to symmetrically glue the four lids. Glue is generously applied to the lid and the lid is glued in the right place. There should be no labels on the jar, and it is advisable to clean the glued areas with emery cloth.

7. Screw the PET bottles into the corks and use a permanent marker to mark the cutouts in the jar. The position of the cutouts determines the direction of rotation of the windmill. The cutouts should be on the same side as shown in the photo, that is, when rotating, the windmill tries to tighten the lid.

8. Cut out the bottles one by one and immediately screw them into place. Screw the jar into the lid - homemade windmill ready. It is useful to check and, if necessary, balance the wheel with a piece of plasticine.

Lids are glued

9. The issue of installing a wind turbine initially caused difficulty, but was unexpectedly easily resolved. The inch standards of the hard drive and the siphon from the sink turned out to be the same, and the motor was perfectly fixed with a union nut on the siphon; if necessary, you can add a rubber washer. Before installation, the engine was disconnected from the lid, the cap nut was inserted and the can lid was secured back. To evaluate the generating capabilities of the motor, wires are soldered to the motor windings.

10. The end of the pole is tightly inserted into the siphon and the entire structure is installed for testing. The windmill is quite sensitive and in a calm wind it immediately began to rotate slowly.

The rotation unit is fixed