Do you even understand what you are writing? Or do you write in order to support a person in his endeavors and he, having spent money on components for his system, ultimately received an absolutely inoperable thing? You answer: "The engine, how will the generator fit" - yes, it will, but where did you get 1.1-1.5A from? What voltage is this? At what speed of rotation of the rotor? Then you write: "The power standard for a 1m tape is, like, 5W ..." - there is no power standard here, but there are tapes of about 5W and about 14W, and about 7W per meter, etc., and this is a very wide spread. We continue: "Since you have wound up so much, it may well be enough to charge the battery" - what does this mean? The fact that the more complex, fancy and intricate the scheme, the greater its return and efficiency? Complete nonsense. To charge a 12V motor battery, you need about 14-15V at a current of about 0.6-0.7A (for a capacity of about 7A / h). Are you sure that the system is capable of producing such parameters for a long time? After all, to charge a discharged battery of a motorcycle, 2-3 hours is not enough. Do you also think that you can charge from 18V? Yes, you can, but the electrolyte will boil away in a week, if not earlier, and the plates will crumble. Good recommendation! Unpretentious in charging - this does not mean that they can be charged with any voltage. Then you write: “It will be very great, because I suddenly forgot to turn off the light and the battery sat down even before it had time to recharge” - you say that the battery is charging only during daylight hours))) This is a windmill, not a solar battery. With a properly working system, with a constant wind, the battery should not be discharged at all, even if you forgot to turn off the light. But the photocell idea itself is good from an automation point of view. Further: the LED strip will probably work, as you say, and at 30 volts, however, for how long? Resistances limit the current, yes, but it will increase in proportion to the increase in voltage, and not remain constant! Diodes do not like excess operating current. So, the result is known: overheating of the diodes and, as a result, a sharp decrease in the service life, or their failure is extremely fast. Then you write: "The capacitance is also not critical, add 1 more 1 microfarad film capacitor" - for what? What is this, a noise filter? Why then 1uF? Why is there a filter at all? And, if not a filter, but an element smoothing pulsations, then just its capacity is critical! Capacitance is the main parameter of a capacitor actually. And 1uF is an empty space for a system described by a person, it will not smooth anything. Even 1000uF, which the author of the questions wanted to set, is very small for his idea. I would understand if it was 5000-7000 or even 10000uF, or even more. At the end, the person asks if there is enough motor battery to keep the tape glowing all night, and you answer that, they say, of course, it will be enough. Did you study physics at school? Or are you still studying? Was it your assumption with a finger to the sky or at least some elementary calculation? Let's take a very rough estimate: a person wrote that he wants to install 10-15m of tape. Even if we take the minimum values, i.e. 10m of tape with a power of 5W / m, then by simple calculations we get 50W of power. Dividing the power of the tape by the battery voltage (approximately 12.8V), we get the current: 50 / 12.8 \u003d 3.9A. The capacity of a conventional motor battery is approximately 7A / h. That. you can estimate how long the tape will work from a fully charged battery: 7 / 3.9 = 1.79h = 1h 47min., i.e. almost two hours. It's not all night. In addition, the minimum parameters are taken into account, and if the length of the tape and/or its power is greater, then the battery life will decrease proportionally. Something like that.
I wouldn’t write all this, but the fact is that the tape costs money, the battery and the photorelay too ... And this is a lot of money, and the person who received approval and support for his idea in the comments of people who do not understand the essence and nuances of the process, joyfully run to the store, spend money on components, and in the end get a system that is inoperative in principle, initially. No need to give advice without understanding the issue!
A simple, obvious, but brilliant idea came to mind. After all, given that a stepper motor is not only a motor that provides mechanical operation of completely different devices (from printers, scanners and other office equipment, to various units used in more serious devices). A stepper motor can also serve as an excellent generator of electricity!
And its main plus in everything is that it does not require high speeds at all, it may well work properly even at low loads. That is, even with the minimum action of the force directed to it, the stepper motor produces energy perfectly. Most importantly, this energy is quite enough for various needs, such as lighting the road for a cyclist using a lamp connected to a stepper motor.
Unfortunately, with a conventional alternator, a standard bike will still need initial revs before the flashlight can emit enough beams of light to clearly illuminate the path. But when using a stepper motor, this drawback is removed by itself, that is, the lighting will be supplied as soon as the wheel starts to rotate.
But the truth is that this miracle of design will still have a number of shortcomings. For example, the most obvious of them is a large magnetic sticking. But in fact, it is not so scary for a cyclist.
That getting started we will need to find some details:
1) Actually the stepper motor itself.
2) a couple of large capacitors.
3) LED lights
4) voltage stabilizer 5-6 volts.
Finding a stepper motor is quite easy due to the fact that it is very common in all office appliances. The only thing to understand is that the larger the stepper motor, the better for us, respectively.
Here several models of stepper motors and various options for their attachment to an iron horse will be described and presented.
To begin with, let's take the largest engine that the author managed to get. He dismantled it from an ordinary office plotter for printing (in fact, this is a printer, only a few times bigger size).
Externally, the engine is quite large.
But before proceeding to the study of the stabilization circuit as well as the power circuit, you should pay attention to the method of attaching this unit to the bike.
If you look at the picture, you will understand that the generator is located closer to the axis of the wheel and the rotation is transmitted from an additional circle.
And yet, since everyone has their own bike model and someone does not want to damage the frame with self-tapping screws, you will need to develop the mount yourself as well as the circle of rotation, there are really a lot of options.
If you have no idea how to screw a large stepper motor to the structure, there is a smaller option:
You just have to choose the generator option that fits the size of your vehicle.
Well, when you figured out the stepper motors, you can proceed to the flashlights and power circuits.
Lights must be LED. the rectification circuit will look like this: a block of rectifier diodes, several high-capacity capacitors and, of course, a voltage regulator. In principle, this is a standard power scheme.
A stepper motor has four output wires as standard, which correspond to two coils. it is for this reason that there are also two rectifier blocks in the image. This homemade electricity generator may well produce up to 50 volts of voltage at high speeds, so it is better to take the appropriate capacitors (voltage above 50). Well, a stabilizer for a voltage of 5-6 volts.
And so what is the essence of homemade, and why was it needed?
It's all about its advantage, even just starting off - your path will already be brightly lit by a lantern powered by our stepper motor - it's also a generator.
I would also like to note that during the movement the lamp will not blink or go out - the lighting will be smooth and even.
A wind turbine at home can be an additional source of electricity. It will be especially useful in cases where the lights are turned off, and you need to charge a device. You can also connect such a wind generator to a street lighting lamp in the yard, while saving on electricity. In general, it is always possible to find application in the household for this device. Moreover, it can be made practically from improvised materials.
In this article, we will show you how to make a simple wind generator from a stepper motor.
What do you need to build a wind turbine?
In order to assemble a wind generator from a stepper motor, you will need the following parts:
- actual motor;
- sheet metal;
- aluminum tube;
- flange (1/4");
- square pipe;
- saw blade;
- pin;
- clamps (can be used from a car);
- PVC pipes of different sizes (for example, 8x4, 30x8);
- washers, bolts, etc. for fastening parts;
- diodes.
Of the tools, a hacksaw, adjustable and gas wrench, sandpaper, tape measure, drill, protractor and tape measure are useful.
The principle of operation of the wind generator
It is not worth dwelling in detail on how a wind generator from a stepper motor works. After all, all such generators have the same principle of operation: the wind makes the blades of the windmill rotate, as a result of which the generator starts to work, which produces electricity.
Wind turbine manufacturing
The first thing to start with is to cut the blades. For this we will use PVC pipes.
What should be considered when cutting blades?
- The length of each blade - the longer it is, the easier they will spin in light wind, but at the same time they will have a rather low rotation speed.
- The rotation will be greater at the ends of the generator blades - this moment must be taken into account in advance and calculate the ratio of wind speed to the speed of rotation of the blades.
- Remember that the power received from the wind will be equal to the wind speed to the third power. Though don't forget about Betz's law, which says that approximately 59.3 percent of energy can be obtained from wind energy.
- The higher the windmill is raised from the ground, the more efficient it will be (more energy will be generated).
Making the blades will not be a big problem. To do this, you will need to cut the PVC pipe into three parts: two at 150 degrees and one at 60, as shown in the pictures.
Note that two pieces of pipe (150 0) are suitable for wide blades. If desired, you can cut them to the desired width.
The next task is to make a hub - the attachment point for the blades. For these purposes, a saw blade with sharpened teeth is suitable. It will need to make six holes in it (three groups of 2 each). Holes are made with an offset of 120 0, and the distance between them in one group should be about an inch. The placement of the holes on the disk is shown in the figure:
In this case, we use three blades, although six can be installed: then the groups of holes will be displaced by 60 0 . We fasten the blades to the prepared disk with holes - we fasten them with bolts and nuts.
The next stage of work is a hinge for turning and a weather vane. You will also need a turntable on which we will fix the generator. It will all look like this:
To make this design, you need a square PVC pipe, a piece of sheet metal and a flange. The “tail” of the wind generator is cut out of iron. In a square pipe we make a cut 20-25 centimeters long and insert our weather vane there - we fix this design with bolts.
By the way, it would not hurt to think over the protection of the generator from precipitation. For example, it can be made from a pipe as shown in the photo:
Next, paint all the details of our windmill and let them dry. After that, we assemble everything into one whole, fasten the engine, the cover to the pipe using car clamps. It is also necessary to install a flange (it is located closer to the engine) using self-tapping screws.
Now it remains only to make a match for the wind generator. For these purposes, a PVC pipe and accessories that are used with plastic pipes are suitable. You can make a mast like this:
The last step will be the direct attachment of the wind turbine to the mast and its installation. Before that, we put a previously made hub with blades on the motor shaft. That's all.
In conclusion, a few words about the battery compartment of the windmill. Two batteries (for example, car batteries) can be used for it. Diodes will need to be soldered between the generator and the batteries so that the current flows directly into the batteries, and does not go into the generator.
Such a home wind generator is suitable for charging batteries and other purposes. You can also experiment and make a more powerful windmill: for example, add blades, change their size, etc.
I already wrote at the beginning of summer about a homemade windmill - an anemometer.
His goal was to organize the collection of wind statistics and the adoption of a decision on the construction of a large, serious windmill based on it. Unfortunately, there was neither a programmer willing to write a program for processing data from an anemometer, nor a specialist in microcontrollers to create an appropriate device. Therefore, alas, I had to observe the wind visually, since the weather vane was always in sight. And unfortunately, these observations are extremely depressing ...
The fact is that the wind in the middle zone of the European part of Russia has extreme turbulence in its surface layers. Literally within 3-5 minutes, the windmill repeatedly stops (or slows down a lot) and spins up so that the blades are not visible. At the same time, the direction of the wind changes in the sector up to 90-120 degrees. It is extremely rare that there are days when a relatively strong and even wind blows. For the whole summer in my area there were only 4 such days. There were several calm days. And in the rest - the wind was very turbulent, both in speed and in direction.
Under such conditions, it is completely pointless to make a “global” wind power generator (for 1-2 kW or more). Not only will it never pay for itself, but it will generally work poorly. Since a powerful generator will require large blades, and they will have great inertia and, therefore, “pass” strong wind gusts. Those. simply will not have time to unwind. Sometimes such gusts, carrying the main power of the "average" wind flow, last only 15-30 seconds.
In addition, any rotating object has a significant moment of inertia in the plane of rotation and is, in fact, a gyroscope. I hope the reader remembers a simple school experience in demonstrating the gyroscopic effect with a bicycle wheel. Being untwisted, it is easily held with literally “two fingers” for one of the protruding ends of its axis. And it is extremely difficult to turn it sideways and make it spin in a different plane. Approximately the same thing will happen with the propeller of a windmill when the direction of the wind changes. Both the axis and the propeller blades will experience monstrous lateral alternating loads.
These circumstances actually put an end to the hopes of getting by with one large windmill. He will work, of course. But rarely and stupidly. With weak turbulent winds, it will still give out meager power, and with strong ones, you will not know what to do with the excess. And of course, you should forget about its payback. It will be just an expensive and beautiful toy, the most stupid investment of money and labor that you can imagine.
Promising designs of windmills are small low power wind turbines having practically zero inertia. It is they who are able to take from the wind almost all the energy that it carries. Such that they would have time to quickly spin up and work out the change of tack. And to obtain high power, it will be necessary to build a kind of wind farm of wind generators located on masts of different heights (so as not to shield each other from the wind). This, by the way, will significantly increase the storm resistance, solving problems with powerful heavy masts and guy wires (the masts will hold each other), with the reliability of the “power plant” - after all, all generators cannot break down at once and scheduled repairs and maintenance will not lead to a complete shutdown of generating capacity.
Having come to such disappointing conclusions, I decided to convert my anemometer into a working model of a wind turbine. Those. instead of stupid contemplation of the weather vane, begin to receive practical benefits from it. Moreover, the windmill generator is a stepper motor with 200 “steps” per revolution and generates electricity quite quickly even at low speeds. Generator power approximately Watts 7-8
First of all, it was necessary to replace the blades with less inertial ones. The mugs from the fan are still quite heavy. I made new windmill blades from the remnants of duralumin reflux for plastic windows. The propeller diameter is about 50 centimeters, which promises reaching the maximum power for the generator even with a wind of 4 m / s. I cut a triangle out of thick plywood. I glued a bushing into it (with epoxy resin), the inner diameter of which coincided with the diameter of the axis of the stepper motor. Having carefully marked out, he made cuts in the plywood “cockpit” and glued the blades into the slots. Additionally fixed them with small screws. Until the epoxy hardened, I tried to balance the screw as much as possible so that it did not vibrate during rotation. After the epoxy had hardened, I checked the balance again and brought it to perfection by cutting off the thinnest strips of duralumin from the edges of the blades.
Generally speaking, undersized wind turbines have a nice feature. There is practically no point in bothering with the most complex calculations of KIEV, blade profiles and their manufacture. The simplest, flat ones will work great too. And the required power can be obtained by simply lengthening them (hence, increasing the sweeping area).
All this greatly reduces the cost of the wind generator, it makes sense to manufacture and use it. In particular, I spent about 3-4 hours on mine (including the weather vane) and without taking into account the polymerization time of the epoxy resin. The costs amounted to "zero", since everything was done "from garbage", i.e. improvised materials.
It would seem, where can such a low-power generator be used? In the long run, I'm going to use it for... water heating. Rather, to compensate for the heat loss of water heated by the sun. The simplest calculation shows the absolute viability of my hopes.
Suppose there is a certain tank - a thermos, 50 liters, where in the evening water heated to 50 degrees is drained from the solar collector. The size of the tank is approximately 40 x 40 x 40 cm. Accordingly, the surface area will be equal to 1 square. meter. The tank is surrounded by thermal insulation with TO thermal conductivity of 0.15 W / m * deg and a thickness of 30 cm. and heat loss will be approximately 0.5 W / deg. Those. in order to maintain a temperature difference of 20-25 degrees between the hot water in the thermos tank and the surrounding air, a generator with a power of only 10-15 W is enough! It will compensate for heat loss and once heated water will never cool down. And if there is a strong breeze, it will also warm up.
Now my generator is spinning without load yet, undergoing “sea trials”. But in the near future I will make him charge the batteries in the lighting of the country toilet and lighting the path to it. And then dragging the network wire there is too lazy and difficult, but changing the batteries in the Chinese lantern is already tired.
Wind is free energy! So let's use it for personal purposes. If the creation of a wind farm on an industrial scale is very expensive, because in addition to the generator it is necessary to carry out a number of studies and calculations, the state does not bear such expenses, and for some reason investors in the countries of the former USSR are not of particular interest. Then privately you can make a mini-windmill for your own needs. It should be understood that the project of converting your home to alternative energy is a very expensive undertaking.
As already mentioned: you need to make long-term observations and calculations in order to choose the optimal ratio of the sizes of the wind wheel and generator, suitable for your climate, wind rose and average annual wind speed.
The efficiency of a wind power plant within the same region can differ significantly, this is due to the fact that the movement of the wind depends not only on the climatic zone, but also on the terrain.
However, you can learn what wind energy is at a minimal cost by assembling a budget installation to power a low-power load, such as a smartphone, light bulbs or a radio. With the right approach, you can provide electricity to a small house or summer cottage.
Let's look at how you can make the simplest wind turbine with your own hands.
Low-power windmills from improvised means
A computer cooler is a brushless motor, which in its original form is of no practical value.
It needs to be rewound, since in the original the windings are connected in an inappropriate way. Winding coils alternately:
Clockwise;
Counterclock-wise;
Clockwise;
Counterclock-wise.
You need to connect adjacent coils in series, or even better, wind it with one piece of wire, moving from one groove to another. In this case, choose the thickness of the wire arbitrarily, it would be better if you wind as many turns as possible, and this is possible when using the thinnest wire.
The output voltage from such a generator will be variable, and its value will depend on the speed (wind speed), install a diode bridge from Schottky diodes to rectify it to a constant, ordinary diodes will do, but it will be worse, because. voltage will drop from 1 to 2 volts.
Lyrical digression, a little theory
Remember the value of the EMF is:
where L is the length of the conductor placed in a magnetic field; V is the speed of rotation of the magnetic field;
When upgrading the generator, you can only influence the length of the conductor, that is, the number of turns of each of the coils. The number of turns - determines the output voltage, and the thickness of the wire - the maximum current load.
In practice, it is impossible to influence the wind speed. However, there is also a way out of this situation, you can find out typical speed wind turbine for your area, design the appropriate RPM propeller for the wind turbine, as well as a reducer or belt drive, to provide sufficient RPM to generate the required voltage.
IMPORTANT: Faster does not mean better! If the rotation speed of the wind generator is too high, its resource will be reduced, the lubricating properties of the bushings or bearings of the rotor will deteriorate, and it will jam, and the winding insulation breakdown in the generator will most likely occur
The generator consists of:
We increase the power of the generator from a computer cooler
First, the more blades and wheel diameter, the better, so take a closer look at 120mm coolers.
Secondly, we have already said that the voltage also depends on the magnetic field, the fact is that high power industrial generators have excitation windings, and low power ones have strong magnets. The magnets in the cooler are extremely weak and do not allow good results from the generator, and the gap between the rotor and the stator is very large - about 1 mm, and this is with already weak magnets.
The solution to this problem is to radically change the design of the generator. Rather, only an impeller is required from the cooler; a motor from a printer or any other household appliance can be used as a generator. The most common are brushed motors with permanent magnet excitation.
As a result, it will look like this.
The power of such a generator is enough to power the LEDs, the radio. It will not be enough to recharge the phone, the phone will display the charging process, but the current will be extremely small, up to 100 amperes, with a wind of 5-10 meters per second.
Stepper motors as a wind generator
A stepper motor is very often found in computer and household appliances, in various players, floppy drives (old 5.25” models are interesting), printers (especially dot matrix), scanners, etc.
These motors without alterations can work as a generator, they are a rotor with permanent magnets, and a stator with windings, a typical connection diagram of a stepper motor in generator mode is shown in the figure.
The circuit has a 5 volt linear stabilizer, type L7805, which will allow you to safely connect mobile phones to such a windmill to charge them.
The photo shows a generator from a stepper motor with installed blades.
The engine in a particular case with 4 output wires, the diagram is accordingly for it. An engine with such dimensions in generator mode produces approximately 2 W in light wind (wind speed about 3 m / s) and 5 m / s in strong (up to 10 m / s).
By the way, here is a similar circuit with a zener diode, instead of L7805. Allows you to charge Li-ion batteries.
Refinement of a homemade windmill
To make the generator work more efficiently, you need to make a guide shank for it and fix it movably on the mast. Then, when the direction of the wind changes, the direction of the wind generator will change. Then the following problem arises - the cable going from the generator to the consumer will twist around the mast. To solve this, you need to provide a moving contact. A ready-made solution is sold on Ebay and Aliexpress.
The bottom three wires are motionless going down, and the upper bundle of wires is movable, a sliding contact or a brush mechanism is installed inside. If you do not have the opportunity to buy, be smart, and, inspired by the decision of the designers of the Zhiguli car, namely the implementation of the movable contact of the signal button on the steering wheel, and do something similar. Or use the contact pad from the electric kettle.
By connecting the connectors, you get a moving contact.
Powerful wind generator from improvised means.
For more power, you can use two options:
1. Generator from a screwdriver (10-50 W);
You only need a motor from a screwdriver, the option is similar to the previous one, you can use fan blades as a screw, this will increase the final power of your installation.
Here is an example of such a project:
Pay attention to how a gear overdrive is implemented here - the wind generator shaft is located in a pipe, at its end there is a gear that transmits rotation to a smaller gear mounted on the motor shaft. An increase in engine speed also occurs in industrial wind turbines. Reducers are used everywhere.
However, in a homemade environment, making a gearbox becomes a big problem. You can remove the gearbox from the power tool, it is needed there to lower high revs on the shaft of the collector motor to the normal speed of the cartridge on the drill, or the grinder disk:
The drill has a planetary gearbox;
An angle gearbox is installed in the angle grinder (it will become useful for the installation of some installations and reduce the load from the tail of the wind turbine);
Gearbox from a hand drill.
This version of a homemade wind generator can already charge 12 V batteries, but a converter is needed to generate the charging current and voltage. This task can be simplified by using a car generator.
The advantage of such a generator is the ability to use it for charging car batteries Basically, that's what it's designed for. Autogenerators have a built-in voltage regulator relay, which eliminates the need to buy additional stabilizers or converters.
However, motorists know that at low idling, approximately 500-1000 rpm, the power of such a generator is small, and it does not provide the proper current to charge the battery. This leads to the need to connect to the wind wheel through a gearbox or belt drive.
You can adjust the number of revolutions at wind speeds normal for your latitudes using the selection gear ratio or with the help of a properly designed wind turbine.
Helpful Hints
Perhaps the most convenient windmill mast design for repetition is shown in the picture. Such a mast is stretched on cables fixed to holders in the ground, which ensures stability.
Important: The height of the mast should be as high as possible, approximately 10 meters. At higher altitudes, the wind is stronger because there are no obstacles for it in the form of ground structures, hills and trees. Never install a wind generator on the roof of your house. Resonant vibrations of fastening structures can cause the destruction of its walls.
Take care of the reliability of the carrier mast, because the design of a windmill based on such a generator is much heavier and is already a rather serious solution that can provide autonomous power supply to a summer house with a minimum set of electrical appliances. Devices that operate on 220 Volts can be powered from a 12-220 V inverter. The most common version of such an inverter is.
It is better to use diesel generators, incl. trucks because they are designed to work on low revs. Average diesel engine large truck operates in the speed range from 300 to 3500 rpm.
Modern generators give out 12 or 24 volts, and a current of 100 amperes has long become normal. After carrying out simple calculations, you can determine that such a generator will give you a maximum of up to 1 kW of power, and a generator from a Zhiguli (12 V 40-60 A) 350-500 W, which is already a pretty decent figure.
What should be a wind wheel for a homemade wind turbine?
I mentioned in the text that the wind wheel should be large and with a large number of blades, in fact this is not the case. This statement was true for those micro-generators that do not claim to be serious electrical machines, but rather specimens for familiarization and leisure.
In fact, the design, calculation and creation of a wind turbine is a very difficult task. Wind energy will be used more rationally if it is made very accurately and the “aviation” profile is ideally displayed, while it must be installed with a minimum angle to the plane of rotation of the wheel.
The real power of wind wheels with the same diameter and different number of blades is the same, the difference is only in the speed of their rotation. The fewer wings, the more revs per minute, with the same wind and diameter. If you are going to achieve maximum RPM, you must mount the wings as accurately as possible with a minimum angle to the plane of their rotation.
Check out the table from the 1956 book "Homemade Wind Farm" ed. DOSAAF Moscow. It shows the relationship between wheel diameter, power and rpm.
At home, these theoretical calculations are of little use, amateurs make wind wheels from improvised means, they use:
Sheets of metal;
Plastic sewer pipes.
You can assemble a high-speed 2-4-blade wind wheel with your own hands from sewer pipes, in addition to them, you need a hacksaw or any other cutting tool. The use of these pipes is due to their shape, after cutting they have a concave shape, which ensures high responsiveness to air flows.
After trimming, they are fixed with BOLTS on a metal, textolite or plywood blank. If you are going to make it from plywood, it is better to glue and twist several layers of plywood on both sides with screws, then you will be able to achieve rigidity.
Here is an idea for a two-bladed one-piece impeller for a stepper motor generator.
conclusions
You can make a wind power plant ranging from low power - units of watts, to power individual LED lamps, beacons and small equipment, to good power values in units of kilowatts, store energy in a battery, use it in its original form or convert up to 220 volts. The cost of such a project will depend on your needs, perhaps the most expensive element is the mast and batteries, it can be in the range of 300-500 dollars.