A generator that allows you to get electrical energy due to rotation (mechanical energy) is called a dynamo. The direct current generated by it, due to its qualities, is not used in everyday life as often as the alternating one. All power plants are equipped with giant alternators (alternators). Despite this, the dynamo remains a relevant device that serves well in some electrical fields, for example, when charging batteries. Therefore, a small generator, assembled with your own hands, will always find a use for itself.
In 1831, the English physicist Faraday discovered an unusual electromagnetic phenomenon. In a copper wire, during rotation between the magnetic poles, an electromagnetic field arose. It was it that excited the movement of electrons along the conductor. On the basis of research, the physicist formulated the law of electromagnetic induction. The conductor was a copper wire wound on a metal rod with a magnetic property. When the magnetic particles in the rod were arranged in accordance with the poles, it turned into a magnet and attracted metal objects to itself. A coil or a permanent magnet can be used to magnetize the rod. The effect will occur with a strong rotation of one electromagnet around another.
In the same year, a device for converting electrical energy into mechanical energy appeared. The first electric motors resembled steam engines: only electromagnets were installed instead of cylinders, metal anchors instead of pistons.
In 1834, Russian academician Boris Jacobi created the first electric motor with a rotating armature. After 4 years, the academician used an improved electric motor on the world's first motor boat. The world's first alternating current generator was built by Pavel Yablochkov. And truly revolutionary was the invention of another Russian scientist M. Dolivo-Dovolsky - a three-phase current generator.
In order to build a dynamo, you will need such basic elements as a body, a rotating armature, a collector, a brush holder, brushes, copper wire with insulation.
Consider the preparation of each element separately.
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| There are different options for making the case. A tin can, a piece of pipe (diameter 100 mm) is suitable for it. First, you need to cut the bottom of the can and make the case heavier. To do this, on the inside or outside of the can, we wrap a strip of iron of the same width very tightly in several rows. Then we rivet or solder the strip to the body. Secondly, we make cores for electromagnets and shoes for them from tin or iron. We take strips of tin along the width of the hull, bend them, put them on top of each other, fasten them with iron wire and solder them along the sides. We attach the cores to the holes in the housing located opposite each other. Using screws, we screw the body to the block (wooden or metal). In the case we make two bearing strips (brass or thick tin, size 110x20 mm) and a stand (80x20 mm) for fixing the anchor. We solder the strips with a cross, in the center we make a hole along the diameter of the axis. The same hole in the rack 10 mm from the end. Copper tubes (10-15 mm with a diameter of 8 mm) can be soldered into the bearing holes. We solder the first bearing to the body with the ends of the strips, after which the system will bend outward. |
| It is necessary to make the anchor carefully, since it largely depends on how the dynamo will work. You can assemble an anchor from tin plates. The thickness of all plates must be equal to the thickness of the body (50 mm), and special precision is required in their manufacture. About 120 circles (46 mm in diameter) will have to be cut out of iron. We divide each circle into eight sectors using a compass, make markings through the center of the circle, in the center of the circles we draw two circles with a diameter of 8 and 38 mm. At the intersection of the large circle with the lines of the sectors, we draw more circles of 8 mm each. On all round plates, where the circles were drawn, we drill eight holes of 8 mm each with accuracy. We tightly fasten the plates with nuts and put them on the axle, we should get an anchor with round longitudinal grooves. Sharp corners in the grooves are rounded off with a file. |
When assembling a dynamo, in particular the collector and brush holders, attention and accuracy are required.
| The collector can be made from a tube (copper, brass) or assembled from plates. You will need a tube with a diameter of 20-25 mm and a length of 25-30 mm, which is sawn into 4 equal parts. Two two-millimeter holes are drilled in the plates. Then we cut out a cylinder (diameter 20-25 mm, length 25 mm) from fiber or ebonite, dry wood is also suitable. We make a hole in the center of the cylinder so that it can fit tightly on the anchor axis. We fix the plates to the cylinder with the help of small screws, each time leaving a space of 1-2 mm between them. You can use twisted wire and insulating tape. The screws must not touch the axis, otherwise there will be a short circuit. The gaps between the plates are filled with rosin. |
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| A brush holder with brushes is used to relieve stress in the collector. The brushes must extend and rotate around the armature axis in order to change the force and angle of pressure on the collector. We will make a 10 mm thick base from fiber, ebonite or paraffin wood. We drill three holes in it so that the bolts fit for the two extreme ones. We take copper bolts or 35 mm radio contacts. The bolts securing the brushes are screwed in with nuts for clamping. The hole in the center should be the same diameter as the copper tube used for the first bearing in the housing. Opposite the central hole in the end of the block, we drill a through hole and make a thread for the fixing screw. We take a screw (for wood - a screw) with a slot or edges on the head. We make a hole slightly smaller than the diameter of the screw, screw the screw. First, screw in 2-3 turns, then turn it out, repeating until it enters freely for three turns. Then, in the same way, we process the next pass with a screw. We make a bearing rack, at the upper end of which we drill a hole, insert a piece of copper tube and solder it. Brushes can be made in many ways, from copper, brass plates or carbon brushes. These can be plates 40-50 mm long with a cross section of 10-15 mm. At the end of the brush, we drill an oblong through hole 20 mm long for the bolts. Such a hole will allow you to change the pressure, bringing the brushes closer to the collector. Fasten the brushes with washers. To make the brushes tightly touch the collector, we sharpen their ends obliquely. |
For winding we will use copper wire with paper insulation with a cross section of 0.5-0.8 mm. It is necessary to purchase half a kilogram of wire, the thickness of which will affect the voltage and current strength. For example, when winding with a 0.5 mm wire, 25 volts will be generated at a current of 1 ampere, if you take a wire of 0.8 - 8 volts at a force of 3 amperes. Before starting work, we divide the wire into two parts. To wind the electromagnet, you will need 450 g of wire 0.5 and 60 g for the winding of the armature. If you bought a wire of 0.8, set aside 430 g for the electromagnet, and 70 g for the anchor.
Do-it-yourself dynamo is assembled in several stages:
A small generator for a bicycle is mounted on the side wall of the tire. It allows you to charge the batteries of mobile phones, receivers and other devices, lights the headlights. The bottle dynamo is also called the side dynamo. When driving, the tire drives the dynamo roller, which rotates the electric generator.
For a bicycle generator, you can take a dynamo hub, a dynamo carriage. A non-contact dynamo will also work. She will be able to charge the phone quite successfully.
Careful setting of the dynamo is very important, taking into account the angle, height and pressure. To start, the bottle-type bicycle dynamo is moved and connected, and the hub dynamo is simply turned on manually or automatically.
The dynamo must be operated strictly according to the instructions.
In the field, a simple “twist”, a dynamo for charging the phone, will always come in handy. Chargers with a built-in battery are relevant. There are mechanical chargers that also do not take up much space. Many modern "twists" are equipped with flashlights.
These devices quite successfully charge mobile phones. For example, when turning the knob 2-3 revolutions per second, you can get a coefficient value from 0.65 to 2.5. I twisted it for a couple of minutes and you can talk on the phone from 2 to 5 minutes. It all depends on the model and conditions of reception. A hand-held dynamo will not be able to power a powerful smartphone with a large display. Mechanical charging will provide results in conjunction with a simple phone along with a hands-free headset.
Charging the dynamo machine will work effectively when the battery is completely discharged, but you can only increase the charge of the phone by twisting the handle up to 50%. When the battery is only half discharged, the spinner becomes a useless toy. If the instructions indicate the maximum charging current - 400 mA with a power of 2 W, then additional energy cannot be squeezed out even with a quick rotation of the handle.
A powerful electricity generator can be assembled using an old bicycle without eights on the rear wheel. A 28-inch wheel and a 52-tooth front sprocket will do, but other options are possible, such as a 26-inch and a 46-tooth sprocket. First of all, we remove unnecessary parts: the front wheel, tires, gear shift, brakes. We put the bike on the stand.
The generator must be self-contained with two large terminals and one small one. We connect two large terminals together, forming a plus, and a small one - with an indicator light. Connect the ground terminal to the housing (minus). We clean the generator, remove the cooling fan from it. We fix the generator on the bracket behind the seat, the spindle should be outside 10-12 cm from the rim. We select a belt, preferably a toothed one, with a circumference of approximately 82 inches. For 26-inch wheels, A78 belts will fit, and for 27-inch wheels, A80 belts.
To adjust the tension of the alternator, we use a spring-type tensioner. The belt does not need to be tightened too much, as the torque is quite low. We fix a voltmeter, a switch and a light bulb on the steering wheel. If there are children in the house, it is necessary to protect the moving parts of the mechanism in order to exclude the possibility of injury.
I made this friction bike generator to power my flashlight and rear lights. I found the idea and a lot of information for this pedal generator project on the Internet.
I recently bought a bike to commute to work and around the city, and decided that for the sake of safety I needed a backlight. My front light was powered by 2 AA batteries and the rear light by 2 AAA batteries, the instructions said that the front light would work 4 hours and the back light 20 hours in flashing mode.
Although these are not bad indicators, they still require some attention so that the batteries do not run out at the wrong time. I bought this bike for its simplicity, the single speed means I can just sit back and ride, but constantly changing batteries gets expensive and makes it harder to use. By adding a bike dynamo, I can power the batteries while I ride.
If you want to assemble a dynamo machine with your own hands, then you will need a few things. Here is their list:
Electronics:
Mechanical parts:
Tools:
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Let's make a diagram of a dynamo for a bicycle. It's not a bad idea to test everything before soldering everything together, so first I built the whole circuit on a breadboard with no solder. I started with the motor connector and diodes. I unsoldered the connector from the printer circuit board. Placing the diodes in this orientation changes the AC output from the motor to DC (rectifies it).
A stepper motor has two coils and you need to make sure each coil is connected to the same set of diode groups. To find out which wires from the motor are connected to the same coil, you just need to check the contact between the wires. Two wires are connected to the first coil and two to the second coil.
Once the circuit is assembled on a breadboard without solder, test it. My motor produced up to 30 volts during normal cycling. This is a 24 volt stepper motor, so its efficiency seems reasonable to me.
With the voltage regulator installed, the output voltage was 3.10 volts. The resistors control the output voltage, and I chose the 150 and 220 ohm options for 3.08 volts. Check out this LM317 voltage calculator to see how I calculated my readings.
Now everything needs to be soldered on the printed circuit board. To make neat connections, I used a small amount of solder gauge. It heats up faster and provides a better connection.
In the .Pdf file you will find how everything is connected on the PCB. The curved lines are the wires and the short black straight lines are where you need to solder the jumpers. Files
The engine mount was made of an aluminum angle and a reflector bracket. Holes were drilled into the aluminum to mount the motor. Then, to make room for the wheel, one side of the corner was cut out.
The wheel was attached by wrapping duct tape around the motor shaft until the connection was tight enough to slide the wheel directly onto the duct tape. This method works well, but it needs to be improved in the future.
Once the motor and wheel were attached to the aluminum, I found a suitable spot on the frame to mount everything. I attached the blank to the seat tube. The frame of my bike is 61 cm, so the area where the generator is installed is quite large compared to smaller bikes. Just find the best place on your bike to mount the generator.
After I found a suitable spot, I made marks for the aluminum bracket with the reflector bracket installed so it could be cut to size. I then drilled holes in the bracket and aluminum and mounted the structure on the bike.
I finished assembling a 12 volt bicycle alternator by attaching a project box with two posts to an aluminum mount.
The dynamo for the bike is assembled, now all you need to do is just connect the wires to the bulbs. I pushed the ends of the wires past the battery terminals to the headlight, then drilled a hole in its housing to let the wires through. The wires were then connected to the battery connector. You will also need to make holes for the wires in the project box.
One of the popular technical devices is the bicycle dynamo. It is about what types of this device exist, what it is used for and their features.
A bicycle dynamo is an electrical generator that generates energy to power electrical appliances installed on a bicycle, such as headlights or a power supply for a navigator.
To date, two types of bicycle dynamos have become widespread, namely: bottle dynamos and hub dynamos.
Regardless of the type, both of them generate electrical energy due to the rotation of the magnet inside the coil. Thus, in bicycle dynamos, the armature is a fixed element, and the stator rotates.
This species got its name for its resemblance to an ordinary bottle. A bottle dynamo machine for a bicycle was the most common in our country during the Soviet Union. It has undeniable advantages, which include:
At the same time, the bottle type has disadvantages, which in some cases make its installation undesirable or even impossible. These should include:
All of these shortcomings are predetermined by design features, and it is impossible to eliminate them without fundamental changes.
The second type, the popularity of which is constantly growing, is the so-called dynamo hub.
In this case, the bicycle dynamo is designed as a wheel hub. The output voltage of such generators is about six volts at a power of up to two, and sometimes three watts.
All the advantages of such a dynamo for a bicycle are determined by its design feature. The "pros" include:
For all that, the dynamo hub cannot be turned off; when moving, it works constantly. Some experts consider this moment a disadvantage, however, objectively, with the load disconnected, the dynamo will not affect the freedom of rotation of the wheel, and therefore it will be fundamentally wrong to consider the impossibility of disconnection as a disadvantage. Another point is the high mass, although with perfect balance, this does not affect the ride quality of the bike to the extent that it will become noticeable in practice. The only serious drawback is the price and complexity of the design, as well as the fact that to install such a generator it is necessary to sort out the entire wheel, and this undoubtedly requires certain skills and training.
So, when choosing a dynamo for your two-wheeled friend, remember about safety, reliability and focus on your financial capabilities. What will be the dynamo for the bike, of course, it is up to you and no one else to decide.
Since this type of generator is gaining popularity, let's dwell on some of its features that you need to know and understand.
First of all, if the bottle generator generates direct electric current, then the bicycle hub dynamo generates alternating voltage. What is the difference? Let's try to figure it out without delving too much into electrodynamics.
Direct current has poles: "plus" and "minus". Such a current always flows in one direction from plus to minus. AC voltage has no polarity. In order for an ordinary incandescent lamp to burn, it does not matter what the current will be, direct or alternating. But for an LED headlight, things are different: LEDs will only work with constant current and the correct connection. If a dynamo hub is installed on a bicycle, then it is necessary to connect the LED headlight through a special rectifier bridge. This will be true for any energy consumers designed to be powered by a DC source.
When installing a bottle generator, there are no difficulties, but a generator hub for a bicycle will make you work.
First of all, since the very design of such a generator provides for installation as a carrier sleeve, the wheel will have to be removed and completely disassembled. First take care of a set of shortened knitting needles. After complete disassembly, fasten the rim to the hub with short spokes. Try to install evenly and evenly, gradually tightening the spokes, and then, pulling up, strengthen the rim completely. Then you need to do the balancing and check for runout and imbalance.
Attention! In a bottle-type generator, there is a power minus on the case. The dynamo hub has no electrical contact with the case, and therefore you can make the wiring completely insulated or use a metal frame as one of the conductors. If a rectifier bridge is installed, then the frame must be attached after it.
Every cyclist dreams of their autonomy, safety and comfort on the road, at least a little reminiscent of a car. In heavy rain, they dream of a roof, in a headwind, they dream of a motorbike or an electric motor, and when driving in the dark, and even on forest paths, in unfamiliar places, everyone dreams of good road lighting.
Modern bicycle technology has come a long way. In the USSR, during our childhood, a dynamo for a bicycle was attached to the fork of the front wheel, was complete with a headlight and wires.
This type of dynamo is called "bottle" for the similarity of the generator with a bottle (see the figure below), but had a number of disadvantages.
The dynamka could be fixed to the side of the tire with a click of the hand (or foot), and the lantern immediately produced light.
The disadvantages of such a dynamo were the following:
However, she had certain advantages, such as:
What irritated me the most was the feeling of having to constantly move quickly to get a bright beam of light, despite the noise and the feeling of resistance. The resistance was such as if the brake lever was constantly pressed lightly.
More than a quarter of a century has passed since then. Powerful capacious rechargeable batteries and, most importantly, economical and bright light sources, such as LEDs, appeared.
But most importantly, another type of dynamo has become widespread in the Russian Federation, which has spread throughout the world since the late 1950s. It's called a dynamo hub.
Dynamo hub for front fork. It is clearly seen that knitting needles of different lengths are installed on different sides.
This device simply combines the function of a wheel hub and the function of generating electricity. They first began to be made in the UK. Their cost ranges from $50 to $300 and up.
A standard bushing produces a current of 6 V, and the output power is about 2 watts. The new bushings are capable of generating up to 3 watts. Since each power output has its own light sources, you should not put a more powerful flashlight on bushings with a lower output power, otherwise the light will be dim.
A 3W LED is capable of blinding a person for a few seconds even on a clear day, and in the dark, using optics, it will serve very well.
The advantages of hub dynamos are:
The disadvantages of hub dynamos are as follows:
Both those and other generators at high speeds can simply burn out the lamps in the headlights. But in modern headlights there may be a voltage regulator on semiconductors, it is better to use them.
If we compare bottle speakers with bushings, then the bushings shine better at low speed, due to the lower frequency of alternating currents.
In conclusion, I would like to say that when installing such a do-it-yourself power generation system, like a dynamo for a bicycle, it is easier to start with a cheap "bottle" Chinese generator. In any case, this will allow you to work, “pump up” your legs and the cardiovascular system a little due to additional resistance and save money and time, since you will have to re-spoke the wheel when installing a hub dynamo.
Do-it-yourself dynamo generator for a bicycle can be assembled according to the video instructions.
A bicycle headlight is a necessary attribute for evening and night walks. They are needed both outside the city and on city streets, since even within the city there is not always enough lighting for a normal and safe bike ride.
When choosing a good headlight for a bicycle, it is necessary to take into account such parameters as lighting brightness, fastening reliability and battery efficiency.
Bicycles are of different types. They differ in the method of fastening, the quality of lighting and the type of charge.
The flashlight can be powered by ordinary AAA batteries, or it can also be from a lithium battery. Currently, rechargeable headlights are becoming increasingly popular, as they have sufficient lighting power and a long period of operation, and also do not require the constant purchase of spare batteries.
Most headlights are mounted on the steering wheel, but there are alternatives. They can be mounted on a fork or even mounted on a cyclist's helmet. Depending on where the headlight is installed, the characteristics of road illumination change when driving.
Modern bicycle lights amaze with their variety of choices in terms of power and lighting quality. Diodes for the manufacture of bicycle headlights are often used the most modern, which allows you to bring lighting to a new level. Far from new is the fact that the road ahead can be illuminated and clearly visible in the same way as in the daytime. In addition, a different reflector pattern can add enough side lighting to improve visibility to the sides.
Attaching a headlight to a cyclist's helmet is a very convenient way to increase the maneuverability of the light beam and widen the diameter of the illumination to meet the required requirements.
Some cyclists who are not satisfied with the modern market for bicycle lights prefer to assemble a bicycle lamp on their own. Such a headlight requires some knowledge in the field of electronics, but the process of making a headlight with your own hands is not too complicated and time consuming.
Many cyclists prefer to use an ordinary LED flashlight, specially selected for cycling, based on its light qualities and features, and mounted on a bicycle or helmet, either on special mounts that can be found in any online store, or on their own using improvised means .
Those who like long trips in places where it is often impossible to recharge a flashlight and other electronics, prefer to install dynamos. A device that allows you not to depend on an outlet and batteries is very easy to do with your own hands, and there will be a lot of benefits from it - it will save you from a rather annoying question where the headlight can be charged while traveling, and even at night you will be able to move around calmly.
In addition, a lantern based on a dynamo can be installed for the city. This method of charging is preferred by those who really do not like to change batteries often or periodically charge batteries, which tend to run out very quickly due to the fact that modern bicycle headlights have fairly powerful LEDs, and often several, which consume battery power very quickly. .
The principle of operation of a bicycle dynamo is that the alternating current generated by the dynamo passes through a rectifier and feeds the LED in the headlight. In this case, there is a possibility of light flickering at low speeds, but this problem is easily solved by installing a smoothing capacitor. The headlight on a bicycle with a dynamo generator will shine with a bright, even light.
There are two types of dynamos that power a bicycle headlight:
There are a large number of schemes for dynamos on a bicycle, allowing you to properly set them up and thereby increase the voltage, power and performance at low speeds of these devices.
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