We make a fan with our own hands. USB fan from a computer cooler. How to make a USB fan with your own hands using a motor
So all you need to prepare is sharp knife, electrical tape, an unnecessary USB cord and, in fact, the executive body of a homemade product. As for the latter, it is customary to use one of two options here: an old cooler from a computer or a motor from a typewriter. Next, we will look at two instructions that will clearly explain how to make a DIY USB fan at home!
Idea #1 - Use a cooler
As a rule, it will take no more than 15 minutes to assemble a USB fan from a cooler. First you need to prepare the cooler. Two wires come out of the device - black and red. Strip the insulation by 10 mm and set the prepared element aside.
Next, you need to prepare the USB cable. Cut off one half of it and peel off the insulation at the cut point. Under it you will see four contacts, of which two are necessary: red and black. You also clean them, while the other two (usually green and white) are best cut off so as not to interfere at hand. 
Now, as you understand, it is necessary to connect the prepared contacts in pairs, according to: red with red, black with black. After that, you need to carefully insulate the cable junctions and make a stand. As for the stand, it's up to your imagination. Some successfully use wire, some are very interesting in carving a landing nest in a cardboard box.
In the end, a homemade mini fan is connected to the computer, and you can enjoy the operation of your own electrical appliance.
Cooler idea
Idea number 2 - Use a motor
In order to make a USB fan from a motor and a CD, it will take a little more time, but still, in an hour you can easily make such an electrical appliance with your own hands. 
First, we prepare all the elements of the device. In this case, you will need an impeller (blades) too. 
To make an impeller, we recommend using an ordinary CD. Draw it into 8 equal parts and carefully cut to the center. Next, heat up the disk (you can use a lighter), and when the plastic becomes more elastic, bend the blades (as shown in the photo).
If the impeller is not bent, no airflow will be created during the rotation of the disc. Here you need to feel the measure, so as not to overdo it too.
When the blades are ready, proceed to the creation of the main mechanism. We recommend inserting a plastic plug inside the disk, in which it is necessary to make a hole for the motor barrel. We carefully fix the core and proceed to create a USB fan support for the laptop. 
Here, as in the previous version, it all depends on your imagination. Of all the tools at hand, the wire option is the most suitable. When homemade usb the fan is ready, we connect the wires of the motor to the wires of the cord, carefully isolate the twist and proceed to test work.
Visual video instructions:
Disc idea
CD Idea #2
As you can see, in order to make a fan from a cooler or a motor from a typewriter, it does not take much time and skills in working with electrical appliances. Even a beginner can handle this task!
Summer has come, which means heat, heat and an eternal lack of coolness. But this problem is fixable, and pretty easy. You only need a few details and some free time to make your life easier with your own hands, fill it with light coolness, which you will certainly get by making a USB fan at home. Of course, you can go and buy a fan in the store, but how nice it will be to sit near the same computer, and a light breeze will blow on you from the USB fan you created. And a thing created by one's own hands always pleases not only the eye, but also develops selfishness.
We offer you to watch a homemade video - usb fan:
Tools for usb fan:
- Regular CD (not necessarily new);
- A tube of silicone glue is empty;
- Wooden block;
- Mini disk;
- USB cable;
- Motor;
- Holder;
- Adapter;
- Silicone glue gun.
Three holes must be made in the tube, one in the lid, and two on the sides. Holes are easy to make using a regular nail, which must first be heated.
It is also necessary to make a slot or recess in a wooden block. This can be done easily with sandpaper.
The mini disk easily turns into a propeller. To do this, it must be drawn into uniform blades, then heated stationery knife and cut along the pre-drawn lines. And after that, we heat the base of each blade with a lighter and with the help of our hands we bend each blade a little to make a propeller.
We take the motor, holder and adapter from a non-working CD drive.
Now let's start assembling the USB fan.
Heat up the glue gun. Lubricate the holder along the axis with silicone glue from a glue gun. The propeller must be firmly planted on this glue. Press on all sides. Then, on the other side of the holder, we drip a drop of glue and glue the adapter. We are waiting for the glue to dry well. This usually only takes a couple of minutes.
Now we take a tube of silicone glue, remove the lid and grease the inside with silicone glue. And inside we insert the motor so that the part that we will connect sticks out of the hole that we originally made.
Then we put the USB cable into the side hole of the glue tube and connect the ends of the wires to the motor.
It is necessary to pour silicone glue into the recess in the wooden bar, and put the wire from the USB cable tightly there, and glue the tube with the motor inside to the base of the bar. And on the other side of the bar, glue the CD on silicone glue.
Now the propeller must be mounted on the side of the adapter glued to it on the sharp edge of the motor, which sticks out of the hole in the glue tube.
And finally, our USB fan can be plugged in and get that long-awaited coolness.
Working in the summer at the computer, or just on vacation, sometimes you want a slight breeze, a “local” coolness. The airflow of an office air conditioner doesn't provide the sweet comfort of a gentle, directed blow that a mini fan provides. It is very easy to make such a device with your own hands.
How to make a "personal breeze"
The most famous invention in this field since ancient times is folding fans. They were made from colored paper and ostrich feathers, from painted silk and carved bamboo sticks. Such a device has only one drawback: to obtain such a desired coolness, you need to hold it in your hand, which is not always convenient. It is ridiculous to imagine a manager or an economist working at a computer and fanning himself with a fan.
Therefore, let's return to our topic and figure out how to provide yourself with a pleasant breath in the heat. To make a mini-fan with your own hands, you need to solve the following few tasks:
- What will be the rotating propeller, from what material.
- Where can I get a motor.
- From what power source will the device work.
- Is it possible to completely do without an engine.
How to make a mini fan?
Let's start with the simplest: making blades. If you take a square from an ordinary sheet of paper, cut it diagonally, leaving about a centimeter intact in the center, you get a blank for a turntable. Then 4 sharp corners are bent to the middle and alternately strung on a nail, having previously stuck it into the center of the workpiece. That's all! Too bad it's just a baby spinner.
For a functional and useful design, take 2 CDs or DVDs. From one you get the blades, from the second - a stand for the device.
The circle that has served its purpose is cut into several equal parts (from the edge to the center). To make the process easier, you can hold the plastic for a few seconds over the fire. Each of the resulting sectors of the softened workpiece is slightly rotated around its axis to form a propeller.
What other components are needed in order to assemble a convenient mini fan? Here is the list:
- Cork from a wine bottle.
- Cardboard or plastic tube for mounting the engine to the stand.
- Small motor.
- Two wires.
- USB cable or batteries.
- Good glue, scissors, a strong large nail or awl.
Where to get a micromotor
It happens that in the home bins are stored appliances that no one has been using for a long time. It can be hair dryers or mixers, blenders and children's cars. Even a motor from an old tape recorder, player or some other mechanism may come in handy. We disassemble the unnecessary device and remove the engine, after disconnecting all the wires.
Since we make a mini fan, the motor is from the old washing machine, refrigerator, vacuum cleaner or other large unit will not work due to its size and noise.
Continuation of the assembly of the device
A hole is made in the cork and placed on the axis of the selected engine. To fix the shaft, it is pre-coated with glue. Then, a propeller cut from the disk is fixed with glue on the part of the axis sticking out of the plug hole.
Next, glue the paper tube along the diameter with glue and put it on the plane of the second disk. Then the motor is installed on top and its contacts are connected to the leads from the USB cable. If, when plugged into the computer port, the propeller spins in reverse side, you need to disconnect the contacts, swap them and solder them again.
By connecting a battery to such a device, you can use it anywhere in the room, in the car, near the pool.
Wind turbine without engine
How to make a mini fan at home and do without a motor? A very popular option is to create a device using small neodymium magnets.
They take the cooler from the computer and separate 4 transformer coils from its case. Instead of copper windings, you need to install and fix the same number of pieces of a magnet. Usually they buy neodymium in the form of semi-arcs or remove them from an unusable hard drive. The magnets are placed exactly in the places where the transformer windings were removed, that is, along the perimeter of the cooler frame.
As soon as the last piece is fixed, the mini-fan will begin its rotation. Using technology with permanent magnets, it is possible to assemble an almost perpetual motion machine. To stop it, one of the pieces of neodymium that replaced the coil is removed from the circuit.
The field of the magnets must be equal in strength to the field of the disconnected coils, otherwise the propeller will not be able to rotate in a constant stable mode. The poles are arranged diagonally, alternating plus and minus.
What to do if none of the above methods are suitable, if there is not enough time or details to homemade fan? In this case, you will have to use the usual factory product.
The question is trivial. First, we recommend determining the installation location of a homemade fan. Two types of engines dominate in technology: collector (historically the first), asynchronous (invented by Nikola Tesla). The first ones are very noisy, switching sections causes a spark, the brushes rub, causing noise. An asynchronous motor with a squirrel-cage rotor is quieter, generates less interference. You can find the starter relay in the refrigerator. By adding a couple of phrases of humorous phrases, we will return the seriousness of the site. How to make a fan with your own hands, not to scare your family. Let's try to answer.
Aspects of designing a homemade fan
The device of the fan is so simple, it makes no sense to tell, paint the insides. What to consider when designing? Remember the growl cyclone vacuum cleaner, the volume is above 70 dB. Inside the commutator motor. More often deprived of the possibility of regulation of revolutions. Decide whether a similar sound pressure level is acceptable at the installation site of a home-made fan? Having chosen the second, we will concentrate on induction motors, simple models do not require a starting winding. The power is low, the secondary EMF is induced by the stator field.
The drum of an asynchronous motor with a squirrel-cage rotor is cut with copper wires along the generatrix, at an angle to the axis. The direction of the slope determines the direction of rotation of the motor rotor. Copper conductors are not isolated from the material of the drum, the conductivity of the Olympic metal exceeds the surrounding material (silumin), the potential difference between adjacent conductors is small. Current flows through copper. There is no contact between the stator and rotor, there is nowhere for the spark to come from (the wire is covered with varnish insulation).
The noise of an induction motor is determined by two factors:
- Alignment of the stator and rotor.
- Bearing quality.
By correctly setting up, maintaining an asynchronous motor, you can achieve almost complete noiselessness. We recommend that you consider whether the sound pressure level is important. The case concerns a duct fan - it is allowed to use a collector motor, the requirements will be set by the location of the section.
The duct fan is placed inside the duct section, mounted, breaking the path. For maintenance, the section is removed.
Noise is losing its dominance. Sound wave, passing through the duct, attenuates. Especially fast is the part of the spectrum that has inconsistent dimensions relative to the width/length of the tract section. Read more textbooks on acoustic lines. The commutator motor can be used in the basement, garage, devoid of people. The neighbors of the cooperative will hear, rather be too lazy to pay attention.
What is good about a collector engine, what are we fighting for the right to use. Three disadvantages of asynchronous:
At the initial moment asynchronous motor does not develop a large torque, a number of special design measures are taken. The fan doesn't matter. Majority household models equipped with asynchronous motors. In production, the number of phases is increased to three.
Search fan motor
One YouTube video suggested using the engine direct current 3 volts from a hardware store. Tops the USB cord, works by rotating the blade of the laser disc. Useful invention? If you are tired of an extra port, the heat will help you survive. It's easier to take a processor cooler, power it from the system unit. A yellow wire goes to 12 volts (red to 5). The black pair is the earth. Collect from an old computer. Citizens of the Russian Federation are simply too lazy to invent, we throw curious equipment into a landfill.
Asynchronous fan motors operate without a starting capacitor ... The peculiarity of fan motors is: they go straight with the winding. A couple of tips to help get the engine:
Make a fan impeller
The question of what to make a fan from has not been resolved, the authors keep silent about the impeller. First things first, the fridge! The compressor is blown by an impeller. You will get the motor, remove it. Come in handy. Concerning washing machine, put the drum on the aircraft propeller. plastic tank fit to make a body. Heat the bending points with a building hair dryer.
Inspect the blender, supply an unnecessary laser disc, which has received the shape of an impeller. You can make a fan yourself using improvised materials. It does not require much power, there is no point in being too zealous, honing the details. We believe readers know how to make a fan with their own hands.
Eternal fan from the CPU cooler
We decided to please readers by telling how to make a fan. The review is far from the first, I had to dig around, looking for something worthwhile. Looks great idea to create eternal fan spinning forever. A mail.ru user posted a design that looks attractive. Let's take a closer look, thinking along the way how to make a fan that runs forever.
You know, of course, system units work quietly ( modern models). The slightest noise means: the cooler's axis has gone astray, or it's time to lubricate the aged fan. Working hours, days add up to weeks system unit will last for years. Made possible by smart technology. Think about it, the noise depends on the magnitude of the friction force. Mechanical energy becomes thermal, acoustic due to the presence of roughness. CPU coolers rotate easily, it's worth blowing.
The author of the video - we apologize for the lack of a name, we justify it: the video is in English - it offers to assemble an eternal fan from an accessory. The accuracy of fitting parts is great, the blade turns easily. Costs are reduced to a minimum. The author of the video posted by the deirones channel noticed: the processor fan is powered by direct current. He climbed inside, found four coils, equally spaced around the circumference, with their axes directed towards the center of the device.
There are no commutators inside, which means a paradoxical fact: the field of the coils is constant.
If the asynchronous motor of a typical fan is powered by 220 volts alternating voltage, which creates a rotating magnetic field, in our case the picture is constant. One could say: inside the rotor sets in motion a commutator that creates the desired distribution. Not true, is confirmed by the further course of thought of the author, the result of experience. Western innovator decides to replace the coil permanent magnet. Indeed, no variable field Why electric current?
Defiantly, the author cuts off the power wire, places neodymium (hard disk) magnets around the perimeter of the frame. Each on the continuation of the axis of the coil. The work is finished, the blades cheerfully began to rotate. We believe that a principle that is hushed up in orthodox literature is simply used. Trade secret of the patent holder.
The initial movement of the blade is obtained by random fluctuations in the air. Reminiscent of a magnetron, the buildup of oscillations is caused by natural chaotic movement elementary particles. The question arose as to what determines the direction of rotation. The design is absolutely symmetrical. We decided to figure it out, we express our observations:
Agree, it is more convenient than to stir up USB ports, constantly wasting batteries. The perpetual fan works from an arbitrary position, it is devoid of wires. We believe that the strength of the magnets plays a decisive role. The simple rule stops working: more is better. The golden mean is slipping. When the blades spin from a random flow of air, overcoming a field of neodymium pieces. Weak magnets are surely powerless to keep a steady rotation. The field strength must be exactly as produced by the coils when subjected to a voltage of +5 or +12 volts.
Correctly create an eternal fan
We discussed how to make a fan, we will measure the direction, strength magnetic field coils. Use special devices. Magnetometer, teslameter, formed by magnetic induction converter, measuring module. When the fields interact, the resulting picture is obtained, which is called cohesion. The converter generates an EMF. The size determines the measured strength of the magnetic field. Like two fingers! It costs 10,000 rubles.
The magnets will be located at a considerable distance from the axis. The coils are much closer. You need to know how the picture changes with distance. According to Coulomb's law, the force falls inversely proportional to the square of the distance, which is true for single charges of an arbitrary sign. Separate magnetic poles in nature have not yet been found (it is not possible to create), the cube of distance is introduced into the law. Let's say the distance to the coil from the axis is 1 cm, the diagonal perimeter is 10. This means that neodymium should be 10 x 10 x 10 = 1000 times stronger than a small coil.
No one obliges to place neodymium magnets on the diagonals of the fan perimeter. The poles lie crosswise. Regulate the strength of the impact over a wide range. By placing neodymium magnets in the center of the sides of the fan frame, we significantly increase the field strength. Let's do the calculation. Let's say the hypotenuse of a triangle with a side of 10 cm is a diagonal. The distance to the center of the square will be 10 / √2 = 7 cm. You see, the ratio drops from 1000, reaching 7 x 7 x 7 = 343. It is important for those who are desperate to find strong neodymium magnets to create an eternal fan.
Let's measure strength! A compass is suitable (there are custom designs assembled by one's own hands, for example, http://polyus.clan.su/index/indikatory_magnitnogo_polja_svoimi_rukami/0-52). One coil should be connected to the power supply. Then find the position, the raised arrow will deviate by about 45 degrees (if you don’t like it, take any other azimuth). Then start experimenting with neodymium. Position the piece different deletions, achieving the coincidence of the deflection of the arrow with the one obtained when using the processor fan coil. Surely the distance is not equal to the diagonal, half of the side, neodymium will have to be broken, cut.
Sawing one edge along the length, we carefully break the parts on the nail, getting the desired field strength to create an eternal fan. We assume that the induction is distributed in proportion to the volume. Today they told intelligibly how to make a fan with your own hands!
Power supply
Those who want to make a fan with their own hands see 3 problems: get the engine, power, make a propeller. The parts must fit together. Three problems are solved, you start making a fan with your own hands. Today at home, an abundance of switching power supplies. Think it started in the 90s. Gaming consoles, Cell phones, other equipment. The equipment breaks down, switching power supplies remain. The voltage is sometimes non-standard, most motors work on any voltage. The RPM will just fluctuate with the voltage. The broken house was lying around Appliances- immediately make a fan yourself.
Homemade fan power supplies
People are constantly trying to make a special fan with their own hands. One issue is more often left out of the discussion: the power supply. The device of the fan itself is so obvious that it makes no sense to dwell on it in more detail. So, it’s clear that there are an unthinkable amount of batteries today. Can they work for a long time? The answer is no. In extreme cases, take the "crown", in Soviet time considered a reliable source of energy. The power supply is bad, the power will gradually decrease, the speed will decrease, and the person will be annoyed. Stability without additional effort is important. A small 12 volt battery is missing - get ready: let's start looking for how to make a homemade fan power source.
The first thing that comes to mind is to screw up the computer. It is known that miniature devices are powered by a USB port. Gadgets are recharged. The USB port is a source of inexhaustible energy. The voltage is low, you need a low voltage DC motor. We believe you can find at home, buy in a hardware store. How much will the power of the port: according to the old standards 2-3 watts. Another thing is to find the host device with updated version interface (2014 recognized as a rarity). The developers promised to give out 50 watts (even more, it's hard to believe). True, there will be more wires, nominal voltages will increase. We remind, according to tradition, power is supplied to the red (+), black (-) wires. White, green - signal.
It is clear that it is difficult to expect high power - even if the port supports it, the motor will not pull. It is recommended to look at the voltage more. The motor must be supplied with a higher voltage. For example, it is recommended to use a CPU cooler. The supply voltage is less than the prescribed 12 volts, the rotation speed will simply decrease. Beware of exceeding - the motor may burn out.
We are looking for energy, the issue is easier to solve than for 3 volts:
12 volt power supply for a homemade fan with your own hands
We suggest not to assemble a switching power supply, to make a regular one with your own hands. Recall that the first ones are distinguished by small transformers. Therefore, the power supply will be relatively large in size. It will consist of the following parts:
- A step-down transformer. We will not name the number of turns in advance, the voltage is unknown, having straightened it with diodes, we get 12 volts. Of course, you can experiment, like a YouTube video about homemade radios, capturing the reader, let's look for a ready-made solution.
- The full-wave bridge, adding three to one diode, we increase the efficiency. Radio components are not very expensive.
- The backbone of the power supply is ready for a home-made fan to serve for a long time, we will straighten the network ripple. After the bridge, turn on the low-pass filter, redraw the circuit from the Internet.
The output is a constant voltage with an amplitude of 12 volts. Try not to mix up the terminals. Where the "plus" is, where the "minus" comes out can be understood by examining the diagram. Below is a drawing of the bridge, see, read the explanations. In radio electronics, the direction of the current is indicated opposite to the true one. Charges flow, according to beliefs, in the direction from plus to minus (towards electrons). Reading the circuit, you will see: for a diode, a transistor, the emitter marked with an arrow looks wrong. In the direction of travel positive charges. Each has marks, on the diagram it is indicated by a huge triangle arrow. Therefore, we always find out, “plus”, guided by the graphic symbols given in the drawing.
The figure shows: the plus will be on the right, it is transmitted according to the arrow of the diode to the lower output terminal. The minus will go up. With an alternating voltage (roughly speaking), plus, minus will alternate from left to right, the name of the rectifier will become clear - full-wave. Works on the positive part of the voltage and the negative. Diodes take power, low-frequency. Solid size, power dissipation is relatively large. You can calculate using a simple formula taken from a physics course. We multiply the resistance of an open p-n junction (leafing through the reference book) by the current consumed by the motor, taking the margin at least 2 times. The body of the motor contains an inscription indicating the power, can be divided by a voltage of 12 volts, simply multiply by 2 - 3, take a diode with equivalent dissipation power (see reference book).
Now let's calculate the transformer ... We went here http://radiolodka.ru/programmy/radiolyubitelskie/kalkulyatory-radiolyubitelya/, we chose the Trans50 program, we will master it. Note that among the software there is one that allows you to calculate the filter parameters. Do you regret that you were going to make a fan with your own hands? They offer to choose one of 5 windings. Steel is everywhere. You can do without, the losses will be great. Steel forms a magnetic circuit, energy goes to the secondary winding. It is better to find an old rusty transformer. The time is bad, in the hungry 90s, landfills are littered with plates of windings handed over for scrap. There were no problems with winding transformers.
It's time to understand how much voltage is required for the correct operation of the circuit. A term borrowed from electronics, effective AC voltage, will help. Voltage, on the active resistance, creating a thermal effect equal to the constant voltage of the effective amplitude. To obtain the required voltage value on the secondary winding, you need to divide 12 volts by 0.707 (one divided by the square root of 2). The authors received 17 volts. Engineering calculation sins with an error of 30%, let's take a small margin (part of the amplitude up to 1 volt will be lost on the diodes).
As for the secondary winding current (required for calculation), type something like “cooler power” in the search engine. Let's do it with the readers. Clever articles write: the current consumption of the cooler is indicated on the case. There will be a necessary parameter, we will substitute in the calculator. The voltage of the secondary winding, the author took 19 volts. The voltage drop across the p-n junctions of powerful silicon diodes is 0.5 - 0.7 volts. Therefore, an appropriate reserve is needed. Smart heads searched, concluded that the processor cooler does not consume more than 5 W, therefore, the current is 5 divided by 12 \u003d 0.417 A. We substitute the numbers for the downloaded calculator, for the tape core we get the design parameters of the transformer:
- Cross-sections of the magnetic circuit for winding 25 x 32 mm.
- The window in the magnetic core is 25 x 40 mm.
- The magnetic circuit is finished with a frame for winding wire 1 mm thick and with a cross section of 27 x 34 mm.
- The wire is wound along the larger side of the window, leaving a margin of 1 mm from the edges, a total of 38 mm.
The primary winding is formed by 1032 turns with a diameter of 0.43 mm. The approximate length of the wire is 142 meters, the total resistance is 17.15 ohms. The secondary winding consists of 105 turns of a copper conductor with varnish insulation with a diameter of 0.6 mm (length 16.5 meters, resistance 1 ohm). Now readers understand: the question of what to make a fan is starting to be solved with a core ...
How effective are the proposed technical solutions? Fans are known ancient egypt. The clip of Michael Jackson, recommending "remember the time" (Remember the time) testifies. The plot was hardly prepared without the advice of archaeologists and historians. We want to report that in Mexico, most ladies use fans. The Spaniards know how to deal with the heat, the country lies on the equator. Think...
It is very hot in the southern regions, nothing will prevent you from acquiring such a "super powerful" portable fan.
Can take 18V electric drill motor, propeller radio-controlled aircraft and laptop battery. 4 volts is best option and not too noisy when working. At 12 volts the device will be heavy duty, loud and will "rattle" (due to vibration) on the table.
Required Components
The motor and batteries are the most expensive parts. You can buy a cheap used drill with a broken battery and just use the motor. Used laptop batteries usually have 6 cells and cannot work if one cell is dead. You can buy these batteries for next to nothing and use working cells to make a powerful battery (http://www.instructables.com/id/Free-lithium-Ion-Battery-Pack).
Required Parts:
- electric drill DC motor;
- laptop battery;
- plastic fan blades;
- 1/8" plywood;
- plywood and 2x1" engine mounts;
- switch (in our case 2P2T switch for 2 speeds); - electric cable.
Checking the engine and batteries
Secure the fan motor to something solid.
You can try applying different voltages to it to adjust the desired wind strength. In our case, for a 4-volt battery, a current of 1.5A turned out to be ideal. An 8-volt battery for good power corresponds to a current of 3A.
Use 4 batteries, 4 in parallel at 4V and 2 sets of 2 batteries in parallel at 8V. So on low power they last about 5 hours, and at high power for about 1.5 hours.
Connect the 2P2T wires with a switch to switch between series and parallel circuit.
Creating an air duct and mounting the engine
First, glue the 2x1” bars together to form a T. Measure the pieces to give the propeller about half an inch of clearance on each side.
After gluing the bars, round off their edges to give them a streamlined look.
To mount the engine, cut 2 triangles out of wood. Soak a piece of 1/8" plywood in water, then bend it and let it dry. You can cut 3 3.5" strips of wood grain perpendicular to the piece to make it easier to bend. Use the T-bars as a base and glue 3 pieces of plywood over it, overlapping the joints and leaving one joint. Then glue the 3 ends of the T to the duct plywood. It is important to also try on the motor mount to make sure there is sufficient clearance.
Then cut two pieces of 1/4" plywood about 4.5 x 1.5 to form the duct support at the top. Glue these supports to the duct and to the "T".
Glue a piece of wood to the "T" to stop the motor from sliding backwards as the motor pushes the air forward and the motor itself then pushes back.
You can use 2 zip ties to secure the motor from below.
Battery layout
Use a 6-cell laptop battery to power the fan. For a bicycle fan in motion, you need a 12V fan. As a desktop fan, 4V or 8V is more than enough.
Wires to the engine
Solder two 14 gauge wires to the motor. Insulate with tape. To prevent the wires from falling into the blades, secure them to the fan support.
Testing
Feed the motor in parallel with 2 sets of 3 combined cells. The voltage should be around 11.8V. Even the multimeter should read 3.38A. The multimeter has some resistance, so the current is actually around 4A. More than 47 watts. This is already a very powerful little fan. At 16V, this fan can already push the bike decently.
Installation of protection
The propeller rotates too fast, so you need to install protection.
Using wire cutters, cut out a circle from the protective grill big fan so that its radius is larger than the duct by about half an inch. Wrap the wire around the duct. Then hot glue the front and back protection.
Switch installation
Install a switch. Now the fan can easily turn on and off. You can apply 2T2P switch, and get two rotation speeds.
