Assembling the fan with your own hands
A simplified diagram of a fan looks like this.
Typical diagrams of most inexpensive 3 speed floor fans are about this:
Pressing each button is followed by the closure of its contact group.
And the other contact group opens at that moment.
Sometimes these contacts burn out or do not reach their plate. Then you lose one of the speeds.
To check it all elementary a Chinese multimeter, in the circuit checker mode.
If the very first wire breaks or there is no contact on it the fan motor will not start. Therefore, if a fan is completely out of order, check it first.
Unless, of course, you have made sure that the plug itself and the power cord from it are intact. This is also caused by the tester.
Place one end of the feeler gauge on the plug pin and touch the other end to the contact pad on the “0” button. If it is working, then you should have zero resistance.
Then you can check the wires at all speeds in the same way. Dipstick on the plug. other dipstick on the offending wire from the corresponding speed button to the motor.
If there are zeros everywhere, then your switch and wires are working.
Next, you check the second contact on the plug and that wire that goes directly past the switch to the motor. Make sure you have a whole cord here, too.
Only then can you move on to checking the motor windings themselves.
Bringing your household fan up to snuff for cheap.
With the onset of summer I thought about buying a fan. There was not much necessity in it, in fact in a strong heat usually “escalate” conditioner, and here in a little bit sultry days or, more likely, the periods of these days, it is quite acceptable to use a banal air blower. After figuring out exactly what I need and studying the market, I found several models that meet my requirements. Since I have no place in the room to install a floor construction, so the fan had to be a table and must be remotely controlled, for laziness! The price tag of those that I found, passed the threshold of two thousand. Not a lot of money, but for a fan I thought it was a bit much! I didn’t expect to use it often. So I decided to wait a little when the toad will be distracted and will not prevent me to spend money. As it’s not uncommon, it’s all decided by chance. I was walking through Leroy, saw a rack of fans and suddenly bought the cheapest one. Couldn’t resist 🙂
The fan is the most common. Two speeds, the ability to turn while working. But without the remote control! This, of course, is a problem, but it is not difficult to solve. For starters I opened the case to get acquainted with the internals and to understand the general plan of forthcoming works.
There was a huge amount of space! This is great! Immediately I went to our Chinese friends for the necessary details. Or rather one at a time. Here it is:
It’s a 220 volt block of four relays with remote switching capability. Remote control with 433 MHz frequency is used as a switch. This remote control is not included in the kit, so the unit cost me some pennies.It arrived surprisingly quickly, in St. Petersburg there was not even a hint of heat! It took about 10 minutes to install, carefully and slowly. I cut off the wires from the buttons and put them on two relays. And I glued the block on a double-sided adhesive tape.
There really is a lot of space inside, the unit sat perfectly! And nowhere in the way!
After reassembling in reverse order, you could start lying on the bed and enjoy the controlled cooling.This was the case for a short time. There was only one disadvantage of it all. This fan blows and hums very strongly, even at its lowest speed! I quickly began to get annoyed with this. We should have done something with it. Again the Chinese helped me out.
The thing is called a dimmer. It can be controlled by a 220-volt bulb and not a very powerful motor, such as in the fan.Although there is enough space in the case, but it was impossible to place the dimmer conveniently, without its modification. So I remove unnecessary bracket and take out the potentiometer on the wires.
Electrical diagram of the fan
The electric diagram of the fan consists of two parts. an electric motor with a starting capacitor and a unit for switching on and adjusting the speed of the blades.
The electric motor is a metal case (stator) in which the windings of copper wire are fixed and connected according to the circuit diagram. In the case in plain bearings is also mounted the rotor, which reacts to the appearance of an electromagnetic field when passing through the stator windings and rotates.
By connecting linked switches S1, S2 and S3 the speed of the air flow can be controlled with windings L1, L2 or L3. The motor winding L4 and the capacitor, C1, attached to the motor housing are used to start the motor.
If the L4 winding or the C1 capacitor is open, the motor will not start when switching on in automatic mode. But if you turn the impeller clockwise by hand the blades will start to rotate. This is how to determine if this circuit is malfunctioning.
To protect the windings from overheating in case of failure in some models of fans, a thermal fuse (marked St° in the diagram) is installed at a tripping temperature of about 125 ° C.
Thermal fuse opens circuit when over temperature exceeds design temperature and voltage is not applied to motor windings. This prevents them from burning out in case the rotor jams when the grease runs out. The fuse is usually installed on the end of the stator windings.
There are two types of thermal fuses. disposable and self-resetting. The latter break the circuit when heated above the temperature indicated on their case, and when they cool down, they close it again. This avoids the need to replace them in case of rotor jamming.
Perpetual fan from CPU cooler
Decided to please readers by telling how to make the fan. Not the first review, had to dig around to find what was worthwhile. Looks great idea to create a perpetual fan, spinning forever. A user has laid out a design that looks attractive. Let’s take a closer look, thinking at the same time how to make the fan to work forever.
You know, of course, system boxes are quiet (modern models). The slightest noise means the cooler has lost its axis, or it’s time to oil the aging fan. Runs for hours, days add up to weeks, the system unit will last for years. Made possible by clever technology. Think of the amount of friction that determines the noise. Mechanical energy becomes thermal, acoustic energy due to the presence of roughness. Processor coolers spin easily, it is worth blowing.
No commutators inside, means paradoxical fact: coil field is constant.
If the induction motor of a typical fan is powered by an alternating voltage of 220 volts, which creates a rotating magnetic field, in our case the picture is constant. You could say: inside, the rotor drives a commutator which creates the desired distribution. Not true, is confirmed by the further course of the author’s thought, the result of the experience. Western innovator decides to replace the coil with a permanent magnet. Indeed, there is no alternating field. why the electric current?
Demonstrably the author cuts off the power wire, places the neodymium (hard disk) magnets by the perimeter of the frame. each on the continuation of the coil axis. The work is finished, the blades began to rotate briskly. We believe the principle is simply used, hushed up in the orthodox literature. Patentee’s trade secret.
The blades get their initial motion from random fluctuations in the air. Reminds a magnetron, the oscillation is caused by natural chaotic motion of elementary particles. The question arises what sets the direction of rotation. The design is perfectly symmetrical. We have decided to look into it and make our observations:
In a review of one CPU cooler (cooler, not a fan) you can see: when stopped, the blade touched by hand begins to move with light jerks. Portal considered washing machine pumps. There is a similar effect. Design is similar: coils (of alternating field) stand in the perimeter, inside there is a magnetized rotor. Due to the action of the permanent magnet, the blade rotates jerkily. Indicates that the CPU fan axis has some torque. The degree of magnetization is small, but enough to work the device. It is possible that the effect occurs without special action. Televisions have a demagnetization loop of the screen mask. Applies to electron-beam models. The literature says: the cause of magnetization can be close speaker of the speaker system, the natural field of the Earth. DC coils stand perimeter. Cooler axis is provided with magnetic moment, you can grasp it: the handle of Archimedes, who promised to turn the Earth upside down with a lever.
You should agree, that it is more convenient to use batteries all the time than to make USB ports. Perpetual fan works from any position, no wires. We believe that the determining role is played by the strength of the magnets. The simple rule of more is better ceases to apply. Slips the golden mean. When the blades will spin from random airflow, overcoming the field of neodymium pieces. Weak magnets are probably powerless to keep the rotation stable. The field strength should be exactly as created by the coils at 5 or 12 volts.
Correctly create a perpetual fan
Discussed how to make a fan, let’s measure the direction, the strength of the coils magnetic field. Use a special instrument. Magnetometer, teslameter, is formed by a magnetic induction transducer, a measuring module. The interaction of the fields produces a resulting pattern, called coupling. The inverter generates an EMF. The size determines the measured strength of the magnetic field. Like two fingers! Worth 10,000.
Magnets will be located at a considerable distance from the axis. The coils are much closer. You need to know the change in the pattern with distance. According to Coulomb’s law, the force falls inversely proportional to the square of the distance, true for single charges of arbitrary sign. Magnetic poles separate in nature are not yet found (not possible to create), the cube of the distance is entered into the law. Let’s say the distance to the coil from the axis is 1 cm, the perimeter on the diagonal is 10. So neodymium must be 10 x 10 x 10 = 1000 times stronger than the small coil.
No one mandates that neodymium magnets be placed perimeter to diagonal on the fan. The poles are crosswise. Regulate the force of influence in a wide range. By placing neodymium magnets on the center of the sides of the fan frame, we significantly increase the field strength. Let’s make a calculation. Suppose the hypotenuse of a triangle with a side of 10 cm is the diagonal. The distance to the center of the square will be 10 / √2 = 7 cm. You see, the ratio from 1000 drops, reaching 7 x 7 x 7 = 343. Vesmo, desperate to find strong neodymium magnets to create a perpetual fan.
Let’s measure the power! COMPASS is suitable (there are custom designs assembled by hand, e.g. http://polyus.clan.su/index/indikatory_magnitnogo_polja_svoimi_rukami/0-52). A single coil should be connected to the power supply. Then find the position, brought the arrow will deflect about 45 degrees (do not like. take any other azimuth). After that, start your neodymium experiment. Place the piece at different distances, making sure that the deflection of the arrow coincides with that obtained when using a CPU fan coil. Surely the distance is not equal to the diagonal, half of the side, you have to break the neodymium, cut.
Troubleshooting when repairing a household fan
Before you start repairing your own hands, you should study the circuit diagram of the device. As a rule, the floor fan is equipped with an asynchronous electric motor consisting of eight windings (operating and starting). For a successful start it is necessary to shift the phase by 90 degrees. A capacitor is installed for this purpose. The device begins to work after you press the inclusion button, after which the indicator light turns on and the motor starts, the speed of which depends on the winding inclusion scheme, for which is responsible switch 3 speeds with a mechanical blockage of the simultaneous inclusion of multiple buttons, which can cause short circuits.
Before you start checking the electric motor:
- Immediately check that the connection cord to the electrical outlet is serviceable. To do this you must first disassemble the switch block, and then with observance of electrical safety measures multimeter check the presence of 220 volts on the contacts of the light bulb.
- Check the condition of the condenser according to these instructions.
- Check for continuity and integrity of all wire contacts and connections in the circuit. Here are the instructions for making the test.
- If you hear a hum or noise when the fan operates, then lubricate the plastic parts inside the gearbox with Lithol or Solidol through the holes that are specially provided for this purpose.
- Check if there is 220 volts at the output of the switch.
Glue, cardboard, toy motor
To make a small propeller you need a piece of corrugated cardboard 30×30 cm.
The support is glued in 2-3 layers, the area is not less than two palms. We make the stand for the motor in the form of a prism with the height of 10-15 cm. For cutting, we use a box cutter. We bend the construction along the ruler.
How to make a mini fan strong and stable? Use a glue gun. No other glue can hold it together as securely.
Then comes the hard part: the propeller. The central hub does not have to be made of wood or plastic. Cut it out of the same cardboard.
DecoBreeze Floor Fan Fan Head Assembly Instructional Video
Use hot melt glue, as thick as possible: the construction must be monolithic. The blades can be made of thinner cardboard. The packaging of a cell phone accessory will do.
This is the most critical element: the blades must be exactly the same shape and weight. Otherwise your propeller will vibrate while working, and quickly fall apart.
We glue the blades (carefully) on the cardboard sleeve, observing the aerodynamics. The planes should be rotated 30-45 degrees in opposite directions. For ease of design, we collect the USB fan with his hands with two blades. They are easier to balance and can cool just as well as a three-blade propeller.
Fan Troubleshooting and Ways to Fix It
To reduce production costs and achieve low noise levels during operation fan motors are fitted with plain bearings. As a result, after a couple of years of operation, the grease is worn out and this is the most common cause of fan failures.
|External manifestation of malfunction||Possible Cause of Failure||Troubleshooting||How to repair|
|After some time after the normal fan operation the fan switches off and then switches back on||Self resetting thermal fuse from overheating of the windings triggers||Check for free rotation of the impeller, disassemble the fan and inspect the stator windings for blackening||Lubricate bearings, rewind|
|The fan turns on, but the blades turn slowly||The grease in the motor bearings has thickened or worn out||If the bearings are not well lubricated, the fan makes a lot of noise when running and there may be a smell of burning from overheating of the motor windings||The fan should be disassembled and the slide bearings should be greased with engine oil|
|Mechanical wear of the electric motor bearings due to lack of lubrication. In this case, often there is a vibration of the impeller in relation to the center of rotation||Rock the impeller about the center to the sides. If the backlash is more than 0.5 mm, then the bearing is worn||Replace the bearing with a new one|
|Fan does not start, blades do not rotate||The cord is not inserted into the socket||Check||Plugging the cord into the socket|
|No voltage in the socket||Check for voltage at the outlet using a working electrical appliance||Connect fan to a properly working outlet|
|Power cord is defective||Check the plug and cord for mechanical damage, check the continuity of the wires with a multimeter||If defective, replace the power plug or cord|
|The switch or speed switch is defective. The battery in the remote control is low||The fan should be opened and the switch should be tested with a multimeter. In the turned on position the resistance between the contacts of the switch should be zero||If the switch is defective, replace it. If you have not got at hand, you can short out the contacts of the switch, and turn off the fan by pulling the plug out of the socket|
|The blower hums and becomes hot when turned on||Rotor shaft is jammed because of grease leakage or thickening||Disassemble the fan, flush with solvent and lubricate the bearings|
|Fan hums and heats up when switched on||Open circuit in start winding or capacitor.||Turn the impeller by hand, if it rotates, it means to replace the capacitor or try to find the place of a breakage of the starting winding|
|Breakage of the rotor winding||Check the windings for mechanical damage and local darkening by visual inspection, check the integrity of the windings using a multimeter||If you can not find the breakage of the winding by external examination, you will have to rewind it, which is economically impractical|
|Thermal fuse has tripped due to motor overheating due to motor malfunction||Use multimeter to check continuity of the thermal fuse. Its resistance should be equal to zero. To check in the absence of the device its outputs can be temporarily short-circuited||If a thermal fuse breakage is detected, it must be replaced with a functioning one. If new fuse burns out again after a short time of the fan operation the electric motor is defective|
For reliable operation of the fan it is recommended before each operating season to disassemble it and lubricate the bearings with machine oil. But no one does, and that includes me. Usually lubrication is done when the blades stop rotating or the fan gets very noisy.
Disassembling the machine
The assembly and disassembly process is not difficult. This does not require any particular skill. The main thing is to follow the exact instructions. When you buy a domestic fan, be sure to check the components and check the performance.
Online calculation of the capacitor capacity of the motor
Enter the data for calculating the capacitors. the motor power and its efficiency
There is a special formula by which you can calculate the required capacity accurately, but it is quite possible to get by with an online calculator or recommendations that are derived from many experiments:
Operating capacitor is taken at the rate of 0.8 uF per 1 kW of motor power; starting capacitor is selected by 2-3 times more.
Floor fan fix
Capacitors must be non-polar, that is, not electrolytic. Operating voltage of these capacitors should be at least 1.5 times higher than the mains voltage, that is, for 220 V line take capacitors with operating voltage of 350 V or higher. And to make starting easier, look for a special condenser in the starting circuit. They are labeled with the words Start or Starting.