How to assemble a construction hair dryer with your own hands. The hairdryer only blows cold air, what should I do? High-quality repair of a construction hair dryer with your own hands Electrical circuit diagram for a technical vertex hair dryer
Repairing any hair dryer begins with its complete or partial disassembly, but before we begin this process, let’s find the answer to the question asked above.
Absolutely any hair dryer can be divided into two main elements - a heating element and an electric motor. The heating element is usually a nichrome spiral, which heats the air. And DC electric motors create a warm, directed air flow.
Electric motors in hair dryers are 12, 24 and 36 Volt, but sometimes in very cheap Chinese models there are 220 Volt electric motors. A propeller is attached to the engine rotor, which removes warm air from the spiral. The power of a hair dryer varies depending on the thickness of the coil and the power of the electric motor.
Let's look at the design of the hair dryer in more detail:
1 - diffuser nozzle, 2 - body, 3 - air duct, 4 - handle, 5 - cord anti-twist guard, 6 - "Cold air" mode button, 7 - air flow temperature switch, 8 - air flow speed switch, 9 - "Turbo" mode button - maximum air flow, 10 - loop for hanging the hair dryer.
The hair dryer body consists of two plastic halves, a front and rear ring and a mesh. The mesh hemisphere is dismantled by slightly turning it counterclockwise. The hardest part to pull out is the back ring where the power cord enters the base. This ring has lugs with holes and latches. The front ring is removable, although a little easier, but it also has two latches on the halves of the body and recesses in the ring (in the photo below only one protrusion is clearly visible and the ring is put on before it).
the main elements of the hair dryer and the diagram in the photographs below:
Rowenta cv8525 hair dryer works, but does not heat the air |
Rowenta hair dryer repair and disassembly: First, the front metal ring is removed, then the back mesh is hidden under two self-tapping screws, unscrew them and remove the back cover from the handle (on the latches). There are five self-tapping screws under the cover; unscrew them.
An inspection revealed a classic contact failure in the button that turns off the air heating. The contact moved away a little and stopped closing the heating circuit of the coil. The repair came down to correctly setting the contact position and fusing the top of the plastic stand with a regular soldering iron.
Remington hair dryer disassembly and repair |
Job instability. The hair dryer turned off periodically. First you need to remove the plugs on the hair dryer handle. You can remove the plugs with a sewing needle or the sharp end of a thin knife.
Under the plugs there are screws for a special U-shaped screwdriver. After disassembling the handle, we see the warm air supply switch (blue), hair dryer power switch (red). Here you need to inspect everything very carefully in case of a very likely break in the conductors or melting on the switches.
We all know this one auxiliary tool in construction, like a construction electric hair dryer, which we are used to using to remove paint and varnish coatings.
Fundamental operating principle construction hair dryer not much different from an ordinary hair dryer that we use to dry our hair.
Accordingly, the electrical circuit of a construction hair dryer is similar to the electrical circuit of an ordinary hair dryer.
An explanation will be given in the above topic:
- electrical diagram construction hair dryer;
- operating principle of a hair dryer;
- possible causes of the malfunction;
- troubleshooting these problems.
Electrical circuit of a hair dryer
Let's look at the electrical diagram \Fig. 1\ of a hair dryer:
One diagonal of the diode bridge is connected to an external 220V AC voltage source.
The other diagonal of the diode bridge is connected to the electric motor.
The electrical circuit consists of the following elements:
- toggle switch that implements the temperature control mode - K1;
- a toggle switch that controls the rotation speed of the electric motor rotor \blowing speed control\ - K2;
- Toggle switch for turning off heating elements - K3;
- electric motor \fan\ - M;
- capacitor - C;
- heating elements - R\TEN\;
- diodes - VD1, VD2.
Through a diode bridge circuit \one diagonal of the bridge\ the rectified current of two potentials \+,-\ is supplied to the electric motor. When moving from the anode to the cathode, the current flows at a positive half-cycle of the sinusoidal voltage.
Two capacitors connected in parallel in the electrical circuit serve as additional smoothing filters.
The blowing speed occurs due to the variability of resistance in the electrical circuit, that is, when the speed switch is switched to highest value resistance, - the rotation speed of the electric motor rotor decreases due to a voltage drop.
The number of heating elements \heaters\ in this scheme is four. The temperature regime of the hair dryer is controlled by a temperature control toggle switch.
Heating elements in an electrical circuit have different resistances; accordingly, the heating temperature when switching from one section of the electrical circuit to another - heating of the heating elements will correspond to its resistance value.
General appearance of a construction hair dryer with its names individual parts, - shown in Fig. 2
The following electrical diagram of a construction hair dryer \Fig. 3\ is comparable to the electrical diagram of Fig. 1
There is no diode bridge in this electrical circuit. Airflow speed control and control temperature conditions, - occurs when switching from one section of the electrical circuit to another, namely:
- when switching to a section of an electrical circuit - consisting of a diode;
- when switching to a section of an electrical circuit that does not have a diode.
When current flows in the anode-cathode junction of the diode VD1, which has its own resistance, the heating element2 will heat up according to two resistance values:
- resistance at the transition anode - cathode of diode VD1;
- resistance of the heating element \TEN2\.
When current flows in the junction, the anode - cathode of the diode VD2, the voltage supplied to the electric motor and heating element1, will take the lowest value.
Accordingly, the rotation speed of the electric motor rotor and the heating temperature of the heating element for a given section of the electrical circuit will correspond to the direct transition of the current of the diode VD2. Heating heating element \TEN1\ for a given area also depends on its internal resistance, that is, the resistance of the heating element is taken into account.
Malfunctions of a hair dryer
The main reasons for the malfunction of a hair dryer can be called a malfunction of electronic elements:
- diodes;
- capacitors.
Most often, this malfunction occurs during a sharp jump external source alternating voltage. For example, the cause of a capacitor malfunction is caused by the fact that the capacitor plates are short-circuited with each other during a voltage surge.
Of course, the possibility of a malfunction such as a break in the stator winding of the electric motor (winding burnout) cannot be ruled out.
Minor malfunctions include the following reasons:
- oxidation of temperature control toggle switch contacts;
- oxidation of the contacts of the toggle switch for controlling the blowing speed;
- oxidation of the contacts of the toggle switch to turn off the heating elements;
- wire break in the network cable;
- malfunction plug\lack of contact\.
Diagnostics to identify the cause of the malfunction is carried out using a “Multimeter” device.
When replacing a capacitor, its capacitance and rated voltage are taken into account.
When replacing a diode, the resistance of two values is taken into account, in the directions:
- from anode to cathode;
- from cathode to anode.
As we know, the resistance value from anode to cathode will be significantly less than from cathode to anode.
With an electric motor, if it malfunctions, things are more complicated. In case of such a malfunction, it is easier to replace the electric motor than to rewind the stator windings. But such work can also be done - whoever is directly involved in such repairs. In this case, the following is taken into account:
- number of turns in the stator winding;
- cross-section of copper wire.
A malfunction such as heating element burnout cannot be ruled out. The heating element is replaced taking into account its resistance value.
Diagnostics and repair of a construction hair dryer
Let's look at the design of electric motors and how exactly diagnostics should be carried out. electric machines, as they are commonly considered in the electrical engineering section.
For clear example, photographs of several types of such electrical machines are presented - related to commutator electric motors. The design and principle of operation allow for two commutator electric motors:
- vacuum cleaner;
- construction hair dryer,
- is no different. The difference in electric motors is only in the speed of rotation of the rotor and the power of the electric motor. Therefore, we will not focus our attention in the sense that explanations are given that are not related to the electric motor of a construction hair dryer.
Electric motor of a construction hair dryer
Electric motor of a construction hair dryer - asynchronous, commutator, single-phase AC.
single-phase AC asynchronous commutator motor
The electrical circuit of the commutator motor \Fig. 5\ looks like this:
In the diagram we can notice that the commutator motor can operate on both alternating and direct current - these are the laws of physics.
The two stator windings of the electric motor are connected in series. Two graphite brushes in contact - in electrical connection with the electric motor rotor commutator.
The electrical circuit is closed on the rotor windings; accordingly, the rotor windings in the electrical circuit are connected in parallel through the brush-commutator sliding contact.
diagnostics of electric motor stator windings
The photograph shows one of the methods for diagnosing the stator windings of an electric motor. In this way, the integrity or breakdown of the insulation of the stator windings is checked. That is, one probe of the device is connected to any of the output ends of the stator windings, the other probe of the device is connected to the stator core.
In the event that the insulation of the stator winding is broken and the winding wiring is shorted to the core, the device will indicate the mode short circuit\zero resistance value\. It follows that the stator winding is faulty.
The device in the photograph indicates a one when diagnosing - this will not mean that this stator winding is suitable for use.
It is also necessary to measure the resistance of the windings themselves. Diagnostics is carried out in the same similar way - the probes of the device are connected to the removed ends of the wires of the stator windings. If the windings are intact, the device display will indicate the resistance value of one or the other winding. If one or another stator winding breaks, the device will show “one”. If the wires of the stator winding are short-circuited with each other as a result of overheating of the electric motor or for other reasons, the device will indicate the lowest \zero\ resistance value or “short circuit mode”.
How to check the rotor windings for resistance with a device? — To do this, you need to connect two probes of the device to two opposite sides of the commutator, that is, you need to make the same connection that the graphite brushes have in electrical connection with the commutator. The diagnostic results are reduced to the same readings as when diagnosing the stator windings.
commutator plate wear
What exactly is a collector? — The collector is a hollow cylinder consisting of small copper plates of a special alloy, isolated both from each other and from the rotor shaft.
If the damage to the collector plates is minor, the collector plates are cleaned with fine-grained sandpaper. Again, this amount of work will be performed directly only by specialists involved in the repair of electric motors.
The electrical circuit \Fig. 7\ consists of a battery and a light bulb; this circuit is comparable to the circuit of a flashlight. One end of the wire with a negative potential is connected to the stator core, the other end of the wire with a positive potential is connected to one of the output ends of the stator windings. If the wires are connected in reverse, that is, “plus” to the stator core, “minus” to the output end of the stator winding, nothing changes.
If there is an insulation breakdown when the stator winding is closed to the core, the light bulb in this electrical circuit will light up. Accordingly, if the light does not light up, it means that the stator winding is not closed to the stator core.
This diagnostic method \Fig. 7\ is not complete. Accurate diagnostics are carried out only with an Ohmmeter or a Multimeter with a set resistance measurement range, for subsequent measurement of the resistance of the stator windings.
Without exaggeration, we can say that a hair dryer lives in every home today. This softly humming accessory blows warm air, has forever entered the women's arsenal, has become an essential item and is used not only for drying hair, but also for styling and creating certain hairstyles. However, sometimes there comes a time when something inside the hair dryer begins to crunch ugly, a wave of warm breeze turns into a north wind, and an inner voice persistently tells you that an urgent repair is needed.
Design of a hair dryer
The basic design of all hair dryers can be considered identical. Any person who owns a screwdriver and basic school knowledge of electrical engineering can deal with it.
Each hair dryer consists of four main parts:
- Electric motor .
Motors come in several types - 12, 24 or 36 volts. This is done in order to protect the user. The current from the network has a voltage of 220 V and is dangerous to human health. Using an electronic circuit, the voltage is reduced, due to which the impeller that forces air to the nozzle is powered by a small DC motor, which is absolutely safe for humans.
The hair dryer is powered by an electric motor, which is supplied with reduced power for safety reasons.
- Fan. Its task is to create air flow. The body of the hair dryer is made special holes, through which the impeller sucks in air and directs it in the desired direction. Typically the propeller is made of plastic and rotates on metal rod, which serves as its axis. On one side, the axis is connected to an electric motor, on the other, it is attached to a support equipped with a sliding sleeve.
The impeller takes air through the cracks in the hair dryer body and drives it towards the nozzle
- Heating element. As a rule, this is a nichrome spiral. When current is applied, it begins to heat up and heat the passing air to the desired temperature. IN good hairdryer the spiral is designed so that the heated air does not burn the hair, i.e. its temperature does not exceed 50–60 o C.
In advanced models of hair dryers, several spirals are installed to ensure the device operates in two or three heating modes
- Electronic circuit. Serves to convert current and adjust operating modes of the device. Using the keys located on the body of the hair dryer, you can disconnect or connect the coil, increase or decrease the air flow speed.
It should be noted that the effectiveness of the device as a whole depends on the coherence of all structural components. If, for example, air channel clogged and the flow rate is slowed down, the spiral will definitely begin to overheat, and this will lead to either its failure or an increased temperature of the outgoing flow. Malfunction of the electronic circuit can lead to a voltage drop on the electric motor, as a result of which the hair dryer will not work at full power.
The first mention of a hairdryer is associated with the name of the French hairdresser Godenfroy. It was he who, in 1888, offered his clients to dry their hair using a patented device powered by “any heat source.” In 1908, the famous Berlin electrical engineering company AEG registered trademark“Föhn”, which translated from German meant “warm alpine breeze”. The first devices were quite bulky and heavy; the body consisted of a metal casing and weighed about 2 kg.
The prototypes of the modern hair dryer were large and heavy
Possible malfunctions of the hair dryer and their elimination
Unfortunately, equipment tends to break down. And often - at the most inopportune moment. Even expensive models produced by reputable companies can fail. The reason for this can be both non-compliance with operating rules and factors beyond human control. For example, power surges, children playing, or teething pets. Situations are different, but in any case, you shouldn’t rush to the store to buy a new device. Perhaps, having understood the cause of the breakdown more closely, you can restore the normal operation of the hair dryer without outside help, with your own hands.
The following repair information does not apply to new generation models equipped with air ionizers and infrared emitters. The design of such hair dryers is much more complicated; it is not recommended to repair them at home.
Lack of power
If problems occur, first of all you need to pay attention to the condition of the power cord and conduct a visual inspection of it. It should not get hot during operation. If there is any damage to the insulation, fractures or swelling, you need to check whether current is flowing to the device.
The hair dryer may not turn on due to damage to the cable insulation
To do this you need:
- Disassemble the case and use a voltage indicator to test the power contacts inside the hair dryer. To disassemble, you need to find and unscrew all the screws on the casing. Sometimes, in addition to them, latches are used - they must be carefully separated so as not to break the fragile plastic. In some models, the screws are covered with decorative plugs or stickers. In this case, carefully remove them by hooking them by the edge with a screwdriver. Before disassembling the hair dryer, do not forget to unplug it from the mains by unplugging the cord from the outlet..
After unscrewing all the screws, you need to carefully pry up the plastic plugs and disconnect the case
- Next, the wires go to the power button. You need to check that the switch moves freely and is not clogged with foreign debris or stuck together dust. If the contacts are working properly, their color will be even, without signs of charring. Overheated copper turns from yellow to dark blue, which is a sign of improper operation.
It is necessary to check all contacts for charring or discoloration, which is also a sign of improper operation of the power circuit
If damage is found, the contacts must be cleaned with a knife or sandpaper, but in no case with a damp cloth. Sometimes this is enough to restore normal operation of the device.
Plug in the device for a few seconds. In this case, the power key must be in the “Off” position. or Off. To check the presence of voltage, bring the indicator to both terminals of the button.
If there is a “phase” on the contact being tested, the indicator light will light up
The best solution to the problem of a damaged power cord is to replace it with a new one. But if it is not possible to replace the cable, you can get out of the situation by stripping the “bad” contacts and connecting them by twisting. The connection point must be carefully insulated with dielectric adhesive tape.
If you repair damage to the power cord by twisting the wires together, be sure to wrap open place electrical tape
If the problem is in the button, you need to clean it and tighten the screws securing the terminals. As a last resort, you can temporarily disable the button by connecting the wires directly. In this case, the motor will turn on immediately after connecting the cord to the outlet.
If the hair dryer control button is out of order, before purchasing new part the wires can be connected directly, however, some modes of the device will stop working
Fan doesn't work
The most common reason for a fan stopping is hair. During operation, the hair dryer pulls small hairs inside and they are wound around the propeller axis. Over time, the rotation slows down and eventually stops altogether. Obviously, it is better to periodically clean the fan and not let the situation become critical. Moreover, this is easy to do - using tweezers or a small brush to remove hairs from the impeller will not be difficult.
From the outside, you can clean the air intake holes, but in order to get to the fan, you need to disassemble the housing
The criterion for normal fan operation is the free rotation of the propeller on the engine axis.
If the situation repeats frequently, you need to carefully examine reverse side air pipe. The air intake grille may be damaged and too many foreign objects are entering through it. You can get out of this situation by sticking it on the grille mosquito net or gauze, but it must be held firmly so that it does not get sucked inside. Some models have an input air filter. It may be time to clean or replace it.
The filter is located at the back of the hair dryer, on the air intake side
Outgoing air does not heat up
The spiral is one of the most vulnerabilities all hair dryers. Despite the fact that modern heating elements are quite reliable, they are greatly influenced by the good condition of all others. structural elements. It’s good if the device has automatic shutdown of the coil when it overheats. If not, then it can burn out if, for example, the propeller is clogged or the electric motor is faulty. The first sign of excess load on the coil is the characteristic burning smell that occurs when the hair dryer is used.
The smell may persist even after the device is turned off, which indicates the need to check the serviceability of the electric motor.
Another indirect evidence of excessive heating of the coil can be high temperature housings. It shouldn't get hot. An abnormal increase in temperature indicates a malfunction.
If overheated, the heating coil breaks
Repair heating element also starts with disassembling the hair dryer. Most often, the gap is visible to the naked eye. If the damage is not total (melting of large areas or breaks in several places), it is not difficult to repair. You just need to connect the ends of the spiral again. It is best, of course, to solder them, but if you don’t have special skills, you can tightly twist them by squeezing the connection with pliers. Since the nichrome wire is quite thin, when turned on, a microelectric arc is formed at the junction and the ends of the spiral are welded.
It is important not only to restore the integrity of the heater, but also to determine the cause that led to overheating. Otherwise, everything will happen again very soon. If an autopsy shows that the spiral is damaged in several places, it is better to replace it entirely. In this case, you need to select a heating element from the same manufacturer as the hair dryer.
Interestingly, having originated as a hairdressing accessory, the hairdryer soon found application in such industries as construction and electrical soldering. Technical hair dryers used in many processing processes building materials, to speed up the drying and heating process adhesive compositions, heat-shrinkable tubes, etc. Today, even to ignite coals in a barbecue, a special high-temperature hair dryer is used.
Video: disassembling and repairing a Maxwell hair dryer
Problems with the electric motor
The motor is designed to rotate the fan. Usually a good hairdryer has a speed switch, with which you select the optimal air supply mode. Control occurs by changing the current supplied to the motor. To do this, there is an electronic circuit inside the case, which, by the way, can also fail.
The electric drive of the hair dryer fan ensures its rotation at different speeds depending on the selected operating mode
Characteristic signs of a damaged motor are a crackling sound when turned on and uneven operation. Dry discharges occur due to breakdown of winding insulation. Sometimes you can hear a hum inside the device, but the fan does not rotate. There may be a smell of burnt wiring.
A DC motor has several windings, the breakage of which is the most common cause of its failure.
Repairing an engine at home is quite difficult. This is due to its small size and the need to use special diagnostic devices. If the armature windings are burned out, then you can rewind them only using special devices. It is much easier to simply replace the damaged part. Here you just need to carefully remove the old motor and install a new one in its place.
Video: how to disassemble and repair a Scarlett hair dryer
Control unit problems
The operation of all components inside the hair dryer is interconnected. And the main coordinating link is the electronic control unit. In addition to transforming alternating current into direct current, it changes the operating modes of the motor and regulates the degree of heating of the spiral. The scheme is relatively simple, but only a specialist can understand it professionally.
The electronic circuit is located near the control buttons inside the handle
Due to voltage surges in the network, violation of operating rules, or moisture entering the electronic board, a malfunction of the unit may occur. Visually, this is expressed in a change in the appearance of parts. Capacitors become deformed and swell. Resistors (resistors) darken and become charred. The connecting traces on the printed circuit board may melt and break. If you have spare radio components and soldering equipment, you can replace and restore the operation of the electronics. But you can replace the entire block.
To repair an electronic board, you must have special equipment and qualifications
If we talk about the procedure for diagnosing a broken device, then it should be carried out according to the principle “from simple to complex.” This means that you first need to inspect mechanical part(cord, buttons, impeller). Then - electrically, check the integrity of the connecting wires, contacts and terminals, operation of the electric motor and spiral. And finally, carry out an audit of the electronics - the control unit, other systems and interlocks. If inspection of the microcircuit does not give intelligible results, it is checked using a tester.
Video: diagnostics and repair of a hair dryer
How to remove a fan impeller
Often the impeller blades in hair dryers are damaged. This happens gradually as foreign debris accumulates and is drawn in by the air flow through the separator. One day the amount of foreign interference exceeds a critical state and the blades crack. This happens when the device is turned on, when the motor picks up speed and the rotational force becomes maximum.
As debris and dust accumulate inside the hair dryer, the fan blades experience increasing resistance as they rotate and finally break.
The first sign of a broken impeller is vibration. In addition, you can hear fragments of plastic cracking inside the case. If this happens, the impeller must be replaced. Needs to be removed protective cover, carefully inspect the device for attaching the propeller to the motor. IN different models connections are different. But the principle, as a rule, is the same - the impeller axis is pressed onto the electric motor drive. In most cases, it is easy to remove by carefully prying it off with a screwdriver. Sometimes this requires removing the motor and propeller from the housing and then disconnecting the blades.
All renovation work carried out only when the power is off household appliances. This is the best guarantee of safety. If the hairdryer is on warranty service, it is more expedient to solve all current problems in specialized organizations. DIY repair and improper use will void the manufacturer's warranty. Before using the device, it would be a good idea to carefully read the manufacturer’s recommendations.
The household uses various electrical appliances that make life much easier for the average person. But during operation they can fail and break. Repairing a hair dryer with your own hands is not difficult, since most problems can be easily fixed at home. But first you need to understand the structure and operating principle of the device.
Design features
Before you begin troubleshooting, you need to understand how the household appliance works. The main components of the hair dryer are as follows:
- motor;
- fan;
- heating elements;
- electrical diagram.
Depending on the number of modes, a hair dryer may have several switches and different external characteristics. The body can be made from different material and fastened with special screws. The heads mostly have a non-standard pattern, it can be a plus sign, a pitchfork or an asterisk. Before disassembling the device, It’s worth taking care of the necessary tools.
In addition, the doors can be secured with special latches. Therefore, it is necessary to act extremely carefully so as not to break off the fragile plastic elements.
The motor of the device can operate on direct current of 12, 24 and 36 V. To rectify the mains voltage, a diode bridge is used. In more simple devices A single diode is used.
Inspection procedure
If the hair dryer is completely devoid of signs of life or functions poorly, then a visual inspection of the power supply circuit is required. It is best to carry out activities in the following order:
Here is a list of the most common problems that affect the performance of a hair dryer. More serious problems also occur, but only experienced professionals can fix them.
Repairing a professional device is quite complicated. Since the parts contained in it are equipped with special controls and various options, such as the Care button. In addition, the spiral is often made of a special alloy, which, when heated strongly, creates negative ions that have a beneficial effect on hair quality.
But such devices also have the same methodology:
- cable;
- switches and various buttons;
- cleaning from dust and dirt;
- inspection of the spiral and motor;
- capacitor and resistor control.
But before carrying out independent repair work, you need to familiarize yourself with the circuit diagram of the device. As you can see, fix it household appliances Drying hair is not that difficult. But if there are any doubts, then you should not repair it yourself, but It's better to take them to a service center.
Since any incorrect action can lead to the device becoming completely unusable, and even specialists will not be able to repair it.
A hair dryer is an electrical device, which is a piece of pipe through which a flow of air heated to 60°C is supplied at high speed in a given direction. Often, for ease of use, the pipe is equipped with a pistol grip.
The photo shows a Melissa Magic hair dryer with a power of 1600 W. There is an operating mode switch on the handle, with which you can turn on the hair dryer and stepwise change the temperature of the air emanating from its nozzle.
Construction hair dryer appearance, operating principle, structure and electrical circuit are practically no different from a hair dryer. Only in it the air flow heats up to 600°C.
The device and principle of operation of the hair dryer
When the hair dryer is turned on, cold air from the room is sucked into its pipe using a rotating impeller mounted on the shaft of a DC electric motor. Next, the air flow passes through a tetrahedral heat-resistant frame made of mica or ceramic, on which a heated nichrome spiral is wound. When cooling the spiral, the air flow heats up to a temperature of 60°C, and in construction up to 600°C, after which it exits the pipe.
There is usually a switch on the body of the hair dryer, combined with a stepwise setting of the operating mode, which allows you to turn the hair dryer into full or half power mode.
The photograph shows the appearance of a typical slide mode switch.
To prevent skin burns when drying hair and destruction of the hair dryer body if the engine malfunctions, it is installed on the frame thermal protection in the form of a bimetallic plate.
When the air is heated above a set temperature, the bimetallic plate bends upward along the arrow in the drawing and opens the contacts. The heating coil is de-energized and air heating stops. After cooling, the bimetallic plate returns to its original position and the contacts close again.
As you can see, the operating principle and design of a hair dryer is not much different from other heating household electrical appliances, and any home craftsman can repair a hair dryer.
Electrical circuit of a hair dryer
Most construction hair dryers and hair dryers have the electrical diagram below. The supply voltage is supplied through a C6 type plug using a flexible cord. Capacitor C1 serves to suppress noise emitted by the motor brush assembly. Resistor R1 serves to discharge capacitor C1 after disconnecting the plug from the socket to prevent electric shock to a person when touching the pins of the plug. In some models, elements C1 and R1 are not installed.
The hair dryer operating modes are controlled using switch S1. In its position shown in the diagram, the hair dryer is off.
When the switch slide is moved one step to the right, its moving contact closes pins 1-2 and the supply voltage through the rectifier diode VD1 is supplied through the current-limiting coil H1 to the motor and heating coil H2. The diode cuts half of the sine wave and thus reduces the rotation speed of the impeller and the heating power of the H2 spiral by half.
When you move the engine one more step, contacts 1-2-3 close, the heating element and the motor are supplied with all the mains voltage and the hair dryer operates at full power.
Typically, hair dryers are equipped with DC motors designed for a supply voltage of 9-12 V. The H1 coil is used to reduce the voltage. To convert alternating current to direct current, a diode bridge VD2-VD5 is used. Electrolytic capacitor C4 smoothes out ripples. Spark suppression capacitors C2-C3 perform the task of extinguishing sparks in the brush-commutator assembly of the engine and suppressing radio interference.
Button S2 is used to switch the hair dryer to cold air mode. When you press it, the H2 coil stops heating.
To protect the hair dryer from overheating, which can occur due to a decrease in impeller speed in the event of an engine malfunction, there is a thermal protection element St, which opens the supply voltage supply circuit to the heater H2 when the maximum is exceeded permissible temperature air flow.
How to repair a hair dryer yourself
Attention! During repairs electric hair dryer caution should be exercised. Touching bare parts of the circuit connected to electrical network may lead to damage electric shock. Don't forget to unplug the hair dryer from the socket!
If you receive a broken hair dryer for repair, then first of all you need to find out by what external signs the hair dryer was recognized as faulty. Based on them, using the table below, you can immediately guess where to look for the fault.
| External manifestations, causes and methods of troubleshooting hair dryer | ||
|---|---|---|
| External manifestation | Probable Cause | Remedy |
| When drying hair, the hair dryer turns off periodically | The power cord is frayed where it exits the hair dryer body or plug | Repair or replace the power cord or plug |
| The air coming out of the hair dryer is hot and has a burning smell. | Insufficient rotation speed of the impeller as a result of hair being wound onto the motor shaft between the impeller and its housing | |
| The hair dryer turns off after a short period of use | Thermal protection is triggered due to insufficient rotation speed or stopping of the impeller as a result of hair being wound onto the motor shaft between the impeller and its housing | Remove hair from the shaft with a sharp tool |
| Hairdryer won't turn on | The power cord is broken or the mode switch is faulty | Repair or replace the power cord or switch |
| Cold air comes out of the hairdryer | The heating shutdown button is faulty, the spiral is broken, the contacts in the thermal protection element are oxidized | Check parts with a multimeter, repair or replace faulty ones |
| The hair dryer only works in one of the mode switch positions | The mode switch is faulty, one of the spirals or diode VD1 is broken | Test the switch, diode and coil with a multimeter, faulty parts repair or replace |
How to disassemble a hair dryer
Disassembling a hair dryer can be more difficult than repairing it, since the body parts are usually connected inside using latches, the location of which is not visible from the outside.
But there is always a self-tapping screw on the handle in the area where the power cord enters the housing, usually closed decorative plug or sealed with a label. Thanks to different colors parts of the body of the Braun hair dryer shown in the photo, you can see which line to take it apart.
This is what the decorative plastic plug in the hair dryer body looks like. Since it is the same color as the handle, it is difficult to notice. To remove the plug you need sharp object, for example, use an awl or a knife with a sharp blade to pry it over the edge.
After removing the plug, the head of the screw became visible, but it turned out that the slot on it was triangular, and its edges were made in such a way that the screw could only be screwed clockwise. The manufacturer has provided that it is impossible to disassemble a hair dryer for repairs at home without breaking the case.
To unscrew a screw with such a head, it was first heated using the tip of a heated electric soldering iron. To do this, just press the soldering iron tip to the head and hold for a couple of minutes. The heating of the self-tapping screw softened the plastic around the thread. Next, while the plastic is still warm, use a flat blade screwdriver equal to length the edge of the slot triangle, the self-tapping screw was unscrewed without difficulty.
To avoid difficulties during the repair of the hair dryer during assembly, the self-tapping screw was replaced with the same size, but with a slot in the head for a Phillips bit.
The removable part of the body was additionally held on by four more latches. Two of them were on the sides of the pipe. To disassemble, I had to press them through the resulting gap using a flat-head screwdriver while moving the parts apart.
After disengaging the side latches, the top ones released themselves. The latches were shallow, so I was able to disassemble the hair dryer without breaking them.
In this hair dryer, the power cord was faulty, and therefore further disassembly was not necessary, since the place where the cord was connected to the electrical circuit became accessible.
Examples of hair dryer repair
Most often, hair dryers break down due to chafing of the power cord or malfunction of the electric motor with the impeller. In modern hair dryers, due to the presence of thermal protection and the use of thick wire for winding the spiral, it burns out very rarely. Out of the dozen hair dryers I have repaired, I have never encountered a burnt coil.
Hair dryer power cord repair
When drying your hair, the hair dryer moves intensively and the power cord constantly bends. Although the wires in the cord are copper and stranded, they break off over time due to repeated kinks. A sign of the beginning of a wire break is the periodic temporary stoppage of the hair dryer while drying your hair.
Therefore, half of the breakdowns are associated with fraying of the power cord at the point where it exits the housing, less often at the plug. The first sign of such a breakdown is interruptions in the operation of the hair dryer while drying your hair. At this stage it is easy to find out the location of the cord defect. It is enough to fix it in the middle and move the cord first at the entrance to the plug body, and then at the entrance to the hair dryer body. If the hair dryer works stably, then the cord is in order and the fault must be looked for elsewhere.
If the wires in the cord are frayed where they exit the plug, you can repair the hair dryer without disassembling it. How to replace the plug is described in the article “Electrical plug, how to connect, repair.”
Typically, the cord wires inside the hair dryer are soldered to a printed circuit board or connected using plug-in terminals, as in the photo above.
To check the cord, you need to ring the wires by touching one probe of a tester or multimeter to one of the pins of the plug. Using the second probe of the multimeter, touch the ends of the wires one by one. One of the wires should show zero resistance. There should also be zero resistance between the remaining wire and the second pin of the plug.
If the wires are ringing, then by moving the cord at this time you can accurately determine where the wire has frayed. In the product being repaired, the cord was broken where it entered the hair dryer.
If the wires of the cord are soldered to the printed circuit board, then you can ring them without unsoldering them by attaching the probes of the device to the pins of the plug. The hair dryer switch should be set to maximum power mode. The heating coil has a resistance of about 30 ohms. Therefore, if the cord wires are working properly, then the multimeter should show the same resistance.
By using online calculator You can accurately calculate the resistance value of a hair dryer's nichrome coil based on its maximum power.
In the hair dryer being repaired, the cord was broken at the point where it entered the body. To restore operation, you need to cut off the defective section of the wire and reinstall the plug-in terminals. To remove the terminals from the wires, you first need to use a knife to bend the antennae holding the wires to the sides, as shown in the photo.
In the next step, the frayed section of the wire is cut off and the insulation is removed from the cord and wires. The length of the cord will be reduced by ten centimeters, which will not affect the performance characteristics.
All that remains is to tin the wires and terminals using solder with an electric soldering iron and solder them together. After putting on the terminals, assembling and checking the operation of the hair dryer, the repair can be considered complete.
If you don’t have a soldering iron at hand, then the wires are cut off at a distance of 3-5 cm from the point of connection to the electrical circuit of the hair dryer and a section of the defective cord is removed. The wires are then connected by one of mechanical methods, depending on the internal free space in the hair dryer handle.
Engine power circuit repair
A Melissa-1600 hair dryer was repaired with the complaint that the air flow from it had become weak and had a burning smell. Upon inspection, it turned out that the impeller was not rotating at sufficient speed. I immediately assumed that there was hair curled around the motor shaft between the impeller and the housing. Usually, in most cases with such signs, this is what happens.
But after disassembling the hair dryer, it turned out that one of the rectifier diodes installed on the motor was torn in half. Testing of the remaining diodes showed their serviceability. Therefore, the engine worked, but only one half-wave of rectified voltage was supplied to it.
The faulty diode was soldered out and in its place, observing the polarity, the first available type KD105 was soldered. The motor supply voltage is usually 9-12 V at a current of no more than 0.5 A. Almost any rectifier diode will provide such parameters.
At the same time, the curled hair was removed from the motor shaft and the bearings were lubricated with machine oil. To do this, just apply a drop of oil to the shaft fixation point in the motor housing and turn the shaft several times by the impeller.
Before installing the motor in the hair dryer, it is advisable to check it. For the motor to operate, a constant voltage of 9-12 V is required. But since the voltage is supplied to the diode bridge, the motor can be powered from either a direct or an alternating current source. Even the simplest adapter from any device will do, delivering the appropriate voltage and current up to 0.5 A.
Voltage must be applied to the input of the diode bridge, its soldering point to the electrical circuit of the hair dryer. If the engine is connected to a constant voltage source, then you need to check first with one connection polarity, and then swap the connected wires. This is necessary to check all the bridge diodes.
Tests of the engine after maintenance and repair showed that its impeller rotated easily when turned by hand and when voltage was supplied from an external voltage source at a sufficient speed.
Checking the hairdryer after assembly showed that its functionality was fully restored. The impeller rotated at high speed, and the burning smell disappeared.
Repair of the cold air switch and button
If the hair dryer cannot be turned on and the power cord is working, then the cause is usually a broken contact in the mode switch. And if all the modes of the hair dryer, but the air does not heat up, then the heating switch off button, the heat protection is faulty, or the coil is burnt out.
Mode switches in a hair dryer are usually soldered into a small printed circuit board, which is fixed in the guides or screwed with self-tapping screws. The photo shows the switch leads soldered into the printed circuit board. On the left side you can see the hot air supply switch.
If the mode switch does not ring, then you can try to clean the internal contacts with a thin tool through the hole located next to its slider. It happens that only the contact of one of the operating modes has burned out, while the rest are in working order. In this case, you can sacrifice the rarely used mode of operation of the hair dryer and switch the switching to a working contact.
It happens that due to burnt contacts as a result of heating, the switch body is deformed and the motor jams. If there is no replacement switch, you can connect the wires directly, leaving only one operating mode for the hair dryer. In this case, you will have to turn on the hair dryer by connecting its plug to the outlet.
If the button to turn off the supply of warm air flow is faulty, and there is nothing to replace it with, then it is enough to short-circuit its leads. In this case, this function will no longer work, but otherwise the hair dryer will work as before.
Thermal protection repair
Thermal protection consists of two contacts in contact, one of which is fixed to a bimetallic plate. When the plate is heated above a given temperature, it bends upward, as shown by the arrow in the photograph. As a result, the contacts open and the power supply circuit of the heating coil is broken.
If the button to turn off the hot air supply is in order and the spiral is intact, then it is obvious that the contacts in the thermal protection relay have oxidized. To restore, it is enough to insert fine-grained sandpaper folded in half into the gap between the contacts and, pressing the bimetallic plate on top with your finger, pull the paper several times.
Malfunctions of the heating element - spirals
If the air flow from the hair dryer is cold when the engine is running, the shutdown button and thermal protection are working, then the breakdown is associated with the nichrome spiral.
A broken spiral can be easily detected by external inspection. A violation of contact in connections in the form of hollow rivets on the frame of the hair dryer ends nichrome wire With the wires coming from the operating mode switch, it is not always possible to determine by appearance. If the rivets are not blackened, then only testing with a multimeter will help.
To restore contact in the rivet joint, you need to further compress it using pliers. The work must be done carefully so as not to break the fragile mica or ceramic frame.
Burnout or breakage of the coil practically does not occur in modern hair dryers, but if such a failure occurs, the coil will need to be replaced with a new one. Splicing spiral wire by twisting or crimping into a piece of aluminum or brass tube will not lead to long-term success. If the spiral is worn out, then after such repairs it will soon burn out in another place.
A nichrome spiral, taking into account the power of the hair dryer, can be purchased new or wound independently from nichrome wire, calculating its diameter and length according to the table.
Removing hair and lubricating the hair dryer motor shaft
Another common malfunction of a hair dryer, which you can fix yourself, having only a standard set of tools on hand, is when the hair dryer is working, but the stream of outgoing air is very hot with a burning smell due to hair winding around the motor shaft or poor lubrication of the motor bearings.
Removing hair from the motor shaft of the BaByliss hair dryer
The BaByliss hair dryer shown in the photo came in for repair with the complaint that the outgoing air stream had become weak and very hot.
When checking, it became clear from the sound of the fan that its speed was too low, and the cause of the malfunction lay in the operation of the engine. To fix the problem, I had to disassemble the hair dryer.
In order to disassemble the BaByliss hair dryer, you first need to remove the nozzle by unscrewing two screws. Next, using a flat blade screwdriver, remove the fixing ring installed on the heated air outlet side. It gives in easily.
All that remains is to separate the body halves, which are held in place by two latches on each side. In the photograph, due to the translucency of the plastic, the latches are clearly visible, as in the photograph in the form of light stripes.
The hair dryer is disassembled and all that remains is to get to the place on the shaft where the hair is wound. The engine is fixed inside a plastic housing, which is a pipe, in such a way that to remove it you need to remove the fan impeller. And the impeller, as a rule, is mounted tightly on the shaft, and here usually great difficulties arise, since it is impossible to grab the impeller with a standard tool, and it is easy to break it.
To solve such problems, I made it from Chinese platypuses special tool- a platypus with the ends of its sponges bent at right angles. With the help of a vice, the ends were easily bent, since they were not hardened.
I also successfully repair snake and zipper runners with this platypus if the links stop closing. Regular pliers often cannot be reached. And thanks to the curved ends of the jaws, it is easy to squeeze the part of the runner that closes the links in any case.
In addition, the upgraded duckbill pliers are convenient for holding axles and shafts, nuts and other objects of various shapes - they do not slip out like with flat-nose pliers.
After removing the impeller from the motor shaft, access to the curled hair appeared. In this model of hair dryer, a brass bushing is mounted on the motor shaft, and an impeller is already attached to it. Usually it is mounted directly on the motor shaft.
All that remains is to remove the hair with a sharp object, such as a knife, awl or needle, and reassemble the hair dryer in the reverse order. To avoid any difficulties when assembling the hair dryer, I advise you to take several photographs when disassembling it.
Removing hair and lubricating the motor shaft of a Viconte hair dryer
With the Viconte hair dryer, the external manifestation of the malfunction was the same as with the BaByliss, but in addition, the air came out with a burning smell and the fan worked with a grinding noise. This indicated that the engine bearings had run out of lubrication.
The sequence and technology for disassembling the hair dryer is similar to the BaByliss hair dryer, so there is no need to describe it.
The supply voltage was supplied via two wires to a diode bridge soldered to the motor terminals. For ease of repair, the wires were soldered using a soldering iron. The colors of the wires do not need to be remembered, since alternating voltage is supplied to the bridge, and the order in which the wires are connected does not matter.
An attempt to remove the impeller from the engine shaft using the platypuses described above was unsuccessful, even with the application of great muscle force. I had to figure out how to remove the hair and lubricate the bearing without removing the impeller.
The idea came to me that instead of having to worry about removing the impeller, I could drill a hole in the motor holder housing, which was done.
The location of drilling the hole must be measured so as not to hit the engine housing or the base of the impeller. First, a hole with a diameter of three millimeters was drilled, and then drilled out to five. The plastic of the case is soft and thin, so the hole can be made with the end of a pointed knife.
To remove hair from the motor shaft, a hook was made from a paper clip. To make such a tool, you need to bend the end of the paper clip, sharpen it on sandpaper and bend the very tip to a length of two millimeters. In a minute all the hairs were removed.
I had to use a medical syringe to lubricate the bearing. It is enough to apply one drop of oil to the shaft entry point into the engine. In order for the oil to get into the bearing, you need to hold the impeller and move the shaft along the axis several times, turning it.
The bearing also needs to be lubricated. opposite side shaft Any machine oil is suitable for lubrication, for example, for pouring into a car engine. If you don’t have oil on hand, you can remove the oil level dipstick from the engine and take a few dripping drops from it.
To check the operation of the fan, a voltage of 10 V was applied to the diode bridge from the DC power supply. The engine will operate at a voltage of 5 to 12 V, so even a charger from any phone will do. It is not necessary to do such a check, but if possible, it is better to make sure that the fan is working as expected.
The check showed normal engine operation, no extraneous noise and sufficient air flow. The hole you make does not need to be closed, as it fits tightly to the body of the hair dryer. If not, you can seal it with tape.
As you can see, the most common hair dryer breakdowns are not at all difficult to fix, and such work can be done by anyone if desired. home handyman. In any case, before buying a new hair dryer, you should try to repair a failed hair dryer.
