If in your arsenal there is an old corner sanding machine, do not rush to write it off. Using a simple electrical circuit, the device can be easily upgraded by adding a speed change function to it. Thanks to a simple regulator, which you can really assemble with your own hands in a few hours, the functionality of the device will increase significantly. By reducing the rotational speed, the grinder can be used as a grinding and grinding machine for various kinds materials. There are new opportunities for the use of additional nozzles and equipment.
Why grinder low speed?
The built-in disc speed control function allows you to delicately process materials such as plastic or wood. At low speeds, the comfort and safety of work is increased. This function is especially useful in electrical and radio installation practice, in car services and restoration workshops.
In addition, among professional users of power tools there is a strong opinion that the simpler the device is, the more reliable it is. And it is better to take the additional service “minced meat” outside the power unit. In this scenario, the repair of equipment is greatly simplified. Therefore, some companies specifically produce remote separate electronic regulators that connect to the power cord of the machine.
Speed controller and soft start - what are you for?
In modern angle grinders, two important functions are used that increase the reliability and safety of the tool:
- speed controller - a device designed to change the number of engine revolutions in various modes work;
- soft start - a scheme that provides a slow increase in engine speed from zero to maximum when the device is turned on.
They are used in electromechanical tools, in the design of which a collector motor is used. They help to reduce the wear of the mechanical part of the unit during switching on. Reduce the load on electrical elements mechanism, starting them into work gradually.
As studies of the properties of materials have shown, the most intensive development of rubbing nodes occurs during a sharp transition from a state of rest to a mode of rapid movement. For example, one engine start internal combustion in a car, it is equivalent in terms of piston group wear to 700 km of run.
When the power is turned on, there is an abrupt transition from a state of rest to rotation of the disk at a speed of 2.5-10 thousand revolutions per minute. Those who have worked with an angle grinder are well aware of the feeling that the machine is simply “pulling out of their hands”. It is at this moment that the vast majority of breakdowns associated with the mechanical part of the unit occur.
The stator and rotor windings also experience no less load. The collector motor starts in short circuit mode, the electromotive force is already pushing the shaft forward, but the inertia still does not allow it to rotate. There is a jump in the starting current in the coils of the electric motor. And although they are structurally designed for such work, sooner or later there comes a moment (for example, during a power surge in the network) when the winding insulation cannot withstand and an interturn short circuit occurs.
When soft start circuits and changes in engine speed are included in the electrical circuit of the tool, all of the above problems automatically disappear. Among other things, the problem of the “failure” of voltage in the general network at the time of launch is solved. hand tool. And this means that the refrigerator, TV or computer will not be at risk of "burnout". And the safety circuit breakers on the meter will not work and turn off the current in the house or apartment.
The soft start circuit is used in grinders of medium and high price categories, speed control unit - mainly in professional models angle grinder
Speed adjustment allows you to process the grinder soft materials, perform fine grinding and polishing - on high speed wood or paint will simply burn.
Additional wiring diagrams increase the cost of the tool, but increase the service life and level of safety during operation.
How to assemble a regulator circuit with your own hands
The simplest power regulator, suitable for a grinder, soldering iron or light bulb, is easy to assemble with your own hands.
Circuit diagram
In order to assemble the simplest speed controller for a grinder, you need to purchase the parts shown in this diagram.
circuit diagram speed controller
- R1 - resistor, with a resistance of 4.7 kOhm;
- VR1 - tuning resistor, 500 kOhm;
- C1 - capacitor 0.1 uF x 400 V;
- DIAC - triac (symmetric thyristor) DB3;
- TRIAC - triac BT-136/138.
Circuit operation
Trimmer resistor VR1 changes the charging time of capacitor C1. When voltage is applied to the circuit, at the first moment of time (the first half-cycle of the input sinusoid), the triacs DB3 and TRIAC are closed. The output voltage is zero. Capacitor C1 is charged, the voltage across it rises. At a certain point in time, set by the R1-VR1 chain, the voltage on the capacitor exceeds the opening threshold of the triac DB3, the triac opens. The voltage from the capacitor is transmitted to the control electrode of the TRIAC triac, which also opens. A current begins to flow through an open triac. At the beginning of the second half-cycle of the sinusoid, the triacs close until the capacitor C1 is recharged in reverse side. Thus, the output is a pulse signal complex shape, the amplitude of which depends on the operating time of the circuit C1-VR1-R1.
Assembly order
The assembly of this circuit will not make it difficult even for a beginner radio amateur. Spare parts are available, you can buy them at any store. Including soldering from old boards. The order of assembly of the regulator on thyristors is as follows:
How to connect the device to the angle grinder, options
The connection of the regulator depends on which type of device is selected. If used simple circuit, it is enough to mount it in the power supply channel of the power tool.
Installing a homemade board
Does not exist ready recipes for installation. Everyone who decides to equip the angle grinder with a regulator has it according to their goals and tool model. Someone inserts the device into the handle of the holder, someone into a special additional box on the case.
V various models the space inside the body of the angle grinder can be different. In some, there is enough free space to install the control unit. In others, you have to bring it to the surface and fix it in a different way. But the trick is that, as a rule, there is always a certain cavity in the back of the instrument. It is designed for air circulation and cooling.
Cavity at the back of the machine
Usually this is where the factory speed controller is located. A hand-made circuit can be placed in this space. To prevent the regulator from burning out, thyristors should be installed on a radiator.
Video: soft start plus and engine speed control
Features of mounting the finished block
When buying and installing a factory regulator inside a grinder, most often you have to modify the case - cut a hole in it to bring out the adjusting wheel. But this can adversely affect the rigidity of the casing. Therefore, it is preferable to install the device outside.
The adjusting wheel changes speed
The numbers on the adjusting wheel indicate the number of revolutions of the spindle. The value is not absolute, but conditional. "1" - minimum speed, "9" - maximum. The rest of the figures serve as a guide for adjustment. The location of the wheel on the body is different. For example, on the angle grinder Bosch PWS 1300-125 CE, Wortex AG 1213-1 E or Watt WWS-900, it is located at the base of the handle. In other models, such as Makita 9565 CVL, the adjusting wheel is located at the end of the casing.
The connection diagram of the regulator to the angle grinder is not complicated, but sometimes it is not so easy to run the cables to the button, which is located on the other end of the device case. The problem can be solved by choosing optimal section wire or by bringing it to the surface of the casing.
The regulator is connected according to the diagram
A good option is to install the regulator on the surface of the device or mount it to network cable. Not always everything works out on the first try, sometimes the device has to be tested, after which some adjustments must be made. And this is easier to do when access to its elements is open.
Important! If there is no experience with electrical circuits, it is more expedient to purchase a ready-made factory regulator or an angle grinder equipped with this function.
Power cord attachment
Device instruction manual
The basic rule when operating a grinder with a homemade speed controller is compliance with the regime of work and rest. The fact is that an engine running on a “regulated” voltage is especially hot. When grinding at low speeds, it is important to take frequent breaks so that the collector windings do not burn out.
It is also highly recommended not to turn on the tool if the speed control is set to a minimum - undervoltage not enough to scroll the rotor, the collector lamellas will remain in short circuit mode, the windings will start to overheat. Unscrew the variable resistor to the maximum, then, turning on the angle grinder, reduce the speed to the desired value.
Compliance with the correct order of switching on and adjustment will allow you to operate the angle grinder indefinitely.
In addition, it should be understood that the adjustment of the speed of rotation on the angle grinder occurs according to the principle of a water tap. The device does not increase the number of revolutions, it can only lower them. It follows from this that if the maximum passport speed is 3000 rpm, then when the speed controller is connected, the angle grinder will work in a range lower than the maximum speed.
Attention! If the angle grinder already contains electronic circuits, for example, is already equipped with a speed controller, then the thyristor controller will not work. Internal circuits The device simply won't turn on.
Video: homemade angle grinder speed controller
Equipping the grinder with an engine speed control circuit will increase the efficiency of using the device. and expand its functional range. It will also save the technological resource of the grinding machine and increase its service life.
(UShM), in the common people of Bulgarians, have a speed controller.
The speed controller is located on the angle grinder body
Consideration of various adjustments should begin with an analysis of the electrical circuit of the angle grinder.
the simplest representation of the electrical circuit of a grinder
More advanced models automatically maintain the rotation speed regardless of the load, but tools from a manual disk are more common. If a trigger-type regulator is used on a drill or an electric screwdriver, then such a regulation principle is not possible on an angle grinder. Firstly, the features of the tool suggest a different grip when working. Secondly, adjustment during operation is unacceptable, therefore, the speed value is set with the engine turned off.
Why regulate the speed of rotation of the grinder disk at all?
- When cutting metal different thickness, the quality of work strongly depends on the speed of rotation of the disk.
When cutting hard and thick material, it is necessary to maintain the maximum rotation speed. When machining thin sheet metal or soft metal (e.g. aluminium), high speeds will cause the edge to melt or wash quickly. working surface disk; - Cutting and cutting stone and tiles at high speed can be dangerous.
In addition, a disc that spins at high speed knocks out small pieces from the material, making the cut surface chipped. And for different types stones are selected at different speeds. Some minerals are just processed at high speeds; - Grinding and polishing is basically impossible without speed control.
By setting the speed incorrectly, you can spoil the surface, especially if it is paintwork on a car or material with a low melting point; - The use of discs of different diameters automatically implies the mandatory presence of a regulator.
Changing the disk Ø115 mm to Ø230 mm, the rotation speed must be reduced by almost half. And it’s almost impossible to hold in your hands with a 230 mm disk rotating at a speed of 10,000 rpm; - Polishing stone and concrete surfaces depending on the type of crowns used, it is produced at different speeds. Moreover, when the rotation speed decreases, the torque should not decrease;
- When using diamond discs, it is necessary to reduce the number of revolutions, since their surface quickly fails due to overheating.
Of course, if your angle grinder only works as a cutter for pipes, angles and profiles, a speed controller is not required. And with the universal and versatile use of angle grinders, it is vital.
Do-it-yourself repair of an angle grinder should be done with great care and without haste. Negative consequences manipulations with force and/or electronic unit can lead to the transformation of a minor breakdown into a complete rejection of the grinder, and then even a professional master will not save it.
Bulgarian - rules for working with electric grinding tools
An angle grinder is called a "grinder" only in repair spaces former USSR for a prosaic reason - the Eltos-Bulgarian plant in Plovdiv was solely engaged in its production. The high-speed cutting wheel is an indispensable assistant in the processing of the most durable metal, when arranging siding on the ceiling, when cutting reinforcement, sheets, profiles and many other repair operations. The grinding capabilities of grinders are no less popular - they allow you to eliminate burrs, roughness from both metal and stone or marble.
Over the past 40 years, the range of angle grinders has grown tremendously, but the rules for handling this convenient and multifunctional tool didn't change much. Moreover - repairs are often prevented by following simple operational guidelines:
- Do not remove the guard over the abrasive wheel unless absolutely necessary. If this cannot be avoided, be sure to wear protective goggles and protect the tool from any side contact;
- Do not process wood, chipboard, MDF and similar materials - saws and hacksaws are available for this;
- Hold the grinder firmly and confidently - when the disc is jammed, the entire tool can be pulled out of your hands, it will be severely damaged and cause serious injury;
- The work of any angle grinder is accompanied by the presence of characteristic sparks - beware of getting them on the electrical wiring, power cord and any other combustible materials;
- Any workpiece - cut or grinded - must be securely fastened. Even if it is necessary to cut a reinforcing bar immured in concrete during construction strip foundation from corrugated board, you should make sure that the entire structure is strong before pressing the "Start" button on the grinder;
- Do not press on the part to speed up the work. The principle of operation of abrasive wheels is to erase the material of the workpieces and does not need a large clamping force.. The accuracy of movements when working with a grinder is as useful as brute force is harmful.
Tool repair - rely on knowledge of its design and common sense
Any angle grinder consists of the following components and mechanisms, the location and condition of which should be confidently understood:
- Anchor. The internal part of an electric motor that rotates when the tool is operated at a controlled angular speed. The higher the rotation speed of the armature, the more power grinders. Unlike the marine "brother", the anchor in the electrical equipment should not slow down under any circumstances;
- Collector - separate place(platform) at anchor, where the power and control windings are brought out. Already from the name it is clear - here the switching of signals to the engine and the control unit takes place. The collector is clearly visible after removing the case - the contact plates are polished and have significant dimensions;
- Electric brushes are a special kind of conductors for supplying current from the power cable to the collector. In working condition, they sparkle weakly and evenly, their glow is visible through the ventilation holes in the grinder body;
- Reducer - special mechanical device in front of the grinder. Designed to transfer the mechanical energy of a rotating armature to a rotating disk. In this case, both the speed of rotation of the working disk and the power developed by it are subject to adjustment;
- The stator is the part of the electric motor of the angle grinder in which the armature (rotor) rotates. The most difficult part of the tool, due to the strict precision of the windings pressed into it. Rewinding the stator of a grinder with your own hands is an adventurous procedure, it is better to entrust it to a specialized workshop;
- Handles-holders, power cable with a plug and a housing with control and regulation devices.
An extremely desirable assistant in the repair will be layout and electrical diagrams, as well as detailed instructions specifically for the model of the angle grinder that needs to be repaired. Unfortunately, many manufacturers do not burden their devices with such excesses. In this case necessary information you can learn from the know-it-all Internet and not repair the grinder with your own hands, counting on “maybe everything is simple there”, of course, if you don’t want to buy as a result of repair procedures new tool…
Do-it-yourself grinder repair - we eliminate typical malfunctions
The main principle in the repair of any electrical equipment is the postulate "move from simple to complex."
Whether it's a household electric cartridge or a turbine in a hydroelectric power plant - repair sequence should rule out elementary faults in the first place. Electricity and electronics are called the "two sciences of contacts" for a reason. Typical malfunctions of angle grinders, coupled with methods for their elimination, are as follows:
- The tool suddenly stopped showing signs of life. With a probability of 90%, we can conclude that the current from the socket does not reach the electric brushes. That is, the problem lies either in the power plug, or in the wire itself, or in the Start button mechanism. It is enough to disassemble the case and “ring” the cable with an ordinary tester for breaks - very often it is enough to replace the wire, and the angle grinder will work like new;
- Are the wire and plug guaranteed to be intact, and the tool is still immobilized? It is necessary to disassemble the trigger, and it is desirable to mark the contacts to be removed - if they are subsequently connected incorrectly, the winding may burn out or the armature may jam. You can replace the start button with any similar one, the operating parameters are marked on it quite legibly;
- The "Start" button and the power wire are in working condition, but the grinder does not want to work? It's time to work on the holders. Very often, it is enough to clean the contact plates on the collector, and a long-awaited spark and a smooth buzz of the mechanism appear. If not, then the brushes need to be replaced. The resource of these devices is usually limited to several years. A number of models of angle grinders are produced with a soldered connection of electric brushes, you need to solder and install new ones in the kit, their partial replacement is not allowed;
- After replacing, carefully inspect the old electric brushes - if they have uneven wear, this is a clear sign of a shift in the center of gravity of the tool or its moving inside. It is better to contact a specialized company for the repair of complex electrical equipment - it is unlikely that you will be able to adjust the balance yourself without experience.
Brush replacement refers to the "top of the first level" in self-correction of faults in electric grinders. You can continue to paint repair recommendations, how to disassemble the grinder gearbox, rewind its winding or reconfigure the electronic filling. But serious breakdowns require a serious approach to work. If you have never seen this gearbox, how will you be able to fix it? The chance of turning on the grinder depends on your common sense - saving on professional repair will result in the loss of the entire instrument.
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Angle grinder Mastermax MCP-2800
Angle grinder device
The angle grinder in our household application is an essential power tool. Depending on the installation of one or another attachment to the grinder, you can perform a varied amount of work.
In my own way appearance and designs similar to grinders and are the so-called grinders, consisting of such parts as:
- protective cover;
- ventilation hole;
- push button switch;
- side handle;
- spindle lock.
The photograph shows the engagement mechanism, or in other words, the interface between the mechanical part of the gearbox and the electric motor.
Gearbox and grinder motor
For the mechanical part, wear is subject to:
- bearings;
- gearbox gears.
I would think that giving a complete explanation of the mechanical part of the gearbox simply does not make sense.
Nozzles for angle grinders have a different assortment, depending on the work being done.
Wiring Diagram - Angle Grinder
Let's concentrate our attention \Fig.2\ on the following schematic representation - the principle of operation of the electric motor.
The image of the red arrow in the figure shows the direction of the current - as it is commonly considered in the section on electrical engineering: » The current in the electrical circuit flows from a source \ terminal \ with a positive potential to a source with a negative potential. Moreover, the positive potential changes its sign to the opposite - from the resistance that has a connection in the electrical circuit.
The electrical circuit here is closed on the collector, more precisely on the contact connections "winding - collector" \ for the rotor of the electric motor \.
That is, the rotor collector through graphite brushes in the circuit has electrical connection.
The two stator windings of the electric motor are connected in series in the electrical circuit.
In my practice, a similar electrical connection \ Fig. 2 \ for all elements of a collector electric motor - I have not seen a wire with one potential have a direct electrical connection to the collector through a graphite brush, and the second wire with a different potential has a series connection through two stator windings with a second graphite brush.
The simplest and most complete explanation of these electrical connections is given directly by circuit diagram collector electric motor \Fig.3\. It is this connection of all elements that is typical for grinder motors, where the electrical circuit is closed on two rotor windings - in this way.
Connection of motor windings
Here we can notice that the two windings of the electric motor rotor for this section are interconnected in series and have a contact electrical connection "collector - brush".
The connection of the two windings of the rotor with respect to an external source of alternating voltage is parallel.
Among the causes of grinder motor malfunctions, one can cite such a malfunction as the wear of graphite brushes that are in contact friction with the motor commutator.
This part, as well as among other parts for power tools, can be purchased in specialized technical departments of stores.
Motor Diagnostics — grinders
Diagnostics of the electric motor of the grinder \Fig.3\ should be carried out for individual sections of the electrical circuit of this circuit.
To do this, you need either an ohmmeter or a multimeter. Device Multimeter previously for measuring resistance - is set to the appropriate position.
To measure the resistance of two separate stator windings - one probe of the device is connected to the brush contact, the other probe of the device is connected to the corresponding pin electrical plug.
If this section breaks, the device will accordingly indicate the absence of resistance.
If in good condition, the device will indicate the presence of resistance of one or another measured section of the electrical circuit.
By connecting the two probes of the device to the two pins of the electric plug of the grinder, the display of the device will show the total resistance for:
- two stator windings;
- two rotor windings,
- that is, it will indicate the total value of the resistance.
Changing the speed of rotation of the rotor of the electric motor \Fig.4\ is carried out through the following electrical circuit.
The electrical circuit consists of:
- resistor R1 \ 0.5 W \;
- resistor R2;
- resistor R3 \ 5 W \;
- diode VD1;
- triode thyristor VS1.
Resistor R2 acts as a potentiometer, due to which the current in the load changes. The load in this explanation is the electric motor.
Triode thyristor - creates current blocking for the reverse direction. The control is carried out by the cathode.
Well, we figured out the simple electrical circuits. It remains to make your decision in cases of malfunction - to give the electric motor for repair or repair it yourself.
Let's go to a repair shop household appliances, - you can already state the cause of the malfunction of your power tool yourself.
This seems to be all.
In the household and industrial production often there is a need to cut and grind metal, stone or other products made of hard materials. Very effective for these purposes is such a power tool as the grinder "Interskol" UShM-125/1100E.
What is this tool?
Angle grinder "Interskol" UShM-125/1100E is an electronic device. In everyday life, it is often called a grinder and is used to work with iron, stone, concrete and other materials. "Interskol" UShM-125 / 1100E - angular using nozzles with a diameter of 125 mm, a power of 1100 watts. It is a product of the Russian company Interskol. Working with a grinder is not limited to cutting. This electrical device you can also grind and polish the surfaces of products if necessary. Wide versatility in application is possible due to design features and technical capabilities of the angle grinder.
Bulgarian "Interskol" UShM-125/1100E. Design features
Grinding and polishing work on surfaces concrete products often accompanied by abundant dust emissions, which is very undesirable for a power tool. Settling dust adversely affects the operational life of any angle grinder. The grinder "Interskol" UShM-125/1100E is assembled in such a way that the dust formed during polishing / grinding does not penetrate into the mechanism. This is made possible by guiding the armature impeller, which sends air flows through the front of the gearbox.
In these corner mount gear is carried out, they are pressed onto the spindle shaft. The entire mechanism of the grinder UShM-125/1100E is assembled in one case, in the back of which there is a comfortable handle. This grinder is a very convenient and powerful machine designed for professional use. Two-handed design (main handle + additional included) provides comfort and convenience during the operation of this power tool.
What is equipped with a grinder?
"Interskol" UShM-125 / 1100E has an electronic system that allows, if necessary, to adjust the speed (from ten thousand per minute to three). The owner of this power tool can reduce them to the required level without worrying that the power of the grinder will also decrease. This quality, which the Interskol UShM-125/1100E grinder has, is especially appreciated by professional tilers. By lowering the speed, glazed tiles and other delicate surfaces can be easily processed.
In addition to the electronic system, the Interskol angle grinder UShM-125/1100E contains a special soft start board, which greatly facilitates the operation of the grinder. The presence of a soft start of the system is especially in demand when working with heavy grinding discs and diamond nozzles for stone surfaces.
What ensures reliable retention of the angle grinder?
Comfort during operation is provided by special handles - holders. They are included with every angle grinder. "Interskol" UShM-125/1100E has one more handle, additional. Although this power tool is compact enough to be held with one hand, an additional handle is included and is indispensable for metal cutting work.
Technical indicators
- The power consumed by the power tool is 1100 watts.
- Voltage - 220 V/50 Hz. Power comes from the electrical network.
- Speed - from 3000 to 10,000 per minute.
- The mass is 2.2 kg.
- The power tool is designed for a circle with a diameter of 125 mm.
- The main handle is three position.
- Smooth start.
- There is a speed control function.
- There is a fixed spindle.
When selling Interskol, UShM-125/1100E is equipped with:
- additional handle;
- a set of gaskets;
- a special key for installing discs and nozzles.
Advantages
One of the most reliable and durable products Russian production Bulgarian "Interskol" UShM-125 / 1100E is considered. Consumer reviews indicate good performance and high reliability of this electric tool.
Among users, the strengths of this angle grinder are:
- the ability to easily turn the gearbox 90 degrees in case of an inconvenient or unusual location of the release key;
- high power;
- the presence of a speed controller. According to consumer reviews, the ability to reduce the speed makes this angle grinder indispensable for work such as cleaning welds, rust removal or old paint With metal structures using various grinding wheels and attachments;
- the complete set with a long cord greatly facilitates carrying and makes it possible to work as a grinder at long distances from the outlet and in other rooms;
- small dimensions and weight make it possible to use "Interskol" UShM-125/1100E to work with small products, since heavier grinders are very inconvenient for this purpose;
- the presence of a quick-clamping protective cover, for the installation of which tools are not required;
- the presence of a power unit that maintains low speeds;
- acceptable cost of production;
- the presence of a smooth descent;
- the presence of the main handle, which can be used in three positions;
- complete set with an additional handle.
The combination of power, dimensions, weight and additional features - positive traits, which distinguishes the angle grinder "Interskol" UShM-125/1100E. User reviews confirm the well-deserved popularity of the tool both among craftsmen who professionally use this angle grinder in production, and among amateurs, lovers of crafting at home.
Disadvantages of UShM-125/1100E
According to many consumers, weaknesses this grinder are:
- Possibility of breakage This mainly occurs as a result of voltage surges from 220 to 260 V. In this mode of operation, the regulator quickly breaks down.
- High cost of spare parts.
- Poor ventilation and lack of armor on the windings. The lack of ventilation, according to user reviews, leads to the fact that the engine located inside the grinder burns out after several weeks of operation. This is due, according to the owners of the tool, to the fact that plastic casing poorly protects the engine from dust.
The long service life of the UShM-125/1100E is possible under the condition of high-quality lubrication and timely replacement of its carbon brushes and bearings.
mending
Any power tool fails sooner or later. Is no exception and "Interskol" UShM-125/1100E. You can repair this device yourself.
All breakdowns of grinders are divided into mechanical and electrical.
For successful and fast elimination troubleshooting will require:
- instructions, which contain a detailed algorithm for disassembling and assembling the structure "Interskol" UShM-125/1100E;
- product diagram;
- wrenches, hammer, vise, press. These tools are used in mechanical troubleshooting;
- tester IK-2 for detecting short-circuited turns (used when electrical breakdowns Bulgarians);
- lubricant, flushing fluid, wipes (auxiliary materials).
Before starting work, you should ensure high-quality lighting of the workplace.
Guided step by step instructions and visual diagram, you can successfully repair the instrument yourself.
Stator failure. Symptoms
The most common stator failure is its burning. Mostly it occurs as a result of burning a power tool. Before proceeding with the repair of the grinder, it is necessary to inspect the structure and determine the nature of the malfunction. When the stator burns out, the rotor of the angle grinder begins to spin uncontrollably.
How to fix?
To begin with, the angle grinder must be disassembled and the faulty stator removed from the housing. You can also check its performance without removing it from the case.
But such a procedure is possible only in a specialized workshop. At home, for such a check, you can use a special device for monitoring short-circuited turns IK-2. It is designed to detect breaks or short circuits in the stator windings, which does not have to be removed from the housing for this. A burnt stator needs to be rewound or replaced.
How to rewind a stator?
If it is not possible to purchase a new stator, then the old one can be repaired by carrying out repair measures, which consist in covering the stator with a new winding.
Sequencing:
- from one edge you need to cut the old winding;
- count the turns and determine in which direction the winding is made;
- measure the diameter of the wire;
- calculate the percentage of filling of the core slots;
- after removing the damaged winding, it is necessary to check the insulation and clean the grooves, wind right amount turns;
- put an insulating wire on the ends of the windings;
- solder the ends of the windings.
When carrying out stator winding, it is important to use alternating current, impregnate new windings. After impregnation, traces of impregnation must be cleaned, both inside the stator and outside, on its body. During operation, it is necessary to check from time to time whether the rotor moves freely inside the stator.
Rotor failure
There are several reasons for malfunctions:
- wear of carbon brushes;
- power outages and short circuits;
- wear of the armature collector lamellas;
- destruction or jamming of rotor bearings.
To eliminate the malfunction of the rotor, experience is needed. It is best to purchase a new tool or have the angle grinder repaired by a specialized service center. If the work is done on your own, then it is very important to have necessary material and follow the procedure:
- the nut and the key are unscrewed, fixing the leading bevel gear of the rotor (11);
- the gear is removed from the rotor shaft (8);
- the rotor is dismantled from the gearbox housing (19);
- using a special puller or improvised means (vice, steel strips, hammer), bearings (9) are removed from it.
What other breakdowns are there?
Some of the most common electrical breakdowns are:
1. Broken carbon brushes. You can also deal with this problem on your own. Procedure:
- the design of the grinder "Interskol" UShM-125/1100E is arranged in such a way that the carbon brushes are located in special brush holders. You can get to them after removing the back cover in the stator housing;
- unscrew the screws that secure the brush holder;
- determine the level of wear of the carbon brushes. This can be done after measuring their remaining length. If the brush is in working condition, then its length should be at least 0.5 cm.
2. Breakage of the power cable. This fault mainly occurs at the points where the wire enters the tool and the plug. Twisting in these cases will not solve the problem. A defective electrical cable must be replaced.
Final stage
After carrying out all the necessary repair measures, the corner Sander going back in the same sequence as it was taken apart. But before the assembly itself, it is necessary to lubricate all the mechanical components of the grinder.
For this purpose, experts recommend lubricants domestic production. Lubricants can be found on the shelves of stores selling household electrical appliances. foreign manufacturers, but they are much more expensive, although their quality is not better than domestic ones. Among huge selection lubricants you should choose those products that have high adhesion rates (they are recommended for gearboxes of all angle grinders). Such lubricants better adhere to the surface.