Makita 9555 stator connection diagram. Do-it-yourself repair of an angle grinder

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Repairing an angle grinder with your own hands should be done with great care and without haste. Negative consequences manipulations with the power 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 technician cannot save it.

Grinder - rules for working with electric grinding tools

Corner grinder called “grinder” only in repair spaces former USSR for a prosaic reason - its production was carried out solely by the Eltos-Bulgarka plant in Plovdiv. The high speed cutting wheel is an indispensable assistant when processing the most durable metal, when arranging siding on the ceiling, when cutting reinforcement, sheets, profiles and many other repair operations. No less popular are the grinding capabilities of grinders - they allow you to eliminate burrs and roughness from both metal and stone or marble.

Over the past 40 years, the range of grinders has grown enormously, but the rules for handling this convenient and multifunctional tool have not changed much. Moreover - repairs are often prevented by following simple operating recommendations:

Do not remove the cover over the abrasive wheel unless absolutely necessary. If this cannot be avoided, be sure to wear safety glasses and protect the tool from any lateral contact;
Do not process wood, chipboard, MDF and similar materials - there are saws and hacksaws for this;
Hold the grinder firmly and confidently - if the disk jams, the entire tool can be torn out of your hands, it will receive severe damage and pose the risk of serious injury;
The operation of any grinder is accompanied by the presence of characteristic sparks - beware of their contact with electrical wiring, power cords and any other flammable materials;
Any workpiece – cut or sanded – must be securely fastened. Even if you have to cut a reinforcing bar embedded in concrete during construction strip foundation from corrugated sheets, 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. Principle of operation abrasive wheels consists of erasing the material of the workpieces and does not require a large clamping force. Precision of movements when working with an angle grinder is as useful as brute force is harmful.

Repairing a tool relies on knowledge of its design and common sense

Any corner Grinder consists of the following components and mechanisms, the location and condition of which should be confidently understood:

Anchor. Interior electric motor, rotating when the tool operates with an adjustable angular speed. The higher the rotation speed of the armature, the greater the power of the grinder. Unlike its marine “brother,” an anchor in electrical equipment should not brake under any circumstances;
The collector is a separate place (platform) on the armature where the power and control windings are routed. Already from the name it is clear - here the signals to the engine and the control unit are switched. The collector is clearly visible after removing the housing - the contact plates are polished and have significant dimensions;
Electric brushes are a special type 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 ventilation holes in the body of an angle grinder;
The gearbox is a special mechanical device at the front of the grinder. Designed to transfer the mechanical energy of a rotating armature to a rotating disk. In this case, both the rotation speed of the working disk and the power it develops 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 complex part of the tool, due to the strict precision of the windings pressed into it. Rewinding the stator of an angle grinder with your own hands is a risky procedure; it is better to entrust it to a specialized workshop;
Handles-holders, power cable with plug and housing with control and regulating devices.

Layout and electrical diagrams, as well as detailed instructions exactly for the model of grinder that needs to be repaired. Unfortunately, many manufacturers do not burden their devices with such frills. In this case, you can get the necessary information from a know-it-all on the Internet and not repair the angle grinder with your own hands, hoping “maybe, everything is simple,” of course, if you don’t want to buy it based on the results of the 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 chuck or a turbine at a hydroelectric power station, the repair sequence should eliminate basic faults first. Electricity and electronics are not called “the two sciences of contacts” for nothing. Typical faults grinders, along with methods for eliminating them, are as follows:

The instrument suddenly stopped showing signs of life. With a 90% probability we can conclude that the current from the outlet 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 the presence of breaks - very often it is enough to replace the wire, and the angle grinder will work like new;
The wire and plug are guaranteed to be intact, but the tool is still immobilized? It is necessary to disassemble the trigger mechanism, and it is advisable 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 clearly marked on it;
Start button and power wire are situated in in working condition, but the Bulgarian woman doesn’t want to work? It's time to start working on the net holders. Very often, it is enough to clean the contact plates on the commutator, and the long-awaited spark and smooth hum of the mechanism appears. If it is not there, then it is necessary to replace the brushes. The lifespan of these devices is usually limited to several years. A number of models of grinders are produced with solder connections for electric brushes; you need to desolder and install new ones in the kit, they partial replacement not allowed;
After replacement, carefully inspect the old electric brushes - if they show uneven wear, this is a clear sign that the center of gravity of the tool or its moving internal part has shifted. 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.

Replacing brushes is the “top of the first level” when self-correcting faults in electric grinders. You can continue to describe repair recommendations on how to disassemble the gearbox of an angle grinder, rewind its winding, or reconfigure the electronics. 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 angle grinder depends on your common sense - saving on professional repair will result in the loss of the entire instrument.

Our company offers power tools for construction and repair, Consumables, related equipment and spare parts of the famous Japanese brand “Makita”. As an official dealer, we provide appropriate certificates for all tools sold. We sell only original spare parts for any Makita tool.

You can select the required part for the tool on this page. To successfully complete your application, you need to familiarize yourself with a few simple steps to prepare your order.

So, how to choose the right part correctly and quickly?

To go directly to the selection of the required spare part or group of spare parts for a particular tool, you must go from the main page of the site to the hyperlink “MAKITA SPARE PARTS”, which is located in the upper right corner home page site. If this step is successfully completed, you will be taken to the “Makita spare parts” page.

Now we can see all the Makita tools grouped by type and schematically depicted. We select the group whose power tool requires repair and replacement of spare parts. You can use vertical scrolling. For example, select “Drills and saws”.

The “Drills and Saws” page contains the entire list of models for which you can order parts. We carefully select from the list of models provided by the site and activate the model you need by clicking the left mouse button. Let's choose one. For example, Makita 6310.

So, after selecting a specific model (in our case, Makita 6310), a page () will appear in front of you, which shows Assembly drawing selected model. Here you can print it on a printer (see Print a drawing). On the right side of the table there is a list of positions, names and quantities of parts in the tool. Each detail of the drawing is interconnected with its position in the list. When selected (by hovering the Mouse pointer over a part), the arrow changes to a hand, which allows you to click the left mouse button to mark the specified part in red. At the same time, the position of the same name in the list is marked in blue, and an application table appears at the bottom of the page. Moreover, it is worth paying attention to the fact that with the mouse you can select both a part in the drawing and its position in the table. The table below appears only when at least one part is selected. Next you need to decide what to do. There are several options under the generated application. You can cancel everything (reset everything) and start the selection again. You can continue the selection in other models (in this case, the order already made will also be displayed on the monitor), or you can go to the order form by clicking the appropriate link.
Notes: Directly in the application (in the table with the selected parts), you can use the arrows in the last column to enter the number of parts you need.

Please note: the minimum order amount is 1000 rubles

Having finally completed the Application, you can proceed to the order form, where you will be asked to fill out three information fields. Contact person (how to contact you), number mobile phone and worker or home phones. After submitting your order for execution, wait for a call from the manager.

The company's employees - experienced professionals - will process the received order and within a day will inform you about the presence or absence of certain parts, their quantity, the price of the part and the total cost of the entire order. If any spare part is missing, you will be informed about the time it will be received from the manufacturer and, by agreement with you, may notify you about this again.

Typically, the order execution time does not exceed three working days. You can learn more about the delivery of goods by visiting the “Delivery” page.

The practice of this service shows that clients are using it more and more often. You receive the tool itself, consumables, and spare parts for them without leaving your apartment. You can discuss all complaints and wishes with the manager or delivery specialist.

In the last article, I talked about how to connect and start a 380 Volt motor in a single-phase 220 V electrical network. Now I will talk about how to connect a single-phase electric motor from a broken washing machine, vacuum cleaner, etc. It can be successfully used for other purposes in household, for example, to drive a sharpener, polishing machine, lawn mower, etc.

Connection diagram for a 220 Volt commutator motor

IN electric drills, rotary hammers, grinders and some models washing machines machines use a synchronous commutator motor. It successfully starts and works in single-phase networks without unnecessary starting devices.

For that, to connect a commutator electric motor, it is necessary to connect the two ends No. 2 and No. 3 with a jumper, one coming from the armature, and the other from the stator. And connect the remaining 2 ends to a 220 Volt power supply.

Remember that when connecting the collector an electric motor without an electronics unit, it will only operate at maximum speed, and when starting there will be a strong jerk, a large starting current, and sparking on the commutator.

The motor may also have a 2-speed motor, then the 3rd end will come out of the stator from half of its winding. When connected to it, the shaft rotation speed will decrease, but this increases the risk of insulation failure when starting the motor.

To change the direction of rotation, it is necessary to swap the ends of the stator or armature connection.

Connection diagrams for single-phase asynchronous electric motors

If single-phase electric motors had only one winding in the stator, then the electromagnetic field inside it would be pulsating rather than rotating. And the launch would occur only after unwinding the shaft by hand. Therefore, for independent launch asynchronous motors an auxiliary or starting winding is added, in which the phase is shifted by 90 degrees using a capacitor or inductance. The starting winding pushes the rotor of the electric motor at the moment of switching on. The main connection diagrams are shown in the figure.

The first two circuits are designed to connect the starting winding while the motor is starting, but not more than 3 seconds in duration. To do this, use a relay or a start button, which must be pressed and held until the engine starts.

Owners of power tools are well aware that any equipment requires periodic maintenance. Some components require lubrication, others wear out and must be replaced. But most often, craftsmen operate the device until the parts begin to spill out of the body. And then it is necessary to take emergency measures to restore the normal operation of the instrument. How can you find out what’s broken, check the grinder’s functionality and carry out repairs yourself?

What is angle grinder used for and how is it designed?

The angle grinder (angle grinder), or “grinder”, has firmly entered the everyday and industrial life of not only the craftsman, but also the common man who likes to comfortably solve plumbing and carpentry tasks. The popularity of this power tool is due to its simplicity, versatility and multifunctionality of use.

With the help of various additional attachments, the grinder can cut metal, grind various surfaces, clean them from rust or old paintwork. The angle grinder's arsenal includes functions such as sharpening cutting tools, gating concrete walls, cutting ceramic tiles or stone.

The device of the grinder

Structurally, the angle grinder is an electric motor with a power of 500 to 2000 W, which converts power electric current into rotational motion. A planetary gearbox, consisting of two main gears with a straight or bevel gear, serves the same purpose. The rotation of the spindle of the working shaft is carried out in direct transmission mode, the speed is determined by the ratio of the number of gear teeth. Some angle grinders are equipped with an electronic engine soft start unit and rotation speed control.

Electric motor type - asynchronous, single-phase. Electromotive force arises when the rotor winding interacts with the magnetic field of the stator, which is fixedly fixed in the housing. Thanks to the angular transmission of torque, the level of safety during operation is significantly increased. If the disk jams in a viscous material, the tool body does not rotate reactively, which prevents possible injury to the operator.

Many have experienced in their own practice the phenomenon of reactivity when operating an electric drill. When a drill bit jams, for example, in hard wood, the body of the device begins to forcefully rotate in the opposite direction, is torn out of the hands and can lead to injury or even disfigurement.

Diagnostics of malfunctions in the operation of angle grinders

Signs of an angle grinder malfunctioning for a sensitive ear and a keen eye appear long before the actual failure of the tool. Before it completely breaks down, the grinder usually starts giving distress signals. It could be:

increased vibration of the housing during operation;
excessive sparking of commutator brushes;
uterine humming of the engine when turned on;
cracking of the gearbox due to broken teeth or dried out gears without lubrication;
jamming of the rotor shaft rotation bearings or their piercing creaking during acceleration;
a specific smell or even smoke emanating from the angle grinder body.

To save the grinder from a large and expensive repairs, you should be attentive to the technical condition of the tool and promptly respond to changes in its operation.

If the first symptoms of improper operation appear in the grinder, it is necessary to urgently diagnose the device and find the cause of the problem. To do this, you need to check two main systems of the device - electrical and mechanical.

Electrical check

The electrical part of the angle grinder consists of:

electric motor;
power buttons;
electronic control unit for start and rotation speed.

The electric motor, in turn, is divided into two main parts - the stator and the rotor (or armature).

The master's task is to sequentially check all these systems and discover the causes of operational problems. To do this you will need a multimeter or tester.

Checking power circuits

First of all, you need to check the integrity of the power cord. Many troubles can occur only because there is damage in the cable and the power supply to the device is uneven. The cord must be completely intact, without signs of damage. During operation, it should not heat up or spark in places of kinks and connections with a socket or grinder. If any of these conditions are not met, the cord should be repaired or replaced.

Using a tester turned on in voltmeter mode, check the input voltage in the angle grinder; it must correspond to the passport values: 220 V. In ammeter mode, the current consumption is measured - it should not exceed 6 A.

Checking the starting and control unit

Next, you should test the start button and electronic control unit. It is possible that the contact group for turning on the device has become oxidized or clogged. If the device is equipped with a soft start system, the disk should accelerate to operating speed gradually, without a sharp increase in speed. Using a multimeter, you need to make sure that voltage is transmitted to the electrical circuit when the button is turned on.

If during operation of the grinder it was noticed that the brushes at the point of contact with the commutator spark excessively or the disk rotates unevenly, abruptly changing the number of revolutions per minute, then most likely the stator or armature windings are involved in this. Since the stator is less susceptible to overloads - it only creates a magnetic field, then most often attention should be paid to the rotor of the electric motor.

Rotor diagnostics - how to “ring” the armature with a tester?

To make sure the rotor is working properly, you need to “ring” it with a tester.

By setting the multimeter toggle switch to the 200 Ohm position, sequentially measure the resistance of the windings on two adjacent armature lamellas. If the resistance is the same everywhere, it means the anchor is intact and operational. If on any of the pairs of lamellas the tester shows a different value from the others, an interturn short circuit has occurred in this place. The anchor needs to be repaired or replaced.

Diagnostics of the rotor operation of an angle grinder

An interturn short circuit usually occurs when the tool overheats during operation. The insulation of the windings melts and this leads to the fact that adjacent turns, consisting of copper wire, come into contact. As a result, the balance of the electromotive force is disrupted and this leads to a loss of power at a certain position of the armature.

Motor stator diagnostics

If the armature turns out to be in good condition, the testing procedure should be carried out with the stator, measuring the resistance of the windings in a similar way. An interturn short circuit in the stator is characterized by bursts of increased speed of the grinder when turned on. The engine, for no apparent reason, begins to rotate “crazily” at increased speed.

An insulation defect in the stator windings can be corrected by repair or replacement. Repairs usually involve rewinding the copper wire.

A specially made template is used to rewind the stator coils. As a rule, it is made from plywood. The size of the template is determined with a margin of 10 mm for each frontal part. To prevent the wire from jumping off the plywood during winding, cheeks are attached to the sides.

Rewinding can be done at home if you have the necessary tools and equipment. It is important to select a copper conductor with a cross-section that exactly matches the original one. The number of turns of the winding cannot be changed either.

Video: how to rewind the stator of a power tool

Checking the mechanical part of the machine

The mechanical part of the angle grinder consists of:

gearbox;
spindle locking button;
flange mounting of working tools;
bearings of the rotating rotor shaft.

To determine faults in the mechanical part of the angle grinder, it is necessary to open the gearbox housing, made of aluminum alloy. As a rule, the gearbox cover is secured with four screws, which must be unscrewed to gain access to the gear pair.

Inspection of gearbox gears

Inspection of the gearbox gear is to determine the strength of the gears, the presence of a sufficient amount of lubrication and the integrity of the teeth.

Checking the lock button

The spindle locking button is a spring-loaded steel rod that prevents the working shaft from rotating. The button is used when changing cutting discs. Failures of the locking rod usually occur when the disk jams or the electric motor is turned on with the button pressed.

Inspection of the flange for attaching nozzles

Attaching the grinder disc (or other working attachment) is produced using a flange threaded clamp. They fail extremely rarely, as they are simple to design and operate. When inspecting, you should pay attention to the condition of the threads on the shaft; if necessary, it can be lubricated with grease, graphite grease or Litol.

In practice, a situation often occurs when the flange nut is “hopelessly” tightened on the disk, and the wrenches do not help even with great physical effort. This can happen, for example, when a disc ruptures. The following method will help you unscrew the nut:

Fixed in a vice metal plate up to 2 mm thick.
The remains of the disc break and are bitten off with pliers.
The grinder's motor turns on.
With the help of a fixed plate, the remains of the disk are “crushed” from under the nut.
When the space under the flange is free, it can be easily unscrewed.

When performing this operation, it is necessary to use personal protective equipment: gloves and safety glasses - disc fragments fly at high speed and can cause injury.

Checking the rotor shaft bearings

Checking the operation of bearings on the rotor shaft involves visual inspection. A serviceable bearing should have a uniform color (without blue, which occurs when the part overheats, and lubricant leaks), and should rotate easily and without sound when turning. If this is not the case, the bearing is repaired or replaced.

General rules for repairing power tools

If, when diagnosing an angle grinder, the causes of the malfunction have been identified, repairs must be started in compliance with certain rules.

the device must be turned off from the power supply;
repairs should be carried out on a well-lit, uncluttered table or workbench;
the order of disassembly must be observed and, accordingly, reassembly device.

If it is difficult to remember the location of parts inside the mechanism, it is recommended to photograph them.

When the device is disassembled, it is strictly forbidden to connect it to the electrical network.

The main causes of grinder malfunctions and their elimination

Below are the most common problems and how to fix them.

Commutator brushes burn (spark)

Sparking in the commutator is most often observed in cases when it is time to replace the carbon brushes. This usually happens after several years of using an angle grinder.

Standard brushes are designed for 7,000 hours of operation, after which they are washed.

Grinders have a simplified system for replacing brushes, so repairs are quite easy and quick:

Using a flat-head screwdriver, unscrew the two plastic caps on both sides of the casing.
Remove old brushes from their nests.
Wipe the collector with an alcohol swab, as there is carbon residue on the lamellas from the work of old brushes. You can also use tweezers with cotton wool or rags soaked in cologne.
Install new brushes into the sockets.
Screw on the plastic caps.
Check the angle grinder in operation.

Video: replacing grinder brushes will help eliminate sparking

Grinder won't turn on

To determine the exact cause of this malfunction, it is necessary to examine the electrical circuit of the device. It is advisable to start from the outlet and end with testing the electric motor. After the location of the circuit break has been found, the flow of electric current in the tool should be restored. Most often, the cause of a break is dust or oxidation of the terminals or contacts of the start button.

Broken spindle lock button

The defect is purely mechanical in nature. This happens when the circle jams or when the rod cavity is severely clogged. In this case, replacing the disk will help special key for a flange, which, as a rule, is always included in the kit of the sold tool. You can keep the shaft from turning using open-end wrench. At the base of the flange mounting there is a specially machined turnkey plane.

Video: repairing the spindle lock at home

The engine has stopped working

If voltage is supplied to the motor, but it does not rotate, you need to check the condition of the brushes and bearings. Brushes may stick, bearings may jam.

If the brushes are sunk, they must be thoroughly cleaned and then the nests in which they are located must be blown out. Additionally, you should check sealing rubber bands on the covers covering the brush nests. After all, the insulation of brushes and commutator from dust depends on them.
If the reason for the engine stopping is in the bearings, they must be removed from the rotor shaft, repaired or replaced. Sometimes flushing and lubrication is enough to ensure that the old bearing continues to function.

The angle grinder works in fits and starts and does not develop full power

The angle grinder motor operates jerkily if an interturn short circuit occurs in the rotor coils. The most common reason is irregular use of the tool, which results in overheating of the motor. Rewinding armature coils is a rather complicated and painstaking task, doomed to failure without certain skills. Therefore, if the armature fails, it is recommended to replace the entire part, along with the bearings. The value of the spare part must exactly match the value of the original.

The grinder gets very hot

Most often, the body of an angle grinder gets very hot due to improper operation of the device. Since the angle grinder is equipped with an asynchronous electric motor, an increase in the workload on it does not affect the rotation speed in any way. This can be misleading for an inexperienced user, as a result of which he continues to work without interruption for an unlimited time. But this cannot be done. The passport of each instrument indicates optimal time operating an angle grinder under load, it usually lasts 5–7 minutes. After this, it is recommended to take a break of 1 minute or let the grinder work for Idling.

When working with a tool, it is important to follow the correct order of stopping the grinder. After turning off the start button, you need to wait until the engine stops completely. If the rotating angle grinder is placed on the ground or a dusty floor, small particles of sand will be sucked through the ventilation holes. They will get inside the engine and will erase the protective insulating layer.

Bulgarian is not gaining momentum

If the tool is equipped with an electronic shaft speed control unit, a malfunction may cause the shaft speed to “float” under load. Most likely, there is a short circuit on the board; the control unit should be replaced.

Gearbox failure

The gearbox gears play an important role in supplying rotational motion from the electric motor to the working tool. In addition, there is a decrease in speed and, accordingly, an increase in power. Grinders with power up to 1100 W use spur gears. If the engine power exceeds this figure, helical gears are used, which have greater fracture strength.

If you hear a crunching or grinding sound from the gearbox when you turn on the motor, the grinder must be turned off immediately. It is impossible to work with such a gearbox; this will lead to complete cutting off of the remaining gear teeth. After stopping the engine completely, you need to remove the gearbox cover to establish an accurate “diagnosis”.

If the cause of extraneous sounds is chipped teeth, the damaged gears must be replaced. In this case, the cavity of their rotation should be thoroughly cleaned of grease and metal fragments that formed from the previous mechanism. After replacing parts, you need to completely renew the lubricant inside the gearbox.

Video: how to repair and adjust the gearbox

If the grinder smokes during operation

When you are engrossed in stone processing or metal grinding, it is easy to not notice how the tool has overheated. If the work is not stopped, very soon acrid, stinking smoke will begin to emerge from under the casing. This is the armature windings burning, in which, unable to withstand the thermal load, the insulating layer melts. If you do not interrupt the work, the grinder may burn out.

If you felt bad smell, you must immediately turn off the grinder and pull it out network cable from the socket.

You can begin disassembling the instrument only after the housing has completely cooled down and the emission of caustic fumes has stopped.

Excessive sparking at the manifold

A fan of sparks flying out from under the commutator brushes usually indicates a violation of the insulation on the armature or a short circuit between the wires in the windings. In this case, you should stop working and turn off the angle grinder from the network. Next, you need to disassemble the body and examine the angle grinder’s anchor in detail. The simplest repair option is to completely replace the anchor.

Bearings broke

If there is something wrong with the bearings, the angle grinder vibrates and makes noise under load; the sound is dominated by a low-frequency hum. This is due to the fact that the damaged bearing begins to hum during operation. Vibration occurs from the appearance of additional play on the bushings securing the rotating shaft. This malfunction can be eliminated by replacing the bearings. To do this you need to do the following:

Remove the brushes from the brush holders.
Remove the plastic housing by unscrewing the fastening screws.
Remove the gearbox cover and disconnect the drive gear.
Remove the armature shaft along with the cooling impeller and bearings.
Using a puller, separate the bearings from the shaft axis.
Reassemble the structure in reverse order.

Video: how to change a bearing on an angle grinder

If the grinder hums but does not rotate

If the angle grinder shaft does not rotate, there are two most likely reasons, both related to the mechanical part of the tool.

The gearbox is jammed.
The bearings are jammed.

To check the versions, turn off the grinder and try to turn the tool disk manually. If the spindle does not rotate or rotates slowly, the reason does not lie in the electrical part; you need to disassemble the gearbox and look for the reason there.

If the soft start does not work

If it doesn't work smooth start, the reason lies in a malfunction of the electronic control unit. The solution to the problem is to replace the entire block. Only a specialist with the appropriate knowledge and diagnostic equipment can disassemble the unit and look for the cause of the problem.

Preventative maintenance of an angle grinder

Unexpected breakdowns can be avoided if you regularly carry out not only visual inspections, but also Maintenance tool. The manufacturer usually indicates the prevention regulations in the passport. In order for the grinder to serve for a long time and without “surprises”, you should:

carry out tool maintenance in a timely manner;
comply with operating and storage standards;
avoid long work tool under load at reduced speed;
do not allow the working part of the tool to become pinched;
Monitor the mechanisms and promptly replace worn parts.

If the angle grinder was operating at low engine speeds, it must be kept at idle for about a minute before turning it off. This will allow the engine to recover and regulate the temperature of the windings.

Preventive disassembly, cleaning and lubrication of mechanical parts will increase the service life of the tool several times. This simple maintenance will help you avoid costly repairs.

The optimal conditions for storing an angle grinder are dry rooms protected from sharp changes air temperature. When storing an instrument for a long time, it is preferable to pack it in a plastic bag in a cardboard box.

All renovation work All work carried out with power tools must strictly comply with safety standards. Under no circumstances should you disassemble the housing while the device is plugged in. Containers with flammable and flammable materials should not be located near the disassembly site.

Most tools used on the farm are not insured against breakage. Grinders, which almost every craftsman has, fail over time. Different models of angle grinders may have similar types of faults. But each brand has its own characteristics in design and components. The famous Makita brand is valued for high quality– strength. However, devices of this brand also tend to break.

Repairs can be done at home. Spare parts for the machine can be easily purchased. Before repairing the device, you must familiarize yourself with the attached diagram.

Types of Makita brand angle grinders and their features

Based on the diameter of the working wheel, brand grinding devices are divided into classes:

Lightweight - have a circle with a diameter of 115–125 mm. They are easy to control.
Medium - the diameter of the circle is 150–180 mm. There are professional models and household ones, differing in motor power.
Heavy – disc diameter 230 mm. This class is represented by models for professional purposes when working with concrete, brick, etc. Characterized by the latest protective systems.

Homemade devices vary in power and price. Professional equipment is designed for long-term heavy loads and has an increased power reserve. Models with power above 1000 W are equipped with a comfortable rear handle, which is covered with special pads that protect against vibration.

As for the design of grinders of this brand, it is characterized by the presence of the following additions:

a labyrinth device used to protect against dirt and dust;
armored coating of motor windings;
special system for soft start and overload protection (Super-Joint-System).

Types of damage

Malfunctions when working with Makita angle grinders can be divided into two types:

electrical (failure of the rotor, stator or defects in the control circuit);
mechanical (bearing failure on the gearbox).

First you need to inspect the device. The mechanism of operation of the grinder is to supply torque from the rotor through a gear to the spindle of the working tool (circle, cutting stone).

Sources of breakdown can be increased loads, untimely replacement of brushes and lubricants. Thanks to the presence of a quick release protective casing, Makita models can be repaired in a short period of time.

Troubleshooting the Control Circuit

The control circuit contains components whose malfunction can be repaired independently. The weak point is the brushes. Therefore, checking them is necessary first of all. You should also check the integrity of the power circuits from the plug to the switch terminals.

If the fault is a broken switch, then it needs to be replaced. If the supply wire is damaged and broken, the damaged parts are removed or the entire wire is replaced.

Stator repair

The appearance of an unpleasant odor, constant overheating and spontaneous acceleration indicate a breakdown of the stator. The stator winding may break or a short circuit may occur. Using a tester or IR-2 device, you can find a short circuit. In the event of a malfunction, a new wire must be wound.

Rotor repair

The reason for the breakdown of the angle machine may be the failure of the stator. This can be understood by the large number of sparks in the collector area and the presence of a burning smell. The rotor is connected to the gearbox. Therefore, when removing it, it is necessary to disconnect it from the gearbox. Rotor repair involves complex technology. It would be more practical to replace it with a new part.

The new rotor is placed in the housing with bearings already installed. The drive gear is also put on. Then you should check the press fit of the bearing and tighten the nut.

Then the rotor and gearbox are placed in the stator. In this case, the bearing should be covered with a boot and rotate easily.

Gearbox repair

If the gearbox is damaged, play in the spindle shaft appears. The gearbox begins to jam and the gear slips. Repairing a gearbox usually involves damaged gear teeth. For each Makita model, the driven gears are either attached to the shaft or pressed onto the spindle. In addition to the driven gear, the gearbox consists of a housing and a drive gear. To execute angle grinder repair, the gears need to be replaced, and the replacement should be done in pairs. You will need a puller to remove the driven gear. You can also use a press. It is not recommended to use a hammer due to the fragility of the housing shell.

Features of assembly after repair

After troubleshooting the Makita angle grinder, components are purchased and repairs are made. The following recommendations should be followed:

assembly must begin by checking the parts for integrity and cleanliness;
assembly begins with putting the bearing on the spindle;
the driven gear is installed after the bearing;
the spindle is placed in the gear housing, using a rubber ring;
When assembling the gearbox, the bolts are lubricated with sealant;
when placing lubricant in the gearbox housing, the volume of its space is taken into account (the volume of lubricant is equal to 1/3 of the volume of the space);
at the end of the assembly, the torsion of the gearbox is checked and the fastening bolts are screwed in;
Carbon brushes are replaced after 7 thousand hours of operation or wear up to 8 mm in length.

Makita grinders very often undergo repair procedures due to the high number of counterfeit devices. A common problem is the breakdown of the gearbox, namely its gears.

Repair of other brands of angle grinders

In addition to the popular Makita brand, other grinding devices are known from the Bosch, Sparky, and Stern brands. All of them are reliable and easy to use. But cases of breakdowns cannot be ruled out.

Bosch grinders often require replacement of bearings. The mechanism of the machine is based on the torsion of the spindle shaft, which is pressed into the driven gear. It also rests on a needle bearing. If the bearing is destroyed, then its race is very difficult to obtain. Moreover, the drive gear is fixed to the rotor shaft with a left-hand thread. As a result, the fixation occurs with a nut. The gear, which is the driven gear, is pressed onto the spindle shaft.

Gearboxes of Sparky angle grinders are characterized by a gear pair placed in a housing. The driven gear is fixed with a press or keyed connection. The key is a ball of small diameter. The drive gear is also secured to the rotor shaft with a key or a right-hand threaded nut. Grinders of this model are also distinguished by easy removal of brushes without removing the handle.

When disassembling Stern angle grinders, the gearbox does not need to be removed from the body. During repairs, keep an eye on the small gear key, which does not hold well. Lubricant must be changed promptly.

You can and should try to repair any instrument. Bulgarians do not differ much in mechanism. The diagram is always included when purchasing the device. Therefore, any craftsman who has necessary tool and devices.

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