Angle Grinder Gains Speed ​​But Doesn't Accelerate

Over time, all kinds of electrical tools can fail. Often the cause of such breakdowns are violations of the operating rules or the poor quality of tool components. One such tool is an angle grinder or angle grinder. If the tool does not work, then you should not immediately buy a new one, since such products can be repaired. To repair the angle grinder, you need to know its design, as well as the principle of operation.

How is the angle grinder

DIY angle grinder repair begins with the fact that you should find the cause of the malfunction. To do this, you need to find out the principle of operation and the design of the tool. The principle of operation of the device is based on the conversion of electrical energy into mechanical energy. Mechanical energy is a rotational movement that drives the working shaft of the tool with the corresponding nozzles.

This means that the angle grinder consists of two parts: electrical and mechanical. Damage can occur in any node, so it is important to know the structural elements of both parts. The main elements of an angle grinder include:

The case is made of shockproof plastic. The design of the case combines an electric circuit with mechanics. The motor rotor rotates by applying electric current. Plain bearings provide rotational movement of the rotor shaft. At the end, the shaft has a toroidal gear. It drives a flat gear, which is located in relation to the shaft at an angle of 90 degrees. Thus, the work of angle grinders. In addition to the two plain bearings on which the rotor shaft rotates, there is another bearing assembly in the angle grinder. It is located on the working shaft of the mechanical part of the tool.

Typical malfunctions of grinders and diagnostic and repair methods

DIY angle grinder repair begins with determining the cause of the breakdown. If it is not possible to determine the cause, then we should follow the method of eliminating breakdowns from simple to complex. For self-repair, it is necessary to identify initially where the breakdown is located. in the electrical or mechanical parts.

Mechanical failures include:

1. Gearbox malfunction. The helical gear is mounted on the rotor shaft, so if the motor is running, but there is no rotational movement of the working part, then the reason lies precisely in the gear mechanism. In order to see what happened to the gears, it is enough to disassemble the tool body. The cause of the gearbox malfunction is most often the licking of the teeth of the large gear of the shank. The reasons for this are the most diverse:
2. lack of lubricant;
3. heavy tool loads;
4. low quality of components;
5. improper operation.

One way or another, after a malfunction is identified, it should be fixed immediately. This can be done by replacing a faulty gear. Most often, on sale you can find them paired with a helical, which is mounted on the shaft. It is recommended to replace two gears in pairs, after which they must be carefully lubricated with special lubricant.

These are the main types of malfunctions of the mechanical part of the tool, in the elimination of which there are no problems. Now let’s pay attention to the more complex part. this is the electrical part. In the electrical part, these types of breakdowns can occur:

Prevention and Maintenance

To avoid repair of the angle grinder, it should be periodically diagnosed. First of all, it is important to care for the mechanical part, which suffers from a lack of lubrication and the appearance of dust and moisture. There are special greases for angle grinders, both domestic and foreign production. over, the lubrication for the gearbox and bearings is different.

The main recommendations for extending the life of an angle grinder are as follows:

1. Perform tool maintenance on a regular basis.
2. Observe operating and storage standards.
3. Eliminate long-term loads, especially for household models.
4. Replace worn gears in a timely manner.

It follows from the foregoing that, despite the complex construction of such a tool as an angle grinder, it will not be difficult to extend its service life or to make repairs.

angle grinder and its operation

angle grinder is called angle grinder (angle grinder). The name of the tool is due to the fact that it was produced by the Altos-Angle Grinder plant in the city of Plovdiv. It is intended for grinding or trimming hard material:

It performs tool sharpening well.

Nowadays, an angle grinder is a very necessary tool, so almost everyone has it.

There are different power grinding machines: from 500 W to 2500, depending on the thickness of the circle. from 115 mm to 230 mm. The most popular in the work are angle grinders with a power of 1.2 W, and the most used disk is 125 mm thick.

Every year, the choice for this construction power tool is becoming wider, but the operating rules are almost unchanged. And even if you always adhere to them, sooner or later malfunctions arise in the mechanism, which you can try to fix yourself, having collected all the angle grinders necessary for repair.

The device LBM

Any angle grinder consists of the following parts:

All these details can be divided into two parts:

How to disassemble angle grinder

How to disassemble an angle grinder? Not such a complicated process. This does not require special knowledge, but it is necessary to do everything carefully and with caution. Each owner needs to know how to disassemble any working tool, because from time to time it needs to be cleaned internally of dirt and dust, and its longevity of service depends on it.

At the present time on the market you can choose a different type of angle grinder, which differ in operating parameters, sizes, quality. Manufacturers are also different. Whatever model of grinder you have purchased, everyone has one model for assembling parts.

Dismantling an angle grinder will require a few tools, you just need a regular screwdriver or a reversible one with a ratchet mechanism.

Having prepared a screwdriver, you can start disassembling:

When disassembling an angle grinder, it is important to remember the sequence of removal of parts in order to assemble correctly.

Types of damage to grinders

Typical minor breakdowns

In the event of a malfunction, it is first necessary to exclude elementary breakdowns:

The angle grinder does not turn on. The angle grinder suddenly became faulty. it stopped turning on. In this case, you need to check the health of the outlet, then the plug and the power cord, maybe the drive simply does not work due to the fact that no current flows into the product.

Significant malfunctions

Having eliminated all minor breakdowns, it is necessary to understand why the tool does not want to turn on, and how to repair it. Most likely, the malfunctions are serious, requiring additional knowledge. This occurs if:

• the case is deformed;
• jammed one of the bearings;
• anchor or stator does not work;
• the teeth of the gear reducer have broken or worn out;
• the collector is out of order;
• the sensor of the control electronics does not show any signs of life.

If it is determined that a malfunction has occurred in the mechanical part of the angle grinder, then one must pay attention to the state of the large gear located on the shaft and to the bushings. If the teeth are partially erased or a shafting of the shafts occurs, they must be replaced immediately.

Failures of the angle grinder happen quite often. Everyone who works with this tool knows about it. What fails most often?

The spindle lock button has broken.

Just one awkward press on the spindle lock button when the disk rotates causes it to break. Sometimes it can be broken if it is used to remove a jammed disk. To prevent this from happening, you need to use an open-end wrench inserted into special holes near the disk mount.

Gear teeth

It mainly occurs when jamming occurs. If rumble is heard in the gearbox, this is a sign of just such a malfunction. When a gear has more than one clove broken, the angle grinder will not be able to cut the necessary material.

The electric motor does not work.

This type of failure occurs with angle grinders, which work in places where there is a lot of dust, and when they are given rest, they are left on the ground. Dust that gets inside spoils the winding. Large loads, especially for a small power angle grinder, result in a motor breakdown.

If the angle grinder is used to cut materials that create a lot of dust, it is recommended to cover the places of the ventilation holes with something.

Bearing rained down

The weakest link, and not only for grinders, are bearings. The high rotational speed quickly wears out the mechanism. The good news is that changing the bearing is easy. Replacing the sprinkled bearing at the angle grinder should be done on time so that there is no breakdown that can no longer be fixed.

Stator failure

It is easy to determine this failure when the angle grinder is turned on, but the drive speed is too intense and differs from normal operation. which means that there is a winding in the stator on the winding. Stator failure is considered the most serious, special skills are needed to eliminate it. When there is doubt in your abilities, it is better to turn to professionals so that you do not have to buy a new tool later.

If the decision to fix it yourself is made, it starts with cutting the frontal parts of the winding, all the residues are removed. The next step is a new pattern winding. It should be identical in the number of turns, with the same density and from a wire of the same thickness as the previous one.

Gearbox

Angle grinders whose power is less than 1100 watts are usually equipped with spur gears. They are on the stator. For grinders with greater power. helical gears. Each of the options has a cone shape, the gearbox shaft angle grinder intersects with the stator shaft at an angle.

Gearbox repair angle grinder mainly consists in the replacement of gears. In the event of a breakdown of the disk gear, it is difficult to replace it, because it is very firmly fixed. It is easy to disassemble the gearbox:

• you need to unscrew the nut from his side;
• gently take the rotor housing in a vice and knock the gear housing out with light strokes;
• change the position of the clamped rotor and knock out the bearing through a wooden board;
• unscrew the gear from the shaft.

Everything. the gearbox is disassembled.

Speed ​​control

Self-repair of an angle grinder is not always feasible. If suddenly something does not come out or not everything is clear, it is better to contact the service center.

Common symptoms

Before it breaks down completely, the angle grinder signals the beginning of the malfunction.

Pay attention to the work of your assistant: you should be alert if:

• the brushes began to spark too much;
• during operation, the angle grinder is heated;
• the motor buzzes inside the case when the tool is turned on;
• the vibration of the case has become much greater when performing work;
• reducer angle grinder cracks inside;
• the sound of a creak of bearings is heard during spin-up or periodic wedging when the rotor shaft rotates;
• The angle grinder is smoky, or an uncharacteristic burning smell emanates from it.

In order not to buy a new angle grinder, you need to be careful about the tool. In the event of any deviations from the usual work, start troubleshooting, determine the cause and repair the power tool.

Breakage prevention angle grinder

The life of the grinder directly depends on the care of the owner for her. Each tool needs good care, then it will work properly for a long time.

Any angle grinder will warm up during operation, but in order to postpone the repair of angle grinders for a long time, it is necessary to adhere to some rules in operation:

1. Do not overload the tool to avoid overheating and smoke.
2. Do not press hard on him while working.
3. Clean and lubricate the necessary parts inside the housing in time.
4. If there is a noticeable malfunction, stop operation and inspect for malfunctions.
5. Replace wearing parts in a timely manner.
6. If the angle grinder is smoking, immediately stop working and do not turn it on anymore.
7. Do not use the tool when processing wood type material.
8. Hold the angle grinder firmly during operation so as not to drop or damage.

Adhering to the listed simple recommendations and rules in working with a tool called an angle grinder, you can extend its service life longer than provided for by the warranty period.

If the machine is not gaining momentum

Causes of damage and further repair actions:

1. The speed control unit has failed. in order to check this, it is necessary to turn on the drive directly without a regulator. If the device is working properly, you will have to change the regulator itself.
2. There was a bend in the electric wire. in this case it will heat up very much, and the speed will decrease. It is necessary to replace the electric cable for the normal operation of the grinder.
3. Dust got into the collector. you need to disassemble the angle grinder and remove all the dirt with alcohol.
4. There was a problem with the brushes. they wear out over time, and they have to be replaced with new ones. It is possible to purchase spare parts for the grinder at Toolparts.com.ua.

The grinder heats up very much

There are a number of reasons:

• the operating mode was incorrectly set. then the engine will start to heat up from increased load, this leads to a burnout of the winding;
• the bearings that are anchored have collapsed. the rotor in this case will begin to cling to the stator, the engine will slow down and the winding will overheat. It is urgent to install new bearings;
• clogged ventilation ducts. through them during operation of the grinder, air enters the device and cools the device. It is necessary to periodically clean them from dust and dirt;
• the impeller is out of order. it is also needed to cool the engine during operation. It is mounted on the rotor, on the other side of the manifold. If the part breaks, you will have to replace it;
• inter-turn circuit. it occurs in the winding of the rotor or stator. To avoid overheating, it is necessary to rewind the coils and replace the old elements of the device with new ones.

Parsing a device

To replace the parts, you have to disassemble the grinding machine:

1. You must first remove the disk using a special key.
2. The handle is unscrewed.
3. The protective cover is removed.
4. Special windows on the sides of the device open and brushes are removed. If necessary, they are replaced with new ones.
5. The gear housing is unscrewed.
6. The stator is removed.
7. The gearbox is disassembled, if necessary, the gears of the device change.
8. After replacing the parts, the device must be assembled.

There is nothing complicated in the device of the grinding machine, therefore, repairs can be carried out independently. But if there is no self-confidence, then the device is better attributed to the master.

Why is angle grinder used and how is it arranged

Angle grinder (angle grinder), or “angle grinder”, has firmly entered the household and production life of not only a craftsman, but also a simple layman who likes to conveniently solve locksmith and carpentry tasks. The popularity of this power tool is due to the simplicity, versatility and versatility of use.

With the help of various additional nozzles, an angle grinder can cut metal, grind various surfaces, and clean them of rust or old coatings. The angle grinder has such features as sharpening cutting tools, shredding concrete walls, cutting ceramic tiles or stone.

Angle grinder device

Structurally, the angle grinder is an electric motor with a power from 500 to 2000 W, which converts the electric current into rotational motion. A planetary gearbox consisting of two main gears with a direct 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 soft start engine and speed control.

Video: Angle Grinder Gains Speed ​​But Doesn’t Accelerate

Type of electric motor. asynchronous, single-phase. An electromotive force occurs when the rotor winding interacts in the magnetic field of the stator, which is fixedly mounted in the housing. Thanks to the angular transmission of torque, the level of safety during operation is significantly increased. In the case of jamming of the disk in a viscous material, there is no reactive rotation of the tool body, which prevents possible injury to the operator.

Many have experienced in their own practice the phenomenon of reactivity when operating an electric drill. When the drill sticks, for example, in hardwood, the body of the device starts to rotate with force in the opposite direction, breaks out of the hands and can lead to injury or even injury.

Diagnostics of malfunctions in the angle grinder

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

• increased vibration of the case during operation;
• excessive sparking of collector brushes;
• uterine buzz of the motor during start-up;
• gear cracking with broken teeth or dry gears without lubrication;
• wedging by bearings of rotor shaft rotation or their piercing creak during acceleration;
• a specific smell or even smoke emanating from the angle grinder body.

To save the angle grinder from large and expensive repairs, you should carefully consider the technical condition of the tool and respond in a timely manner to changes in its operation.

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

Checking the electrical part

The electrical part of the angle grinder consists of:

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

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

The task of the wizard is to consistently check all these systems and find out the causes of malfunctions. To do this, you need a multimeter or tester.

Power circuit check

First of all, you need to check the integrity of the power cord. Many troubles can occur only due to the fact that the cable is damaged and the power to the device is uneven. The cord must be completely intact, with no signs of damage. During operation, it should not be heated or sparked in places of bends and connections to a power outlet or angle grinder. If at least one of these conditions is not met, the cord should be repaired or replaced.

Using a tester included in the voltmeter mode, check the input voltage in the angle grinder, it must correspond to the rating indicators: 220 V. In the ammeter mode, the current consumption is measured. it should not exceed a value of 6 A.

Checking the starter and control unit

Next, test the start button and the electronic control unit. Perhaps the contact group of the inclusion of the device in the work was oxidized or clogged. If the device is equipped with a soft start system, the disk should accelerate to working revolutions gradually, without a sharp set of speed. Using a multimeter, you need to make sure that the voltage when the button is turned on is transmitted to the electrical circuit.

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

Rotor diagnostics. how to “ring” an anchor with a tester?

To make sure the rotor is in good working order, it is necessary to “ring” it with a tester.

By setting the multimeter toggle switch to 200 Ohm, successively measure the resistance of the windings on two adjacent armature slats. If the resistance is the same everywhere, then the anchor is intact and operational. If the tester shows a value different from the rest on any of the pairs of lamellas, an interturn closure occurred at this point. Anchor is subject to repair or replacement.

The inter-turn circuit, as a rule, occurs when the instrument overheats during operation. The insulation of the windings is melted and this leads to the fact that the neighboring turns, consisting of copper wire, come into contact. As a result, the balance of the electromotive force is disturbed and this leads to a power failure at a certain position of the armature.

Diagnostics of the motor stator

If the armature turned out to be serviceable, the testing procedure should be carried out with the stator, by measuring the resistance of the windings in a similar way. The inter-turn short circuit in the stator is characterized by surges in the increase in speed of the angle grinder when turned on. The engine, for no reason, begins to "rush" to rotate at high speed.

The insulation defect in the stator windings is repaired by repair or replacement. Repair, as a rule, consists in rewinding a copper wire.

A specially made pattern is used to rewind the stator coils. As a rule, it is made of 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 to it.

Rewinding is done at home in the presence of the necessary tools and devices. It is important to choose a copper conductor with a cross section that exactly matches the original one. The number of turns of the winding can also not be changed.

Video: how to rewind the power tool stator

Checking the mechanical part of the machine

The mechanical part of angle grinder consists of:

• gearbox;
• spindle lock button;
• flange fastening of the working tool;
• bearings of a rotating rotor shaft.

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

Reducer gear inspection

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

Check Lock Button

The lock button for fixing the spindle is a spring-loaded steel rod that prevents the working shaft from rotating. The button is used when changing cutting blades. Damage to the locking rod usually occurs when the disk is jammed or the motor is turned on with the button pressed.

Inspection of flange for attaching nozzles

The disk is mounted with an angle grinder (or other working nozzle) using a flange threaded clamp. They fail extremely rarely, as they are simple to set up and operate. During inspection, you should pay attention to the condition of the thread on the shaft, if necessary, it can be greased with solid oil, graphite grease or Lithol.

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

1. A metal plate with a thickness of up to 2 mm is fixed in a vice.
2. The remnants of the disc break and bite with pliers.
3. The angle grinder motor turns on.
4. With the help of a fixed plate from under the nut, the remains of the disk are “chipped”.
5. When the space under the flange is freed, it will easily loosen.

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

Checking the rotor shaft bearings

Checking the operation of the bearings on the rotor shaft consists in their visual inspection. A serviceable bearing should have a solid color (without the blue that occurs in the case of overheating of the part, and smudges of grease), when scrolling, it should rotate easily, without sound. If this is not the case, the bearing is being repaired or changed.

General rules for repairing a power tool

If the causes of the malfunction were determined during the diagnosis of angle grinders, it is necessary to start repair in compliance with certain rules.

• the device must be turned off from the power supply;
• repairs should be made on a well-lit, non-cluttered table or workbench;
• observe the procedure for disassembling and, accordingly, reassembling the device.

If it is difficult to remember the location of the 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 malfunctions angle grinder and their elimination

Below are the most common problems and their solutions.

Collector brushes burn (spark)

Sparking in the manifold is most often observed when it is time to replace the carbon brushes. This usually occurs after several years of operation of angle grinders.

Standard brushes are designed for 7000 hours of operation, after which they are erased.

A simplified brush replacement system is provided on angle grinders, so repairs are quite easy and quick:

1. Unscrew the two plastic covers on both sides of the casing with a flat screwdriver.
2. Remove the old brushes from the nests.
3. Wipe the collector with an alcohol swab, as the lamellas are left with soot from the work of the old brushes. You can also use tweezers with cotton wool or rags soaked in cologne.
4. Install new brushes in the sockets.
5. Screw in plastic covers.
6. Check angle grinder in operation.

Video: replacing the brushes the angle grinder will help eliminate sparking

angle grinder does not 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 place of circuit interruption is found, the flow of electric current in the instrument should be restored. The most common cause of breakage is the dusting or oxidation of the terminals or contacts of the start button.

Spindle lock button failure

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

Video: spindle lock repair at home

Engine stopped working

If voltage is supplied to the motor but it does not rotate, check the condition of the brushes and bearings. Brushes can get stuck, bearings can jam.

1. If the brushes are sunken, they must be thoroughly cleaned, and then blow the nests in which they are located. In addition, check the rubber bands on the covers that cover the brush sockets. After all, the isolation of brushes and the collector from dust depends on them.
2. If the cause of the engine stop in the bearings, they must be removed from the rotor shaft, repaired or replaced. Sometimes flushing and lubrication are enough for the old bearing to continue its work.

Angle grinder works in fits and starts, does not develop full power

The angle grinder operates jerkily if an interturn circuit is formed in the rotor coils. The most common reason is abnormal operation of the tool, as a result of which the motor overheats. Rewinding the coils of the anchor is a rather complicated and painstaking task, without certain skills doomed to failure. Therefore, when the anchor fails, it is recommended to replace the entire part, together with the bearings. The nominal value of the spare part must exactly match the nominal value of the original.

the angle grinder gets very hot

Most often, the angle grinder body is very hot due to improper operation of the device. Since the angle grinder is equipped with an asynchronous type electric motor, an increase in the working load 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 interruptions for an unlimited time. But this cannot be done. The passport of each tool indicates the optimal operating time of the angle grinder under load, usually it is 5-7 minutes. After this, it is recommended to take a break of 1 minute or let the angle grinder idle.

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

angle grinder is not gaining momentum

If the tool is equipped with an electronic control unit for shaft rotation speed, a malfunction in its operation can lead to the fact that under load the speed of the shaft “floats”. Most likely, there was a circuit on the board, the control unit should be replaced.

Gearbox failure

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

If a crunch or a rattle is heard from the gearbox when the motor is switched on, the angle grinder must be switched off immediately. You cannot work with such a gearbox, this will lead to total cutting of the remaining gear teeth. After the engine is completely stopped, the gearbox cover must be removed to establish an accurate “diagnosis”.

If the cause of extraneous sounds is a chipped tooth, damaged gears must be replaced. In this case, the cavity of their rotation should be thoroughly cleaned of grease and metal fragments that were formed from the previous mechanism. After replacing parts, the grease inside the gearbox must be completely renewed.

Video: how to repair and adjust the gearbox

If the angle grinder smokes during operation

Carried away by the processing of stone or grinding metal, it is easy not to notice how the tool overheated. If the work is not stopped, very soon, pungent smelly smoke will come out from under the casing. This is the winding of the armature, in which, unable to withstand the heat load, the insulation layer melts. If you do not interrupt the work, the angle grinder may burn out.

If you feel an unpleasant odor, immediately turn off the angle grinder and unplug the power cable from the outlet.

The disassembly of the tool can only be started after the body has completely cooled and the allocation of caustic fumes has ceased.

Excessive sparking on the manifold

A fan of sparks flying out from under the brushes of the collector indicates, as a rule, a violation of the insulation at the armature or a short between the wires in the windings. In this case, stop working and turn off the angle grinder from the network. Next, you need to disassemble the case and examine in detail the anchor of an angle grinder. The easiest repair option is a complete replacement of the anchor.

Bearings are broken

If something is wrong with the bearings, the angle grinder vibrates a lot and makes noise under load, the low-frequency hum dominates in the sound. This is due to the fact that a damaged bearing starts to buzz during operation. Vibration occurs from the appearance of additional backlash on the sleeves of the mounting of the rotating shaft. This malfunction is eliminated by replacing the bearings. To do this, do the following:

1. Remove brushes from brush holders.
2. Remove the plastic housing by unscrewing the fixing screws.
3. Remove gearbox cover and disengage pinion gear.
4. Pull out the armature shaft with cooling impeller and bearings.
5. Using a puller, separate the bearings from the shaft axis.
6. Assemble the structure in reverse order.

Video: how to exchange a bearing for an angle grinder

If the angle grinder is humming but not spinning

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

1. Jammed gear.
2. The bearings are jammed.

To check the versions, turn off the angle grinder and try to turn the tool disc manually. If the spindle does not rotate or rotates tightly, the reason is not in the electrical part, it is necessary to disassemble the gearbox and look for the reason there.

If soft start does not work

If soft start does not work, the reason lies in the malfunction of the electronic control unit. The solution is to replace the entire unit. Disassemble the unit and look for the cause of the problem can only a specialist who has the appropriate knowledge and diagnostic tools.

Preventative maintenance of the angle grinder

Unexpected breakdowns can be avoided by regularly conducting not only visual inspection but also tool maintenance. The manufacturer usually indicates the rules of prevention in the passport. In order for the angle grinder to serve for a long time and without "surprises", it follows:

• timely maintenance of the tool;
• comply with operating and storage standards;
• avoid prolonged operation of the tool under load at reduced speed;
• avoid pinching the working part of the tool;
• monitor mechanisms and change worn parts in a timely manner.

If the angle grinder worked at reduced engine speeds, it must be kept at idle for about a minute before turning it off. This will enable the motor to recover, adjust the temperature of the windings.

Preventive disassembly, cleaning and lubrication of mechanical parts will increase the tool life by several times. Such simple maintenance will avoid expensive repairs.

The optimal conditions for storing the angle grinder are dry rooms, protected from sudden changes in air temperature. For long-term preservation of the tool, it is preferable to pack it in a plastic bag in a cardboard box.

All repair work carried out with a power tool must strictly comply with safety standards. In no case can you disassemble the case when the device is connected to the network. Do not place containers with combustible or flammable materials near the disassembly site.

Typical malfunctions of grinders and diagnostic and repair methods

angle grinder suddenly stopped working.
The first thing to do. physically disconnect from the network and manually rotate the disk. If the disc does not spin or spin very tight. immediately disassemble the tool for visual inspection. If it turns easily, then the most probable. electricity does not reach the motor brushes. That is, the problem is either in the power plug, or in the wire itself, or in the button mechanism "Start". It is enough to disassemble the housing and "ring" cable with a conventional tester, or in any other way, for a break. After eliminating the break or replacing the wire, the angle grinder will work.

How to fix a Bosch angle grinder. Power dropped. High sparks. Tool repair. GWS eight hundred fifty ce

: Group: Life channel :.

and the power wire is in good condition, the angle grinder does not work.
Check brushes and brush holders. There may be a break or complete wear of the brushes. The resource of these devices is usually limited to several years, of course, it all depends on the intensity of use. Repair open or replace brushes.

Further more serious malfunctions follow, respectively, and repair requires certain knowledge and skills.

When determining mechanical defects, an angle grinder should pay more attention to the condition of the plate (large gear), shank (gear on the shaft) and bushings. Uneven wear of the teeth or the shafts of the shafts indicates the immediate replacement of worn parts.

Breaking out the spindle lock button.
The reason is just one careless movement, namely, pressing (intentionally or accidentally) the button when. Sometimes breakdowns occur due to attempts to remove a jammed disk using the button. Many grinders on the spindle, where the disk is mounted, have slots specifically for the usual open-end wrench, look at your angle grinder, most likely you have one. So, it’s better to use them and the open-end wrench, than the disk lock button.

Failure of the electric motor.
Often this happens with tools that work in dust and which are forced to rest in the sand or on the ground: sucked dust grinds the winding. However, you can kill the motor without dust. strong overloads, especially if the tool is low-power. Therefore, small grinders often burn out not only the anchor, but also the stator. In small grinders, there is also a breakdown of the electronic unit. If you use an angle grinder to cut highly dusty materials, in particular slate, a well-worn stocking helps to protect the tool in place of the ventilation slots in the case.

Bearings.
Another sore spot for grinders (as well as other twisting power tools). Strong immunities against dust stand out few cars, and a high speed suggests rapid wear. In general, bearings are not the worst damage, they change easily. However, it is important to replace on time, otherwise there is a greater likelihood of a more serious breakdown, the repair of which is comparable to the purchase

Stator
If, when turned on, the disk starts to gain momentum and accelerates too much, there is definitely a coil closure on the stator winding. Stator repair is one of the most serious failures and requires appropriate skills. If you are not confident in your abilities, then it is more advisable to entrust it to professionals or use the services of a repair shop.

We begin the stator repair with the angle grinder by cutting the frontal parts of the winding, the remains of which are removed. Next, we make a new winding using a template sandwiched between two large plates on the axis, which can be inserted into an electric drill. The main thing is to achieve an identical number of turns made with the proper density and withstand the thickness of the wire. We insert two coils into the stator housing, we make the conclusions from the same winding wire, isolating them with flexible tubes of the corresponding diameter.

Gearbox
In models with power up to one thousand one hundred watts, spur gears are usually used, mounted on an anchor, but an angle grinder with more power, for example, one thousand five hundred watts, requires helical gear wheels. Both versions have a conical shape, since the axis of the gearbox rod intersects with the armature shaft, and transmission is possible only by angular engagement of the teeth.
As a rule, an angle grinder consists only in the replacement of gears. If the disk gear is broken, then it will be very difficult to remove it for replacement; in the gearbox this assembly is best fixed.

Speed ​​control
Almost all modern models of drills, jigsaws, screwdrivers have a speed control. But not all angular grinders (grinders) are equipped with such a mechanism. For a cut-off stone, the regulator is in principle not needed, but for grinding it is simply not replaceable. The proposed circuit of a homemade controller is very simple and reliable. There are not many details and they are not expensive. If you already have an angle grinder without a standard one, then you can easily improve it.

You can assemble it separately in a box with a socket and use it as a carrying case with a power regulator. And you can immediately assemble the regulator in the case of an angle grinder and pull out the handle of the resistor.

Terms of use angle grinder and preventative maintenance

The power tool must not be allowed to last for a long time under load at significantly reduced speed (this can be determined by ear) compared to the speed, and moreover, the tool cannot be clamped (blocked), otherwise it will burn out within a few seconds.

After operating at reduced speeds, do not immediately turn off the power tool. To prevent local overheating, it is necessary that it works for a while (more than one minute).

It is important to strictly observe the terms specified in the operating instructions for the replacement (addition) of grease and its quantity.

Prevention consists in completely or partially disassembling the tool, cleaning, lubricating and replacing (if necessary) some parts.
Timely replacement of relatively cheap parts that wear out quickly will allow you to save more expensive components of long-term use, which in the end will lead to savings in the operation of the tool, eliminate premature repair and extend the tool much longer.