The brushes on the angle grinder are burning, what is the reason

Replacement methods

After it has been established why the brushes on the angle grinder are burning and the cause of this malfunction has been eliminated, you can start replacing them. There are two options for the process itself:

  • The easiest way to carry out this event is on those models of household electrical tools where there is free access to the brush compartment without disassembling the case. In this case, this can be done quickly: just open the lid, remove the worn part and insert a new one of the appropriate type.
  • However, this method is not always available. In other cases, you will have to disassemble the device. The first step is to remove the cutting disc from the angle grinder and disconnect it from the power supply. Then disassemble the tool according to the instructions. Usually it is enough to carefully remove a few screws and split the case in half. Then you need to disconnect the copper contact of the old part and remove it from the seat. When installing a new spare part, you need to firmly connect the leash in place and check the reliable pressing of the brush to the collector by the spring mechanism. Be especially careful to match the type of component to be replaced with that used in this angle grinder. If the discrepancy is only in size, the problem is solved with a needle file, fine file or sandpaper.

Angle grinder device

To understand the operation of the mechanism and why breakdowns are possible, you need to have an idea, at least schematically, about the main components of the tool.

Regardless of the model, manufacturer and technical characteristics, any angle grinder has the following parts:

  • The moving part of the electric motor, it is called the armature, or, which will be technically correct, the rotor. As a rule, this element is combined with a working shaft that transmits torque.
  • Collector contacts, which is a commutation board, through which voltage is removed from the current collectors.
  • Brushes pressing against it provide electrical contact. When pressed lightly, they begin to spark strongly.
  • Internal stationary winding. stator. The rotation of the armature in it is achieved due to electromagnetic induction.
  • Mechanical reduction gear for speed regulation.
  • Other components: housing, usually plastic, handles, start button, power cable.

Damage angle grinder sparking armature and damage gear

As a working tool, the angle grinder is subject to high loads and extended operating times. In spite of the maximum tightness, dust, small fragments of processed materials, and scale periodically get inside the case. This negatively affects both the mechanical parts and the electrical part.

As a result, the conductive parts are contaminated and the collector lamellae gradually burn out due to its overheating. In turn, this leads to the destruction of the collector brushes, which will be signaled by increased sparking.

Angle grinder sparking armature repair | sparking commutator damaged power tools

Why brushes quickly burn out?

What are the reasons for the rapid combustion of brushes on the tool?

Repair an angle grinder that stops working randomly. replace the carbon brushes

Body, handles for holding, start key. power cable.

A detailed description of what the angle grinder consists of

How to choose the right angle grinder brushes?

In addition to the geometric shape and dimensions, the brushes differ in the material from which they are made. Previously, this element was made in the form of copper wire with a conductive brush at the end. Hence the name. Of course, the resource of such products was low, and they needed frequent replacement.

Modern brushes are made of carbon materials by high-temperature pressing. The resource of the engine is determined precisely by the durability of these replaceable elements; with the low quality of the current collector, the armature collector plates are quickly destroyed.

There are the following types of brushes:

Produced from graphite bonded with special substances. Sometimes soot is added to the mixture. After forming under pressure, the product is fired to give strength.

They are made from the same composition as conventional graphite ones, but at the end of the process they are subjected to high-temperature treatment in electric furnaces. At a temperature of 2500 degrees, a progressive carbon saturation occurs, giving the product additional strength and durability. The manufacturing cost is higher, but the performance makes up for this disadvantage. The most common option for use in motors is an angle grinder.

The production material is practically the same, but the production technology is different. No heat treatment is performed after high pressure pressing. Reliability is lower, therefore such products are used in less critical electrical appliances. Benefits. low cost.

They are used in critical devices, for example, low-voltage generators. Produced on the basis of various metals: copper, tin, lead, babbitt. The same graphite is added to the mixture, but in smaller proportions. After forming. heat treatment or firing at a temperature of 250 degrees. They are characterized by high strength, resistance to aggressive liquids and gases. The disadvantage is the high cost, therefore, they are practically not used in household electrical appliances.

The choice of a brush for an angle grinder is determined by the manufacturer. Information can be found in the technical data sheet of the tool, or ask the service center.

IMPORTANT! Service your angle grinder in a timely manner and it will serve you faithfully.

Hello, Alexander. This often happens when the instrument is new. I had the same doubts about mine. But after that she worked for 5 years, until I myself started to change the brushes, at that time I was completely unable to do this. In your case, I suppose it’s the same. The only thing that is alarming is the “non-native” brushes. Did the seller tell you about the replacement himself, or did you just assume? In any case, your instrument is still under warranty.

Hello! The rotor is burnt out (when measuring the resistance of the windings in one place, it differs), it is also visually visible. How to choose a replacement for an angle grinder Klauss K-4001 500w ?

The brushes on the angle grinder wore off very quickly

bfg9k wrote. The cover, the handle. everything is removed. the angle grinder got stuck in the lining and flew out of my hands. Although I sawed with outstretched arms above my head, I did not touch.

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bfg9k wrote. got stuck there and tried to work until I turned off the power (5 seconds passed). the angle grinder is very hot, I waited for it to cool down.

Due to overload, short-circuited turns appeared on the rotor.

bfg9k wrote. Turned on the angle grinder for 10 seconds, does not work again. I disassemble, and the brushes are almost completely worn out! In 10 seconds! New.

From it still unearthly light should come from the ventilation slots in the area of ​​the brush assembly. called. all-round fire.

angle grinder fire on brushes, power loss?

The fact that sparks can also be due to the stator. for sure, he himself was “pricked9amp;” during the repair, changing the armature in vain. I had to rewind the stator (from time to time I do a little repairing of the power tool).

You can measure the inductance, there are still devices for determining the short circuit of the turns. In a highly clinical case. visually and / or by resistance. According to the burnout of the lamellas of the anchor collector. if the burnout is uneven, then most likely there is a problem with the anchor, if it is uniform, it is probably a stator. The anchor for interwinding / breakage can be checked with an ohmmeter: the resistance between adjacent lamellas is measured sequentially, and between diametrically opposite ones. in both cases there should be no sharp differences, no more

5% (due to slightly different wire lengths in different grooves). For an angle grinder with a power of about 600-700 W, the resistance of the stator windings is approximately within 4-6 Ohm (the same for both), the armature. between adjacent lamellas about 1-1.5 Ohm, diametrical. I don’t remember 🙁

Thank you so much! I will look for kz. but everything points, judging by the uneven burning of the lamellas, to the short circuit in the rotor.

The brushes on the angle grinder are burning cause

Why BRUSHES on an angle grinder are SPIRIT and BURN so quickly, let’s analyze the reasons and methods of elimination. Strong sparking is often a sign of imminent tool breakage. It is necessary to understand in a timely manner the reasons for the appearance of an increased spark of education and take measures to eliminate it.

Causes of sparking of brushes of the electric motor Wear of brushes. With severe wear of these elements, the electric motor does not develop at full speed, and it may also not turn on (constantly or periodically). In this case, with the electrical device turned on, you can press the brush against the armature with a screwdriver with an insulated handle. If an increase in engine speed is observed, then the problem is identified correctly. Most likely, replacing worn-out parts with new ones will correct the situation. Sometimes it is also necessary to replace the springs of the brush holders. Turn-to-turn closure of the armature winding. A malfunction of devices with electric motors may be an armature breakage. In this case, sparking will be observed in the area of ​​both brushes, in addition, the armature winding will be very hot due to the fact that some contacts receive a current of greater magnitude than others.

DIY from an angle grinder.

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The “Bulgarian9” itself has nothing to do with it. This phenomenon applies to all motors of the collector type. Motors of the so-called series type are installed on a hand-held electric tool. This is when the stator winding is not included in the circuit in series. This is because initially the myth of the type of electric motors was created However, the use of a sequential circuit allows it to be included in the AC circuit. The speed of such a motor is not limited by the frequency of the current, as it is in brushless electric machines. Because of the increased speed, a number of requirements are imposed on the collector unit, which are aimed at reducing sparking under the brushes, not a decrease, thereby, the heating of the engine. And so, the spark is increased if:

Something like that. Choose from this list that doesn’t just suit your situation.

Why on angle grinder brushes burn out quickly (put new ones burned out in three minutes)?

Let me argue a bit with the previous answers. All, under no circumstances should you put copper-graphite brushes. They are denser and do not cause mechanical damage to the anchor. Which then leads to a possible closure of its winding, and this turns the contact surface into something like emery, this again gives quick wear for simple graphite brushes.

Copper-graphite brushes are mounted only when the contact surface of the armature has a special coating; otherwise it is made of a special alloy.

There is another variant of the reason for the rapid wear of the brushes. the beating of the armature. Edelweiss is about the wear of the bearings of the electric motor bushings, depending on what is installed. However, this is a rarer case.

And as another possibility, it is worth mentioning the not possible presence of micro-breakdown in the winding. In the electric motor, heating occurs just at the time of this heating, micro-breakdown does not appear, something like that happens. only very weak, no brushes start to burn out quickly.

brushes, angle, grinder, burning

The best option would be to take your angle grinder to a workshop. They would check it there. if desired, they would polish the contact surface, ring the winding, replace the bearings with a different sleeve. If this is not with your hands, then you can at least try to grind the anchor yourself. Disassemble the engine, clamp the armature in the drill at maximum speed and grind it. Only you need to use the smallest grain size. micron. It is not here practically not to make any effort to it, but only to touch it slightly. And then it is not the second stage to carry out. initially rubbing the emery cloth against each other, thereby erasing the surface layer and such a situation will already be like polishing. And the final stage is the option to polish with a piece of cloth, as it is also called felt, moistened with machine oil. Do not forget that the removed layer must be minimal. a micron or two, starting from the existing damage.

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Here you need to decide exactly. your brushes burned out, as it is also called, worn out?

If they burned out, then this I have not yet seen, when the motor is shorting, then the brushes themselves do not burn, since they are made of such a material that, by and large, has no right to burn, unless it is subjected to a large current, alas, then it will be a bunch of sparks not short circuit at the bottom. What, as I understand it, did not happen with you.

Therefore, I will assume that there has been a rapid deterioration. Then, of course, talk not about the wear of the brushes, but the wear of the motor manifold. With this I have met many times. When, due to wear on the collector, the brushes did not first wear out.

Here’s what happens. the collector itself is divided into parts, here’s a look at

To determine the wear of the collector, you have to get to it without checking the coating.

So I will answer myself, since I figured out what the reason is, it turns out I added problems to myself! Like an office, when the brushes on the angle grinder were worn out, the machine did not start to work in jerks, it was necessary to stop immediately. alas, for the reason that there was nothing to finish, I still cut her further. The worn-out brushes hung on the limiters did not create a huge arc in a circle, alas, the machine continued to turn the disk, I did not saw it, the arc burned out like an electric welding groove on the armature collector, not when I installed new brushes, they did not have a plane of pressing against the armature collector did not burn out just very quickly idle work. Having disassembled the angle grinder, I saw a gloomy situation, the attempt to grind the anchor collector at the turner did not end with luck, I had to buy a new anchor, since it was impossible to replace only the collector, besides, honestly, no one even wanted to take on it. The result of the doped 40X40 profile turned into the purchase of a new anchor, that’s not the whole reason for this action.

What spare parts for grinders change independently, and how to properly maintain a power tool

an angle grinder at home is like a telephone connection. When the oil is good, no one remembers it. Should a breakdown happen, it immediately becomes obvious that not a day can be done without. Self-repair of this useful electrical appliance is possible even for a novice master.

First of all, consider the device of an angle grinder.

Internal movable engine component. Usually it is integrated with the working shaft, through which the rotational energy is transmitted to the gearbox.

Armature breakout board. Through its contacts, operating voltage is supplied from the brushes.

Contact elements pressed against the collector plates.

The outer winding of the motor, inside which the armature is required to rotate. Located along the inner contour of the tool body.

A mechanical component that reduces the speed on the working shaft while simultaneously increasing.

Self-Troubleshooting Angle Grinder

As a rule, breakdowns in an angle grinder are associated with the electrical part. Mechanics breaks down only when untimely maintenance (especially lack of lubrication).

IMPORTANT! If your power tool is unstable, noisy, and there is a smell of burnt wiring, stop work immediately and find the cause.

A malfunction is cheaper and easier to prevent when the first signs appear:

  • sparking inside the body of an angle grinder, in the area of ​​electric brushes;
  • indistinct operation of the start key;
  • revolutions spontaneously change;
  • the engine turns on. turns off when the position of the tool in space changes;
  • angle grinder suddenly stopped working.

No matter how trite it may sound, you first need to check the voltage in the network and in the outlet, or the extension cord from which the power tool is powered. Then check the serviceability of the power cable.

IMPORTANT! Do not check the power cable by turning on the tool and bending the wire, looking for the breakage point. Disconnect the angle grinder from the mains before starting repairs.

It is necessary to open the housing of the angle grinder, and check the integrity of the supply wire visually and using a tester. Having securely connected the contacts of the device, bend the cable vigorously, observing the indicator readings on the tester. If a break is found, replace the whole wire, or repair the break with refractory solder. Then, insulate the repair site securely with heat shrink tubing. Electrical tape will not work for this case.

If the cable is working properly, go to a typical malfunction. Most often, brushes burn on an angle grinder. Symptoms are easy to see. the angle grinder sparks inside the case during operation.

Causes of wear of collector elements

The angle grinder, like most power tools, was originally designed to operate on a DC power source. Then, by turning on the rotor and stator windings in series, it became possible to be powered from alternating current without limiting the number of revolutions, as is the case with brushless motors. Therefore, increased requirements are imposed on the unit with the pantograph. And if the brushes on the angle grinder are on, the reason may be:

  • Fault in the rotor winding: turn circuit, breakage of the coils. This is characterized by reduced revs and loud buzzing.
  • An equivalent reason is poor contact between the lamellas and the winding.
  • The springs of the brush holder mechanism are weakened.
  • Armature runout due to bearing failure.
  • Reservoir production.
  • The paths between the lamellas are clogged with graphite dust, or they are short-circuited. They can be cleaned with a saw blade for metal.
  • Deformation of the rotor shaft.
  • As a result of rewinding the armature, the current-carrying coils are reversed.
  • Brushes of the wrong brand are selected.
  • Normal wear and tear of the current collector.

Not all of these causes the brushes to wear off quickly, but none of them can be ruled out.

How to replace brushes on an angle grinder?

As a rule, the brushes together with the spring block are located inside the tool handle. This design allows you to save on the production of the case, and make it more compact, and, therefore, convenient.

The brush holder is located in the tool handle

There are examples in which the fastening screws of the brushes are taken out to the outside of the body. On the one hand, this allows them to be inspected and replaced faster. However, it is better to change the brushes in conjunction with cleaning and lubricating the power tool, so the case will still have to be disassembled. It is also advisable to remove the rotor from the stator and measure the resistance of the windings. It must be the same.

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We measure the resistance of the windings in the rotor

Then you should clean it from dust, lubricate the bearing and, if necessary, grind the collector’s contact plates with sandpaper. zero. After this procedure, the grooves between the contacts must be cleaned from copper dust with a stiff brush. A good collector should look like this:

Graphite brushes must be selected individually. Parts may not fit other tool

In this video, the wizard shows the sequence of replacing brushes.

What to do if the drill sparks after purchase

In 80% of cases, the drill starts to spark after purchase. The reasons for this phenomenon can be different. Most often this happens due to the fact that the brushes have not yet “got used” to the collector. To eliminate sparking, you need to drive it a little at idle for 30-50 seconds.

If the sparks from the new drill continues to spark further, the reason is most likely due to the following:

  • poor assembly at the factory;
  • poorly balanced anchor;
  • uneven stator.

Have you had similar situations? What did they do?

Choice of electric brushes

This element is a hexagonal geometric shape with the same parallel faces. To ensure electrical contact, a copper leash is pressed into it.

The sizes and shapes of the brushes are different, as well as the material for their manufacture. The original arrangement was simple: copper wire and a conductive brush. But due to the great wear and tear, this design had to be modernized.

Modern collector elements are produced by compressing carbonaceous materials with increasing temperature and pressure.

If, when working with an angle grinder, as, indeed, with a drill, the tool functions in jerks, with a characteristic burning smell, then the root cause lies in the wear of this small part.

It is not recommended to neglect their replacement, as this will inevitably lead to the failure of the device.

In this case, work must be stopped, the reason why the brushes on the electric motor are burning, and the repair must be started.

Why do brushes sparkle in an electric motor?

Sparks, including on a serviceable engine, appear due to mechanical action between the brushes and the collector.

The brush, moving along the collector from one of its contacts to another, alternately forms and breaks a connection with each of them.

Now remember what happens if you pull out any working electrical appliance from the socket. usually at such a moment a spark jumps between the plug and the socket. In the case of a brushed motor, this is the same phenomenon.

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Therefore, a slight sparking even on a working electric motor is permissible, since a connection and a gap constantly occur here.

Malfunction in the stator winding

A defect similar to the short circuit of the rotor winding occurs for the stator winding. You can check the presence by measuring the resistance of parts of its windings. If there is a strong difference, it is necessary to rewind the winding or replace.

An increased spark indicates the presence of abnormalities in the work. It is required to carry out activities to identify and eliminate deficiencies. Failure to take action will shorten the life of the engine, and possibly the entire power tool where it is operated. The best option is to use the services of a service center for the repair of household appliances.

Wear of brushes

With prolonged use or poor-quality material of the brushes, they cease to tightly press against the contacts of the collector. Due to poor contact, the engine does not pick up speed or does not start immediately. A worn out brush is easy to identify visually.

Sometimes it is not possible to correct the situation by replacing only the worn out part. Replace the brush holder and spring.

Causes of severe sparking and how to eliminate them

Now let’s move on to strong arcing. It occurs mainly for the following reasons:

  • contamination of collector contacts with carbon deposits
  • ingress of graphite dust between the collector contacts
  • turn-to-turn circuit in the armature winding

1) Carbon deposits are caused by overheating of the engine. The presence of carbon deposits leads to even more friction, which leads to even more rapid overheating and even more carbon formation. Which leads to breakdown very quickly.

Excessive sparking is obtained here due to the fact that carbon deposits form additional resistance, in which the spark, when broken, turns out to be larger and more powerful.

In general, carbon deposits should be removed immediately.

This is done with zero sandpaper. That is, it is necessary to remove the collector together with the anchor and carefully clean it. Ideally, it is desirable to carry out cleaning on a lathe so as not to disturb the correctness of the circle. But, as a rule, this is not possible, so manual stripping can be dispensed with. The main thing is not to overdo it.

2) During the operation of the drill, the brushes are erased, due to which graphite dust is formed. It can easily accumulate between the contacts of the collector and lead to short circuits between them, since it is a conductor of electricity and has its own resistance. Because of this, the current is distributed unevenly, which leads to the appearance of large sparks in some places.

brushes, angle, grinder, burning

In a working drill, erasure occurs rather slowly, so the graphite dust hardly accumulates. Accordingly, its accumulation signals that the brushes are in the wrong position during operation. This usually happens when they are not close to each other in their groove, but, on the contrary, have some backlash.

This often happens when replacing brushes, when they are not selected quite suitable in size. Therefore, when replacing this point, you should pay close attention.

Repair of such a malfunction is carried out by removing dust with a sharpened tool and replacing brushes with a more suitable size.

3) In the event of a turn-to-turn short circuit in the armature, the current flows in a larger value to some contacts and in a smaller value to others. Because of this, in some places, more current flows than necessary, as a result of which large sparks are formed.

It is necessary to deal with the identification of such a closure when the two previous points did not give much effect. It is produced on a special device that creates an alternating magnetic field. When an anchor is placed in this field, it begins to rattle, since induced currents appear in it.