The brushes sparkle strongly on the angle grinder

Varieties of devices for taking current

Underestimating the importance of this part in good condition has serious consequences. Timely measures to prevent them will extend the life of the tool.

First you need to understand the types of pantographs:

  • The manufacture of graphite brushes for an angle grinder is carried out by mixing a base substance with a binder. As a result of pressing carbonaceous materials under pressure and further firing, a product with additional strength and wear resistance is obtained. Then the graphitization process begins, which consists in heating to a temperature of 2500-2600 degrees in special furnaces. This is the most common type of such products, although it is quite expensive, but the service life partly compensates for it.
  • For the production of carbon brushes for an angle grinder, the same graphite or carbon black is used, only additional hardening is excluded from the cycle. This significantly reduces both the cost of the product and its durability.
  • The raw material for the manufacture of metal-graphite brushes, as the name suggests, includes metal in addition to the main element. This is usually copper powder, but the addition of tin, lead or silver is not excluded. the metal component can be up to 80 percent. Applications for such parts are found primarily in industrial generators and electric motors. For household needs, these products are too expensive.

Before purchasing a replacement set of brushes, you need to find out their type and dimensions in the technical data sheet of the tool.

Why brushes burn out quickly on an angle grinder

I found the reason: why brushes burn out quickly on an angle grinder. And in this video I eliminate the cause.

Body, handles for holding, start button, speed controller, power cable.

A detailed description of what the angle grinder consists of

Self-Troubleshooting Angle Grinder

You, the breakdowns in the angle grinder are connected to the electrical part. Mechanics breaks down only when untimely maintenance (especially lack of lubrication).

IMPORTANT! If your power tool is unstable, noisy, or there is no smell of burnt wiring. stop work immediately do not find the reason.

It is not easier to prevent a malfunction at a cheaper price when the first signs appear:

  • sparking inside the case 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.

As trivial as it may sound, first you need to check the voltage in the network not in the outlet, as it is also called 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 without bending the wire, look for the breakage point. Disconnect the angle grinder from the mains before repairing.

It is necessary to open the housing of the angle grinder, do not check the integrity of the supply wire visually without 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, as it is also called, restore 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. often brushes burn on the angle grinder. It is quite easy to see the symptoms. the angle grinder sparks inside the case at work.

Why brushes quickly burn out?

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

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

A detailed description of what the angle grinder consists of

How to replace brushes with 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 removed from the body. On the one hand, this allows them to be inspected and replaced faster. However, it is better to change brushes in conjunction with cleaning and lubricating the power tool, so that 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.

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:

Collector after thorough cleaning

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

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

Read more:  Which Side Cut Tile Angle Grinder

How to replace brushes with an angle grinder?

You, the brushes, together with the spring block, are inside the tool handle. This design saves on the production of the case, does not 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 of the body. This allows them to be inspected and not replaced faster. However, it is better to change the brushes in a complex with cleaning not by lubricating the power tool, so the case will have to be further disassembled.
It is also advisable to remove the rotor from the stator, not to measure the resistance of the windings. It is the same.

We measure the resistance of the windings in the rotor

Then you should clean it from dust, lubricate the bearing, not if you want to 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:

Collector after thorough cleaning

Graphite brushes must be selected individually. Parts of course do not fit with another tool

In this case, the video master shows the sequence of replacing brushes.

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 a pantograph. And if the brushes on the angle grinder are on, the reason may be the following:

  • 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 were selected.
  • Normal wear of the current collector.

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

Why are brushes burning in an angle grinder??

The attached figure clearly shows the electrical circuit and the device of the components of the electric motor.

Tool motor image

The angle grinder motor works under extreme conditions. Despite the protection, dust gets inside, most often in the form of small metal filings. Metal is known to be a conductor. When it gets into the contact area of ​​the brushes and the collector, microcircuits occur and the copper plates get very hot. Reflow and mechanical connection of the collector contacts may occur.

Type of electric motor collector to be repaired

In this case, the brushes overheat, and the working surface burns out intensively. Hence sparks and increased wear.
Another reason why brushes sparkle is fine sand and wood dust getting inside. When the collector is dirty with sawdust, the contact between the brushes and the collector is broken, and sparking occurs under intense load, with all the ensuing consequences.
Therefore, for prophylaxis, it is necessary to periodically disassemble the case of the angle grinder and clean the dust from the collector.

It is necessary to periodically blow out the motor angle grinder

This simple procedure will prolong the life of both the brushes and the armature collector. It is advisable to at least vacuum the angle grinder after every dusty work, especially in the area of ​​the ventilation holes.

What is it?

These components are made by mixing carbon black with graphite and other binding components. hardeners. This mixture is a good conductor of electric current.

Rectangular brushes are widely used. They may differ in terms of length and width, depending on the specific electrical appliance in which they are installed.

Harbor Freight Angle Grinder How To Replace Brushes

A copper wire without a winding is mounted in the “body” of each brush, to the free edge of which a plate of an individual configuration is soldered. The wire is inside a spring, which rests on one edge against the brush, and the other against this plate. The spring has a free pressing action, and the brush fits snugly against the collector as it rotates.

In the process, the brushes are erased due to constant friction. This creates the need for their planned replacement. For this, the manufacturer supplies the power tool with a spare set of brushes.

In other situations, you can observe the appearance of sparks in the area of ​​\ u200b \ u200bthe location of the brushes. This fact is accompanied by the characteristic sparking sound and the smell of burnt graphite. If the brushes sparkle on the angle grinder, this is a sign of a malfunction of its components. In this case, you need to diagnose the device.

The essence of the problem

The sparking of the brushes makes it impossible for the power tool to operate at full power. Since they are the connecting link in the electrical circuit, disruption of their operation leads to interruptions in the supply of current. This negatively affects the motor winding and reduces its service life.

Sometimes the fault can be found in the brushes themselves. They burn out quickly due to cracks, chips, scratches, overheating. Replacing the old brush set will solve the problem. If the reason for the sparking is not in the brushes, then the new ones burn in the same way.

How to troubleshoot?

Examine the collector for mechanical damage. If dust, dirt, sand gets on it at the time of work, scratches, dents, chips may form. Assess their degree, if any.

Read more:  Sparks Of Angle Grinder In The Area Of ​​Brushes Cause

For minor damage, the collector lamellas can be turned with sandpaper or on a lathe. The groove must be very accurate, as any inaccuracies will lead to a greater deterioration in the performance of the brushes.

Angle grinder brushes malfunctions and their elimination

The angle grinder is a high-speed electric tool equipped with a collector motor. In this engine, the current is supplied to the armature. the inner rotating part. Such feeding is carried out by a sliding method, and the only way to make contact between the power source and the moving part is with graphite “brushes”. They are “fuses” against overvoltage and fail first.

A sign of their obvious malfunction is strong arcing with the release of sparks through the ventilation grilles, accompanied by a characteristic sound.


There may be several reasons why angle grinder brushes spark and wear out strongly:

  • malfunction or increased wear of the brushes themselves;
  • violation of the density of contact between them and the collector plates;
  • deterioration of the clamping action of the brush spring;
  • breakdown between collector lamellas;
  • axial runout of the armature due to bearing wear;
  • short circuit in the armature winding;
  • introducing structural damage to the mechanism during repair.

The above reasons are the result of improper operation of the angle grinder or poor assembly of its components.

In order to avoid the appearance of sparks in the area of ​​\ u200b \ u200bbrushes, you should follow the rules for the safe use of an angle grinder.

  • Do not turn on in case of high humidity, pronounced voltage drops in the network, dirt in the brush block, contamination of the air duct grilles in the housing.
  • Avoid overheating of the engine, load that slows down the rotation of the mechanism at the time of operation.
  • Do not use a low-power angle grinder for cutting “heavy” materials.

Sandpaper groove

The armature shaft is fixed in the chuck of any torque mechanism (lathe, drill). Rotation starts, the abrasive is applied to the collector. Forceful pressing and the use of coarse-grained sandpaper are excluded. The minimum grit value is 1000 P.

Using a multimeter, detect the presence of a breakdown in the armature winding. Set resistance test mode. Attach one probe to the lamella and the other to the contact of the corresponding winding path. The absence of an open circuit will be indicated by an audible signal. If there is no signal, this trace is broken. You will need to replace the armature or rewind its winding.

Determine if the bearings are running out. If it is found, replace the bearings and measure with a micrometer the diameter of the edges of the armature shaft at the points of its abutment to the subassemblies.

What to do if a drill sparks: other cases

If your drill is very sparking and hot

Why brushes on an electric motor spark strongly. Why brushes sparkle in a vacuum cleaner: how to eliminate possible malfunctions

How to replace brushes yourself?

The installation process is carried out in stages:

  • The punch turned off from the socket must be unscrewed to remove the top cover.
  • Using a small screwdriver, you need to easily hook the brush holder, get it out and remove the old parts.
  • Insert new ones into the holder, press to the edges, put them in place inside the device.
  • Check that the brushes reach the contacts for smooth operation of the power tool.
  • Close the lid and fix it with screws.

Tip: if the warranty period for repairing the power tool has not yet expired, it is better to take it to a service center for service.

When performing work on their own, experts recommend:

  • When erasing one brush, both contacts must be replaced
  • During the repair, at the same time, it is necessary to clean the collector from dust and carbon deposits.
  • Contacts must be better ground to the collector using fine-grained emery paper
  • Better component placement than matching tool models

Replacing the perforator brushes is a simple process. It is easy to do at home.

Why electric motor brushes sparkle.

Devices with a collector motor can spark during operation. 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 increased sparking and take measures to eliminate it. The article discusses the most likely reasons for the appearance of this negative phenomenon.

Even on a serviceable electric motor, there is usually a slight sparking of the brushes. If the appliance turns on normally, develops speed at full power and at the same time sparks are hardly noticeable, then there is no reason for concern.

Causes of sparking of electric motor brushes

Let’s analyze the most common malfunctions of the brush-collector assembly.

1) Worn 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 correctly identified. 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.

2) Turn-to-turn closure of the armature winding. A malfunction of devices with electric motors can 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. When repairing this malfunction, rewind the armature winding or completely replace the part.

3) Failure of the stator. When the stator breaks down, usually only one of the brushes sparks. To check it, you need to measure the resistance of the windings. The same resistance of both windings (usually 4 ohms) indicates a good stator. Different resistances on the windings indicate that the stator is faulty and its winding must be rewound.

Read more:  Angle Grinder For Wood Which Is Better

Battery sparks

Cordless drills use rechargeable batteries for portability. They can create an internal spark, so if the drill sparks inside it is part of normal operation. However, they should never spark around the battery compartment. If the battery sparks when installed in a drill, or even sparks when not attached, it is probably a short. Cleaning the battery contacts may fix the problem, but in other cases arcing is not safe and the battery needs to be replaced.

Why electric motor brushes sparkle

Collector motors differ from other types of motors by the presence of a collector-brush assembly. The unit provides electrical connection of the rotor circuit with circuits located in the stationary part of the motor, and includes a collector (a set of contacts located directly on the rotor) and brushes (sliding contacts located outside the rotor and pressed against the collector).

During the operation of the commutator motor in a power tool, sometimes sparking of the brushes can be observed. In some cases, this symptom leads to an early breakdown of the power tool, and in some. does not bode well. One way or another, it is useful in each case to understand what is the cause of the sparking in order to take the right measures in a timely manner if necessary. In this article, we will look at the causes of brush sparking, as well as measures to combat the problems causing this phenomenon.

Root cause

Obviously, the intermittent mechanical contact of the brushes with the collector cannot but lead to sparking, because in fact, the rotor’s electrical circuit breaks down and closes again many times a second.

The rotor contains a winding, which is a predominantly inductive load. The rupture of such a circuit is inevitably accompanied by a transient process, which is associated with the appearance of small arcs from the self-induction of the rotor winding or the rotor and stator windings. Of course, brushes wear out over time, like collector plates, but sometimes problems arise even before wear.

In fairness, we note that for the above reason, even a serviceable collector motor cannot work without sparks at all, there is always a small spark on the collector. A fully functional device normally reaches full power, develops operating speed and still sparks a little. It’s another matter if the sparking is strong. here a justified concern arises.

Sparking brushes as a sign of wear

If the brushes are already badly worn out, simply due to the age of the engine, then the engine will not be able to reach full speed and reach full power. In this case, the sparking will be very strong, and the engine will not start the first time.

How can you verify that this is the case? If the worn brushes are pressed against the manifold with a screwdriver, the contact will become tight, and the engine will start. But as soon as the clamp is loosened, sparks will reappear. the distance between the plates and brushes will be filled with small arcs. The brushes are clearly worn out. they should be replaced with new ones. Sometimes replacement is only possible together. with brush holders and springs.

A short circuit may have occurred in the rotor winding.

The armature (rotor) winding of a collector motor traditionally contains several sections. If at least one is damaged, if there is an interturn short circuit, then more current will be supplied to one section than to the others. This will lead to overheating of the winding in one place, and to uneven sparking on the collector. on some transitions on the plates, sparks will be stronger than on others. This requires an anchor rewind or a whole new anchor.

Is the stator winding OK?

A similar malfunction is possible inside the stator, when part of the winding overheats, and strong arcing is observed near one of the brushes. Check the resistances of both halves of the stator winding, they must be the same. If one of the parts of the stator winding has a resistance much less than that of the other, then rewinding or replacement of the stator is required.

See also: How to check the condition of an electric motor winding

A dirty collector is the reason for an unnecessary short circuit on it, as a result, extra sparks appear

brushes, sparkle, strongly, angle, grinder

Dust on the collector is formed as a result of gradual wear of the brushes. this is graphite dust. It accumulates between the plates (lamellas) of the collector, and creates “unauthorized” closures. Sparks appear due to short circuits. Just clean the collector with sandpaper, remove any dirt between the lamellas.

Be sure to check how the brushes are located, whether one of them is displaced relative to the normal position, correct the brushes if necessary. When the brushes are positioned crookedly, graphite dust is generated in an inordinate amount than when the brushes are correctly positioned.

Another reason for contamination is carbon deposits on the collector due to its overheating. When all other causes of sparking have been eliminated, it is necessary to clean the contacts from carbon deposits in order to improve the contact of the brushes with them.

If the contact is good, the resistance does not increase beyond the rating, and unnecessary sparks do not arise. You can clean off carbon deposits like graphite dust. sandpaper, only rotating the rotor with the collector clamped in special pads.

Strong sparking. brush. Great Encyclopedia of Oil and Gas, article, page 2

Why are the brushes on the vacuum cleaner burning?

If this happens while the motor is running, the rotor or stator winding may burn out completely.