Sparks Angle Grinder After Brush Replacement

By her own “Angle Grinder” nothing to do with it. This phenomenon applies to all collector type engines. Engines of the so-called series type are installed on a hand-held electric tool. This is when the stator winding and the armature winding are connected in series. This is because initially this type of electric motor was designed to operate on direct current. However, the use of a serial circuit allows you to include it in an alternating current circuit. The revolutions of such an engine are 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 presented to the collector assembly, which are aimed at reducing sparking under the brushes, and thereby reducing engine heating. And so, the spark is increased if:

  1. Defective armature winding. Inter-turn circuit, break in one or more sections of the winding. A characteristic sign is a drop in speed and increased noise.
  2. Loss of contact of the winding with the collector plates. Equivalent to a winding break referred to in paragraph 1.

In general, something like this. Choose from this list that suits your situation more.

Subject: what to do if the brushes in an electric motor are strongly sparked.

During the operation of various electrical equipment having an electric motor containing a collector, it can sometimes be found that during motor operation, strong sparking occurs in the area of ​​contact between the brushes and the collector. This phenomenon indicates that the electric motor works with some deviations from the norm. This very sparking means that in the near future your electric motor will fail. Not many people know what to do with this negative effect, how to remove it, thereby prolonging the operability of their electrical equipment. In this article, we will deal with this issue, understanding the initial causes of sparking.

So, I’ll initially say that sparking itself during the operation of collector electric machines is normal, only it should be very small, barely noticeable to the eye. It’s not normal when the electric motor is running and sparks are directly pouring from its brushes and sparks fly out. That’s bad. The very phenomenon of spark formation is associated with an intermittent electrical contact occurring during the rotation of the armature, at the moment of the mechanical transition of the brush from one contact, on the collector, to another. At this time, the circuit breaks and the current flowing through the coils of the armature ends its passage precisely with a spark, a small arc discharge. Therefore, the greater the power and current strength in the circuit, the more noticeable the sparks will be. But besides this, there are other factors that contribute to the increase in sparks.

In order to fully answer the question of why the brushes in the electric motor sparks, we will analyze the main reasons. Firstly, if the collector contacts become dirty, or soot forms on them over time, the amount of spark from this will naturally increase. It is known that poor contact leads to an increase in resistance in this place. This means that breaking the contact during operation will be accompanied by a stronger electric arc. This leads to a decrease in motor power, to his great heat, to accelerate and increase the formation of even more carbon on the collector contacts, which in turn will lead to engine damage. The way out of this situation will be the following. You disassemble the device, the engine, and gently erase the contacts with sandpaper (zero), making stripping in the direction of movement of the brushes.

You should also pay attention to the state of the gaps between the contacts on the collector. It often happens that they are clogged with graphite dust, which is a conductor with a certain resistance. Naturally, if these gaps are dirty, then you also tidy them up (clean with a pointed tool). Do not forget to check the condition of the brushes, their generation, pressure force, freedom of vertical movement. If problems are found with the brushes, be sure to fix them. Please note that when replacing graphite brushes, it should be taken into account that they are different. In this case, try to find exactly the type that the old ones were.

Brushes, larger than normal, can still spark due to the formation of short-circuited turns at anchor. Consequently, during the operation of such an electric motor, at some contacts of the collector (which are associated with this damaged winding), increased current values ​​will appear, and as a result, increased spark formation. In this case, there is already a need to check the anchor for the existence of such short-circuited turns. This should be done when cleaning the collector and checking the brushes did not produce a tangible result.

Check the anchor in an alternating electromagnetic field. If there are short-circuited turns, then in such a field the anchor will begin to rattle, since induced currents will begin to form in it. To do this, you can make a home-made device from a power transformer, after making a wedge-shaped cutout on its core, into which you need to put an anchor to check.

Let’s try to reason logically:

This means that the same current flows through both brushes, whatever it is, regardless of its shape and size. That is, from an electrical point of view, both brushes are in equal conditions, which is confirmed by this:

Inequality of currents could occur if a leakage to the ground appeared on some part of the stator-rotor-stator circuit. But this also disappears:

It turns out that all versions with winding defects were covered with a copper basin?And there remains only the mechanics:1. Bad brush pressure2. Curve landing brush3. Horseradish brush material (it would be interesting to swap them)

But the inner voice suggests that another reason is still possible.One of the reasons for brush sparking is the large emf of self-induction when opening the collector lobe. In some cases, such a spark can develop into a circular fire.In our case, only one brush sparkles. That is, there is an asymmetry. Assuming there is a short-circuited coil in one of the stator shoes?Then the behavior of the rotor windings will vary, depending on which shoe they are near. Rather, depending on their orientation relative to each shoe. When the rotor rotates, all of its windings alternately pass by both shoes. But the brushes relative to the shoes do not change position.Thus, it would be logical to assume that the unevenness of the shoes (due to the short winding of one of them) is the reason for the uneven behavior of the brushes. That is, each rotor collector plate opens on both brushes in different conditions, with different self-induction emfs.

Differences in shoes can be and not only because of short circuit in a winding. If you consider that the described angle grinder is already old, which has been seen, then during this time one-sided production of bearings on the rotor shaft can easily arise. After all, there are more than enough lateral loads, and the bearings are not eternal.And the gap between the rotor and the stator shoes is small. Therefore, even a small one-sided wear of the bearings can noticeably introduce asymmetries in the clearances. And then one shoe will be further, and the other closer to the anchor. The mutual inductance in this case can change at times, and this can also cause the consequences that I described above.

Strong sparking on angle grinders

Strong sparking on angle grinders

Mentioning Robert Ivanovich Boch), I had in mind a machine of high power, which is difficult to hold in my hands during a normal start-up

Than 1.5 kW, a soft start should not be thrown out. If covered, then replace. We tried the Interskol angle grinder. Scary, it escapes from the hands. Togo and look in the forehead with a drive. Strong sparking on the angle grinders. Good evening, everyone. In order not to produce an extra topic, I decided to ask for advice here. The situation is this: we have an interskol of 230 mm at 2300 watts. A soft start powder sometimes works quite correctly, and sometimes such a picture. You press a button, at the first moment there is a sharp jerk, and then it starts as if with a soft start. Guys, can this be cured? And if so, how. In principle, it’s not to say directly that some kind of hellish problems are due to this, but, you understand, the situation is not good. P.S. Angle grinder for about three years, operated in professional conditions: for a long time, a lot and sometimes with large (but not transcendental) loads.

Post has been editedDevil666: 12 July 2014. 22:13

Strong sparking on the angle grinders, guys question angle grinder umsh 125 arsenal threw out the speed controller, now how to connect the stator

Attached Images

Strong sparking on schotkah LBM

Devil666, Conder is obsolete, very similar. The capacitor must be changed

Strong sparking on angle grinders

From my experience. After replacing the brushes, and a minute run after LATR with increasing voltage (from a minimum to about 150 volts) everything seemed to be normal. A minute later (I think that the brushes were at least a little, but they were rubbed) I began to increase the voltage higher. After 170-180 volts, circular fire began. And with a small voltage (with slow rotation) the rotation was even and uniform. Something does not fit. When I slightly opened the springs of the brushes, the fire disappeared.

Why spark brush motor.

In the process of operation, devices with a collector electric motor can spark. Strong sparking often indicates an early breakdown of the tool. It is necessary to timely understand the reasons for the appearance of increased sparking and take measures to eliminate it. The article discusses the most likely causes of this negative phenomenon.

Sparks Angle Grinder After Brush Replacement

The basis of devices with AC electric motors is a brush-collector module, which provides electrical contact of the rotor with the static part of the appliance.

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

Reasons for sparking motor brushes

We will analyze the most common malfunctions of the brush-collector assembly.

1) Brush wear. With severe wear of these elements, the electric motor does not develop revolutions at full power, and may also not turn on (continuously or periodically). In this case, when the appliance is turned on, a brush with an insulated handle can be used to press the brush to the anchor. If the increase in engine speed is observed, then the problem is identified correctly. Most likely replacing worn parts with new ones will fix the situation. Sometimes replacement of brush holder springs is also required.

2) Inter-turn short circuit of the armature winding. A malfunction of appliances with electric motors can be a breakdown of the armature. 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 larger current than others. When repairing this malfunction, the armature winding is rewound or the part is completely replaced.

3) Stator failure. When a stator breaks down, usually only one of the brushes sparks. To check it, it is necessary to measure the resistance of the windings. The equal resistance of both windings (usually 4 ohms) indicates a working stator. Different resistance on the windings indicates that the stator is faulty and its winding must be rewound.

4) Closing the collector contacts. As a result of wear of the contacts, graphite dust is formed, which accumulates between them, closing them. In this case, when the appliance is operating, large sparks are observed. To eliminate the breakdown, it is necessary to clean the gaps between the contacts from graphite dust. It is also necessary to check the brushes of the collector, since when they are correctly positioned and correctly selected, dust appears in a minimal amount.

5) Contamination of collector contacts. If the contacts become soiled, both brushes will spark, so the electric motor will not be able to reach full speed. Sludge on the collector appears when it overheats. Bad electrical contact will lead to an increase in resistance in the element, which in turn will lead to even greater sparking and tanning. In this case, it is necessary to clean the collector contacts from soot. This is done with sandpaper of minimal grain size. It is important not to spoil the contact shape when cleaning. Therefore, special pads should be used for cleaning. At home, you can use a screwdriver for cleaning. An anchor is clamped into the cartridge, rotating at minimum revolutions we carefully lean sandpaper on the collector. The direction of rotation of the armature during cleaning should coincide with the direction of its rotation in the appliance.

Why spark brush motor

Collector electric motors differ from other types of motors by the presence of a collector-brush assembly. The assembly provides electrical connection of the rotor circuit with the circuits located in the fixed 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, sparking brushes can sometimes be observed. In some cases, this symptom leads to an early breakdown of the power tool, and in some it does not bode well. One way or another, it is useful in each case to understand what the cause of sparking is, in order to take the right measures in time if necessary. In this article, we will consider the causes of sparking brushes, as well as measures to combat the problems that cause this phenomenon.

It is obvious that the intermittent mechanical contact of the brushes with the collector cannot but lead to sparking, because in fact, many times per second, the rotor electric circuit breaks and closes again.

The rotor contains a winding, which is a load mainly of an inductive nature. The breaking of such a chain is inevitably accompanied by a transition process, which is associated with the appearance of small arcs from self-induction of the rotor winding or the rotor and stator windings. Of course, the brushes wear out over time, as do the collector plates, but sometimes problems arise even before wear.

In fairness, we note that for the reason mentioned above, even a working collector engine cannot work without sparks at all, there is always a slight spark on the collector. A fully serviceable device normally reaches full power, develops working revolutions and sparks a little anyway. Another thing, if the spark is strong, there is a reasonable concern.

Sparking brushes as a sign of wear

If the brushes are already very 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 to verify that this is so? If the worn brushes are pressed with a screwdriver to the collector, the contact will become tight and the engine will start working. But it is worth loosening the clamp, as sparks 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 possible only together with brush holders and springs.

Perhaps a short circuit has occurred in the rotor winding

The winding of the anchor (rotor) of the collector motor traditionally contains several sections. If at least one is damaged, if there is an interturn 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. At individual junctions on the plates the sparks will be stronger than on others. It requires rewinding the anchor 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 sparking is observed near one of the brushes. Check the resistance of both halves of the stator winding, they should be the same. If one of the parts of the stator winding has a resistance much less than the other, then rewinding or replacement of the stator is required.

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

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

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” faults. Sparks appear due to short circuits. Just clean the collector with sandpaper, remove dirt between the lamellas.

Be sure to check how the brushes are located, if one of them is offset from the normal position, adjust the brushes if necessary. When the brushes are crooked, graphite dust is produced in an excessively large amount than with the correct arrangement of the brushes.

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

If the contact is good, the resistance does not increase beyond the nominal, and there are no extra sparks. It is possible to clean the soot like graphite dust. With sandpaper, only rotating the rotor while the collector is clamped in special blocks.

Andrey Povny (Google, VK)

Drill sparks on brushes. What to do

So, your drill sparkles on the brushes and you do not know what to do in such a situation. This article will explain why this is happening, whether it needs to be fixed, and if necessary, how.

It is immediately worth noting that the presence of the specified sparking during operation is a perfectly acceptable phenomenon. True only if the sparks are small and there are not so many. If they directly pour in, then this may indicate a malfunction.

If your drill is already out of warranty, then you can try to fix everything yourself.

But first, we describe the causes of this phenomenon.

Why spark brushes in an electric motor

Sparks, including on a working engine, appear due to mechanical stress between the brushes and the collector. The brush, moving along the collector from one of its contacts to another, alternately forms and breaks the connection with each of them. And now remember what happens if you pull out any working electrical device from the outlet. Usually at such a moment a spark jumps between the plug and the outlet. In the case of a brush motor, this is the same phenomenon.

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

Reasons for strong sparking and ways to eliminate them

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

  1. Soot collector contacts
  2. Graphite dust between collector contacts
  3. Interturn circuit in the armature winding

Let’s go through each item separately.

1) Pollution is caused by overheating of the engine. The presence of soot leads to even greater friction, which leads to even faster overheating and even more soot formation. Which very quickly leads to breakage.

Excessive sparking is obtained here due to the fact that soot forms additional resistance, in which the spark at break is larger and more powerful.

In general, carbon deposits should be removed immediately.

This is done with zero sandpaper. That is, you need to remove the collector with the anchor and carefully clean it. Ideally, it is advisable to clean on a lathe so as not to disturb the correctness of the circle. But, as a rule, this is not possible, so you can do with manual stripping. The main thing is not to overdo it.

2) When the drill is running, the brushes are erased, which causes the formation of graphite dust. 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.

A working drill erases rather slowly, so graphite dust hardly accumulates. Accordingly, its accumulation signals that the brushes during operation are in the wrong position. Usually this happens when they do not stand close in their groove, but, on the contrary, have some backlash.

Often this happens when replacing brushes, when they are selected not quite suitable in size. Therefore, when replacing this moment, close attention should be paid.

Repair of such a malfunction is carried out by removing dust with a pointed tool and replacing the brushes with more suitable ones.

3) In the event of an inter-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 a current of greater value passes than necessary, as a result of which large sparks form.

It is necessary to deal with the identification of such a closure when the two previous points did not give a special 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, as induced currents appear in it.

Some people make such a device themselves from a power transformer, in the core of which a cut is made, where the anchor is placed.

If the cause was in the inter-turn circuit, then you need to rewind the winding or completely replace the armature.

These are the causes of excessive sparking on the brushes of the drill. Remember, if you do nothing with this, then most likely the engine will soon break down. Therefore, do not be lazy and follow the recommendations specified in the article.

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:

  • The rotor is the part of the electric motor that rotates during operation and is adjustable in speed, also called an anchor;
  • Collector. A place on the rotor where the control winding wires are located;
  • Brushes. Parts that serve as current conductors from the cable to the collector winding;
  • Gearbox. A mechanism that acts as a drive from a rotating rotor to a spinning disk, consists of a spindle, bearing, two gears (large and shaft gear);
  • Stator. The part of the electric motor in which the rotor operates;
  • Impeller cooling angle grinder;
  • Start button;
  • Network cable with electric drive;
  • Protection cover;
  • Body angle grinder;
  • Additional handle.

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:

  1. We unscrew the screws from the body and remove one side of the product.
  2. We remove the nut due to which the disc is held, we unscrew the bolts of the protective casing.
  3. We remove the brushes.
  4. Disconnect the wires from the engine.
  5. We unscrew the bolts that secure the gearbox inside, and very carefully remove it, the rotor is also removed.
  6. We unscrew the bolts that hold the stator, and remove it.
  7. We assemble the angle grinder back, alternately put everything in place in the reverse order and fasten it.

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:

  1. 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.
  2. The cable and plug are intact, but the drive does not work. You need to check the start button. It is easier to repair an angle grinder switch by purchasing a new button and replacing it. Since it is rarely repairable. Basically, the plastic breaker rod breaks inside. If you want experiments, you can disassemble it by numbering the contacts, and put everything back in place so that after assembly there is no short circuit.
  3. The above details are unharmed, and the angle grinder does not want to work. So it’s time to check the brushes. Perhaps it’s time to change them in the angle grinder. Brushes from work are constantly heated, so they quickly wear out and more often than other parts need to be replaced, moreover, in pairs.

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.

The most common breakdowns

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.


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.