The vacuum cleaner motor sparks in the area of the brushes: reasons, how to fix it, if it works poorly, it smells

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

Root cause

It is obvious that intermittent mechanical contact of the brushes with the commutator cannot but lead to sparking, because in fact, the electrical circuit of the rotor is broken and closed again many times per 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, as do commutator plates, but sometimes problems arise even before they wear out.

In fairness, we note that for the reason mentioned above, even a serviceable commutator engine cannot operate without sparks at all; there is always a small spark on the commutator. A fully functional device normally reaches full power, develops operating speeds and still sparks a little. It’s another matter if the sparking is strong - there is a reasonable concern here.

Sparking brushes as a sign of wear

If the brushes are already badly worn, 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.

There may be a short circuit in the rotor winding

The armature (rotor) winding of a commutator 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 - sparks will be stronger at certain transitions on the plates than at others. This requires rewinding the anchor or a completely 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 part of the stator winding has a resistance much lower than the other, then rewinding or replacement of the stator is required.

A dirty collector causes an unnecessary short circuit on it, resulting in unnecessary sparks

Dust on the commutator 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” short circuits. Sparks appear due to short circuits. Simply clean the collector with sandpaper, removing dirt between the lamellas.

Be sure to check how the brushes are located, whether one of them is displaced relative to its normal position, and adjust the brushes if necessary. When the brushes are positioned crookedly, graphite dust is formed in disproportionately large quantities than when the brushes are positioned correctly.

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

Source

Why do engine brushes spark?

A distinctive feature of all electric motors is the presence of a commutator-brush assembly in their design. It provides an electrical connection between the rotor circuit and the circuits in the stationary part of the motor, and consists of a commutator (a series of contacts on the rotor itself) and a brush (moving contacts outside the rotor, pressed against the commutator).

When an electric motor is started and running, it almost always sparks. Sometimes this does not mean anything terrible, but sometimes it signals that the device will soon fail. In any case, it is useful to know why the electric motor sparks in the first place - this will help, if necessary, take timely measures. In this article, we will look at the reasons for the occurrence of sparks during operation of the electric motor and ways to combat problems that cause increased sparking.

First, let's define it - inconsistent contact between the brushes and the commutator leads to sparking by default. This is due to the fact that during operation the electrical circuit of the rotor closes and opens many times per second.

The rotor contains a winding. This winding is a load of mainly inductive nature. This, in turn, means that by breaking such a circuit, we start a transient process associated with the appearance of small arcs from the self-induction of the winding - both the rotor itself and the stator. It is clear that brushes and commutator plates wear out over time, but sometimes problems arise not only because of it.

Taking into account the above facts, it must be admitted that even a serviceable and well-fitted electric motor cannot operate without sparking at all. A working device in normal mode develops operating speed, gains power and sparks a little. But if there are a lot of sparks, this is a serious cause for concern.

Brush wear as a cause of sparking

The first and main reason for sparking is wear of the brushes. If there is significant wear, the engine will not be able to develop full speed and gain full power; in addition, it will spark very strongly and will not start immediately.

How can I determine if this is the reason? If you press the worn brushes against the commutator with a screwdriver or other tool, this will seal the contact and start the engine, but after the pressure is loosened, strong sparking will appear again - the space between the brushes and plates will be filled with small arcs. With such symptoms, we can conclude that the brushes are worn out and require replacement. Sometimes it is possible to replace the brushes separately, but more often it is necessary to replace the entire set, including the brush holder and springs.

Short circuit in the rotor winding as a cause of sparking

The rotor winding in a commutator motor consists of several sections. If one of them is damaged and an interturn short circuit occurs in it, then the current will flow into it with greater force than into the others. Because of this, part of the winding will begin to overheat and begin to generate an increased number of sparks. This is exactly how this reason can be established - sparking will increase only in a separate area, and not evenly. This can be corrected by rewinding the rotor or replacing it.

Why brushes spark, the main reasons

The brushes are the weakest part. Most often it is from them that the vacuum cleaner motor sparks. Here are some reasons for sparking.

Wear of parts

There is a metal holder inside the brushes. When the graphite layer wears down to metal, the collector copper comes into contact with the holder steel. Hence the sparks.

Wrong angle

The design of the brushes includes a spring. Over time, its clamping ability weakens. This leads to misalignment. That is, the brushes are displaced relative to the plane of contact with the commutator elements.

The holder is secured to the body with two screws. They can also weaken during long-term operation of the vacuum cleaner. And this will again lead to a change in the angle of inclination.

Poor contact

The two previous reasons result from poor contact between the graphite surface of the brushes and the copper commutator. The electrical circuit breaks. It is short-lived, but it is enough for the electric motor to start working intermittently. That is, in jerks.

Dirt entry

Another reason is why the brushes on the vacuum cleaner burn. Dirt collects on the surface of the collector. Usually this is dust and graphite residues from old brushes. The contact between the two conductors weakens, causing the electrical circuit to break.

Attention! This problem can be solved simply - the collector surface must be cleaned with zero-grit sandpaper.

Motor short circuit

Sparks inside the vacuum cleaner can occur not only due to faulty brushes or their poor contact with the collector. The winding sparks - these are copper wires treated with a special varnish that does not allow electricity to pass through.

Sparking is a violation of insulation. In this case, sparks scatter in the direction of movement of the armature, that is, in a circle. The motor itself begins to hum, popping noises appear, and the power of the vacuum cleaner drops.

This fault can only be determined using a multimeter. This device measures the voltage and resistance of the winding.

Attention! The vacuum cleaner cannot be operated with such a malfunction.

Homemade brush

Under no circumstances should it be installed in household appliances, especially vacuum cleaners, home-made units and parts related to power supply. You can make a graphite brush with your own hands. But it is almost impossible to adjust it to the required technical and electrical parameters.

The vacuum cleaner motor acts as a compressor. Therefore, it works under load all the time. And it doesn’t matter to him at what frequency the voltage is applied to him. For an electric motor, it is important that there is always a balance between the load and the power of the device.

And if there is no load, the engine will go into overdrive. It will simply be torn off its fastenings in a split second.
If the power is reduced, and this is directly related to the brushes, then the vacuum cleaner loses its functional qualities. That is, it simply stops sucking up dust.

Homemade brushes will lead to the second point. That is, there is a high probability that the device will simply be useless in the household. In addition, no one canceled safety precautions. With homemade parts, her requirements are reduced to a minimum.

Electric motor design and operating principle

The operating principle of an electric motor is based on the interaction of a conductor with a current located in a magnetic field.
The magnetic field is created by the stator.

The main element of its design for a DC motor is a permanent magnet, for alternating current it is an excitation winding. The rotor (armature) has its own winding, to which voltage is supplied using a brush-commutator unit. The interaction of magnetic fields causes the rotor to rotate.

The collector consists of a set of contacts, which are copper plates located directly on the rotor. Micanite or mica cuffs act as insulators for each individual contact. Graphite brushes are sliding contacts pressed against the commutator.

Purpose of brushes on angle grinders

Before you find out the reasons for sparking brushes on an angle grinder, you need to understand their purpose. Commutator brushes are used not only in the design of angle grinders, but also in the design of all modern power tools - drills, hammer drills, jigsaws and others. In the design of grinders and other power tools, 2 brushes are used, which have a simple design. This design is based on the following elements:

The main part is rectangular in shape and made of coal or graphite
A contact is a wire core of the appropriate diameter through which electric current flows. The contact connects the wire to the graphite part
A spring is a mechanism that ensures the main part is pressed against the collector. There may be no spring on the element, and this indicates that such a brush is intended for installation in a power tool, where the brush holders have a built-in pressing mechanism in the form of a curved plate

The devices are designed to transmit electric current to the rotor of a power tool. The voltage removed from the stator is supplied to the rotor, which is reproduced using carbon brushes and a commutator. Supplying current to the collector ensures its rotation. When the rotor rotates, the devices come into contact with the collector (copper lamellas are the leads of the armature windings), thereby ensuring the continuous flow of electric current.

During the use of devices, they wear out, so they are classified as consumables. The service life of brushes depends not only on the working life of the power tool, but also on the materials from which they are made. The wear of brushes is affected not only by mechanical impact due to friction, but also by thermal impact. Electric current passing through a conductor causes it to heat up. The higher the current, the higher the heating temperature. When current passes through the graphite brushes, they also heat up. The higher the load on a power tool, the higher the current, which means the temperature increases, which negatively affects the integrity of consumables.

This is interesting!
There are no differences between the brushes for the corresponding power tools (except for the method of fastening), since they are selected solely according to such a parameter as the dimensions of the main part.

Causes

Transient processes occur in the rotor windings due to intermittent mechanical contact of the brushes with the commutator plates, which causes the formation of small arcs.

Important : a fully serviceable engine does not exclude sparking during operation. There are other reasons that cause severe sparking and create the possibility of motor failure.

Brush wear

With prolonged use or poor-quality brush material, they no longer press tightly against the contacts of the commutator. Due to poor contact, the engine does not gain speed or does not start immediately. A worn brush can be easily identified visually.

Sometimes it is not possible to correct the situation by replacing only the worn part. The brush holder and spring should be replaced.

Short circuit in the armature winding

The consequence of such a defect is uneven sparking on the collector. It will be stronger on some plates than others. Due to the presence of an interturn short circuit, the current in certain sections of the rotor winding will be stronger than in others.

Rewinding the rotor or replacing it will eliminate the problem.

Fault in the stator winding

A defect similar to a short circuit in the rotor winding occurs in 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 it.

Pollution

The product of brush wear is graphite dust, which is an additional source of increased sparking. Dust accumulates between the plates, which creates additional conditions for the formation of sparks. Preventive cleaning of the commutator with sandpaper and removing dirt between the plates will keep it clean.

Brushes not installed correctly

If the brushes are deviated from the norm towards the commutator surface, a significantly larger amount of graphite dust is generated during operation. Misaligned brushes must be corrected.

Poor contact between brushes and commutator

The electric motor spends part of its operating time in overheating mode. Under such conditions, carbon deposits form on the collector. Poor contact leads to increased brush sparking and even more carbon deposits.

Mechanical problems

Mechanical reasons are caused by non-compliance with the requirements of design and technological documentation. Most mechanical causes can be eliminated by turning the manifold on a lathe. Refer this repair operation to a qualified technician. Here are some types of faults that may indicate a breakdown:

Causes of severe sparking and how to eliminate them

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

contamination of collector contacts with carbon deposits
graphite dust getting between the collector contacts
interturn short circuit in the armature winding

Let's go through each point separately.

1) Soot contamination occurs as a result of engine overheating. The presence of carbon deposits leads to even more friction, which leads to even faster overheating and even more carbon deposits. Which very quickly leads to breakdown.

Excessive sparking here results from the fact that carbon deposits form additional resistance, which causes the spark to break when it breaks, becoming larger and more powerful.

In general, carbon deposits should be removed immediately.

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

2) When using a drill, the brushes wear out, which causes the formation of graphite dust. It can easily accumulate between the collector contacts 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 large sparks in some places.

In a working drill, wear occurs quite slowly, so graphite dust hardly accumulates. Accordingly, its accumulation signals that the brushes are in the wrong position during operation. This usually happens when they do not stand tightly in their groove, but, on the contrary, have some play.

This often happens when replacing brushes, when they are selected to be not 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 some pointed tool and replacing the brushes with more suitable ones.

3) In the event of an interturn short circuit in the armature, the current flows in a larger value to some contacts and a smaller value to others. Because of this, more current flows in some places than necessary, resulting in large sparks.

Identifying such a short circuit should be done when the two previous points did not give much effect. It is produced using a special device that creates an alternating magnetic field. When an armature 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 cutout is made where the armature is placed.

If the reason turns out to be an interturn short circuit, then you need to rewind the winding or completely replace the armature.

These are the causes of excessive sparking on the drill brushes. Remember, if you don't do anything about it, the engine will most likely break down soon. Therefore, do not be lazy and follow the recommendations indicated in the article.

Carbon-graphite brushes used in electric motors. What to do if they spark.

So, your drill sparks on the brushes and you don’t know what to do in this situation. This article will tell you why this happens, whether it needs to be fixed, and if so, how.

It is immediately worth noting that the presence of the specified sparking during operation is a completely acceptable phenomenon. This is true only if the sparks are small and there are not so many of them. If they just fall out, this may indicate a malfunction.

Note that on a new, working power tool, the brushes may also spark strongly at first, since they need to first get used to. Grinding in usually takes 10-15 minutes of work. If after this everything remains as it was, then it is better to take the instrument back to the store with a claim.

If your drill is no longer under warranty, you can try to fix it yourself.

But first we will describe the reasons for this phenomenon.

Why do the brushes of a screwdriver spark and what can I do about it?

If the screwdriver sparks with rare and small sparks, this does not necessarily indicate a malfunction. A newly purchased tool may behave this way in the first 10–15 minutes of use, while the brushes are grinding in. If enough time has passed and the sparking does not stop, it is better to return the screwdriver.

But what if the problem appeared after years of operation of the power tool, and the warranty period has long expired?

Possible reasons

The reason why sparks appear even on a new engine is the mechanical interaction of the commutator and brushes. Moving during operation of the tool from one commutator contact to another, the brushes alternately create and break contact with each of them.

To make it easier to understand the principle, remember the situation when you unplug an electrical appliance from a socket. When the circuit breaks, a spark occurs between the socket and the plug. So it is in this case. Minor sparking is completely normal.

But if sparks fly in a sheaf, this situation may be due to the following reasons:

collector contacts in soot;
graphite dust from the brushes got between the contacts;
a short circuit has occurred in the armature winding.

Collector contamination

The mechanics of contamination of the commutator contacts are as follows: the electric motor overheats, carbon deposits settle on the commutator, which creates additional friction. As a result, the engine overheats again, even when operating at low speeds, the amount of carbon deposits increases, friction increases - and so on until the engine burns out altogether.

The solution to the problem is obvious and consists in cleaning the contacts. Do this using the finest (zero) sandpaper:

Remove the manifold with the armature.
Without applying excessive force, go over the contacts with sandpaper.
Insert the module into place.

It is best to carry out cleaning using a lathe so as not to disturb the geometry of the part. But in practice, you can get by with manual work.

Dust in contacts

With regular use, even at low speeds, the screwdriver brushes wear out. As a result, graphite dust is formed. It accumulates on the motor contacts. And since graphite dust has its own resistance, an uneven distribution of current occurs, sparks appear, a characteristic smell - a complete feeling that the brushes of the screwdriver are burning.

If the brushes are installed correctly, their wear occurs very slowly and does not lead to such problems. Take your instrument apart and see what's going on there. Please note:

the parts of the mechanism must fit tightly, without play;
if a replacement was made, a brush of a not quite suitable size could be installed;
Foreign objects, dust, or construction chips could get into the grooves.

Carefully remove dust from the brushes and grooves using a pointed tool. To prevent further sparking, replace or tightly reinstall all necessary parts.

For replacement, buy original parts from the manufacturer. Ultimately, this will save money and nerves.

Short circuit in anchor

If you have cleaned the commutator contacts, checked the condition and tightness of the brushes, and the electric motor continues to spark, most likely the problem is in the armature winding.

A special device for creating an alternating magnetic field helps to detect it. If you place an armature in it, it will begin to rattle because induced currents appear in it.

If a problem is found in this module, rewinding the winding or completely replacing the armature will help.

Whatever the reasons for the appearance of sparks in a power tool - dirty contacts, a short circuit in the armature or clogged brushes - they cannot be ignored. Otherwise, you can wait until the screwdriver finally fails.

Prevention

To prevent or at least minimize the risk of all these problems, follow a few simple rules:

After work, wipe the tool and screwdriver attachments you used with a damp cloth. This will prevent dust from getting inside, onto the collector contacts;
If the life of the screwdriver is not enough for your tasks, do not lean on it or press it into the surface. Purchase a tool with appropriate power and speed ratings;
Use original spare parts to replace faulty ones. This will protect the instrument from premature global failure.

Operating principle of a commutator motor

The main elements of the device are located in rotation bearings, which in turn are enclosed in a static frame. Both the motor and the stator have individual windings made of insulated cores - armatures. Electric current flows through the latter, and, as a result, magnetic fields with north and south poles (N and S) are formed.

Due to their interaction, the dynamic part of the motor, the rotor shaft, rotates. A commutator with a brush mechanism and armatures is precisely what is needed in order to supply the necessary voltage to the windings, due to which the shaft rotates.

The motor brushes of power tools spark: the reason is that they spark strongly at the armature of a drill or grinder

Commutator motors are widely used in household electrical equipment. Small dimensions, lightness, and ease of operation determined their presence in grinders, rotary hammers, circular saws, and screwdrivers. The main disadvantage is increased wear of the brush-collector pair. The failure of this unit is predetermined by the sparking that occurs in it.

Electric motor design and operating principle

The operating principle of an electric motor is based on the interaction of a conductor with a current located in a magnetic field.

The magnetic field is created by the stator.

Causes

Transient processes occur in the rotor windings due to intermittent mechanical contact of the brushes with the commutator plates, which causes the formation of small arcs.

Important: a fully serviceable engine does not exclude sparking during operation. There are other reasons that cause severe sparking and create the possibility of motor failure

Brush wear

Sometimes it is not possible to correct the situation by replacing only the worn part. The brush holder and spring should be replaced.

Short circuit in the armature winding

Rewinding the rotor or replacing it will eliminate the problem.

Fault in the stator winding

Pollution

Brushes not installed correctly

If the brushes are deviated from the norm towards the commutator surface, a significantly larger amount of graphite dust is generated during operation. Misaligned brushes must be corrected.

Poor contact between brushes and commutator

You need to use fine-grain sandpaper to clean the surface of the commutator. To increase the stripping effect, use a screwdriver. Clamp the engine rotor into the chuck and remove carbon deposits with sandpaper at low speeds. Afterwards you need to finally polish it on a felt wheel.

Mechanical problems

The surface of the collector is uneven;
The shaft runout exceeds the value specified in the technical documentation;
Individual collector plates protrude beyond a common level for all;
Insulation protrusion (mica);
The brushes in the brush holders move with jamming;
On the contrary, the brushes are inserted into the brush holders with a large gap, which creates vibration during operation;
The brush holders are installed far from the commutator;
Uneven tension of the springs, resulting in a difference in the pressure applied to the brushes.

Engine diagram

For a more visual understanding of the operating principle of a commutator motor, there are two visual types of representation - simplified and detailed. The first format (Fig. below) is a conventional diagram, focusing on connecting the windings to the network.

More complex designs (Fig. below) have additional taps on the rotor and stator. For example, to power automation or regulate speed. The presence of thermal protection allows you to minimize the likelihood of overheating of the upper layer of the unit winding. This element removes voltage when the relay is activated, stopping the operation of the shaft.

Why do brushes spark?

Brushes can be called the weakest element of a commutator motor: during operation of the unit, they are subject to constant friction, which leads to their wear . This point is especially noticeable on copper surfaces, where a layer of coal dust accumulates during brush operation.

Design Features

In normal sliding mode, a small break occurs in the electric current circuit. Microscopic arcs appear, and this is a faithful companion of sparks. Here you can add a decent inductive reactance of the motor windings.

At maximum load on the unit, even with new brushes, there will always be a spark. Visually this may not be so noticeable, especially on low-power models, but sensitive equipment located in a room with a working vacuum cleaner will make this known in a specific background. Therefore, filters are installed on televisions, personal computers and other devices to eliminate such interference.

Wear

The part of the brush that comes into contact with the commutator is made of carbon. Over time, its length decreases, as does its total volume. As a result, the spring pressure weakens, and gaps appear, and with them sparks.

Graphite brushes for vacuum cleaner

Homemade brush

The element must fit tightly into the grooves and be positioned strictly perpendicular to the axis of the rotor shaft. If the brush is smaller than the required size, a skew will appear. This will again lead to sparking, and at the same time a decrease in engine performance. Therefore, here it is better to give preference to industrial options rather than homemade ones.

Why do brushes burn out on angle grinders?

In addition to sparking, power tool owners often encounter brushes on their grinders burning. This phenomenon differs from sparking in that rapid wear of the main part of the element occurs. Immediately after installing new elements, they wear out immediately when using the power tool for the first time. We have to figure out why the brushes on the grinder burn.

The main reason lies not in the brushes themselves, but in the commutator. If the lamellas fall out or wear out on the collectors, this leads to an increase in load. This load is experienced by graphite elements, which, when the angle grinder is turned on, begin to wear out quickly - this process of accelerated wear is called combustion. Elements literally burn due to the passage of large current. Many people call this process abrasion, but in reality brushes cannot quickly wear out due to mechanical stress. The cause of combustion is strong sparking, as a result of which the graphite literally simply burns out.

The reasons why brushes on an angle grinder burn are as follows:

Loss or wear of the copper lamellas of the collector. What wear on the collector lamellas looks like is shown in the video. The material also shows how you can try to eliminate such a malfunction.
An interturn short circuit between the lamellas or the rotor winding helps to increase the current, from which the brushes heat up and begin to burn. To identify the cause, you will need to ring the anchor
If the power tool is heavily overloaded - if you use the grinder for a long time without breaks, the result of such use will manifest itself in the form of brushes burning out in 5-10 seconds

There is also such a thing as all-round fire. This phenomenon occurs during large impulses of the armature current, for example, during overloads, short circuits, and also when the network voltage decreases. A circular fire appears when the arc is re-ignited. An increase in load and even a short circuit occurs when using an angle grinder to cut wood. When processing wood, the cutting disc becomes clamped, thereby increasing the current by 15-25 times the nominal value. Most often, the commutator is the cause of element combustion, so if you had to change 2-3 pairs of brushes in a month, then it’s time to diagnose the power tool.

Abnormal sparking of the electric motor

Sparks appear due to the mechanical action of the brush and commutator. This phenomenon occurs even with a working engine. The brush moves along the commutator, in turn forms and then breaks the connection with the contacts. A small number of sparks that burn is considered an acceptable phenomenon for a working unit, but if it sparks a lot, then it is necessary to diagnose the vacuum cleaner.

The actual cause of the breakdown may be an incorrect angle of inclination. Correct position: two brushes rotate parallel to each other and along the same path. If the device is used for a long time, the brushes in it may move, so it is necessary to control this process so that they do not become bent. If popping noises occur, strong sparking appears, the product body turns black, we may be talking about an interturn short circuit.

Another cause of malfunction is wear of parts. In this case, the vacuum cleaner is completely disassembled. Brushes create contact between special electrodes; they are components of an electric motor, so you first need to diagnose it, replace old parts and continue to use the equipment. Some experts recommend purchasing additional spare parts for a new product.

Poor contact between equipment elements can occur when new brushes are installed. They must be tightly installed. The malfunction occurs in the presence of dust; in this case, clean the contacts regularly. If the contact is poor, then you can let the device run for 10 minutes at neutral speed.

With excessive tension, which is associated with high friction, dirt is formed. The more carbon deposits appear, the faster the unit breaks down. Contacts must always be clean.

Why do brushes spark in an electric motor?

Sparks, including on a working engine, appear due to mechanical action between the brushes and the commutator. The brush, moving along the commutator from one of its contacts to another, alternately forms and breaks a connection with each of them. Now remember what happens if you unplug 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 small spark even on a working electric motor is acceptable, since connections and ruptures constantly occur here.

Replacing brushes

The simplest and most obvious cause of sparks is wear on the brushes. Despite the fact that commutator motors are equipped with special spark-extinguishing capacitors, which, in addition to increasing the service life of these elements, also reduce radio interference, over time the brushes wear out and need to be replaced.

To replace the brushes, you first need to get to the electric motor. To do this you will have to disassemble the vacuum cleaner. In most cases, this is quite simple to do with a screwdriver, but do not forget to unplug the device. Having disassembled the vacuum cleaner and provided convenient access to the engine, we find the brush holders. Depending on the design, to remove the brushes from the brush holder, you usually need to pull out the latches, which may require a screwdriver.

Causes of malfunctions and methods for eliminating them

Depending on which part of the drill has become unusable, repair interventions will depend. Let's look at the most common external signs of breakdowns.

A breakdown will be indicated when the brushes begin to spark, the drill does not develop full power, and problems periodically arise with turning it on, and it begins to work only after the application of physical force. The tool must be diagnosed; if, at the end, the serviceability of the capacitor is revealed, the external integrity of the armature is revealed, and it also turns out that the resistance of the stator windings has the same resistance, then it is necessary to pay attention to the wear of the brushes.

Diagram of the internal structure of a drill-driver.

In order to check this point, you need to use a screwdriver to press the brushes of the hammer drill against the armature. It is necessary to remember that the handle of the tool must be dielectric, otherwise there is a possibility of receiving an electric shock. If upon contact the drill starts working at full power, then the problem is in the brushes. In this case, they must be replaced with new ones. But sometimes such a replacement does not have the desired effect, so it is recommended to change the holders as well.

Experts recommend not waiting until such a part wears out and sometimes doing a preventive inspection of them. The main sign of the need for replacement is increased sparking in the ventilation slots located on the body. As soon as it begins to be observed, new brushes should be prepared immediately.

If the hammer drill does not work at full speed or the brushes spark again, you need to clean it. For this purpose, using “0” sandpaper, the collector is cleaned in the direction in which the armature rotates. Next, it is necessary to cut through the dielectric spacers that are located between the collector plates. This procedure is performed using a cutter, and if possible, it is best to do the entire procedure on a lathe.

Drill chuck design diagram.

Another method can be used. The anchor is clamped into the drill chuck, and then at low speed, pressing the sandpaper to the commutator, turn it on.

The hammer drill may not work if non-original brushes are installed on the imported model. But if strong sparks appear, there is a possibility that the armature has burned out, which is also indicated by strong heating of the winding. Sparks can be caused by an interturn short circuit. If the drill has one of two brushes, then most likely the problem is in the stator. He simply simply burned out.

In order to verify this, it is necessary to measure the resistance of the windings using a tester. It should show the 4 ohm mark on both elements. If the indicators differ, this will be direct evidence of a stator malfunction. Then you need to start rewinding the windings.

There may also be a problem with the power cables. If the hammer drill is used quite intensively, then there is a possibility that they have become frayed in some place. As a result, the drill may not work immediately. To determine the location of the breakdown, you need to “ring” the wire all the way to the trigger. If even during diagnostics it turns out that they are working properly, then you should check the key itself.

Breakdowns can also occur with the motor. In this case, you should pay attention to the armature (which most often happens) or the stator. Models from expensive companies use a coil wire, which is coated with a special heat-resistant varnish. While cheaper analogues do not pay due attention to insulation. Therefore, if such a hammer drill works for a long time without breaks, then the engine does not have time to cool down and, in the end, burns out.

The heating element sparks in the washing machine

Now we know why a washing machine sparks - if the sparks are strong and appear only when the electric motor is running, then the problem is in the motor. But sometimes the reason lies in something completely different. For example, a worn heating element can easily spark in a washing machine - in some cases, sparks are visible even through the glass. If this really happens, you should immediately turn off the power to the washing machine without touching its body.

Next, we gain access to the heating element and check it with a multimeter (in diode testing mode, with sound indication), touching it with probes to the current-carrying contacts and to the housing - if the heating element “breaks through” onto the housing, the multimeter will beep and change readings. Instead of a multimeter, you can use dial gauges (in ohmmeter mode) - here it is easier to notice the slightest fluctuations in resistance. If the heating element fails, it must be unconditionally replaced - the heating elements are not repaired.

Sometimes the junction of the heating element with the wires can spark - in this case, you just need to clean the oxidized contacts.

Before checking the heating element, do not forget to drain the water from the tank by unscrewing the filter. Otherwise, you risk flooding your floor and even your neighbors.

Sign of wear on motor brushes

Brush wear as a cause of sparking

Short circuit in the rotor winding as a cause of sparking

Malfunction of the stator winding as a cause of sparking

The malfunction is very similar to the previous one and is diagnosed in the same way - uneven sparking. If everything is in order with the rotor winding, then check the resistance of the stator winding - it should be the same for each half. A significant difference in resistance indicates the need to rewind or replace the stator.

Collector contamination as a cause of sparking

As the engine operates, its brushes wear out and graphite dust forms on the commutator. It accumulates between its plates and creates additional unwanted short circuits, which, in turn, spark. In this case, it will be enough to remove dust and dirt between the plates using sandpaper.

It would also be a good idea to check the position of the brushes - any deviation from the normal position greatly accelerates the formation of dust and wear of the brushes.

Another reason for contamination of the collector is carbon deposits on it due to overheating during operation. When all other causes of sparking on engines have been checked and eliminated, clean the commutator contacts from carbon deposits - this will improve the contact of the brushes with it and reduce the number of sparks generated. Carbon deposits are removed in the same way as graphite dust - with sandpaper. The only difference is that the rotor must be rotated while the commutator is clamped.

Source

Eliminating bad contact

Brushes often spark if they have poor contact with the commutator. This happens if you installed new ones. To ensure a tighter fit of the brushes to the collector, you can use sandpaper or simply let the vacuum cleaner run at medium speed for about 20 minutes. It is imperative to check the condition of the bearings, as their wear can cause runout and uneven rotation of the rotor. Insulation protrusions between the collector plates, scratches on the surface, and various irregularities manifest themselves in a similar way. Abrasive paper is used for polishing.

The device of the collector electric motor of the vacuum cleaner

The brushes should not dangle in the brush holder, but have free movement, which is provided to them by the spring, the condition of which also plays an important role.

If you decide to replace the brushes, be sure to pay attention to how tightly the spring presses them against the commutator. Sometimes, in order for the brushes to press harder, it is enough to stretch the spring a little.

Sparking vacuum cleaner brushes: causes, elimination

Introduction

The advantages of commutator electric motors - high speeds, small dimensions and weight compared to asynchronous (and even more so synchronous) motors of the same power - have determined their widest use in hand tools and non-stationary household appliances. But there is also a drawback.

This is a brush mechanism that is not only subject to accelerated wear, requires regular maintenance and replacement of elements, creates additional noise and interference, but can also (if this maintenance is neglected) cause irreversible equipment failure and even a fire.

Is it possible to solve these problems without resorting to troublesome and expensive visits to service centers?

Safety precautions Causes of sparking Troubleshooting

Safety precautions

I would like to believe that the repairs described in this article simply will not be carried out by a person who has no idea what electricity is and how not to get hurt from it. But since a vacuum cleaner is not a floor lamp or an electric razor, but one of the most “evil” household appliances (at least because of its power), let us recall 3 most important points (the first is true for any equipment, and the second and third are purely vacuum cleaner):

All operations (except testing, of course) must be carried out only with the plug disconnected. There is no hope for a switch (in the device itself, in an extension filter or somewhere else): firstly, it does not create a visible break, secondly, it does not always break the phase and, finally, it can turn on accidentally. The plug (not “pushed”, but lying at a noticeable distance from the socket!) will not turn on by itself.
Motor rotors of such power as in vacuum cleaners (usually from 0.5 to 2 kW), and even together with the compressor impeller, have a considerable moment of inertia. And the start-up is very fast. The result is a strong jerk of the stator in the direction opposite to rotation at the moment of switching on. And the more noticeable the more the motor is freed from other parts. And the conductors are usually short, and can break, short out, or whip your hand... Therefore, no holding your fingers to a place not intended for this, from which, with a sharp turn, it is easy to slide onto elements that are under tension or in motion. Before testing, the stator (the rest of the housing) must be securely fastened - if not in a vice, then at least pressed to the floor through a rigid insulator that will not touch the moving parts when bent. In general, such tests (as well as all work without removing voltage near live parts) should be carried out by two qualified electricians.
The speed of the commutator motor is not limited by the frequency of the supply voltage or by any design features. There simply must be a dynamic balance between the generated power and the load. If the latter is not present at all, literally in a split second the motor goes haywire in the most literal sense: it can not only burn out its bearings and brush mechanism, but also fly apart like an abrasive disk, with no less danger for surrounding people and objects. Therefore, if the disassembly has progressed so far that even the compressor impeller has been dismantled (the friction of which with the air is the only load in the vacuum cleaner), you CANNOT turn on the engine for even a second! And even with an impeller, but with a completely free flow of air through it (no hose, no filters), the speed will be significantly higher than the nominal speed, and the current consumption will be lower. It is pointless to study brush sparking in this mode. You need to provide at least a little air resistance - cover the inlet of the compressor by 80 percent with a flat object or 100 percent with a not very dense carpet, fine mesh... But everything must be rigid or securely fastened in a taut state so that the compressor cannot suck in anything: even a soft foreign object in it is instant death for a thin aluminum impeller.

Causes of sparking

The rotor (armature) of a commutator motor contains several (from 3 to 36) windings, the terminals of which are riveted and (not always) soldered with refractory solder in special holes in copper contact plates - lamellas.

The latter are installed at intervals of 0.5–1 mm along the cylindrical surface of the heat-resistant dielectric and form the collector itself.

The current through the diametrically located brushes, pressed by springs and sliding along the lamellas, is always supplied to the winding whose magnetic field is currently perpendicular to the stator field, and due to this provides the greatest rotating force.

In principle, a sliding contact cannot avoid sparking at all. Especially with high power and inductive loads. However, sparking should not exceed certain limits, which, of course, can be represented by photographs, but best of all is experience when a person has seen the operation of a mass of similar devices or the operation of a given product in fully working order.

Why do the brushes in a vacuum cleaner spark?

There are quite a few reasons for increased sparking:

Wear of the brushes themselves.
Their insufficient grinding (for new ones).
Their distortion is due to wear, cracking or displacement of the brush holders.
Weakening of springs.
Interturn short circuit in windings.
Armature runout due to bearing wear.
Oxidation and/or contamination of the lamellas.
Their production.
Clogging of gaps with conductive dust.
Defects of individual lamellas (cavities and burns, wobbling in the dielectric, “licking” of the top layer towards the next gap, etc.).

Accordingly, to eliminate it, we must first establish which of the reasons we have.

Troubleshooting

Since first there is a visual inspection, let us remind you: if you missed the chapter on safety precautions, come back! Most of the test instructions are there too!

As with all searches among a large number of options, it is best to start by cutting off those that are clearly unsuitable. For example, if one of the brushes sparks much more than the other, then the problem is there: defects in the lamellas, windings and bearings would affect both equally. That is, it remains to check only the first 4 points.

* Sparks are drawn in the direction of rotation. Therefore, the different sparking of the brushes can be apparent: when we look radially at both at the same time, the lamellas under one of them move towards us, and under the other - away from us. It is possible to draw a conclusion about the different quality of contact only by looking at both sides and taking this nuance into account.

Washing machine motor sparks

If the washing machine sparks from below, then the problem is most likely in the electric motor that drives the drum. In most cases, brushed motors are used here, which wear out over time and begin to suffer. But don’t be upset - most often a complete replacement is not necessary, and self-repair of the engine will result in a simple replacement of the brushes. Let's try to look at the repair work in more detail.

Brushes for electric motors of washing machines

Brush motors transfer electricity to the windings using graphite brushes that rub against a rotating commutator. A high rotation speed causes wear to the brushes, as a result of which they become the cause of sparking - contact with the lamellas becomes worse, sparks and even an unpleasant odor appear. And the more wear, the more sparks appear at the point of contact between the rotating rotor and brushes. The solution to this problem is very simple - you just need to change the brushes for the electric motors of the washing machine. After this, the engine can continue to operate. In order to replace the brushes, you need to remove the belts from the motor shaft, disconnect the connecting terminals through which power is supplied, unscrew the motor fasteners and carefully remove it - at this stage we may be hindered by the tank to which the motor being removed is attached. A little skill and patience - and the engine will be removed.

The drill sparks on the brushes - what to do?

So, your drill sparks on the brushes and you don’t know what to do in this situation. This article will tell you why this happens, whether it needs to be fixed, and if so, how.

If your drill is no longer under warranty, you can try to fix it yourself.

But first we will describe the reasons for this phenomenon.

Why do brushes spark in an electric motor?

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Therefore, a small spark even on a working electric motor is acceptable, since connections and ruptures constantly occur here.

Causes of severe sparking and how to eliminate them

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

contamination of collector contacts with carbon deposits
graphite dust getting between the collector contacts
interturn short circuit in the armature winding

Let's go through each point separately.

Excessive sparking here results from the fact that carbon deposits form additional resistance, which causes the spark to break when it breaks, becoming larger and more powerful.

In general, carbon deposits should be removed immediately.

This often happens when replacing brushes, when they are selected to be not 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 some pointed tool and replacing the brushes with more suitable ones.

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

If the reason turns out to be an interturn short circuit, then you need to rewind the winding or completely replace the armature.

Changing the angle of inclination

If the angle of inclination of the brushes relative to the stator is incorrect, sparking may also occur. The correct position is when both brushes are strictly on the same line passing through the axis of rotation of the commutator. Over time, due to constant vibration, the brush holder mount may become loose or even suffer mechanical damage. Carefully inspect the surfaces of the components. Parts that have cracks, chips or signs of corrosion must be replaced.

Each manufacturer introduces design features into its product line, and therefore different types of vacuum cleaners have different types of brush attachment. However, in general, all models have the same device, and the brush holder is usually screwed on with two screws and allows for adjustment.

Brush wear

In recent years, many manufacturers have supplied their vacuum cleaners with a set of spare brushes. But if you happen to purchase the device without additional spare parts, they can be purchased at stores that sell power tools.

Brushes are graphite and copper-graphite. It will be better if you remove the old elements from the electric motor of your vacuum cleaner in advance and go to the store with them, so as not to make a mistake in your choice.

Eliminate pollution

The commutator surface at the point of contact with the brushes must be clean. Coal or metal dust formed when the brushes rub against the rings or commutator can have a detrimental effect on the contact. Contamination of the latter causes sparking, from which carbon deposits are formed. Self-repair of a vacuum cleaner in this case involves routine cleaning. If the surface has traces of contamination, it is necessary to get rid of them using fine sandpaper, and then degrease it by wiping with alcohol or gasoline. You should also pay attention to the space between the contacts on the rotor. If they are clogged with dirt or graphite dust, they should also be cleaned and degreased.

There are different types:

There are also improved models of brushes in a plastic case. In appearance, they are no different from the above, only they have protection in the form of a housing or a plastic shell.

Why the Brushes on the Grinder Spark Strongly

Why the brushes on an angle grinder spark

Very funny without being witty. By the way, there are not a huge number of your posts with comments of a malicious nature. Not a sign of brain. Keep it simple. I don’t care about straightening: I anchored the slippers, the lamellas came off, I polished them with a file, what’s the problem? Naturally, I’ll immediately throw it in the trash, you don’t have to waste yourself, what difference does it make if it’s still a corpse? Does this give you any peace?

The armature in the engine rotates with movement, about 20 t.rpm. The collector, when performing repairs, is ground, ground with special stones on a working tool, and you. Ratfil is not super glue, which will not withstand such temperatures. Okay, it will be short right away. A small bang is not in the trash can.

What if it spins! Burnouts on the collector, instead of plastic there is coal, which the speakers cannot withstand. You are a happy person if you don’t understand how the collector breaks at such speeds, with a friendly greeting through the body. And you don’t ask for advice, write how to extend the life of the instrument.

Simplicity is enough for every sage. Others, having read, will take the same risk, as well.

P.S. I almost forgot to implement it. Maybe this nest is deformed, or otherwise covered inside with dirt, and when it’s not finished, even a brand new brush is not able to move freely along the nest and gets stuck. Remained in a semi-hung position, poor contact with the collector.

Last edited by Alex9797; 09/07/2016 at 13:16. Why do the brushes on an angle grinder spark a lot? No! I changed it for new ones. He pressed with his finger: the spring squeezes out, put it in: looked. There is a brush in a brush holder, which is placed on pins. Everything is visible. This is far from the first change; for 30 years everything was fine. Not important. the brush there was not worn out at all

The grinder wheezed as usual when the brushes were worn out, replaced them, turned them on, they burned out in 3 minutes, bought new ones that were more expensive than 3.5 pairs of different ones, the same thing, I didn’t even realize what happened to the anchor.

Integrity of rotor and stator windings

More serious problems that cause strong sparking of an electric motor are interturn short circuits of the rotor or stator windings. It is difficult to fix such a breakdown on your own. Signs of a problem with the winding are:

It will not be difficult for experienced electricians to figure out how to carry out electrical measurements:

For home craftsmen without special equipment, rewinding a faulty electric motor element is very problematic. Therefore, it is necessary to contact a service workshop. When you contact a repair center, for example, with a Samsung vacuum cleaner, they may offer to replace its windings or purchase a new motor.