An acquaintance gave me a repair * balgarka *, he says: they say she used to work, but now she doesn’t work. The machine itself is of the old model, as I understand it, the cutting disc is attached perpendicularly to the engine rotor (a dangerous thing). So when I disassembled it, I found that someone had tried to repair it before me. The wires inside were all twisted and in addition cut off. I need a wiring diagram for this canoe (drawing or sketch) to make it clear. The machine includes: a stator, a rotor (two brushes), a capacitor with three leads and a power button. Please help me figure it out, otherwise some kind of hat comes out, took to make the apparatus and did not.

Connection diagram * grinder * If without a smooth start, that's the whole circuit. The switch can only break one wire.

An interference suppression capacitor is placed with extreme terminals on the input after the button, the middle one on the stator iron.

Attached Images

Connection diagram * grinder * Yeah. As I understand it, the engine is connected in series. What does the smooth start circuit look like? It would be interesting to see.

Connection diagram * grinder *

Connection diagram * grinder *

or is this connection more complicated and requires additional details?

Yes, additional parts are required and not every grinder can fit them.

Page 2

Electric motors. frequency workers. connection diagrams.

• Mark this forum read

	Posted by Sayan, 20 Sep 2009		+ 201 Replies Views
	Started by Nub, 22 Jun 2008		+ 167 Replies 104182 Views
	Started by bim, 29 Jan 2008		+ 1153 Replies 1,506,144 Views
	Started by bim, Oct 26, 2011		0 replies 10,643 views
	Started by Nub, 24 Apr 2008		+ 1178 Replies 572175 Views
	Started by Semko, Jan 18, 2018		+ 16 Replies Views
	Started by orio55, 12 Mar 2017		+ 2837 Replies Views
	Posted by Nikomas, Today, 04:16 AM		+ 14 Replies Views
	Started by Kotelev, 19 Mar 2015
	Started by Pavel47, Jan 19, 2018		+ 14 Replies Views
	Started by lekalschik, 22 Apr 2013		+ 373 Replies 42226 Views
	Posted by Treugolnik, 13 Jan 2008		+ 1041 Replies Views
	Started by aftaev, Feb 14, 2010		+ 628 Replies Views
	By SergeyIL, Oct 22, 2014		+ 2107 Replies Views
	Started Timur05, Today, 12:22		+ 24 Replies 637 Views
	Started by IvanIvanov76, 20 Jan 2018		+ 66 Replies 1113 views
	Started by DocR, 02 Sep 2012		+ 82 Replies 26528 Views
	Posted by SEAswater, Yesterday, 16:44
	Started by dx1, 07 Jan 2018		+ 76 Replies 2477 views
	Started by PetrK, 05 Dec 2016		+ 103 Replies 4637 views
	Started by Valen, 12 Feb 2012		+ 76 Replies 39633 views
	Started by Wagner_POMA, Jul 26, 2013		+ 90 Replies 7055 views
	Started by N-S-Iv, 25 May 2017		+ 27 Replies 1218 views
	Started by duke_nuke, 24 Dec 2017		+ 117 Replies 3431 views
	Started by aleksandr16rus, 20 Jan 2018
	By archstyle, 26 Dec 2017		+ 45 Replies 1213 views
	By Impartial, 30 Sep 2016		+ 37 Replies 1460 Views
	By killdozer, 15 Jan 2018		+ 52 Replies 1448 views
	Started by Trefoil, Jan 14, 2018		+ 45 Replies 1062 views
	Started by Dr_Law, 18 May 2010		+ 1852 Replies 453353 Views

• You cannot create a new topic

www.chipmaker.ru

Repair of an angle grinder - do it yourself

Angle grinder Mastermax MCP - 2800

Angle grinder device

The angle grinder is an essential power tool in our household use. Depending on the installation of this or that attachment to the grinder, a varied amount of work can be performed.

In appearance and design, such grinders are so-called grinders, consisting of such parts as:

• protective cover;
• ventilation hole;
• push button switch;
• side handle;
• spindle lock.

The photograph shows the gearing mechanism, or in other words, the pairing of the mechanical part of the gearbox with the electric motor.

Grinder reducer and electric motor

For the mechanical part, the following are subject to wear:

• bearings;
• gears of the reducer.

I would think that giving a full explanation of the mechanical part of the gearbox simply does not make sense.

Attachments for angle grinders have a different assortment, depending also on the work carried out.

Wiring diagram - angle grinder

Let's concentrate our attention \ Fig. 2 \ on the following schematic image - the principle of operation of an electric motor.

The image of the red arrow in the figure shows the direction of the current - as it is commonly believed in the section on electrical engineering: »The current in the electrical circuit flows from the source \ clamp \ with a positive potential to a source with a negative potential. Moreover, the positive potential changes its sign to the opposite - from the resistance, which has a connection in the electrical circuit.

The electrical circuit here is closed on the collector, more precisely on the contact connections "winding - collector" \ for the rotor of the electric motor \.

That is, the rotor collector through the graphite brushes in the circuit has an electrical connection.

The two stator windings of the electric motor are connected in series in an electrical circuit.

In my practice, a similar electrical connection \ Fig. 2 \ for all elements of a collector electric motor - I have not seen that a wire with one potential has a direct electrical connection to the collector through a graphite brush, and the second wire with a different potential has a series connection through two stator windings with a second graphite brush.

The simplest and most complete explanation for these electrical connections is given directly by the electrical circuit of the collector electric motor \ Fig. 3 \. It is this connection of all elements that is typical for grinder motors, where the electrical circuit is closed on two rotor windings - in this way.

Motor winding connection

Here we can notice that the two windings of the rotor of the electric motor for this section are connected in series with each other and have a contact electrical connection "collector - brush".

The connection of two rotor windings relative to external source alternating voltage - parallel.

Among the causes of malfunctions of the electric motor of the grinder, such a malfunction as wear of the graphite brushes, which are in contact friction with the collector of the electric motor, can be cited.

This part, as well as other parts for power tools, can be purchased from specialized technical departments of stores.

Diagnostics of the electric motor - grinders

Diagnostics of the grinder's electric motor \ Fig. 3 \ should be carried out for individual sections of the electrical circuit of this circuit.

To do this, you need either an Ohmmeter device or a multimeter device. The device The multimeter is preliminarily for measuring resistance - set in the appropriate position.

To measure the resistance of two separate stator windings, one probe of the instrument is connected to the brush contact, the other probe of the instrument is connected to the corresponding pin of the electrical plug.

If this section breaks, - the device will accordingly indicate the absence of resistance.

If it works, the device will indicate the presence of resistance of one or another measured section of the electrical circuit.

By connecting two test leads of the device to two pins of the electric plug of the grinder, the display of the device will show the total resistance for:

• two stator windings;
• two rotor windings,

That is, it will indicate the total value of the resistance.

The change in the speed of rotation of the rotor of the electric motor \ Fig. 4 \ is carried out through the following electrical circuit.

Electrical diagram consists of:

• resistor R1 \ 0.5 W \;
• resistor R2;
• resistor R3 \ 5 W \;
• diode VD1;
• triode thyristor VS1.

Resistor R2 acts as a potentiometer, due to which the current in the load changes. The load in this explanation is the electric motor.

Triode thyristor - creates current blocking for the reverse direction. The control is carried out at the cathode.

Well, here we figured out the simple electrical circuits. It remains to make your decision in cases of malfunction - to send the electric motor for repair or to fix it yourself.

By contacting let's say a repair shop household appliances, - you can already state the cause of the malfunction of your power tool yourself.

This seems to be all.

zapiski-elektrika.ru

Grinder repair

An anchor is a rotating element of an electric motor containing windings. A collector is a place on an anchor to which all windings are brought out. It looks like a row of insulated plates. The stator is the stationary part of the electric motor containing the windings. The brushes are carbon parallelepipeds that supply current to the collector.

Reducer - a mechanical device for transmitting rotation with changes in power and rotation speed.

The most popular tool in everyday life after a drill is an angle grinder or, as it is often called, a grinder. The grinder is used for cutting metals, wood, concrete, grinding different surfaces, cutting openings, doors, niches. If there is a grinder, then you can always find a use for it and it is especially offensive when it ceases to function normally, jerks, twitching, a burning smell appear ...

The grinders are all arranged in the same way: an oblong body in which the engine and gearbox are located, a handle and a protective casing are screwed on the side.

On the body of the grinder there is a sticker with the initial data. Here you can find both the personal number of the grinder and the supply voltage - 230 V. This refers to the maximum permissible voltage in the network. The frequency of the current in the network is 50 Hz. Consumption current - 5 A. Power consumed from the network - 1100 W, it is obtained as a product between voltage (220 V) and current (5 A) multipliers. The rotational speed of the disk installed on the grinder is 2800-11000 rpm. The armature itself rotates at a higher speed than the disc. Specifically on this grinder, step regulation of the rotation speed is possible. The disc installed on the grinder has outside diameter 125 mm, disc fixing nut with M14 thread.

A household tool designed for a phase voltage of 220 V has an armature winding and a stator winding. The transfer of energy from the network to the armature is carried out using graphite brushes. The mains voltage is supplied to the switch, which is mechanically connected to the power button of the grinder. The stator winding consists of two halves that are not electrically connected. The armature winding consists of many windings, but at any given time, the brushes connect only two armature windings.

When the grinder is turned on, the current is supplied to the input of half of the stator winding, the output of the stator winding is connected to the brush holder into which the brush is inserted with the help of a spring. The brush transmits current to half of the armature winding, on the other hand, the other brush receives current and through the brush holder transfers current to the other half of the stator winding. The current went in and out of the grinder. If the entire electrical circuit is in good working order, then the armature will begin to rotate.

Reverse, i.e. the change in the direction of rotation of the disk can be carried out by interchanging the wires going to the brushes from the stator windings. Just disconnect the wires on the brushes and swap them.

At the end of the grinder's body there is a red wheel for stepwise control of the armature rotation speed and a screw for removing the casing.

In this type of grinder, the brushes themselves are located inside the case and there is no access to them, but the developers have simplified the replacement of the brushes when removing the casing. After unscrewing the screw, the plastic plate is removed and the outer casing moves towards the cord, exposing all the insides, including the brush holders.

The speed control mechanism is electronic. The whole circuit is filled with epoxy resin and only the speed control wheel and the radiator are taken out. What is hidden inside is the trade secret of the company. When the unit fails, the speed stops being regulated, but remains at the maximum level. In any case, you should not despair, but in series with the grinder, you can turn on the most common dimmer - the dimmer. It can be used to adjust the speed of any collector motor. alternating current, the main thing is that the engine power does not exceed the dimmer power.

On both sides of the body there are steel brush holders with springs in the form of a curled steel strip. The spring is needed to keep the brush pressed against the armature collector even with strong vibrations and heating of the armature itself.

The spring presses the brush and as the brush is erased, the spring sinks lower and lower into the steel brush holder. Brushes wear off and shrink. When their length becomes insufficient, the grinder stops working. V expensive models there is a spring inside the brush, which pushes the brush away from the armature collector. In cheap models, the brushes are not supplied with a built-in spring.

When choosing new brushes, it is better to contact the service centers of your specific grinder manufacturer. The fact is that just as a graphic artist chooses twenty different simple pencils with different softness, so the manufacturers of grinders specially develop brushes for a certain type of collector. If you use other brushes, for example from a generator for a VAZ, then the anchor will most likely burn out soon, but for the first time such brushes will work as a solution to the problem.

The grinder's power button is a plastic box with a mechanical linkage. The box is bulky enough to assume that it commutes high turn-on currents and that the button goes not only into this equipment.

At the head of the grinder there is a reducer that increases the rotational speed of the disc to 11000 rpm. The stem of the reducer, on which the disc is put on, contains a sheared washer, which firmly sits on the shaft and has a support platform with a rubber ring for seating the disc.

Nearby there is a foot with cuts, which fixes the protective cover. For greater safety, the protective flap can be slid and then locked. The foot is pressed down to the grinder and the flap is shifted to the desired level, after which the foot is released and it fixes the flap.

Nuts for fastening the disc are self-tightening SDS and conventional with wrench holes.

The gearbox is supported by four screws. If you unscrew them and open the cover carefully with a screwdriver, you will see the parts of the gearbox. The gear on the armature shaft has a left-hand thread and is threaded to the armature shaft.

The gearbox uses rolling bearings, i.e. ordinary bushings abundantly lubricated with grease. The teeth on the 1100 W model are straight, apparently this is quite enough for locksmith work, but in the 1500 W models, gears with curved teeth are used.

In order to remove the armature, gently remove the brushes, remove the gearbox and pull the armature out of the body using the gear. At the other end of the armature, closest to the cord, a rolling bearing is put on, which is recessed into the plastic of the body. Pull firmly and carefully to remove the anchor.

The anchor is a steel rod on which a steel cage made of plates is pressed. Coils of insulated copper wire are laid in the grooves of the cage. All the ends of the windings are brought out to the rear end of the armature, called the collector. At the front end of the armature is a gear for transmitting rotation.

To gain in the force that needs to be applied to the disc for operation, a gear transmission is used. For a 2 kW grinder, the armature gear has 10 teeth, and the circle gear has 41 teeth. It turns out that at a wheel speed of 8000 rpm, the armature rotates 8000X41 / 10 = 32800 rpm. If we take into account that the number of collector contact plates is 36, then 32800X36 / 60 = 19680 Hz. This is approximately the frequency that interferes with the network and to eliminate which ferrite rings are needed.

The disc gear is located on the shaft. In production, the gear was heated and the shaft was cooled. After that, the gear was put on the shaft. The resulting connection is notable for its low cost, simplicity and practically does not make it possible to remove the gear without damaging the gearbox housing. Heating the assembled part will cause expansion of both the shaft and the gear. The only thing that can be used to remove the gear is a puller. In this case, the grips of the puller legs must be thin and strong enough to fit into the small gap between the body and the gear.

The shaft gear is threaded. Probably, the manufacturers calculated that the armature gear flies more often than the gear gear. On this model, the gears are helical to increase the power output.

The gear has a RIGHT thread. To spin the gear, you need to wrap it with a rag so as not to break the teeth when unscrewing it, clamp it with a gas wrench and turn it COUNTER-CLOCKWISE.

After removing the gear, it becomes clear that the thread is not made throughout the entire height of the gear, but only in its small section. The unthreaded section allows you to put on the gear evenly, without distortions.

Malfunction		Elimination
Manifold sparking, odor, body heat, popping sound	Collector dirty	Disassemble, remove the anchor, clean the collector
The collector burned out	Replace anchor
The grinder does not turn on	Brushes worn out	Disassemble and replace both brushes
Break button	Disassemble, replace the button
Defective power cable	Splicing the breakdown site and isolating
Mechanical sound when rotating the disc	Gearbox worn	Disassemble, replace the gear, lubricate with cyatin (grease, lithol)
The disc is constantly gaining momentum and the grinder goes into gear	Turning closure of the stator windings of the grinder	Disassemble, replace windings (if possible)

www.volt-220.com

Do-it-yourself grinder repair

Any, even the most reliable tool ever fails, and this happens, as a rule, at the most inopportune moment. Do-it-yourself grinder repair allows you to revive the tool with some minor malfunctions. In order to carry out the necessary work at the right time, you need to know the design of the apparatus and have an idea of ​​the possible causes of its breakdown. In most cases, repairing a grinder with your own hands is not very difficult and can be done by anyone. Moreover, the tools of different companies differ little from each other, except perhaps in the arrangement of parts and appearance.

Grinder device.

Instrument device

The grinder or, more precisely, the angle grinder (angle grinder) is based on the transformation of the torque of the electric motor into the rotation of a special disk, the axis of which is perpendicular to the axis of the motor. Depending on the type of disc, the tool allows you to cut or grind workpieces.

The schematic diagram of angle grinder is given. Any tool consists of the following main parts: a solid body made of two halves, with a handle for ease of use (or without it); electric motor of different power; electrical part; reducer with overload clutch. The latter provides a decrease in the rotation speed and rotation of its axis by 90 °, and the safety clutch blocks excessive acceleration of the disk in case of violations in the gearbox.

The base of the gearbox is made up of 2 bevel gears for changing the direction of rotation. In devices with a power of up to 1.1 kW, spur gears are most often used on the engine anchor, and with higher power, helical gears.

Do-it-yourself grinder repair allows you to revive the tool with some minor malfunctions.

When repairing a grinder with your own hands, you should initially proceed from two principles: analyze the circumstances that preceded the failure of the tool, which will help to establish the cause, and repair the tool, moving from simple to complex. First, you need to eliminate the simplest malfunctions, and then look for more complex breakdowns in the gearbox or electric motor.

The electrical part of the grinder is considered the most capricious piece of equipment. Its parts may fail if the device is overloaded during operation, water or dust gets in, from overvoltage in the network. In a mechanical system, bearings are often the weak link. Breakdowns in this part are caused by a violation of the operating mode, dirt and foreign objects entering the gearbox, insufficient care of the tool (untimely and poor-quality lubrication).

The uninterrupted operation of any good grinder depends on the observance of the following conditions: the use of the device only for its intended purpose, compliance with regulatory technical characteristics, exclusion of debris from entering the case and cleaning from dust, high-quality and timely lubrication of the mechanical part of the tool, carrying out Maintenance according to the attached instructions in full and within the specified time frame.

The basis of the electrical part is a 220 V AC motor, consisting of a stator and a rotor. An important element is a collector through which electric voltage is supplied to the rotor with the help of copper-graphite brushes. The motor is started through a starting capacitor. To control it, a special circuit and a trigger mechanism in the form of a push-button switch are assembled. The speed control is carried out by the rotation speed control mechanism.

Typical faults and required tools

One of the most common malfunctions is that when you press the start switch, the grinder does not turn on. When repairing a grinder with your own hands, you will need the following tools and devices:

Diagram of the inside of the grinder.

• tester;
• ohmmeter;
• megohmmeter;
• a set of keys;
• screwdriver;
• hammer;
• pliers;
• vice;
• tweezers;
• scissors;
• soldering iron;
• emery cloth;
• brush.

The first step in determining the cause of such a malfunction is to completely disconnect from the network and try to manually rotate the disk. If the disc is not going to spin or is spinning very tightly, then the reason is usually related to the mechanical part. In the case when the disc rotates freely by hand, one can hope for an elementary reason causing the lack of electricity to the motor.

An attempt to repair the instrument begins by checking the integrity of the supply cord and plug. To do this, the tester detects a wire break, and when it is detected, the cord is simply replaced with a new one.

The next step is to test the pushbutton switch. After disassembling the trigger, all contacts are checked for a short circuit. Sometimes, to fix a button malfunction, it is enough to clean the contacts with a small sandpaper or solder the wires if they are broken at the junction with the switch. Most often, the button cannot be repaired and is replaced with a similar power (the brand and parameters are indicated on the switch body).

If the check of the cord and the button has established that the cause of the malfunction is not in them, then the next step is taken - checking the brushes. They are sufficiently loaded elements during operation, and their periodic wear - natural process... To check them, the body of the grinder is opened, and the brushes are removed one by one from the brush holders. Wear assessment is carried out visually: more than 40% is considered critical. Unsuitable brushes must be replaced, and new part must be exactly the right size. At the same time, the condition of the collector assembly is assessed: there should be no burning or damage on the surface. It is advisable to clean the contact surface with alcohol.

Malfunction of the electric motor

The most typical malfunctions of an electric motor are an open or short circuit of the turns of the stator or rotor windings. In addition, damage to the magnetic circuit and the collector can become the causes of failure. To determine the cause, the motor is disassembled, that is, the armature (rotor) is removed from the stator. First of all, a visual inspection is carried out, which, when a short circuit occurs, easily determines the place of winding burnout.

The cause and location of the damage can be determined using LATR, by directly supplying electricity to the engine (bypassing the electric circuit of the grinder) and gradually raising the voltage up to 240-250 V.

In this way, the following breakdowns are detected:

• a short circuit between the turns of the rotor winding is manifested by an increase in sparking along the collector node in proportion to an increase in the input voltage;
• a characteristic manifestation of a closure is an attempt to turn the rotor in different directions at a low voltage;
• an open loop or poor contact of the rotor winding with the collector is detected when a narrow spark appears on the brushes, and with a tendency to increase in proportion to the rise in voltage;
• the breakdown of the stator winding is ascertained with an abrupt increase in the spark on one of the brushes at a higher voltage;
• imbalance of the rotor is determined by a large spark on the collector and noise during rotation.

Another way to determine winding burnout is to measure the insulation resistance with a megohmmeter. Wire breaks in the windings can be detected by measuring the resistance between the contacts on the collector with an ohmmeter. The most accurate measurements can be made with a special device PUNS-5.

Mechanical faults

If it is impossible to manually scroll the disc, wedging it during operation, or if there is no rotation with obvious signs of turning on the electric motor (buzzing), a malfunction of the mechanical part can be assumed. Most characteristic signs: breakage or abrasion of gear teeth, seizure or destruction of bearings, jamming of gears when foreign objects enter.

The condition of the gears is assessed visually. The presence of uneven wear of the teeth or damage to at least one tooth requires replacing the gear with a new one, and both gears must be replaced at the same time. An important sign of their destruction is the appearance of characteristic sounds: rattle, rumble.

Our company offers power tools for construction and repair, consumables, related equipment and spare parts of the famous Japanese brand "Makita". As an official dealer, we provide the appropriate certificates for all instruments sold. We sell only original spare parts for any Makita tool.

You can choose the required part for the tool on this page. To successfully complete your application, you need to familiarize yourself with a few simple steps to prepare your order.

So how to choose the right part correctly and quickly?

To go directly to the selection of the required spare part or a group of spare parts for a particular tool, you must from the main page of the site go to the hyperlink "MAKITA SPARE PARTS", which is located in the upper right corner home page site. If this item is successfully completed, you will be taken to the "Makita Spare Parts" page.

Now we see all the tools of the Makita company grouped by type and schematically shown. We select the group whose power tool requires repair with the replacement of a spare part. You can use vertical scrolling. For example, let's select "Drills and Saws".

On the page "Drills and Saws" you can find the entire list of models for which you can order parts. Carefully select the model you need from the list of models provided by the site and activate the model you need by pressing the left mouse button. Let's choose one. For example, Makita 6310.

So, after choosing a specific model (in our case Makita 6310), you will see a page () that shows an assembly drawing of the selected model. Here it is possible to print it on a printer (see Print drawing). On the right in the table there is a list of positions, names and quantities of parts in the tool. Each detail of the drawing is interconnected with its position in the list. When you select (when you move the mouse pointer over a part), the arrow changes to a hand, which allows you to mark the specified part in red by pressing the left mouse button. At the same time, the position of the same name in the list is marked in light blue (blue), and an application table appears at the bottom of the page. Moreover, it is worth paying attention to the fact that with the mouse you can select both the part in the drawing and its position in the table. The table below appears only when at least one part is selected. Next, you need to decide what to do. There are several options under the generated order. You can cancel everything (reset everything) and start the selection over. You can continue the selection in other models (in this case, the order already made will also be displayed on the monitor), or you can go to the order form by clicking the appropriate link.
Notes: Right in the application (in the table with the selected parts), you can use the arrows in the last column to put down the number of parts you need.

Please note: the minimum order amount is 1000 rubles

Having finally completed the Application, you can proceed to the order form, where you will be asked to fill in three information fields... Contact person (how to contact you), number mobile phone and work or home phones. Having sent the order for execution, wait for a call from the manager.

The company's employees - experienced professionals - will process the received order and within a day will inform you about the presence or absence of certain parts, their quantity, the price of the part and the total cost of the entire order. In the absence of any spare part, you will be informed about the time of its receipt from the manufacturer and, in agreement with you, may notify you again about this.

Usually, the order execution time does not go beyond three working days. You can learn more about the delivery of goods by visiting the "Delivery" page.

The practice of this service shows that customers are using it more and more often. And the tool itself, and consumables, and spare parts for them you get without leaving your apartment. You can discuss all claims and wishes with a manager or a delivery specialist.

Schematic diagram of the grinder

Almost every craftsman, who often works with metal, knows the structure of the electric circuit of the grinder. The grinder is the most commonly used tool for cutting metal. This tool is a source of increased danger, therefore, the electrical and mechanical components of the structure should be checked before each use.

Principal wiring diagram of the grinder.

The angle grinder, which in the post-Soviet territory bears the name “Bulgarian”, was 3-4 decades ago the dream of every home craftsman. 30-40 years ago this working tool was produced by one manufacturer, the Eltos-Bolgarka plant, located on the territory of Bulgaria in the city of Plovdiv. At the moment, manufacturers offer consumers various models and modifications of this tool, however, the main structural units have practically not changed. Most of the structural elements on different models and modifications differ only in size.

The electrical component of the grinder design

For the entire period of its existence appearance the instrument remained practically unchanged. The grinder has an oblong body in which an electric drive and a gearbox are mounted. A handle is fixed on the side surface of the tool to hold the tool in the working position; additionally, to protect the master, a protective casing is attached to the tool body, covering the working element.

The device is an ordinary grinder.

The grinder, like any tool, may fail during operation. In most cases, repairing work equipment and its electrical component is required to eliminate breakdowns.

In order to make repairs, you need to know the device not only of the mechanical part, but also the wiring diagram of the tool. For quality repair you should study the principle of operation of the grinder. The electric diagram of the grinder includes the following structural elements:

• anchor;
• collector;
• electric brushes;
• reducer;
• stator;
• start and lock button;
• power cable with a plug for connecting to a household network.

Each of the components is designed to perform certain functions in the electrical circuit, and the failure of any of them leads to a stop in the functioning of the device. For example, an armature is a rotating element in an electrical circuit. It transfers rotary motion to the grinding disc. In order for the tool to function properly, the armature must rotate at high speed. The higher the rotation speed of this structural element, the higher the power of the device.

Functions performed by the components of the grinder

Grinder anchor device.

The collector is an anchored platform, to which all power and control cables are brought out. The task of the collector is to conduct the signals passing through the windings to the engine and the control unit. When removing the housing cover, the collector immediately catches the eye by the presence of large polished plates.

Electric brushes in the design of the device are used to transfer electric current to the collector from the power cable. During operation, if the brushes have a normal technical condition, then the resulting even glow is visible through the ventilation holes of the case. If the glow is not observed during the switching on of the device or has a pulsating character, then this is a sign of problems with this electrical component of the device.

The gearbox is one of the most important structural components. Its purpose is to transfer the rotational energy from the rotating armature to the grinding disc, ensuring its rotational movement. The gearbox is responsible for the frequency and power of rotation of the grinder's working tool.

The stator is a technically complex unit of the device design. The stator design includes windings, which, when interacting with the armature windings by means of a magnetic field, set the latter in motion. The stator coils have a certain number of turns, calculated in accordance with the requirements of electrical engineering. If this unit fails, rewinding of the coils is required. This operation requires certain knowledge and skills. It is better to entrust the rewinding of the stator to a specialist workshop.

Electrical diagram of the grinder device

The internal structure of the grinder.

In the process of carrying out repairs, it is not enough to know the purpose of the main structural elements of the instrument's wiring diagram, you still need to be able to read it. The wiring diagram of the grinder is not very complicated. However, even such a design can in some cases cause difficulties when carrying out repairs.

The wiring diagram of the grinder is arranged in a certain way. Two stator coils are connected in series through a cable to a household network with a voltage of 220 V. These coils are not electrically connected to each other. The switching on and off of these windings is carried out mechanically using a switch. This switch is mechanically associated with the start button. Each of these windings is connected through a switch contact with a corresponding graphite brush.

Further, the electrical circuit with the help of two windings connected in parallel to the graphite brushes goes to the rotor coils. The circuit is closed at the collector terminals. The anchor winding includes a large number of separate small windings, but only two are connected to the graphite brushes.

Most often, a grinder breaks down precisely because of breakdowns of its electrical components and a break in the electrical circuit.

To diagnose and detect faults in the electrical circuit, a special device is used - a multimeter. This device may be required not only to check the performance of the grinder, but also any other electrical tool or device.

The most convenient way to start diagnostics is from the electric current injection site. Verification is carried out in stages, checking and ringing each of the elements of the electrical circuit of the device.

Minor repairs of the grinder

Causes of malfunction of the grinder.

If, after pressing the start button, the tool does not start, it is likely that the cause of the breakdown is a small malfunction that you can fix on your own. Diagnosis is best done on a simple to complex basis. Most often, the break in the electrical circuit is the section from the power supply to the graphite brushes. During the repair process, remove the casing and test the circuit at the section where the electric current is supplied to the start button. If there is no current supply to the button terminals, then the supply electric cable should be replaced.

If the electric current flows to the start button, but is not transported further, then the breakdown of the tool consists in the failure of the start button. In case of failure of the button, it should be replaced. For this purpose, carefully disassemble the trigger and replace the start button. When connecting, pay special attention to the terminals, since incorrect connection can lead to burnout of the instrument windings.

Replacing graphite brushes

Failure of graphite brushes is one of the most common breakdowns of a grinder.

The service life of this structural element of the tool is about 1.5-2 years. The process of replacing brushes is not particularly difficult. To replace these structural elements, you will need to open the tool body. After opening the case, using a screwdriver, the brush holders, which are fixed to the collector, are lifted and shifted.

Replacement of brushes should be done only with branded ones purchased from special stores. When purchasing a new brush, compare it with the original one removed from the tool. The new brush should completely, in all respects, match the one removed from the grinder. After installing new brushes, you should check the smoothness of its movement.

After installing and checking the smoothness of movement of the brush, it is fixed with a brush holder. After fixing the brush holder, the tool body is closed.

Replacing brushes is the only operation that during the repair process should be carried out on your own, it is better to entrust the rest of the repairs to specialists.

Do-it-yourself grinder repair

As you know, nothing is eternal and even the tools of brand manufacturers break, not to mention the so-called "consumer goods". And the grinder (angle grinder) is no exception. By the way, they began to call angle grinders "grinders" at the time of the Union, because then this tool was produced in Bulgaria and the first models were supplied from there. The grinder, as a tool, has become very widespread due to its versatility and ease of use. There are also many varieties and models of grinders, but the principle of operation and device is not fundamentally different. Therefore, having considered the device of the tool, possible malfunctions and repair methods, they can be applied to any model of the grinder.

Grinder device relatively simple. The basis of the tool is its body, inside which there is an electric motor, a starting device and a gear transmission to the spindle, on which various attachments are attached.

The body is made of strong impact-resistant plastic. Depending on the power, there are different dimensions and shapes of the tool. Some models have an angular speed regulator, which is designed to optimally select the speed for various types of work.
Another component could be a gearbox. The gearbox is designed to create optimal conditions for the transfer of rotation from the rotor of the electric motor to the cutting or grinding wheel. This leads to a decrease in the number of revolutions on the output shaft of the gearbox. Correctly selected rotational speed and wheel diameter are the key to the most efficient tool performance.

A button for replacing the working disk, when pressed, which locks the disk in a certain position, preventing it from scrolling when removed.

The overload clutch acts as a limiter in the event of a sudden reactive torque. On the other hand, when the disc is jammed in the material, the grinder itself begins to rotate abruptly, which can lead to injury to the worker. This clutch does not allow such rotation.

The electric motor consists of a stator and a rotor as standard. The stator is located in the guide lugs of the plastic housing of the grinder. On the back of the stator there is a special device called a brush mechanism. It contains copper-graphite brushes. Brushes are required to transfer voltage to the rotor through the manifold assembly.

The rotor is located inside the stator and is fixed in the housing in bearing assemblies, which are inserted directly into the tool housing. The front bearing assembly is usually made in a metal plate, or this plate can be made of an aluminum alloy.

The gearbox housing of the grinder is almost always made of aluminum alloy and has several threaded holes for attaching an additional handle. By screwing the handle into various holes, you can change the planes of location during operation.

The reducer consists of two gears, with the help of which the direction of the output shaft changes by 90 degrees and the rotation speed is reduced. The ratio of the number of teeth on the primary gear to the number of teeth on the secondary gear is called the gear ratio.

Typical malfunctions of grinders and methods of diagnostics and repair

The grinder suddenly stopped working .
The first thing to do is disconnect physically from the network and manually rotate the disc. If the disc does not spin or is spinning very tightly, immediately disassemble the instrument for visual inspection. If it turns easily, then the most likely thing is that electricity does not reach the brushes of the electric motor. That is, the problem lies either in the power plug, or in the wire itself, or in the mechanism of the "Start" button. It is enough to disassemble the case and "ring" the cable with a conventional tester, or in some other way, for the presence of a break. After eliminating the break or replacing the wire, the grinder will work.

The wire and plug are guaranteed to be intact, but the tool still does not work.
It is necessary to disassemble the trigger mechanism, and it is advisable to mark the removed contacts - if they are subsequently connected incorrectly, then the winding may burn out or the anchor may jam. Repair of the trigger mechanism is not often possible - it is easier and more reliable to replace the trigger button with any similar one with suitable power parameters. Such a button is not so expensive and you can buy it in any store of the corresponding profile.

The start button and the power wire are in working order, the grinder does not work.
Check brushes and brush holders. There may be a breakage or complete wear of the brushes. The resource of these devices is usually limited to several years, of course, it all depends on the intensity of use. Eliminate open or replace brushes.

Then there are more serious malfunctions, respectively, and repair requires certain knowledge and skills.

- breakage or licking of the gear teeth of the gearbox;
- jamming of bearings;
- failure of the armature or stator;
- failure of the control electronics;
- failure of the collector;
- deformation of the body;

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

Breaking out the spindle lock button.
The reason is just one careless movement, namely pressing (deliberate or accidental) on the button when the disc is spinning. Sometimes breakdowns occur due to attempts to remove a jammed disc using a button. Many grinders have slots on the spindle where the disc is attached specifically for a regular open-end wrench, look at your grinder, most likely you have one too. So, it is better to use them and an open-end wrench than a disc lock button.

Chipped gear teeth.
Usually they arise due to jamming (in such a situation, tool breakage is not the worst thing that can happen). A rumble in the gearbox is a sign of a malfunction. If the gear has lost two or three teeth, then the tool will not be able to cut.
In this case, it is necessary to change the gears by a pair and the gear itself and the bevel wheel. When you go to the store for gears, do not forget to write down the name of your grinder and its power.

Failure of the electric motor.
This often happens with tools that work in dust and which are forced to rest in the sand or on the ground: the sucked-in dust grinds off the winding. However, you can ditch the motor without dust - by strong overloads, especially if the tool is low-power. Therefore, in small Bulgarians, not only the anchor, but also the stator often burns out. Small grinders also have a breakdown of the electronic speed control unit. If you use a grinder to cut very dusty materials, in particular slate, a stocking put on in place of the ventilation slots in the housing helps a lot to protect the tool.

Bearings.
Another sore spot of the Bulgarians (as well as other twisting power tools). Few machines stand out with strong immunities against dust, and high rpm suggests rapid wear. In general, bearings are not the worst failure, they are easy to change. However, it is important to make a replacement on time, otherwise there is a greater likelihood of a more serious breakdown, the repair of which is comparable to a purchase.

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

We start repairing the grinder's stator by cutting off the frontal parts of the winding, the remnants of which we take out. Next, we make a new winding using a template sandwiched between two large plates on an axis, which can be inserted into an electric drill. The main thing is to achieve an identical number of turns, made with the proper density and withstand the thickness of the wire. We insert two coils into the stator case, we make conclusions from the same winding wire, insulating with flexible tubes of the appropriate diameter.

Reducer
In models with a power of up to 1100 W, spur gears are usually used, mounted on an anchor, but grinders with a higher power, for example, 1500 W, require helical gear wheels. Both options are tapered, since the axis of the gear stem intersects with the armature shaft, and transmission is possible only by angular engagement of the teeth.
As a rule, repairing the grinder's gearbox consists only in replacing the gears. If a disk gear wheel breaks down, it will be very difficult to remove it for replacement, this unit is best fixed in the gearbox.

Speed ​​regulator
Almost all modern models of drills, jigsaws, screwdrivers have a speed controller. But not all grinders (grinders) are equipped with such a mechanism. In principle, a regulator is not needed for cutting metal with a cut-off stone, but for grinding it simply cannot be replaced. The proposed scheme of a home-made regulator is very simple and reliable. There are not many parts and they are not expensive. If you already have a grinder without a standard speed governor, then you can easily improve it.

Can be assembled separately in a box with a power outlet and used as a carrier with a power regulator. Or you can immediately assemble the regulator in the grinder body and remove the resistor handle.

Grinder rules and preventive maintenance

The power tool must not be allowed to operate under load for a long time at significantly reduced speeds (this can be determined by ear) in comparison with idle speed, and even more so, clamping (blocking) of the tool must not be allowed, otherwise it will burn out within a few seconds.

Do not turn off the power tool immediately after operating at reduced speed. To prevent local overheating, it needs to run for some time (more than 1 minute).

It is important to strictly observe the intervals for changing (adding) the lubricant and its quantity specified in the operating instructions.

If the noise increases during the operation of the grinder or if its performance deteriorates, it is necessary to conduct a prof. service.

Prevention consists in complete or partial disassembly of the tool, cleaning, lubrication and replacement (if necessary) of some parts.
Timely replacement of relatively cheap parts that wear out quickly will save more expensive durable components, which in the end will lead to savings in tool operation, eliminate premature repairs and significantly extend the life of the tool.

Do-it-yourself grinder repair. Grinder device

After a certain period of use, the grinder is characterized by such breakdowns as wear of graphite brushes, burnout of the stator windings and so on. Of course, wear itself also takes place in terms of mechanics. For a complete acquaintance with the topic: "How to repair a grinder", - consider the electrical circuit of an alternating current collector motor, since such an electric motor is installed in the grinder.

AC brushed motor circuit

The diagram (Fig. 1) shows the electrical connections of the stator windings, rotor and graphite brushes. The graphite brushes in the electric motor are installed in the brush holders. The brushes are in contact with the collector lamellas. One ends of the stator windings are connected to an external power source. The other ends of the stator windings are connected to graphite brushes, the electrical circuit is closed on the rotor windings.

The speed controller of the grinder is connected by wires to the collector motor circuit in series. The connection diagram of the speed regulator should be indicated on the regulator body itself, or in the operation manual of the grinder.

Grinder device

On the device of the grinder, everything is indicated in the figure and no clarification is required. With the help of the driven and driving bevel gears, rotation is transmitted from the electric motor to the gearbox shaft.

Collector motor malfunctions

Possible reasons for the breakdown of the electric motor of the grinder are as follows:

• wear of the rotor collector;
• wear of graphite brushes;
• burnout of the stator windings;
• burnout of the rotor windings;
• lack of contact connection of the ends of the stator windings with graphite brushes;
• mechanical damage to the cable wire at the base of the plug;
• mechanical damage to the wire along the length of the cable;
• failure of the capacitor,

as well as other possible causes associated with any rupture in the electrical circuit.

Checking the collector motor

The cause of the malfunction of the collector motor is detected by a measuring device, for example, such devices as:

If a measuring device is not available, any break can be detected with an indicator screwdriver.

So let's say that the burnout of the stator windings (Fig. 3) is usually caused as a result of general overheating of the electric motor. In this case, the insulation of the wires in the stator winding is disturbed and the winding itself can short-circuit to the frame body. To establish such possible reason malfunctions, one tip of the probe of the device is connected to the brought out end of the stator winding wire, the second tip of the probe is connected to the stator frame housing.

To check the rotor winding, the probes of the device must be connected to the lamellas (plates) of the collector (Fig. 4).

That's all for now. Follow the rubric.

Please tell me the cross-section of the stator winding wire of the grinder Kolner 580 wt. Number of turns 167

08/09/2014 at 13:38

Hello Damir. Here, in general, it is not necessary to carry out computational calculations. You need to take a piece of wire from the stator winding of the grinder and measure the cross section copper wire calipers \ turning measuring tool \ or with this piece of wire, contact the seller and consultant when purchasing a wire. It is advisable that the rewinding of the stator of the electric motor is carried out by an appropriate specialist, since the resistance of the winding is also taken into account here.

06/14/2015 at 18:00

Hello gentlemen electricians!
Please tell me why the electric motor of the grinder can warm up during idle rotation for 2-3 minutes after switching on to a cold one after replacing the rotor.
Initially, when working with a diamond disc on a new grinder, it was overheated by stopping the disc at full rotation of the rotor. Dismantled, checked the rotor - an open circuit on the collector (two black lamellas). No more items were checked. We installed a new rotor - it began to warm up without load.

06/15/2015 at 06:26

Hello Pavel. I believe that with this malfunction, you will also need to inspect and check for resistance the stator winding of the grinder's electric motor. A possible reason for the rapid heating of the electric motor is the cause of the turn-to-turn circuit in the winding, that is, the insulation is broken (coating the wires with varnish). When the rotor stops abruptly, a current is generated in the electric motor circuit that exceeds the nominal value several times. This is just my personal judgment and I would also like to know the opinion of my friends, participants in the correspondence.
Victor.

01/17/2016 at 00:33

Hello!
Please tell me - after replacing such an anchor of the perforator http://rotorua.com.ua/product/jakor-perforatora-einhell-858/ the barrel of the perforator began to rotate in the other direction. What could be the reasons? Defective anchor or some mismatch? thanks for the answer.

01/18/2016 at 05:32

Hello. Maybe you need to switch the reverse? If, when switching to reverse, the perforator barrel will still rotate in the opposite direction, try changing the wires going to the brush holders.

Comments are closed.

Do-it-yourself grinder repair

The angle grinder (grinder) is very popular in everyday life when carrying out various repair and construction work, therefore the device is often exposed to overloads and harsh operating conditions, which invariably leads to the occurrence of a depletion in the mechanism. Repair of a grinder in most cases can be done by hand.

What is produced in the grinder

In the device, almost every grinder component is exposed to loads, which can, for various reasons, lead to a general failure of the device:

1. The rotor is the most loaded part of the grinder, because it is subjected to both electromagnetic and mechanical influences:

• Numerous armature windings (part of the rotor) have a fairly thin wire with a protective lacquer paint, which is destroyed by temperature overheating or jamming of the grinder shaft. The wire burns out or a short circuit occurs between the turns. In such a situation, DIY repair of the grinder is carried out only by replacing the rotor.
• The collector on the rotor is a powerful group of contacts that are generated mechanically due to the friction of the brushes and burn out due to sparking.
• Bearings are located on the rotor shaft, which are sufficiently heavily loaded, which causes depletion to the extent of their destruction. Therefore, if extraneous noise occurs during operation, do-it-yourself repair of the grinder with replacement of bearings must be carried out immediately. In this case, there is a transmission groove on the rotor shaft, which is also generated with a decrease or destruction of the "tooth" shape. The elimination of the breakdown is carried out only by replacing the assembly.

1. The stator has several powerful electrical windings that are very rarely damaged.
2. The mechanical transmission requires periodic cleaning and lubrication, and if increased gaps in the pair are found, they must be replaced.
3. Electric brushes are made from graphite-based materials, which results in faster wear and tear. Replacing brushes is a fairly easy undertaking, and individual models of grinders can be repaired without disassembly, because have direct access to the brushes.

Simple DIY repair

Do-it-yourself grinder repair to avoid defeat electric shock it is imperative to carry out in accordance with the rules of electrical safety, therefore, in the absence of such knowledge, skills and abilities, it is recommended to contact professional craftsmen. Troubleshooting and repairs should be carried out in a specific sequence:

• The instrument does not turn on, while the buzzing, like from a transformer, does not arise - it indicates a malfunction in the electrical circuit: the speed control button is corny burned out, there is no contact in the brushes due to their use, or one of the conductors is broken. Do-it-yourself grinder repair is carried out in a sequential check of all electrical elements to identify a break: wire, button, contacts on brushes, motor windings.
• When you try to turn it on, the instrument emits a humming sound without rotating the shaft - there are serious mechanical and electrical violations. It is necessary with the device switched off to check the free rotation of the shaft, because it can be partially jammed, which prevents the rotor from spinning. If the motor shaft rotates easily by hand, and when turned on, it does not spin, then there is a short circuit in the device. Do-it-yourself grinder repair comes down to complete disassembly and replacement of the rotor with brushes.
• High sparking in the area of ​​the brushes with the impossibility of bringing the motor shaft to full speed - increased production of brushes with weak contact. Immediate repairs are required as sparking causes increased heating of the device, and the resulting arc is capable of breaking through the electrical part of the grinder, which is unsafe.
• The detection of crunches, knocks, any strong vibration manifestation with a properly working electric motor of the device indicates the development of a transmission mechanism or bearings. Failure requires immediate total disassembly of the tool with rigid rejection of all worn out parts. Ignoring the urgency of the repair leads to the complete failure of the grinder.

Self-repair rules for grinders

For the sake of safety and the possibility of repairing the grinder with your own hands, you must adhere to a number of rules:

• Disassembly and assembly are carried out in the exact reverse order, while very often the identification of serious breakdowns can make it impossible to quickly assemble the tool, therefore, the sequence of operations and the location of all components must be recorded on paper or photo.
• Disassembly of the tool is carried out only when completely disconnected from the mains. Experiments with connecting the disassembled device to a 220 V network are unacceptable, because this can cause a short circuit with a striking arc.
• The basis for repairing a grinder with your own hands is the timely replacement of failing parts with similar ones. at the same time, "Kulibinskie" modifications are unacceptable.
• Replacement of bearings is carried out only for similar ones due to special removable and mounting devices that do not allow breaking the working parts.
• The filling of new grease should be standardized and with the use of a suitable technical specifications lubricant. Excessive lubrication or the use of an inappropriate lubricant leads to increased load with overheating.

Attention, only TODAY!

Click Class

Tell VK

Dear visitors!!!

After a certain period of use, the grinder is characterized by such breakdowns as wear of graphite brushes, burnout of the stator windings and so on. Of course, wear itself also takes place in terms of mechanics. For a complete acquaintance with the topic: "How to repair a grinder", - consider the electrical circuit of an alternating current collector motor, since such an electric motor is installed in the grinder.

AC brushed motor circuit

The diagram (Fig. 1) shows the electrical connections of the stator windings, rotor and graphite brushes. The graphite brushes in the electric motor are installed in the brush holders. The brushes are in contact with the collector lamellas. One ends of the stator windings are connected to an external power source. The other ends of the stator windings are connected to graphite brushes, the electrical circuit is closed on the rotor windings.

The speed controller of the grinder is connected by wires to the collector motor circuit in series. The connection diagram of the speed regulator should be indicated on the regulator body itself, or in the operation manual of the grinder.

Grinder device

On the device of the grinder, everything is indicated in the figure and no clarification is required. With the help of the driven and driving bevel gears, rotation is transmitted from the electric motor to the gearbox shaft.

Collector motor malfunctions

Possible reasons for the breakdown of the electric motor of the grinder are as follows:

• wear of the rotor collector;
• wear of graphite brushes;
• burnout of the stator windings;
• burnout of the rotor windings;
• lack of contact connection of the ends of the stator windings with graphite brushes;
• mechanical damage to the cable wire at the base of the plug;
• mechanical damage to the wire along the length of the cable;
• failure of the capacitor,

as well as other possible causes associated with any rupture in the electrical circuit.

Checking the collector motor

The cause of the malfunction of the collector motor is detected by a measuring device, for example, such devices as:

• arrow tester;
• ohmmeter;
• multimeter.

If a measuring device is not available, any break can be detected with an indicator screwdriver.

So let's say that the burnout of the stator windings (Fig. 3) is usually caused as a result of general overheating of the electric motor. In this case, the insulation of the wires in the stator winding is disturbed and the winding itself can short-circuit to the frame body. To establish such a possible cause of the malfunction, one tip of the probe of the device is connected to the withdrawn end of the stator winding wire, the second tip of the probe is connected to the stator frame housing.

To check the rotor winding, the probes of the device must be connected to the lamellas (plates) of the collector (Fig. 4).

That's all for now. Follow the rubric.

Tweet

Tell VK

Click Class

Please tell me the cross-section of the stator winding wire of the grinder Kolner 580 wt. Number of turns 167

Hello gentlemen electricians!
Please tell me why the electric motor of the grinder can warm up during idle rotation for 2-3 minutes after switching on to a cold one after replacing the rotor.
Initially, when working with a diamond disc on a new grinder, it was overheated by stopping the disc at full rotation of the rotor. Dismantled, checked the rotor - an open circuit on the collector (two black lamellas). No more items were checked. We installed a new rotor - it began to warm up without load.

Hello!
Please tell me - after replacing such an anchor of the perforator http://rotorua.com.ua/product/jakor-perforatora-einhell-858/ the barrel of the perforator began to rotate in the other direction. What could be the reasons? Defective anchor or some mismatch? thanks for the answer.

Angle grinders (angle grinders), popularly called grinders, are a popular and reliable tool. But everything breaks down sometime. It is not difficult to repair a grinder with your own hands if you have an instruction that tells you the step-by-step procedure for repairing a grinder. Below you will find answers to any questions about the repair of a gearbox, rotor, stator, carbon brushes of angle grinders.

Angle grinders are very popular among home craftsmen. The ability to replace the working bodies allows cutting, grinding, polishing operations.

Availability of the device smooth start makes the work of the tool safe and convenient. Repairing an angle grinder is simple and can be done by yourself. For those who decide to repair the angle grinder on their own, you will need a diagram of an angle grinder of the required type, tools, lubricants and this instruction.

Any do-it-yourself grinder repair begins with an investigation of the malfunctions that arise. The grinder's device is quite simple. The rotating rotor transmits torque to the shaft (spindle) of the working body through a helical gear. The required working tool is installed on the spindle, be it a cut-off stone, a grinding or polishing wheel, and the required technological operation is performed.

By the way, about the shape of the tooth. Spur gears are installed on low-power grinders. Helical gears are used in grinders with a power of over 1000 watts.

Angle grinders, like any tool, break down over time. The causes of malfunctions of the grinder may be different. They appear not only from improper operation of the tool, but also from untimely replacement of carbon brushes and lubricating fluids.

Regardless of the model of the angle grinder, faults all appear in the same units. Malfunctions of grinders are conventionally divided into electrical ones. For novice repairmen, malfunctions are divided into simple and complex.

Mechanical malfunctions of angle grinder

The grinder is an angle grinder designed for cutting, grinding, polishing work. The grinder in the process of work is subjected to heavy loads, works in a dusty environment.

Excessive loads when using a grinder in the "Cut" mode cause increased wear not only of the bearing, but also of the gear teeth of the gearbox.

The main malfunction of the grinder in the mechanical part, wear or destruction of the sleeve bearing on the shaft of the large helical gear of the gearbox.

It is not difficult to troubleshoot a grinder if you have its diagram, description and recommendations for implementation at hand renovation works.

Repair of plain bearings

The weak point of any angle grinder is the bearings. And although there are few of them in the design, only three, they are the ones that most often lead to mechanical failures. Bearings are adversely affected by:

• high rotation speed;
• work at limiting conditions;
• insufficient lubrication;
• dust or dirt;
• untimely replacement or destruction of carbon brushes.

The design of any grinder provides for a quick and easy replacement of any bearing.

Malfunctions of the grinder associated with wear or destruction of the sleeve bearing on the gearbox shaft are characterized by the appearance of an unpleasant extraneous sound.

Destruction of the sleeve bearing is detected by checking the backlash of the working tool installation shaft. It is determined by wiggling the shaft in different directions when installing the working tool.

At the next installation of the working tool, check the shaft play by swinging its end in different directions. Backlash should be absent or minimal.

The appearance of a backlash indicates the need to replace the plain bearing.

Bearing repair consists in removing it from the housing and removing it from the gearbox shaft.

It is better to remove the bearing from the shaft using a puller. It is best to get the inner race of a damaged bearing using a tap of the required diameter, previously screwed into the race.

The bearings are removed from the rotor using a puller or folk method.

Keys or metal strips are inserted into the vice, the bearings are placed on the keys and, using a soft metal adapter and a hammer weighing at least 400 g, are driven out of the shaft axis.

Grinder gearbox repair

The degree of wear of the gears of the grinder reducer is checked for the contact patch. The gearbox is pre-cleaned from old grease. A special blue is applied to the small gear of the reducer, the reducer turns. Next, you need to remove the driven large helical gear and look through a magnifying glass at the contact patch. It should take in total not less than 50% of the tooth surface.

Otherwise, the gears must be replaced or the tooth profile corrected. has been described more than once on the pages of this site.

But such a malfunction can only be eliminated by an experienced craftsman. Most often, licked, cut or destroyed gears are changed entirely, and in pairs.

How to properly disassemble the grinder gearbox

When repairing a gearbox of any grinder, the most difficult task is to remove the gears and press out the support bearing.

Dismantling the gearbox begins with removing the gearbox cover, pos. 1, and disconnecting the stator housing and freeing the rotor, pos. 2. The released rotor is clamped in a vise and the nut fastening pos. 3 of the leading small gear is unscrewed.

The spindle bearing is pressed into the gearbox cover. To get the bearing, in some grinders, you must remove the circlip securing the support bearing and remove the bearing.

The destroyed bearing pos. 1 in the gear housing pos. 2 is easiest to reach by prying it with a screwdriver.

In other models, the gear in the spindle is fixed by a circlip.

The large driven gear on the spindle is attached in several ways:

1. The gear is pressed onto the spindle.
2. The gear is secured with a key.

The small drive gear is either screwed on the shaft along the left-hand thread (in some Sparky models, the thread is right-hand), or is fixed with a keyway and clamped with a nut.

How to remove the gears of the reducer

Spur gears are used in grinders up to 1000 W, and helical gears are used in angle grinders.

Repair of gears consists in replacing them, and only in pairs.

Continuous and trouble-free operation of the gearbox is subject to availability.

Spindle lock button repair

The spindle lock button is intended for quick removal of the working tool. The button breaks when pressed while the disk rotates. Repair of the grinder consists in a complete replacement of the button.

The button should be pressed only when the grinder is completely stopped.

Electrical malfunctions of the grinder

The electrical circuit of the main part of the grinders is almost the same. The rotor transmits the torque through the gearbox to the working tool. The rotor rotates in the stator field. The control circuits consist of a button that regulates the speed and performs a smooth start of the tool, carbon brushes, which ensure the transfer of alternating voltage to the collector lamellas. Power is supplied to the instrument via the connecting cable.

The main electrical malfunctions of the grinder include:

• breakage of the supply cable at the entrance to the tool;
• destruction or wear of carbon brushes;
• failure of the power button;
• open or short circuit of the stator;
• open or short circuit of the rotor;
• delamination or development of collector lamellas.

Electrical malfunctions of the grinder are best determined with a tester or other device. Suitable for these whole and homemade device popularly called "Arkashka" .

The grinder scheme is quite simple and does not require special knowledge. You just need to be careful and safe when performing repair work and know electrical engineering in the amount of high school.

Finding a Broken Power Wire

One of the common breakdowns of the grinder is the inability to turn on the tool or spontaneous stop during operation. The cause of this kind of malfunction is a break in the power cable pos. 27 at the entry point. The malfunction is eliminated by replacing the cable or throwing out the failed section. The fault is easily found with a tester.

If there is no tester at hand, but there is a screwdriver with a neon indicator light, then the malfunction can be found by alternately connecting the power wires to the phase.

Malfunctioning carbon brushes

The reliable operation of any power tool is highly dependent on the integrity and correct work carbon brushes. Good fit of carbon brushes, their correct location relative to the collector lamellas affects the performance of the rotor collector.

Remember! The length of the carbon electric brush must not be less than 8 mm.

Timely replacement of carbon brushes avoids most of the malfunctions.

The wear rate of carbon brushes is characterized by the types of sparking at the collector site. Sparking should be uniform over the entire contact patch of the carbon brush and lamellas and should not exceed a length of more than 8 mm. Circular sparking indicates a malfunction in the rotor circuits.

Repair of the power button and speed controller

Power button malfunctions most often manifest themselves in a difficult and unreliable turning on of the tool at start-up. Such a malfunction spontaneously appears and disappears.

It is unacceptable to work with a grinder with a faulty power button. This malfunction leads to jamming of cutting discs during operation and their destruction with unpredictable consequences.

The malfunction is eliminated by completely replacing the button with a new one.

V modern models Bulgarians have a built-in soft starter with a speed controller. It cannot be repaired, but will require a complete replacement. No, advanced left-handed craftsmen can, of course, fix such a node.

Stator repair

The failure of the stator is indicated by the spontaneous spinning of the machine shaft, the grinder begins to gain maximum speed. Such a malfunction indicates the appearance of an interturn short circuit in the stator winding.

Some malfunctions can only be rectified by specialists. Prolongation of uninterrupted operation of the stator is possible only by timely cleaning, lubrication and replacement of carbon brushes and bearings.

Usually, the stator rarely fails. This is caused by frequent overheating of the tool during operation. The malfunction is manifested by strong heating of the grinder body and the appearance of a smell of burnt insulation.

In the stator, there can be both an open circuit and a short circuit. Without disassembling the stator, these faults can be easily found using the IK-32 device.

Malfunctions are eliminated by replacing the stator. For those who like to craft with their own hands, we can recommend. There is nothing complicated about it.

The stator can be removed easily, but in different models of angle grinders in their own way.

Stator removal procedure:

• remove the grinder gearbox;
• remove the rotor, having previously removed the mounting bar;
• remove the plastic protection of the stator;
• unscrew the screws securing the stator in the housing;
• remove the handle cover and disconnect the power wires to the stator;
• remove the stator by tapping on the housing with a wooden hammer or block.

Repair of a rotor angle grinder

Failure of the rotor in the grinder is caused by improper use of the tool, frequent overheating, untimely replacement of carbon brushes, contact with the collector lamellas of abrasive particles and dust.

First, the length of the spark on the manifold increases, then a burning smell appears and, at the last stage, smoke. The operation of a faulty gearbox is accompanied by a knock and hum.

The destruction of even a pair of teeth leads to incorrect operation of the tool.

The life of the rotor can be extended by preventing dust from entering the tool, preventing overheating of the tool, changing carbon brushes and lubricants in a timely manner, using only those working tools and of the diameter recommended by the manufacturer of the power tool.

The rotor is a complex unit that requires repair at service centers. But lovers can do it with their own hands.

Repair of the collector and rotor lamellas

Removing the rotor is easy.

To remove the rotor from the angle grinder:

• remove the cover of the grinder handle;
• free and remove the carbon brushes;
• unscrew the screws securing the gearbox housing to the main body;
• remove the gearbox housing;
• remove the rotor.

The removed rotor must be carefully inspected. If large grooves are rubbed on the lamellas, they should be removed by turning the manifold in a lathe.

With minor grooves, the defect is eliminated by grinding. The rotor is clamped into the chuck of an electric drill and the wear is removed using a needle file and sanding paper. The process is simple.

The drill is clamped in a vise or securely mounted on a flat surface. The end of the rotor, on which the lamella is located, is inserted into the drill chuck and securely clamped. The bearings have been previously removed from the rotor.

The other end of the rotor must be supported with a set of wooden blocks. The drill turns on and a small number of revolutions is set. At the first stage, use coarse sanding paper No. 40..80, at the final stage, a finer one, No. 120..200.

After grinding, the grooves must be milled between the lamellas. This is best done hacksaw blade specially sharpened. After milling the grooves of the collector, the edges of the lamellas must be deburred using a diamond file. Correctly ground lamellas should be free of burrs.