Angle Grinder Archives

Makita 125 Angle Grinder Variable Speed

2nd April 2020

Angle grinder, which is popularly called the angle grinder, is a universal tool with which you can perform a list of works: cutting, grinding, cleaning metal, wood, stone and other materials. This tool has found its application in industry. It is ideal for both professional repair work and household chores.

Adjustable Speed Angle Grinder 230 mm
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Now on the market there are a large number of different models of angle grinders designed for home or professional use. The latest angle grinder with speed control is equipped with special nozzles of any size, characterized by the presence of descent safety locks and additional functions. With all the variety of models and sizes, an angle grinder has a common task, which is to facilitate the person’s workflow as much as possible and save time.

Which angle grinder to choose? Household and professional tools

When buying an angle grinder, you should take into account such indicators as rotation speed, power, the presence of additional functions and disk sizes.

Indispensable in everyday life are angle grinders. This is a conventional angle grinder, which are compact in size and demanding on the operating mode. After 10-15 minutes of operation, the owner of a conventional grinding machine is forced to take a mandatory break to prevent its overheating. The household angle grinder is not designed for daily use. Their technical indicators are much lower than that of professional devices that can be used for a long time without fear of overheating. In addition, professional angle grinders are equipped with brass inserts and a metal housing. This is due to the fact that they have to be used in extreme conditions: laying pipelines, earthwork, etc. For such an environment requires a tool that is as much as possible protected from dust and moisture.

Universal angle grinders

Universal are considered an angle grinder with speed control. These machines are ideal for jobs such as cutting, grinding and polishing any materials.

angle grinder with speed control and soft start are mainly used in those cases when it is necessary to polish stone or wooden surfaces. This is due to the structural features of these materials, the processing of which at high speeds is undesirable, as it leads to the destruction of the surface and rapid wear of the nozzles.

The best manufacturers of grinders

Angle grinders are produced by domestic and foreign companies. High results were achieved by the German manufacturer Bosch, Japanese Hitachi and Makita. Mostly they produce models for professional use: an angle grinder with speed control, power exceeding 1200 W, and various disk diameters. Angle grinders make it possible to carry out any kind of complex work. Using special diamond blades, it is possible to cut concrete and stone, to cook walls under wire. The presence of an additional side handle provides control over a powerful power tool during its operation.

Bosch: Model GWS 850 CE

The Bosch angle grinder with speed control and an output of 850 watts is ideal for grinding with diamond cups in natural and artificial stone. This angle grinder is one of the most popular electronic tools in the work of professional stonecutters, who every day are faced with the need to polish in places where granite or marble are cut. This angle grinder is lightweight, which greatly facilitates operation: the master can hold it with one hand.

The Bosch GWS 850 CE angle grinder with speed control is warranted for one year of professional use.

You can adjust the grinding speed using six positions. The rotation speed range of grinding nozzles and discs is from 2,800 to 11,000 rpm.

The quality of polishing directly depends on the speed of rotation of the nozzles. The smaller it is, the higher the quality of work. This requirement applies to granite, marble, glass and other surfaces that can be operated with a grinding tool equipped with an adjustment function. To work with marble surfaces, experts recommend a choice of speed at which the grinder produces 2800 revolutions. Wooden surfaces can be treated with special nozzles at the highest speeds. The maximum speed for this angle grinder is 11,000 revolutions.

Video: Makita 125 Angle Grinder Variable Speed

Bosch GWS 850 CE comes with a key, handle and two mounting washers for discs and nozzles.

Nozzles for polishing work

The quality of polishing work depends on the adjustable speed and correctly selected nozzles. For grinding marble and granite surfaces by experienced engravers who work with stone professionally, flexible diamond blades are recommended. For wood, an emery petal circle is suitable. For polishing metal products and surfaces, it is best to use circles containing felt or felt, which is attached to the nozzles with a special Velcro. Felt nozzles are also suitable for polishing glass. But in this case, you need to purchase a special diamond paste. Painted or varnished surfaces must be treated with lamb wool tips.

Household Makita GA5030 angle grinder

Makita angle grinder with speed control is considered one of the best models of household angle grinders. Its price is 2500 rubles. The Makita GA5030 has a low weight that does not exceed 1.8 kg, which is an advantage of this tool compared to other similar models in this price category.

Professional Angle Grinder Makita 9565Cv

Angle grinder Makita angle grinder 125 mm speed control provides the implementation of any kind of work at speeds from 2800 to 11000 rpm. Makita 9565Cv requires a 125 mm diameter drive and 220 volt power. Power Consumption Angle Grinder. 1400 watts. 125 mm angle grinder with speed control 9565Cv is a professional power tool, the design of which contains:

adjustment of rotation speed, which makes it possible to optimize the operating mode. The spindle receives a certain speed necessary for a specific task: cutting, grinding or grinding;
power button lock. This is important to ensure safety during operation, especially in cases of unplanned power outages (turning off the light, pulling the plug out of the socket). Thanks to the secondary start-up fuse, the owner of the Makita 9565Cv is protected against arbitrary switching on the angle grinder and does not risk injury;
double isolation;
speed stabilization system, which, due to changes in disk loads, facilitates the process of working with massive labor-intensive parts;
two-position side handle, which ensures reliable holding of the power tool during operation. A convenient version of the handle performs an anti-vibration function.

9565Cv angle grinder is an angle grinder "Makita" 125 with speed control and smooth descent, due to which the power tool is protected from critical overloads when turned on. A soft start protects the angle grinder system and the numerous parts contained in it (disk, winding, engine brushes) from a strong power surge. Turnovers are typed smoothly, the angle grinder does not tremble in the hands.

How to choose the required disk size?

For angle grinders, discs with a diameter of 115 to 230 mm are intended. Working is the part that extends beyond the apparatus. Nozzles tend to wear off during use. Disks with a diameter of 115 mm quickly wear out and are suitable for cutting products with a thickness of not more than 3 cm. over, this diameter is unsuitable for working in hard-to-reach places. For such operations, 180-230 mm discs are better suited.

Metabo WEV 10-125 Quick

This is another angle grinder with speed control. 125 mm is considered the optimum disk size for the Metabo WEV 10-125 Quick. Among all the well-known 125-mm angle grinders, this model is considered the best in terms of power. It features a wide range of adjustment of spindle speeds and a constant speed under the influence of a variable load. This is ensured by built-in electronics, which protects the engine from the overload grinder and produces a smooth start of the system. The angle grinder has an automatic safety clutch and corner brushes that turn off if voltage suddenly drops. This is important for safety during operation of a powerful angle grinder.

Hitachi G13SS

The ergonomic shape of the model, the presence of a removable handle in its design, which allows it to be installed on either side, the ease of replacing carbon brushes are advantages for Hitachi G13SS that many users have already appreciated.

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What to consider when buying?

If you want to purchase an angle grinder, you need to get acquainted with the technical indicators of the model you like. Best of all, if there is a soft start. This will protect the owner of the angle grinder from possible jerks when turning on the power tool and from knocking out fuses. The problem of increasing the load on the system of an angle grinder can occur when the speed is reduced. In such cases, overheating occurs. It is desirable that the angle grinder be equipped with modern sensors that regulate the speed of revolutions during overload and overheating. The more complex the model system, the higher its class and the more expensive it is. At the same time, more and the amount of work that can be done using expensive power tools.

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Work Protection With Angle Grinder

31st March 2020

Any cutting device has high security requirements. Especially when it comes to cutting metal and other hard materials.

An angle grinder, or an angle grinder (angle grinder), is the most dangerous power tool, and when working with it, safety precautions must never be neglected. Even experienced professionals sometimes get injured using an angle grinder in violation of the instructions.

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Safety precautions

There are several types of protective equipment required for the operation of this device.

Personal protective equipment

Guaranteed eye safety when using an angle grinder are safety glasses. They have several varieties:

Open glasses. They resemble ordinary glasses for vision correction or protection from the sun, but have a denser structure and increased thickness of the plastic. These glasses protect your eyes from sparks and small fragments. Their disadvantage is exposure to dust. When working with ceramics and stone, dust is formed that can cause eye irritation. In this case, the following type of glasses will do.
Closed glasses. They fit tightly on the contour of the face and do not allow dust to penetrate the eyes. Also protect eyes from shards and sparks. Some models have a ventilation system that prevents fogging on the inside of the lens. This version of the glasses will cost a little more, but it has more advantages.

Glasses must be worn regardless of the nature of the material being cut or ground.

Face mask

Another safety feature when working with an angle grinder is a face shield. It can be reinforced with a special mesh, which makes it stronger. Such a mask is much better than glasses, because it protects not only the eyes, but also the rest of the face.

The main cause of injury is a saw blade split. Its fragments flying with great speed can injure not only a person working with an angle grinder, but also people nearby.

Principles of Safe Operation

Video: Work Protection With Angle Grinder

The presence of personal protective equipment undoubtedly reduces the risk of personal injury when using the angle grinder. But it is worth remembering also other safety requirements.

Protective cover. This device must always be on the angle grinder. Some negligent operators remove protection in order to wear a larger diameter wheel that is not designed to work with this angle grinder. Sometimes the casing is removed in cases where it is necessary to use an angle grinder at an uncomfortable angle. Such actions are not allowed. Of course, the protective casing does not provide absolute safety, but in most cases it will protect you from getting injured. Recently, a protective modification for the angle grinder has appeared a useful modification. It is called dust extraction. The name is clear. this device helps to direct dust particles in the opposite direction from the operator, which greatly simplifies the work.
Hand protection. To prevent sparks and hot metal particles from getting on the skin of the hands, it is recommended to use special welding gaiters. Small sparks, getting on the skin, do not bring obvious pain. But when a large burning particle gets in, it causes severe pain. At this moment, the hand may flinch, thereby creating a traumatic situation. Gaiters help to avoid getting hot metal on your hands.
The choice of abrasive wheel. To work with an angle grinder, you should use an exclusively suitable circle for it. If you use a circle with a diameter larger than the specified, then it can split, even without touching
with the cut object. The fact is that different models of angle grinder have different speeds, and abrasive wheels have different revolving resistance.
You should also not use circles with visible external defects such as chips, deep scratches or cracks.
It is forbidden to install a disk for sawing wooden products on an angle grinder. Firstly, it is dangerous. the saw blade can meet with a knot, because of which the tool can be pulled out of the hands. Secondly, the disk will soon become unusable, because it is not adapted to such a load. The speed of the circular saw is much lower than that of the angle grinder.
Sawing object. If the workpiece is small, you need to fix it with something. The best option for this would be to use a vise. Never cut the product with one hand while holding it with the other. In this case, the sawing element may be pulled out of the hands.

If the product is large and installed motionless, the bite of the abrasive disc must be prevented. General rules:

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Always unplug the angle grinder when replacing a disc. This is to prevent accidental startup.
When choosing an abrasive disc, give preference to a trusted manufacturer.
When working, make sure that the power cord is away from the cutting circle.
When using an angle grinder, eliminate the possibility of winding hair and clothing onto a rotating disc.

The correct location of the power tool in your hands is the key to safe use. Do not neglect the instructions for working with the angle grinder, this tool is capable of causing severe injuries when neglected.

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Angle Grinder Status 125 Variable Speed

30th March 2020

Engine power angle grinder is 1250 W

Set the optimal settings for specific tasks. With speed control on any material, an even cut is obtained.

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Disc diameter 125 mm

The most popular disk size for household and repair work.

3 year warranty
14 days to return
Official Manufacturer’s Warranty

TOP SALES

Description

Specifications

Equipment

Feedback (151)

The Dnipro-M brand is well known to the Ukrainian consumer due to the ratio of reliability, comfort and reasonable price. He deservedly takes a leading position and receives in return the respect and trust of customers.

Video: Angle Grinder Status 125 Variable Speed

Internal characteristics. an important aspect when choosing an angle grinder. Consider in advance what tasks the tool will perform and, in accordance with this, choose an angle grinder. Let us consider in more detail the main indicators of the GL-125S model. The 1250 W engine produces up to 11,000 rpm. For this model, a circle with a diameter of 125 mm is suitable, which is quite enough to perform basic household tasks. Such a size can make a shallow cut of corners, pipes, tiles and other materials. However, remember! To remove a protective casing and establish circles of the wrong diameter or disks for circular saws are forbidden!

Among the advantages of the GL-125S model it is worth noting:

External parameters are equally important when choosing a power tool. The compact design weighs only 2.2 kg, which allows it to be transported, stored and carried out in small rooms and even at height without any problems.

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If you still have questions regarding the tool or its purchase, fill out the callback form below.
We will contact you within a few minutes (during business hours).

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Guard For Working With Angle Grinder

27th March 2020

It is not permissible to install larger circles on the angle grinder than those for which it is intended. Getting to work with an angle grinder, you need to be extremely assembled. A protective casing and glasses are prerequisites for safe operation.

The screen is a semicircular plate with two ribbons, frontooccipital and parietal. Their adjustment can be smooth or step to fit in size and securely lock the protection during operation. A plastic visor may be provided to protect not only the face, but also the frontal part of the head.

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With helmet mount. the screen is attached to the safety helmet with a lifting and fixing device that moves it up / down. From a metal mesh. such protective shields are a fine-mesh strong mesh and protect against large solid particles.

And breakaway particles can cause eye injury. Therefore, do not neglect the goggles for the angle grinder. Eyes are the most important organ of the human body, they must be protected and taken care of their safety when performing various work operations.

First of all, these are construction glasses. special devices that protect the eyes from the smallest particles of the processed material and exposure to radiation hazardous to the organs of vision.

They partially or completely close the organs of vision and are offered with different types of glasses: mineral, organic or made from various modern polymeric materials. They are indispensable when performing welding operations, working with lasers, and bright light sources. Used in the glass and metallurgical industries.

The most convenient and modern welding masks are chameleon masks. Working with an angle grinder is associated with sparks and fragments that are inevitable when cutting material, so protection from them will not be superfluous. A respirator is required when cutting concrete or slate and is desirable when working with metal, especially indoors. Glasses and a shield protect only from small particles, however large a splinter flying off directly, they will not stop!

Video: Guard For Working With Angle Grinder

Buy safety glasses for angle grinder

The diameter of the circle must not exceed the diameter of the standard protective casing. An angle grinder, it is an angle grinder, is a very traumatic tool. If the angle grinder were not so indispensable for many types of work, it would probably be worth introducing a restriction on the use of this tool. In general, it is very important to know how to work the angle grinder.

Glasses or their replacement mask must be closed. Sparks and splinters fly along a complex path and are able to fly behind glasses or a mask if they are open from the side. The protective cover is the first barrier between the operator and the circle rotating at great speed.

Many who use the angle grinder more or less regularly, at least once, but have come across it. Most often, the destruction of the circle occurs when it is clamped (jammed) in the slot. The protective cover is installed so that sparks and debris are not ejected towards the operator. As it would not be inconvenient in some cases to work with the casing, its removal from the tool is unacceptable.

Hands are in close proximity to the rotating circle and must be protected from sparks, abrasive particles and metal fragments. Clothing should not be wide and well dressed. Each type of work (type of processed material) has its own abrasive tool. Circles of large diameters (both new and used and reduced in diameter) may not withstand high speeds and collapse.

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You can also not use damaged circles: with cracks, chips and potholes, having deviations from roundness or flatness. This can lead to a back strike and the final destruction of the circle with the creation of a traumatic situation.

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Bosch 850 Angle Grinder Adjustable

26th March 2020

The presence of an angle grinder in the household makes it easy to solve the problems of processing solid-state surfaces in the repair process. In addition, this equipment, also known as the “angle grinder,” may be needed in locksmith events, as well as when removing unwanted raids. Today there are many models of angle grinders from different manufacturers, but the choice is recommended to make in favor of reputable companies. These include the Bosch GWS 850 CE Professional, which comes in a wide configuration, is characterized by build quality and reliability. Despite positioning as a professional unit, the angle grinder is quite suitable for private needs. The tool is not difficult to handle, but a set of useful options and high performance will not be superfluous. However, this model should not be overestimated either, as competing grinders also have something to offer.

Model Overview

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The device is presented in the line of professional equipment, which is designed for a wide range of operations. In particular, the Bosch GWS 850 CE angle grinder handles the processing of metal materials, stone and wood. The operator will be able to perform cutting, grinding, painting, and also remove traces of paintwork and rust. High power helps the instrument to perform the listed actions qualitatively. However, this does not affect the dimensions and ergonomics of the device. The user can easily manage all the capabilities of the unit without outside help. of course, basic training and knowledge of the handling of an angle grinder will still be required.

In addition to compactness and maneuverability, the device will please the owner with electronic filling. Actually, the introduction of control systems with a hint of intelligence has long been practiced by other manufacturers, but this concept is implemented most successfully and without serious errors in the Bosch GWS 850 CE angle grinder.

Specifications

Not only advanced electronic systems, but also the basic technical potential speak of the accessory of this unit to professional models. So, the German angle grinder has the following characteristics:

The power potential is 850 watts.
The number of revolutions. a range from 2 800 to 11 000 with the possibility of adjustment.
The size of the grinding wheel in diameter is 12.5 cm.
Grinding spindle thread. M14.
The length of the spindle thread is 2.2 cm.
The mass of the device in full is 2.6 kg.
The mass of one tool is 1.6 kg.

The main thing that the tool pays attention to is a high level of power and an extensive speed range. Thanks to these characteristics, the Bosch GWS 850 CE angle grinder shows its effectiveness even when working with stone surfaces.

Features and benefits of the model

The user controls the instrument using an electronic settings system. Compared with the adjustment in traditional models, this innovation allows you to set the machine optimal parameters for working with a specific material. In addition, the Bosch GWS 850 CE is equipped with a soft starter. This means that a sharp start of processing is excluded, as a result of which the largest number of errors are made. The user of this angle grinder will start work quietly, slowly and accurately. To ensure stable processing in the future, the device is also equipped with a current limiter, which will eliminate the negative effects of voltage drops.

Video: Bosch 850 Angle Grinder Adjustable

So that the operator can easily and quickly change the components of the machine, a fixed spindle is provided in its design. Facilitates maintenance operations and the location of carbon brushes with direct access. To increase the overall structural strength, the Bosch GWS 850 CE angle grinder was provided with reinforced plastic and armored winding. On the one hand, protective barriers protect the user himself, on the other hand, they increase the tool wear resistance.

Maintenance

The manufacturer strongly recommends keeping the tool clean and in good condition. For this, it is necessary to use work elements that correspond to the characteristics of the material and processing conditions. It is also necessary to regularly check all slots and ventilation openings of the device, since their contamination can lead to breakage directly during the operation. In case Bosch GWS 850 CE spare parts or accessories are required, the manufacturer’s service department provides original components upon request. In addition, the user can get a wiring diagram of the device. then, in accordance with it, independently determine the malfunction and eliminate it. However, without appropriate preparation, such actions are not recommended.

Operation Nuances

You can start work if several conditions are met. Firstly, the tool must be in good condition, and all its components and functional parts must be correctly selected from the point of view of the upcoming processing. Secondly, the workpiece must be securely locked. During operation, the Bosch GWS 850 CE angle grinder must not be subjected to excessive pressure. Even coarse abrasive work should be carried out with moderate tension, correctly grasping the handle of the tool. After the operation is completed, it is not necessary to turn off the machine immediately. You should leave it idling for a few minutes. This must be done, as sudden changes in voltage in the mechanical elements adversely affect the durability of the device.

Each material has its own processing characteristics. For example, in the process of cutting metal should lead the working body against rotation. This will bring the Bosch GWS 850 CE to the end of the intended section without leaving the laid line. In the case of stone, another nuance is important. The dust generated is dangerous for breathing, therefore, an effective suction of dirt should be provided, and work must be done in a respirator.

Almost all Bosch angle grinders are renowned for sophisticated ergonomics in every way. And the adjusting capabilities, and the device handles with protective coatings cause only positive feedback. Despite its high performance, the power tool can be operated even with one hand. this is evidenced by user experience. In terms of the direct function of the processing machine, the Bosch GWS 850 CE also shows its best. Opportunities for working with stone and metal are implemented in accordance with advanced German standards.

Price issue

Professional equipment is not cheap. The difference with a budget power tool can be several thousand rubles. However, in the case of the Bosch GWS 850 CE, the price is quite acceptable and averages from four and a half to five thousand rubles. Given the high level of the manufacturer, the considerable power of the device and acceptable functionality, the price really looks attractive. But, with a detailed analysis, the angle grinder all falls into place. In addition to electronic adjustments and a really high-quality housing, the German company does not offer anything special. Therefore, the price justifies the purchase, but no more.

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Conclusion

If you need a modern functional tool for periodically solving simple problems at home, then the modification of Bosch GWS 850 CE Professional may be one of the best options. The tool is easy to use, convenient and safe. In addition, the ability to process metal and stone makes it almost universal in terms of operation. However, if you plan to purchase an angle grinder for permanent work at construction sites, you will have to think about it. If we talk about the purely professional qualities of the device, it will not please anyone with anything special. Sufficient power, functionality at an average level. these same qualities are provided by less famous models of the segment. Ergonomics can be called the only trump card of this angle grinder, so if a short cable does not bother you, then you should consider this option.

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Angle Grinder Vityaz 125 Variable Speed

26th March 2020

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power 2400W, disk 230mm

Power 850 W, disc 125 mm, speed control

800W, 125mm drive, 1.9kg weight, no speed adjustment

circle diameter 125 mm, power 1500 W, weight. 2.4 kg, speed control 2200-7500 rpm

230 mm angle grinder, power 2600 W, soft start

disk diameter 125mm, 840W, 11000 rpm., weight 2.1 kg angle grinder

Voltage 230 V, power 1150 W, number of revolutions 11000 rpm, disk diameter 125 mm.

Video: Angle Grinder Vityaz 125 Variable Speed

circle diameter 125 mm, power 850 W, weight. 1.9 kg, speed control 2800-11000 rpm

Mains voltage, V, 220. Current frequency, Hz, 50. Disk diameter, mm, 115. Spindle thread, M14. The number of revolutions, rpm, 11000.

electronic current limiting system, interlock system

angle grinder 125 mm, power 1100W, with speed adjustment

circle diameter 125 mm, power 1100 W, weight. 2.0 kg

230mm, soft start, model DISCONTINUED from production

Electromash angle grinder 180-2000 Voltage / frequency: 230 V / 50 Hz Power: 1800 W Number of revolutions: 8000 rpm Disk diameter: 180 mm&

angle grinder Kress 1400 WSXE / 1 220 V Frequency. 50 Hz Type of grinder. angular power. 1400 W, Revs. 6500-12000 rpm Circle diameter. 125 mm spindle

Voltage / frequency: 230 V / 50 Hz Power: 1100 W Number of revolutions: 3000. 7500 rpm Disk diameter: 125 mm Angle grinder Vityaz MShU-125 / 1100Е

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electronic stabilization of revolutions, aluminum gear housing, soft start

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How to Insert Brushes into an Angle Grinder

26th March 2020

Angle grinders in Soviet times were made in Bulgaria. Therefore, the angle grinder began to be called the angle grinder. Currently, there are many firms producing angle grinders of various models. But the basic elements are the same. Having familiarized yourself with the device, possible breakdowns and tool diagnostics, you can repair the angle grinder of any modification with your own hands.

The device and purpose of the angle grinder

angle grinder is designed for grinding and cutting various materials.

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How to Insert Brushes into an Angle Grinder

The main elements of the angle grinder

The angle grinder consists of the following elements:

The aluminum alloy flat gear housing dissipates heat better.
Carbon brushes.
Grip mount
Electronic soft start system. Prevents jerking when turned on and reduces starting loads on the engine.
Quick detachable guard.
Ball bearings.
Electric motor
Switch angle grinder.

A wide selection of bearing products is offered by the Thermopolis company. https://termopolis.com.ua/

Main malfunctions, their causes and diagnostics

The main breakdowns and causes:

Burns, sparks and twitches. Reasons: violation of the insulation of the armature winding, wear of the brushes, collector, clogging of the brush holders. Even after replacing the brushes, the angle grinder sparkles and twitches if the brush holders are clogged.
Clapping sound. Brushes or interturn circuit of any of the windings.
Crispy sound. The reason is in the bearings.
Mechanical rumble and heavy tapping. Gearbox malfunction.
angle grinder has stopped working, does not turn on. If the disk is manually spinning tightly or not spinning, the cause is the gearbox. If it turns easily, check the electrical circuits. If chains work, check motor and brushes.
The spindle lock button has broken. The reason is clicking on it during rotation of the disc or jamming of the disc.
angle grinder works in fits and starts. Check engine for interturn short circuit.
Vibrates. The reason is in mechanics. Check bearings, rotor shaft and gearbox.
Heats up. If it heats up in the engine area, the cause is worn out brushes or a short circuit in the turns of the windings. If the gear case is warming, then the grease has dried or the gears have worn out.
It does not gain momentum or power drops. The reason is in the electronics or engine. Check soft starter control board and speed controller, brushes and collector.
Smokes. The reason is overheating of the tool. Check motor windings for insulation melting.
Humming and not spinning. Check motor bearings and gearbox.

How to disassemble and assemble an angle grinder

To troubleshoot the angle grinder must be disassembled.

Remove the nut that holds the working disk.

Turn off bolts of fastening of a protective casing.

Remove the housing bolts from the angle grinder and those that secure the housing to the gearbox.

Remove the top of the rear housing. Turn off bolts of fastening of a cord. Remove the wires and button from your grooves. In some models, for example, in DWT, the rear case is not disassembled into parts, but is removed entirely.

Disconnect the motor wires.

Remove the brushes.

Disconnect the gear housing from the body of the angle grinder. Together with it, the engine anchor is removed.

Remove the gearbox bolts located around the casing mount.

To disconnect the anchor from the aluminum housing, unscrew the nut located in the gear housing.

Reassemble the tool in the reverse order.

The clamping nut is not untwisted

During operation, the disk can tighten so tightly with a nut that it begins to crumble. It is not possible to unscrew the nut with a wrench. And you do not need to do this, since you can break the angle grinder. First, break the disc all the way to the nut. Then find the metal plate a little thinner than the working disk. Use it to drain off the rest of the disc under the nut. It can be easily unscrewed with a key or hands. In order not to bring the tool to this problem, put the washer under the nut.

How to remove a tightened nut

The casing cannot be removed

In some grinders, for example, Bosh, the casing is not bolted, but latched. To remove it, you need to turn the cutout of the casing perpendicular to the angle grinder. To dress, turn until it clicks.

Stator check

The stator is checked with a multimeter.

Inter-turn closure. Set the resistance mode to 200 ohms. Connect the test leads to the ends of one winding. A unity means an open, and zero means a short circuit between the turns. If it shows a resistance of more than 1.5 ohms, then check the second winding. Both windings should have approximately the same resistance.
Breakdown on the mass or shorting of the winding with the metal housing of the stator. In the multimeter, set the maximum resistance mode. Connect one probe to the end of the winding, the other probe to the metal housing of the stator. The unit indicates the absence of breakdown.

Anchor Check

First visually inspect the collector and winding. There may be visible damage: black marks, bent turns of the winding, raised, worn or burnt collector plates. After inspection, proceed with the tester.

Set the resistance to 200 ohms. Connect the test leads to two adjacent collector plates. If the resistance is the same between all adjacent plates, then the winding is working. If the resistance is less than 1 ohm and very close to zero, there is a short circuit between the turns. If the resistance is above the average two or more times, then there is a break in the turns of the winding.

The determination of the breakdown to mass is done in the absence of a winding break. Put the maximum resistance on the scale of the device. Depending on the tester, it can be from 2 MΩ to 200 MΩ. Connect one probe to the shaft, and the other to each plate in turn. In the absence of faults, the resistance should be zero. Do the same with the rotor. Connect one probe to the iron body of the rotor, and move the other along the plates.

Checking the power button

Put the tester in dialing mode.

Insert one probe into the output of the button and the other into the opposite input.

Click the button. A sound signal indicates the health of this part of the button.

Do the same with the other input and output of the button.

How to ring the start button

Video: How to Insert Brushes into an Angle Grinder

Power cord check

Connect one probe to the plug pin, the other to the button inputs. In one of two positions there should be a sound signal. Do the same with the other pin of the plug.

Check soft start and speed control

If the power button and power cord are working but the engine does not turn on, check the softstart control board. Remove the screw that secures the control board. Remove it carefully. Call all items. If there is a speed regulator in the angle grinder, then it can be connected in series with the power button and have one board with soft start. But may have a separate fee. It is checked similarly to soft start.

Precautions before starting repairs

Read the instructions. Read the description and assembly diagram of the angle grinder.
Unplug the tool.
Prepare a workplace on a table with good lighting.
Fix on paper or in the photo the order of disassembling the tool in order to properly assemble it after repair.

DIY troubleshooting

If you are unsure of your abilities, it is better to take the tool to the workshop.

Power cord and power button

Damaged cord and button must be replaced. On the button, unscrew the bolts securing the incoming and outgoing wires. Disconnect it from the chain and install a new one.

Soft start and speed control

If only the triac is out of order in the control board, then a new one must be put in its place. Pre-grease the metal part of the element with thermal grease. If other elements of the board burn out, replace it completely.

Brushes

Brushes must be checked periodically. When one is worn by 40%, change both. And also clean the brush holders.

To remove the brushes, you must either remove the rear housing or remove the plugs in the housing.
Clean brush holders of dust and carbon deposits. Wrap a cloth around the screwdriver and moisten with alcohol. Nagar is cleaned off with a file. The brush should walk easily in the brush holder, then it will be well pressed by the spring.
Insert new brushes.

Brush holder cleaning

Stator Rewind

For high-quality winding coils, you will need an enamel wire and an electric cardboard.

Remove the winding and old insulation from the housing. Carefully consider the grooves. When the coils burn, insulation is burned and a short to the case occurs. Deposits remain on it, which must be removed with a file or a diamond bur. Deposits will interfere with the new winding. She may tear.

The winding is saturated with varnish. To disconnect the wires and count them, you need to strip out the insulation. Preheat the winding with an industrial hairdryer or any burner.

Burn matches or lighters with any fire to make the enamel completely burnt out. Take a micrometer and measure the thickness. Record the diameter of the wire and the number of turns.

Take any wire and make a loop out of it so that it fits in the grooves of the stator. Under the diameter of this loop, select a cylinder for winding coils. For example, spray can. If its diameter is not enough, then wrap the can with paper.

Wrap both windings from the enamel wire. Fasten the frontal parts with glass tape or thick thread. The thread should not break and melt. At the loose ends, put on shrink cambric.

Make sleeves from the electric cardboard and insert them into the grooves. Place the windings in them.

Check the resistance in the windings of the tester. If everything is fine, continue.

So that during operation the wires do not vibrate and do not rub against each other, they must be impregnated with any oil-based varnish. Put the starter preheated in the oven vertically and squeeze the varnish onto the winding with a syringe. When the varnish starts to leak from below, turn the stator over and soak on the other side.

When the varnish is dry, proceed to connect the windings. Connect the two ends of the different windings to each other and connect to the nearest brush. Connect the other two connected ends to the start button. Connect the wire from the second brush to the button.

Rewind stator on video

Anchor Repair

If the balance is disturbed, the anchor must be replaced. The winding and collector are subject to repair. Small short circuits are eliminated. If a significant part of the winding is damaged, it can be rewound.

A not very developed collector is corrected by a groove. But if the plates are erased to a plastic base or partially burnt out, then the restoration is carried out by soldering or galvanic building.

Badly damaged collector

If the collector was completely worn out, then after soldering it will be enough for no more than a month of active use. And not completely damaged plates after such a repair can withstand several brush changes and do not evaporate. You will need to cut the copper plates in size and solder them with a lot of solder. Strain excessively with a file and polish.

With galvanic build-up, reduced copper is very solid. The life of the collector is like new.

Completely restored collector

By galvanic build-up, it is possible to restore both a completely wiped collector and partially damaged plates. The restored collector must be grooved and the plates divided with a drill or hacksaw blade.

In order to rewind the anchor correctly, you need to correctly disassemble it and remove the parameters for the template:

Winding direction.
How many grooves and slats.
The number of conductors in the groove.
The winding pitch, i.e. how many grooves between the grooves of one section. For example, if the conductors exit the first groove and enter the sixth, then step = 5.
How many conductors are in one groove, so many coils in one section.
Wire thickness.

For example, 80 conductors in a groove, 12 lamellas and 24 grooves. 12 sections of 2 coils. The winding passes in two circles, so we divide 80 conductors in the groove by 2, and another 2, since there are 2 coils. We get 20 turns of one coil.

Anchor winding pattern

We solder the beginning of the wire to the lamella 1 and pass it through the first and sixth groove. We make 20 turns. The first coil of the first section is ready.
We solder the wire on the lamellas 2 and repeat the winding through the same grooves. The second coil of the first section is ready.
We solder the wire on the lamellas 3. Pass the coil through the second and seventh groove. We wind the first coil of the second section and solder the wire to the lamellas 4.
The second coil of the second section is fixed on the slats 5.

How to remove the old and rewind a new winding:

Use a hacksaw or wire cutter to remove the frontal parts of the winding.

Carefully, without damaging the slot insulators, knock out the rods of the remaining parts of the winding with a hammer and a metal chisel.

Use a file to remove any remaining impregnation. Count the conductors in the groove and measure the diameter of the wire. Draw a diagram. Cut the insulation sleeves from the cardboard and insert them into the grooves.

After winding, weld the conclusions of the sections with the collector plates. Check the winding with a tester.

Soak the winding with epoxy.

Anchor Bearings

Bearings crumble or jam over time. They need to be changed.

Disassemble the angle grinder, remove the anchor from the stator.
An anchor is inserted into the gear housing by a bearing. If the housing cannot be removed, fasten the rotor in a vice and tap the gear case with a wooden block.

Gearbox disassembly and repair

The gearbox must be disassembled not only for repair, but also for preventive cleaning and lubrication.

Remove the bolts and disassemble the gear housing. You will see dirty grease that needs to be removed.

old grease will spill out of it. Clean parts with a rag or toilet paper. Flush the housing and parts with kerosene.

Apply new grease recommended by the manufacturer in the tool manual.

Spindle lock button

If the button has flown out, then such an angle grinder cannot be operated.

Spindle lock button

Since the spindle can spontaneously lower to the gear and block it during operation.

Spindle Lock

The locking unit consists of a spindle with a rubber ring, a spring and a plastic button.

To replace the button, disassemble the gearbox.
Remove the spindle from the housing.
Put the spring on the button on the inside.
Insert the spindle into the gear case from the inside, and the button from the outside. Press until it clicks.
Assemble the gearbox.

Spindle lock button replacement and gearbox repair

Care and proper operation of the angle grinder

For the angle grinder to work for a long time, follow the rules:

Watch integrity of isolation of a wire, plug. Do not remove protection.

Lubricate and clean the entire tool.

After turning off the angle grinder, wait until the rotation of the circle stops, then lay it on the ground. When the engine stops, the tool through the ventilation holes sucks together with the air stream particles of earth and other hard fractions that hit the motor windings. As a result, an open or short circuit occurs.

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Try not to use the angle grinder in the winter on the street. While you are running, the engine heats up. The air is icy. As a result, condensation forms. Moisture for the engine is fatal.

Always place the circles recommended by the tool manufacturer. If the angle grinder is 180 mm, do not put more than 200 mm there. The larger the circle, the less speed should be. You will have to remove the protection, and the speed will be exceeded. Oscillations and vibrations will increase. As a result, the circle will fly apart. This is not only fraught with serious injuries. The bearing of the gearbox is broken, the gears are erased.

If you are actively using an angle grinder, then you are a good master. It’s not difficult for you to understand the device’s device and repair it with your own hands. First, find the fault and determine which nodes should be checked. Repair the angle grinder carefully, without haste, so that a minor breakdown does not turn into a major one.

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Mini Speed Angle Grinder

26th March 2020

Each master has at hand such a reliable tool as an angle grinder. Using this device, you can not only perform high-quality material cutting, surface grinding, but also sharpen kitchen knives. Since for certain types of work a minimum rotation of the disk is required, it is recommended to purchase a device with speed control.

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Features

Angle grinder with speed control is a versatile and multifunctional tool that makes it easy to cope with any task in construction and repair. The main difference between such an angle grinder is the ability to independently set the speed of rotation of the disk, depending on the type of material being processed. Manufacturers produce a device with an electric motor, the power of which can be from 500 to 1500 watts. For cutting workpieces, you can choose machines with an average capacity of 800 watts, but if you plan to grind, it is recommended to give preference to more powerful models, since the area of contact with the surface of the processed material in this case is larger.

an angle grinder with speed control is absolutely safe to use, since all models are equipped with a full range of protective systems that prevent injury. We list the main ones.

Soft start device. It is responsible for the smooth operation of the tool after pressing the start button. This device can also act as a limiter for inrush current, which extends the life of the device.
Safety clutch. In the case when during the processing of material the disk of the angle grinder begins to “bite” or wedge, this device starts an emergency stop.
Emergency brake. Performing processing of solid material, the tool can be twisted and pulled out of the hands. The brake helps to stop disk rotation in 3 seconds.

Impregnation of the coil with a special composition. Since the cutting and grinding of the material is accompanied by the appearance of abrasive dust, its penetration into the device is prevented by the additional treatment of the coil with a protective layer. This avoids short circuit problems.
Heat dissipating slots. Protect the device from overheating during intensive work.
Balancing system. Circles of the machine may unevenly grind, after which shaking and beating of the apparatus may occur during processing of the workpieces. Smooth work helps a special automatic balancing.
Overload fuse. When the cutting part is heated to a temperature above 160 degrees, the automatics are triggered, and the speed of rotation of the disc is initially reduced to 200 rpm, then it completely stops.

an angle grinder with a speed regulator weighs from 2 to 5 kg, their performance depends on the diameter of the disk and the number of revolutions. Mini-models that are suitable for working with circles of 115 and 125 mm are very popular with masters. Their speed ranges from 10,000 to 11,000 rpm. An angle grinder with circles of 115 mm is usually used for cutting material with a thickness of not more than 28 mm and is well suited for grinding wood, tile, porcelain and glass. Devices with 125 mm circles are considered the most demanded, since they cope well with grinding the surface of any material and cutting parts with a thickness of 30 mm. If it is necessary to perform cutting and grinding of steel pipes, bricks and concrete, it is recommended to use a device with a circle of 150 mm, while metal processing should be carried out at high speeds, and stone. at lower speeds.

The cutting disc is mounted in an angle grinder with speed control by means of a spindle stop and a protective key; in some models there is also a self-clamping system. Additionally, manufacturers also equip the tool with a casing that protects the craftsman from dust, sparks in the eyes and destruction of the circle on the go.

What is the adjustment for?

The quality of cutting and grinding of the material directly depends on the set speed of revolutions in the angle grinder. Since hard and thick workpieces lend themselves well to cutting at maximum speeds, and aluminum, on the contrary, can melt when heated, when working with them, you should adjust the speed of rotation of the disk. Management of operating modes is provided only in models equipped with a special regulator. This function is useful and used in several cases.

When processing stone. This material is well cut and ground at low speeds, for each type of stone its own disc speed is separately selected.
For finishing fragile surfaces that require careful handling. At high speeds, such products may deteriorate.
When replacing one circle size with another. In this case, a speed adjustment is needed.
When using crowns and discs with diamond coating. To avoid overheating and breakage, processing of the workpieces should be carried out at low speed.

If the tool only plans to carry out rifled operations, then there is no need for a speed controller. In universal use, the angle grinder is indispensable. The system for adjusting the speed in the angle grinder is represented by integrated circuits. They are reliable in operation, operate with a soft start system and a tuned module.

Video: Mini Speed Angle Grinder

Advantages and disadvantages

Angle grinders with speed control are on the construction market in a huge assortment. Depending on the design features and technical characteristics, they can have both pros and cons. So, household models are compact and light in weight, but their functionality is limited. In such a device, productivity is also reduced, during operation they quickly overheat and require constant stops.

As for professional tools, they are very powerful and endowed with additional functions that allow them to be used for a long time without overheating the mechanism. Such an angle grinder is of excellent quality, easy to operate and designed for both cutting and grinding of workpieces. The disadvantages of these models are the high price and heavy weight, since the device frame and additional components are made of durable material.

The main advantage of an angle grinder with speed control, regardless of their modification, is the ability to set a specific mode of operation. Thanks to this, the apparatus becomes multifunctional and allows the processing of various materials.

Models and their characteristics

Today, angle grinders equipped with speed control are in great demand among craftsmen. This type of tool is well suited for cutting, polishing and grinding workpieces. The construction market is represented by an angle grinder manufactured by both domestic and foreign companies. Well-established models of several brands.

Bosch GWS 850 CE. This device is lightweight, which simplifies its management. The power of the machine is 850 watts, it is well suited for polishing marble and granite. The instrument comes with a six-position disc speed controller. The minimum speed of 2800 revolutions, the maximum of 11000 per minute, for processing wood the machine uses a special nozzle, designed for high speed. The manufacturer additionally equips the device with a handle, a key, discs and washers for attaching nozzles.

Makita GA5030. This is the lightest grinding machine (its weight is 2 kg), which is designed for simple household work. Using the device, you can easily cope with the cutting, grinding and polishing of various materials. Thanks to the additional handle, the workflow is greatly simplified; disks with a diameter of 115 and 125 mm can be installed on this model. The tool has a power of 1400 watts, thanks to the speed control it is classified as a professional model. In addition, the angle grinder has a power-on lock, a stabilization system of revolutions, in order to protect the device from overheating, it is recommended to periodically turn it off during intensive work.

Metabo WEV 10-125 Quick. This modification is available with the ability to change the speed and maintain a power of 1200 watts, the design provides an electronic engine protection system against overloads. The speed of rotation of the cutting wheel automatically changes depending on the type of work and is fixed at variable loads. Of all the 125-mm machines produced, this model is the best, it is characterized by a large number of revolutions and speed control. The angle grinder also has a safety clutch and replaceable brushes, which are disconnected when the voltage drops in the mains. In addition, the manufacturer supplemented the tool with an overheat indicator, stabilizer and a long cable.

Hitachi G13SS modification can complete the review of the popular angle grinder with speed control. Due to its high power indicators and the possibility of using it with discs with a diameter of 150 and 230 mm, it is highly rated among the types of equipment. The device is perfect for both repair and construction work. The machine can cut metal workpieces and grind parts from different materials. A distinctive feature of the device is its narrow grip and low weight, which makes it comfortable to use.

Selection tips

An angle grinder with a speed control is one of the most popular and widely used tools. Since this tool is represented by various modifications, it is difficult to make the right choice in favor of a particular device. The first step is to determine how the device will be used for domestic or professional purposes. In the event that infrequent and simple works are planned, then a small low-speed machine is suitable. For the simultaneous implementation of high-quality cutting and grinding of the material, it is best to opt for professional models.

In addition, it is worth paying attention to the following characteristics of the device:

performance:
minimum and maximum speed;
additional functions;
drive options that can be used with the tool.

An important criterion when choosing is the frequency of operation of the device. For constant and intensive work, you need to buy models in which the outer case is made of durable metal and supplemented with brass inserts. When installing the pipeline, it is advisable to use devices with a maximum level of protection against water and dirt.

How to use?

Despite the fact that all models of the angle grinder with speed control are reliable, they still require proper care and operation. Therefore, it is periodically necessary to replace the working nozzles and contact brushes, add oil to the gearbox and clean the engine compartment of dirt. In addition, a technical check of the tool is also provided, it should be carried out at least once a month.

When replacing disks, the device must be turned off, the gearbox locked with the button, then remove the old nozzle and put in a new one, pressing it tightly with the nut. Oil filling is simple: to do this, remove the gearbox cover, having previously unscrewed the fixing bolts. As for cleaning the housing from dust, it is carried out using a vacuum cleaner.

Work with an angle grinder must be carried out in accordance with all safety regulations. The craftsman needs to wear protective gloves, goggles or a face shield. Do not start cutting the material with a broken or cracked disc, as it may cause injury. Grinding with a cutting disc is also not allowed, and cutting is cleaned.

For cutting and polishing various materials requires a certain speed of rotation of the disk, it can be adjusted using a special automatic system, which is controlled on the body by moving the lever. Thus, it is possible to easily reduce or increase the speed. In addition, you can lower the speed using large diameter discs.

See how to properly do-it-yourself the speed control of an angle grinder in the next video.

Criteria for choosing a good angle grinder

Disc diameter

The disc is the main consumable for an angle grinder. It is he who cuts, grinds, cleans. When choosing a diameter, it is important to consider that the "useful area" of the disk, and therefore the cutting depth, is about four times less than its diameter. That is, it cuts only the extreme 1 / 3-1 / 4 of the disk. There are disks of 5 diameters:

115 mm is the smallest disk. It is not suitable for main cutting due to the small depth of cut (less than 25 mm), but is good for small jobs and grinding. There are also machines with 100 mm discs designed exclusively for grinding and polishing, but they are narrowly specialized and not widely used in everyday life.
125 mm is the most popular disc size for a household angle grinder with a cutting depth of about 40 mm. With discs for various purposes allows you to cut almost all materials;
150 mm is suitable for cutting concrete, brick, metal pipes;
180 mm is useful to those who started repair or construction;
230 mm. discs for professional grinders with a cut depth of up to 70 mm, rarely used for domestic needs. As a rule, the larger the disk for which the angle grinder is designed, the greater the weight of the tool assembly.

Power

It ensures stable operation of the tool under loads and allows you to work for a long time without a break for rest of the tool. The power of the grinders varies from 0.5 to 2.6 kW and is not rigidly tied to the size of the disk, that is, you can meet a machine with a 125 mm disk with a power of both 600 W and 1.5 kV. For domestic purposes, an angle grinder of 600-900 watts is sufficient. For long and complex work with heavy circles, it is worth choosing an option with a power of 1.5 kW or more.

Speed

Shows the spindle speed on which the disk is mounted and can be up to 7000-9000 for models with large disks and up to 12000 rpm for models with small disks. Good grinders for adjusting the speed have a manual regulator, which allows you to reduce the speed of rotation if necessary.

Number of pens

Convenience and safety of work depend on this parameter. Angle grinders are one-handed and two-handed. The first option is common among relatively light models, both domestic and professional. A light angle grinder can simply be supported with a second hand on the body. Two-handed angle grinder. heavy professional and semi-professional models, effective and safe work with which requires physical strength and reliable grip. It is good if the handle / handles of any angle grinder have a rubberized coating or vibration damping system.

Extra features

High-quality angle grinders have useful features that facilitate operation and extend the life of the angle grinder. Their presence indicates the professional purpose of the tool and significantly affects the price. They are found in a good household tool:

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“Soft start” (start without jerking);
automatic shutdown of brushes during short-term power outages;
auto-balancing of the disk (reduces the runout of the disk with uneven erasure, and hence the vibration in the hands);
the ability to lock the power button for continuous operation;
the ability to change the casing without a tool;
automatic (electronic) regulation of disk rotation speed;
improved dust protection of the stator and anchor;
dust removal system (the presence of a special nozzle for connecting a construction vacuum cleaner).

Which manufacturer of grinders is the best?

Rating of the best angle grinders

“Expert Price” chose the 12 best grinders of 2018-2019, who have outstanding characteristics in their class.

source

Speed Control Angle Grinder Without Power Loss

25th March 2020

To perform many types of work on wood, metal or other types of materials, not high speeds are required, but good traction. It will be more correct to say. moment. Thanks to him, the planned work can be performed efficiently and with minimal power loss. For this, DC motors (or collector) are used as a drive device, in which the supply voltage is rectified by the unit itself. Then, to achieve the required performance characteristics, it is necessary to adjust the speed of the commutator motor without losing power.

Features of speed regulation

It’s important to know, that each engine consumes during rotation not only active, but also reactive power. In this case, the level of reactive power will be greater, which is associated with the nature of the load. In this case, the task of designing devices for controlling the speed of rotation of collector motors is to reduce the difference between active and reactive powers. Therefore, such converters will be quite complex, and it is not easy to make them yourself.

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With your own hands you can construct only some semblance of a regulator, but you should not talk about maintaining power. What is power? From the point of view of electrical indicators, this is the product of the current consumed, multiplied by the voltage. The result will give a certain value, which includes the active and reactive components. To select only the active, that is, reducing the losses to zero, it is necessary to change the nature of the load on the active. Only semiconductor resistors have these characteristics.

Consequently, need to replace the inductance with a resistor, but this is impossible, because the engine will turn into something else and obviously will not set anything in motion. The task of lossless regulation is to save moment, not power: it will still change. Only a converter can handle this task, which will control the speed by changing the duration of the opening pulse of the thyristors or power transistors.

Generalized controller circuit

An example of a regulator that implements the principle of controlling a motor without loss of power can be considered a thyristor converter. These are proportional feedback integrated circuits that provide tight regulation characteristics, ranging from acceleration-braking to reverse. The most effective is the pulse-phase control: the pulse repetition rate of the unlocks is synchronized with the network frequency. This allows you to save time without increasing losses in the reactive component. A generalized scheme can be represented in several blocks:

power controlled rectifier;
rectifier control unit or pulse-phase control circuit;
tachogenerator feedback;
current control unit in the motor windings.

Before delving into a more accurate device and the principle of regulation, it is necessary to determine the type of commutator motor. The control scheme for its performance will depend on this.

Varieties of collector engines

At least two types of collector motors are known. The first includes devices with an armature and field winding on the stator. The second can include devices with an anchor and permanent magnets. It is also necessary to decide, for what purposes is it necessary to construct a regulator:

If it is necessary to regulate with a simple movement (for example, rotation of a grinding stone or drilling), then the revolutions will need to be changed in the range from some minimum value, non-equal to zero, to the maximum. Approximate indicator: from 1000 to 3000 rpm. For this, a simplified circuit for 1 thyristor or for a pair of transistors is suitable.
If it is necessary to control the speed from 0 to maximum, then you will have to use full-fledged converter circuits with feedback and strict regulation characteristics. Usually, self-taught masters or amateurs find themselves precisely collector motors with an excitation winding and a tachogenerator. Such a motor is the unit used in any modern washing machine and often failing. Therefore, we consider the principle of control of this particular engine, having studied its structure in more detail.

Motor design

Structurally, the engine from the Indesit washing machine is uncomplicated, but when designing a controller for controlling its speed, it is necessary to take into account the parameters. Motors can be different in characteristics, because of which control will also change. The operating mode is also taken into account, on which the design of the converter will depend. Structurally, the collector motor consists of the following components:

An anchor, it has a winding laid in the grooves of the core.
A collector, a mechanical rectifier of an alternating voltage of a network, by means of which it is transmitted to a winding.
Field Stator. It is necessary to create a constant magnetic field in which the armature will rotate.

Video: Speed Control Angle Grinder Without Power Loss

With increasing current in the motor circuit, switched on according to the standard scheme, the field winding is connected in series with the armature. With this inclusion, we increase the magnetic field acting on the anchor, which allows us to achieve linear characteristics. If the field is unchanged, it is more difficult to obtain good dynamics, not to mention the large power losses. Such engines are best used at low speeds, as they are more convenient to control at small discrete movements.

By organizing separate control of the excitation and the armature, it is possible to achieve high accuracy in the positioning of the motor shaft, but the control circuit will then become much more complicated. Therefore, we consider in more detail a controller that allows you to change the speed of rotation from 0 to the maximum value, but without positioning. It may come in handy., if a complete drilling machine with the possibility of threading will be made from the engine from the washing machine.

Scheme selection

Having found out all the conditions under which the motor will be used, one can begin to make the speed regulator of the collector engine. It’s worth starting with choosing the right scheme that will provide you with all the necessary features and capabilities. Remember them:

Speed regulation from 0 to maximum.
Providing good torque at low speeds.
Smooth speed control.

Considering the many schemes on the Internet, we can conclude that few people are engaged in the creation of such "units". This is due to the complexity of the control principle, since it is necessary to organize the regulation of many parameters. The opening angle of the thyristors, the duration of the control pulse, the acceleration-deceleration time, the slew rate. These functions are handled by a controller circuit that performs complex integral calculations and transformations. Consider one of the schemes that is popular with self-taught masters or those who just want to use the old engine from a washing machine with benefit.

All of our criteria are met by a collector engine speed control circuit assembled on a specialized TDA 1085 chip. This is a completely ready-made driver for controlling motors that allow you to adjust the speed from 0 to maximum value, ensuring torque is maintained through the use of a tachogenerator.

Design features

The chip is equipped with everything necessary for the implementation of high-quality engine control in various speed modes, from braking to acceleration and rotation at maximum speed. Therefore, its use greatly simplifies the design, while doing the whole universal drive, since you can choose any speed with a constant moment on the shaft and use not only as a conveyor belt or drilling machine drive, but also to move the table.

The characteristics of the chip can be found on the official website. We will indicate the main features that will be required to design the converter. These include: an integrated frequency to voltage conversion circuit, an accelerator, a soft starter, a Tahoe signal processing unit, a current limiting module, and more. As you can see, the circuit is equipped with a number of protections that will ensure the stability of the controller in different modes.

The figure below shows a typical circuit for switching on a microcircuit.

The scheme is simple, therefore it is completely reproducible with your own hands. There are some features that include limit values and a way of controlling speed:

The maximum current in the motor windings must not exceed 10 A (provided that the configuration shown in the diagram). If you use a triac with a large forward current, then the power can be higher. Note that you will need to change the resistance in the feedback circuit to a smaller side, as well as the inductance of the shunt.
The maximum rotation speed is reached 3200 rpm. This characteristic depends on the type of engine. The circuit can control motors up to 16 thousand rpm.
Acceleration to maximum speed reaches 1 second.
Normal acceleration is provided in 10 seconds from 800 to 1300 rpm.
The engine uses an 8-pole tachogenerator with a maximum output voltage of 6000 rpm 30 V. That is, it should produce 8 mV at 1 rpm. At 15,000 rpm, it should have a voltage of 12 V.
To control the engine, a triac on 15A and a voltage limit of 600V is used.

If it is necessary to organize the reverse of the motor, then for this it will be necessary to supplement the circuit with a starter that will switch the direction of the field winding. A zero-speed control circuit will also be required to permit reverse. The figure is not indicated.

Management principle

When setting the speed of rotation of the motor shaft by a resistor in the output circuit 5, a pulse sequence is generated at the output to unlock the triac by a certain angle. The speed of the revolutions is monitored by the tachogenerator, which happens in digital format. The driver converts the received pulses into analog voltage, due to which the shaft speed stabilizes at a single value, regardless of the load. If the voltage from the tachogenerator changes, then the internal controller will increase the level of the triac control output signal, which will lead to an increase in speed.

The chip can control two linear accelerations, allowing you to achieve the required dynamics from the engine. One of them is set by Ramp 6 output circuit. This regulator is used by the manufacturers of washing machines themselves, so it has all the advantages in order to be used for domestic purposes. This is ensured by the presence of the following blocks:

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Voltage stabilizer to ensure normal operation of the control circuit. It is implemented according to conclusions 9, 10.
Speed control circuit. It is implemented according to the conclusions of MC 4, 11, 12. If necessary, the controller can be transferred to an analog sensor, then conclusions 8 and 12 are combined.
Block starting pulses. It is implemented according to conclusions 1, 2, 13, 14, 15. Performs the adjustment of the duration of the control pulses, delay, their formation from a constant voltage and calibration.
Sawtooth voltage generation device. Pins 5, 6, and 7. It is used to control the speed according to the setpoint.
Amplifier control circuit. Conclusion 16. Allows you to adjust the difference between the set and the actual speed.
Current limiting device at pin 3. With increasing voltage there is a decrease in the tripping angle of the triac.

Using similar scheme provides full control of the collector motor in any mode. Due to the forced regulation of acceleration, it is possible to achieve the necessary acceleration speed to a given speed. Such a regulator can be used for all modern engines from washing machines used for other purposes.

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Aeg Angle Grinder Variable Speed

24th March 2020

Angle grinder or simply “angle grinder” is one of the most popular and indispensable tools in everyday life. With its help, you can cut or process the surfaces of various materials: brick or ceramic tile, concrete products, stone and even iron. Starting a home renovation, it is advisable to stock up on this tool in advance.

There are more and more manufacturers of similar equipment in the world. And each brand strives to make its models as convenient and functional for users as possible. Therefore, it is often very difficult to choose a particular model. Consider the best, according to customers, angle grinder 125 with speed control and soft start.

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TOP 10 best angle grinder with speed control according to customers choice

MILITARY AG900VS

Convenient and inexpensive angle grinder with a disk diameter of 125 mm and the ability to adjust the speed. Despite its very small size, it impresses with its power (900 watts). The tool is quick and easily cope with the tasks, whether grinding or cutting materials.

Ergonomic handle ensures safe operation with an angle grinder. Disks are easily removable and, conversely, are fixed on the unit. It provides speed adjustment. The tool does not overheat. The cord length is 2.5 meters.

Convenient to operate.
Good power.
Low price.
The small sizes.

Flimsy bearings.

Bort bws-905-r

A compact 125 mm angle grinder that attracts attention with its low cost and high power. Light weight (1.8 kg) allows you not to be distracted by fatigue and work for a long time, without rest and respite.

In the model, the speed is regulated, you can install the spindle. the angle grinder is equipped with a protective cover, additional brushes and a handle, a key for changing discs. On the case there is a button designed to lock the power on when pressed accidentally.

A light weight.
Convenient to work with one hand.
Low price.
Strong case.

Short network cable.
Heats up quickly.

Hammer USM 1200 E

High-power angle grinder with the ability to install discs up to 125 mm in diameter. It is characterized by high performance, the user can easily perform both cutting and grinding work. Speed adjustment allows you to adjust the angle grinder to the mode that suits the operator.

A feature of the grinder is the handle, which can be fixed in two positions. left or right, increasing the convenience of its use. The spindle lock also makes the unit particularly attractive, making it easy to replace accessories.

Sufficient power (1200 W).
It holds revs well under load.
The presence of spare brushes.

The start button must be pressed throughout operation.
Hard network wire.

BISON Angle Grinder-125-1100 TM3

Excellent angle grinder with soft start at an affordable price. Its power (1100 W) allows you to perform even quite complex and lengthy work. The model has an ergonomic body, it is simple and easy to operate. The additional handle that comes with the kit can be fixed in two positions, which makes its operation even more convenient.

In addition to adjusting the speed of the disk, the device is equipped with a button that blocks accidental switching on, as well as overload protection.

Good power.
Smooth start.
Comfortable ergonomics.
5 year warranty.

Tight power button.
Short network cable.

Sturm! AG9512P

Easy-to-operate 125 mm angle grinder with speed control at an attractive price. It will become an indispensable assistant to its owner in performing a variety of types of work: cleaning surfaces or grinding them, cutting metal and other materials.

Video: Aeg Angle Grinder Variable Speed

The tool is equipped with a removable additional handle that can be installed on the unit body in three different positions. It also has a protective cover that prevents dust, debris and sparks from reaching the operator and spreading it over long distances. Locking on the angle grinder allows you to protect all family members from injury if you accidentally press a button.

Convenience of operation.
Soft network cable.
Installation of the handle in 3 positions.

Short brushes.
Short cord.

BOSCH GWS 850 CE

A simple and reliable angle grinder with a 125 mm disc, which attracts with its low cost and high performance. It is easy to cope with the processing of any surface, cutting various materials. Drives and brushes are easy to remove and install.

The angle grinder is equipped with an ergonomic handle, which makes operation even easier and more convenient, as well as a protective cover that prevents spraying and flying sparks over long distances.

Light weight (1.9 kg).
Reliability.
Compact size.
Long cord.

There is no protection against arbitrary inclusion.
Inconvenient casing mount.

AEG WS 13-125 XE

Great tool in compact sizes. It has a moderate price and high power. The angle grinder copes excellently with the assigned tasks, and is equally good at grinding surfaces and cutting materials.

A feature of the model is a simple replacement of equipment (discs, brushes) and adjustment of the casing, without the use of keys and other additional tools. The handle included in the kit is convenient in operation, it does not vibrate and is firmly fixed to the case.

Good power (1300 watts).
Low noise.
It is convenient to hold in your hand.
Easy to change nozzles.

Sufficiently large weight (2.4 kg).
Heats quickly at low revs.

Metabo WEV 15-125 Quick

Reliable in work, functional unit. Its price may confuse the buyer somewhat. However, it is worth the money spent. The user will never regret the choice made during a long operating time.

The model is characterized by high performance due to the incredible engine power of 1550 watts. At the same time, the angle grinder fits perfectly in the hand, as it has small dimensions. It is easy to operate thanks to its convenient housing and ergonomic removable two-position handle.

Safe to use.
Reliability
Good build.
Long network cable (4 m).

High price.
Shaky speed control mechanism.

DeWALT DWE4257

The angle grinder is equipped with an active dust extraction system, reinforced gear design, and unique graphite brushes. It has a function to block accidentally turning on the button, protection against overloads. The kit also includes an additional removable two-position handle, key, protective cover.

Convenient to use.
High power (1500 W).
Convenient location of the speed controller.
Lack of gaps on the case.
Reliability.

High price.

Makita 9565CVK

Good angle grinder, characterized by reliability and functionality. A powerful 1400 W motor provides the user with incredibly high performance, regardless of the type of work performed, whether grinding or cutting.

The compact size coupled with the light weight of the model allows you to easily control the tool. The angle grinder provides automatic shut-off of the brushes during heavy wear, limitation of the starting current, blocking of accidental switching on.

Great performance.
Light weight (1.8 kg).
Multifunctional.
Convenient spindle stop button.

Cost.
Tight power button.

comparison table

For a more convenient comparison of all the 125 mm angle grinder from our rating, we compiled a table in which we indicated the most important technical characteristics of each model.

How to choose a home angle grinder?

Considering the option of purchasing a grinder, it is recommended, first of all, to pay attention to the following parameters:

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power. The amount of work performed, productivity depends on it;
the ability to adjust the speed so that for each type of work to select the optimal frequency of rotation of the disk;
network cable length;
installation of the handle in different positions (two, three), so that it is more convenient to grind or trim the material;
the presence of a casing that protects the user from fragments, dust, sparks;
the ability to change equipment without using keys;
the presence of additional functions, for example, blocking accidental pressing of the power button of the instrument, anti-vibration system, protection against jamming of disks.

How to work?

When working with an angle grinder, it is imperative to observe safety precautions, since this tool is quite traumatic. The basic rules for using the grinder are:

hold the tool firmly so that it does not fall out of your hands, does not bounce from the material being processed;
install only grinding wheels for the diameter of which the angle grinder is designed;
make sure that the network cable does not fall under the rotating disk;
maximally steady on your feet to avoid loss of balance;
turn on the grinder only if the user is completely ready for work;
replace nozzles only with the angle grinder turned off and pulled out of the socket;
be sure to turn off the unit after performing a particular job, do not move around the room, the room with the tool turned on;
after turning off the angle grinder, turn on the lock for accidentally pressing the "start" button, if the model provides such a function.

source

Which angle grinder to choose? Household and professional tools

Universal angle grinders

The best manufacturers of grinders

Bosch: Model GWS 850 CE

Video: Makita 125 Angle Grinder Variable Speed

Nozzles for polishing work

Household Makita GA5030 angle grinder

Professional Angle Grinder Makita 9565Cv

How to choose the required disk size?

Metabo WEV 10-125 Quick

Hitachi G13SS

What to consider when buying?

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Safety precautions

Personal protective equipment

Face mask

Principles of Safe Operation

Video: Work Protection With Angle Grinder

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Description

Specifications

Equipment

Feedback (151)

Video: Angle Grinder Status 125 Variable Speed

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Video: Guard For Working With Angle Grinder

Buy safety glasses for angle grinder

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Model Overview

Specifications

Features and benefits of the model

Video: Bosch 850 Angle Grinder Adjustable

Maintenance

Operation Nuances

Price issue

Conclusion

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Video: Angle Grinder Vityaz 125 Variable Speed

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The device and purpose of the angle grinder

Main malfunctions, their causes and diagnostics

How to disassemble and assemble an angle grinder

The clamping nut is not untwisted

How to remove a tightened nut

The casing cannot be removed

Stator check

Anchor Check

Checking the power button

How to ring the start button

Video: How to Insert Brushes into an Angle Grinder

Power cord check

Check soft start and speed control

Precautions before starting repairs

DIY troubleshooting

Power cord and power button

Soft start and speed control

Brushes

Brush holder cleaning

Stator Rewind

Rewind stator on video

Anchor Repair

Anchor Bearings

Gearbox disassembly and repair

Spindle lock button

Spindle lock button replacement and gearbox repair

Care and proper operation of the angle grinder

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Features

What is the adjustment for?

Video: Mini Speed ​​Angle Grinder

Advantages and disadvantages

Models and their characteristics

Selection tips

How to use?

Criteria for choosing a good angle grinder

Disc diameter

Power

Speed

Number of pens

Extra features

Video: Mini Speed Angle Grinder

Video: Speed Control Angle Grinder Without Power Loss