Causes of breakdown of angle grinder and repair methods

Even the simplest repair of an angle grinder in a service shop can cost a third to half of its cost. Therefore, before turning to professionals, you should always try to fix it on their own. The more so, that the tables of the most widespread malfunctions and the reasons of their occurrence are given in the machine operators’ passports. For home repair in most cases, you can get by with a set of the most common tools: screwdrivers, pliers, wrenches and multimeter. The only place where mandrels, pullers or similar devices may be required is the removal and installation of bearings. And spare parts for angle grinder repair can be easily purchased at well-known online stores.

Successful repair of bearing assemblies will help to observe the following recommendations.

  • Need to know the design of the controlled angle grinder. You should read the technical documentation that came with your shredder. Knowing the location of components and parts will help you properly disassemble and reassemble the grinder during repairs.
  • Performing the work of replacing the bearings will help as the availability of the necessary tools. These tools are not complicated and are almost always available in the home handyman’s arsenal: screwdrivers, wrenches, hammers, puller sets or other hand tools (vise, extensions, punches of various designs) for fixing and removing bearings.
  • When repairing grinders, there is a certain order of operation. This should be taken into account taking into account some of the differences due to the characteristics of the particular model.
  • Replace bearings if there is even a small shaft, Since a damaged bearing can completely damage the entire power tool.
  • Make sure that the power tool is switched off before carrying out repairs.

Bearing open for Hammer crusher. 220V photo

The tool used must be in good condition:

  • Design elements of the pullers (legs, rods, stops, screw-type devices) are in accordance with the technical documentation;
  • The screwdrivers have straight sides, and the straight rod is firmly seated in the handle;
  • The key jaws are parallel and have no cracks or indentations;
  • The hammers are firmly fastened to the handles.

Following these guidelines will allow you to properly and safely disassemble angle grinders, replace defective bearings, lubricate all parts, and reassemble the grinder for future use.

How to remove/remove the needle bearing from an angle grinder

The new needle roller bearing is easy to push in, but the removal requires the use of the original extractor. The following video by the author describes how to make such a device and shows its practical operation.

The puller is an expander collet with shoulder strips at the ends of the moving blades. The collet is machined to size and the center hole is drilled for a petal expander. The extractor is inserted into the bearing and the collar faces upward after the rod moves along the bore, and rests against the end face of the ring. Using not very impressive looking, but reliable levers made of reinforced steel with ground edges, resting on an inserted washer, the bearing can be extracted from the housing.

Important: A needle roller bearing has a significantly longer service life than a plain bearing. However, the spindle shaft wears out during operation and must also be replaced. In the video above, the author finds the following replacement. However, in most cases this can cause additional problems.

How to disassemble the gearbox correctly: Tips

When the gearbox completely fails to work, it requires complete disassembly to replace parts and thoroughly clean. To perform the work, you need to prepare a bench vice. All work must be carried out in a certain sequence of operations:

  • Use a wrench to unscrew the bolt holding the gear housing.
  • The rotor body is clamped with great care in a vise.
  • By hammering lightly, the body is extracted.
  • Find a convenient position of the rotor to remove the bearing. The vise is clamped again.

Lay a block of wood and knock out the bearing. To remove the pinion from the gearbox axis is necessary:

  • Wrap the rotor with a rag and secure it with the jaws of a vice.
  • Gear is also wrapped with rags, using a gas wrench, turn it counterclockwise.

Main modules used

As a rule, the most common cause of failure of the angle grinder is an electrical malfunction. The main percentage of electrical failure of angle grinders is the failure of carbon brushes.

Interskol angle grinder control circuits repair

The control circuits of different models differ slightly from each other. It all depends on the power of the tool, availability of innovative developments. Some lathes have an electronic block that controls the smoothness of starting.

Interskol angle grinder 125 angle grinder control wiring diagram

How to assemble the gearbox of an angle grinder

Interskol angle grinder 125 brushes pos.55 mounted in special brush holders pos.44. which can only be reached by removing the rear cover pos.51 stator housing pos.42.

After removing the cover remove screws pos.50 holding the brush holder housing.

Determine brush wear by measuring the remaining length of the brushes. The length of the carbon brushes must be at least 5 mm.

Power supply through cable pos.53. Where the cable enters the angle grinder and the plug pos.53 cable can break off. The malfunction can be eliminated by replacing the entire power cord or the defective part. No twists allowed.

The power cable supplies voltage to the switch pos.41 inserted into the housing pos. 47. There is a lever for controlling the switch button pos.46. When servicing, use silicone grease on the trigger lever.

Angle grinder control wiring diagram Interskol angle grinder 230

Power up the cord pos.50 is fed to the switch pos.46, to which the electronic unit pos.40, carbon brushes pos.38 inserted in the brush holders pos.37. The electrical part of the angle grinder also includes the stator pos.32 and rotor pos.27.

Brush replacement on Interskol angle grinder 230 no need to remove the back cover. It is enough to unscrew the brush holder cap pos.36 and pull out the brush holder with carbon brush. But replace breaker, electronic unit, capacitor pos.42 can only be done by disassembling the back handle pos44,45. To do this, unscrew the four screws 4×16 pos.44.

How to repair the rotor of an Interskol angle grinder

Rotor failure occurs for the following reasons:

  • The carbon brushes have failed or are out of order;
  • Short-circuited or broken windings;
  • The armature collector lamellae have failed:
  • Rotor bearings collapsed or jammed.

Repairing a rotor requires special knowledge, tools, and equipment. It is preferable to buy a new rotor or have it repaired by a specialized service center. But remember, this costs money. For persons with a special talent we recommend to rewind the rotor by hand.

To remove bearings from armature use puller. But you can also use improvised means. For example: vise, metal strips, hammer, soft metal shoes, etc.

Dismounting bearings from the armature angle grinder 125

On the rotor pos.31 there are two bearings: one at the rear, near the manifold pos.32.

And on the impeller side the bearing pos.28 size 6000-2 RS. Russian analogue 180100.

Bearings are dismounted after removal of the rotor from the gearbox housing. To pull the rotor out of the gearbox, you must remove the bevel drive pinion pos.26 sitting on the rotor shaft.

To do this unscrew nut M8×3,5 pos.25, dismantle pinion Z=12. It is secured with a key pos.30. The bearings are removed with a bearing puller.

Remove the bearings from the armature of the 230 angle grinder

To remove the bearings from the armature pos.27, it is necessary to pull the rotor out of the gearbox housing pos.19. Unscrew the M8 nut pos.20, remove lock washer pos.21, remove drive pinion pos.22. Pull rotor out of gearbox housing by gentle rocking. The bearing will remain in the gear housing. It is closed by the bearing cover pos.25, which is attached to the gearbox housing with three screws M5×8 pos.26. There is a bearing of size 6201-2RS in the gearbox housing. Russian analogue 180201.

Main electrical faults on Interskol angle grinder

As a rule, the most common cause of angle grinder failure is an electrical malfunction. The main percentage of failure of grinders on the electrical part is the failure of carbon brushes.

Interskol angle grinder control circuit repair

The control circuits on different grinder models are slightly different. It depends on the power of the tool, availability of innovative. Some angle grinders have an integrated electronic unit that controls the smoothness of the start-up.

Interskol angle grinder 125 angle grinder control wiring diagram

The Interskol angle grinder 125 angle grinder has an electric brush pos.55 fixed in special brush holders pos.44. which can only be reached by removing the back cover pos.51 of the stator housing pos.42.

After removing the cover unscrew the screws pos.50 holding the brush holder housing.

Brush wear is determined by the remaining length of the brushes. The length of the working carbon brushes cannot be less than 5 mm.

Power supply via cable pos.53. Where cable enters the angle grinder and plug pos.53 cable can break off. The malfunction can be eliminated by replacing the whole power cord or the defective part. No twisting allowed.

The power cable supplies voltage to the switch pos.41 inserted into the housing pos. 47. There is a lever pos.46. For maintenance work blow out the actuating lever with silicone grease.

Angle grinder control circuit diagram Interskol angle grinder 230

Power by cord pos.50 is applied to the switch pos.46, to which the electronic block pos.40, carbon brushes pos.38 inserted in the brush holders pos.37. The electrical part of the angle grinder also includes the stator pos.32 and rotor pos.27.

Replacement of carbon brushes on Interskol angle grinder 230 does not require removing the back cover. It is sufficient to unscrew the brush holder cap pos.36 and pull out the brush holder with carbon brush. But to replace the switch, the electronic unit, the condenser pos.42 is only possible by disassembling the back handle pos. 44,45. To do this remove the four 4×16 screws pos.44.

How to repair the rotor of an angle grinder Interskol

Rotor failure occurs for the following reasons:

  • The carbon brushes are broken or have failed;
  • Short-circuited or broken windings;
  • The armature collector lamellae are worn out:
  • The bearings in the rotor are broken or jammed.

Repair of rotor requires special knowledge, tools and equipment. It is preferable to buy a new rotor or have it repaired by a specialised service center. But remember, it costs money. For those who are particularly gifted, we recommend rewinding the rotor with your own hands.

Use the bearing puller to dismount the bearings from the armature. But you can also use improvised means. E.g. vise, metal strips, hammer, soft metal plate.

Disassembling bearings from the armature of the 125 angle grinder

On the rotor pos.31 there are two bearings installed: the rear one, near the collector pos.32.

And on the impeller side the bearing pos.28 size 6000-2 RS. Russian equivalent 180100.

The bearings are removed after removing the rotor from the gear housing. To pull the rotor out of the gearbox remove bevel drive pinion pos.26 seated on the rotor shaft.

To do this unscrew nut M8×3,5 pos.25, dismantle pinion Z=12. It is secured with a key pos.30. Bearings are removed with a bearing puller.

Dismantle bearings from the armature angle grinder 230

To remove the bearings from the armature, pos.27, you need to pull the rotor out of the gearbox housing pos.19. Unscrew M8 nut pos.20, remove the lip washer pos.21, disassemble the drive pinion pos.22. Gently wiggle the rotor out of the gearbox housing. The bearing will remain in the gearbox housing. It is covered by bearing cover pos.25, which is fixed to the gearbox casing with three screws M5×8 pos.26. The gearbox housing contains bearings of size 6201-2RS. Russian equivalent 180201.

Angle grinder repair costs

Experienced specialists in our workshop will carry out warranty and post-warranty repair of Makita bolt cutters. Note that the price in which it costs, depends on the category of its complexity, which, in turn, is determined by the power of the tool, the nature of the fault, as well as the cost of spare parts. We use only original spare parts from the main supplier. By the way, we can also repair your Makita torch of any complexity.

If you have any questions about tool repair, please call us at ext. 120

How to Disassemble an angle grinder Makita

How to disassemble a Makita angle grinder

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Anchor is a rotating element of the electric motor, containing windings.Collector. a place on the armature, to which our customer stays windings. It looks like a row of plates insulated with each other.Stator. the non-moving part of the electric motor that contains the windings.Brushes. carbon parallelepipeds that supply current to the collector.

Gearbox. a mechanical device for transmitting rotation with a change in power not rotational speed.

The most popular tool in the home after the drill is an angle grinder or, as they call it more often, the angle grinder.

angle grinder is used for cutting metal, wood, concrete, grinding various surfaces, cutting openings, doors, recesses.

If you have an angle grinder, you can always find a use for it, and it is especially frustrating when it ceases to function normally, there are jerks, jerking, burning smell.

angle grinder all arranged similarly: elongated body in which the motor and gearbox, side bolted handle and protective casing.

On the body of the angle grinder there is a sticker with the initial data. Here you can find both the personal number of the angle grinder and the supply voltage. 230 V. Here we mean the maximum permissible mains voltage. Frequency of current in the network. 50 Hz. The current consumption is 5A.

Power consumption from the network. 1100 W, it is the product of the voltage (220 V) and current multipliers (5 A). The speed of the disc mounted on the angle grinder is 2800-11000 rpm. The armature itself rotates at a higher speed than the disc.

Specifically on this angle grinder step speed adjustment is possible. Disc installed on the angle grinder has an outer diameter of 125 mm, the mounting nut has a disc thread M14.

Household tool designed for 220 V phase voltage has an armature winding and a stator winding. The power transfer from the mains to the armature is carried out by means of graphite brushes.

The mains voltage is applied to the switch, which is mechanically connected to the pushbutton of the angle grinder. The stator winding consists of two halves electrically unconnected.

The armature winding consists of multiple windings but at any one time the brushes only connect the two armature windings.

When you turn on the angle grinder, current is fed to the input of half of the stator winding, the output of the stator winding is connected with the brush holder in which, using a spring, is inserted a brush.

Brush carries current to half of the armature winding, on the other side the other brush receives current and carries current to the other half of the stator winding via the brush holder. Current in and out of the angle grinder.

If the entire electrical circuit is serviceable, the armature will start rotating.

Reverse, t.е. change the direction of disc rotation can be made by swapping the wires going to the brushes from the stator windings. Simply disconnect the wires on the brushes and swap.

At the end of the angle grinder housing is located a red wheel for stepped speed control armature and a screw for removing the hood.

In this type of angle grinder brushes themselves are located inside the body and access to them is not, but the developers have simplified replacement of brushes by removing the casing. After unscrewing the screw, the plastic plate is removed and the outer casing is moved towards the cord, exposing all the insides, including the brush holders.

The speed control mechanism is electronic. The whole circuit is encased in epoxy and only the speed control wheel and radiator are exposed. What is hidden inside. trade secret. When the unit fails.

The speed is no longer adjustable, but remains at the maximum level. In any case, do not despair, and in series with the angle grinder can include the most common dimmer. dimmer.

With it you can regulate the speed of any alternating current collector motor, the main thing is that the power of the motor does not exceed the power of the dimmer.

Servicing a Makita GA 5030 \ Fixing a Makita 5030 \ Repair of power tools \ maintenance tool

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How to change the rotor on a 230 Makita GA9020S angle grinder \ Repair a large Makita angle grinder \ Tool repair

On both sides of the housing are steel brush holders with springs in the form of a twisted steel strip. The spring is needed to keep the brush pressed against the armature collector even when the armature itself is subjected to strong vibrations and heat.

The spring holds the brush and as the brush wears away, the spring sinks lower and lower into the steel brush holder. Brushes wear out and shrink. When their length becomes insufficient, the angle grinder stops working. In expensive models, there is a spring inside the brush, which pushes the brush from the armature collector. The brushes of cheaper models do not have a built-in spring.

When selecting new brushes, it is best to consult your particular angle grinder manufacturer’s service center.

The fact is that, just like a graphic artist selects twenty different simple pencils with different softness, so the manufacturers of angle grinders specifically develop brushes for a particular type of collector.

If you use other brushes, for example from a VAZ alternator, the armature is likely to burn out soon, but for the first time as a solution to the problem such brushes will do.

The button on the angle grinder is a plastic box with a mechanical lever transmission. The box is bulky enough to suggest that it switches a lot of currents on and that the button goes not only to this equipment.

In the head part of the angle grinder is a gearbox, which increases the speed of the disc to 11000 rpm. The gear rod on which the disk is put contains a cut off washer that firmly sits on the shaft and has a supporting pad with a rubber ring for disk seating.

Next to it is a foot with kerfs that locks the protective cover. To increase safety, the guard can be moved and then locked. The foot pressed down to the angle grinder and move the shield at the required level, then the foot is released and it locks the shield.

Nuts for fixing the disk are self-clamping SDS and conventional with keyholes.

Repair of angle grinder with their own hands. eliminate typical malfunctions

The main principle in the repair of any electrical equipment is the postulate “move from simple to complex”.

Whether it’s a household electric cartridge or a turbine at a hydroelectric power plant. the repair sequence should rule out elementary faults first. Electrics and electronics are not called “the two sciences of contacts” for nothing. Typical malfunctions of bolt cutters together with the methods of their elimination are as follows:

  • The tool suddenly stopped showing signs of life. With 90% probability we can conclude that the current from the socket does not reach the electric brushes. That is, the problem is either in the power plug, or in the wire itself, or in the mechanism of the “Start” button. It is enough to disassemble the housing and “test” the cable with an ordinary tester for breaks. very often it is enough to replace the wire, and the angle grinder will work like new;
  • The wire and plug are still intact, and the tool is still immobilized? It is necessary to disassemble the starting mechanism, and it is desirable to mark the removable contacts. if you later connect them incorrectly, you can burn out the winding or jam the armature. The trigger can be replaced by any similar button, the working parameters are marked on it quite legibly;
  • The “Start” button and the power cord are in working order, but the angle grinder does not want to work? It’s time to take care of the brushes. Very often it is enough to grind the contact plates on the collector, and there appears a long-awaited spark and a steady humming of the mechanism. If it is not there, it is necessary to carry out the replacement of brushes. The life of these devices is usually limited to a few years. A number of models of lathes are produced with soldered connection of electric brushes, solder and put new ones in a set, their partial replacement is not allowed;
  • After replacement, carefully inspect the old electric brushes. if they have uneven wear, it is a clear sign of a shift in the center of gravity of the tool or its movable inner part. It is better to contact a specialized firm for repair of complex electrical equipment. independently adjust the balance without experience is unlikely to succeed.

Brush replacement refers to the “top of the first level” in self-troubleshooting in electric grinders. You can go on and on to describe repair recommendations, how to disassemble the gearbox of angle grinder, to rewind its winding, or to reconfigure the electronic stuffing. But serious breakdowns require a serious approach to work. If you have never seen this gearbox, how will you be able to repair it? The chance of a power angle grinder depends on your common sense. saving on a professional repair will cost you the entire tool.

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