How to remove the bearing from the angle grinder armature

How to properly repair the angle grinder with their own hands

The bearing units in bucking machines are under great strain as the work progresses. This is the reason for frequent failure of angle grinders due to wear or destruction of the bearings. You can remove the defective bearing and replace it with a new one, provided you have the appropriate knowledge and tools.

Anchor angle grinder: self-troubleshooting

Angle grinder is used to perform many tasks in the economy. Regular use may cause the unit to break down. The most frequently broken element is the armature. It is subject to high thermal stress, as well as mechanical and electromagnetic effects. As a result, many handymen have to think about repairing this part.

Design of the armature

Anchor of an angle grinder consists of a current-conducting winding and a magnetic core. The armature contains the shaft that performs the torsion. The magnetic wire is made up of plates and slots which are insulated between each other by a coating of varnish. A certain sequence of laying the anchor winding conductors in the grooves has been developed. The conductors form a coil. Its ends are connected on lamellae. The layout of the beginning of the starter coil and the end of the last coil are made so that they are shorted to one lamella.

When the angle grinder motor overheats continuously, the armature melts. Contacts of wires that connect primary winding to collector can fall off as a result of high temperature. All this leads to the fact that the current is not supplied.

Anchor malfunction

There are criteria on the basis of which you can conclude that you need to repair the armature:

  • the number of sparks coming from the brushes on the motor collector increases;
  • appears vibration at low speed;
  • The operating shaft begins to move in different positions.

The presence of these signs indicates a breakdown of the armature. Subsequent use can be hazardous.

  • breakage of electric current conductors;
  • short-circuiting between the coils;
  • insulation failure, which causes shorting of the winding to the metal surface of the rotor
  • soldering of the manifold terminals;
  • unequal abrasion of the collector.

As a result of these faults, the motor gradually stops working. To find out the cause of the angle grinder‘s failure, you should carry out diagnostics. It can be checked visually or with the appropriate tools.

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Rules for visual inspection

Standard diagnostics involves a visual analysis of the device. The continuity of the wire and the current flow to the motor collector must be analyzed. The angle grinder should be inspected from the inside if the power supply is normal. It should not be too difficult to disassemble the unit. It is best to photograph the location of the main modules of the device during disassembly. After disassembly, visually inspect the armature for such properties:

  • The armature should run freely;
  • No black stains or odor, which may indicate a melted winding, the insulating varnish of which leaves traces;
  • Absence of crumpled turns and solder residue, which leads to short circuits
  • There should be no burnout on the lamellar contacts, otherwise you should check the binding of the lamellar cock and the winding bus bar;
  • No worn or burned out wafers;
  • the space between the lamellae should not contain graphite residues from the brushes.

If visual inspection does not reveal any defects, it is necessary to carry out a check with an instrument. Anchor on an angle grinder can be checked with both a tester and an ordinary light bulb.

Inspection with a tester

Set the multimeter in the ohmmeter position. Set the resistance to 200 Ohm. The probes are connected to the lamellae, which are next to each other. If the gauge reads less than 1 ohm, then a short circuit is present. If the value is greater than the average value, a short circuit may be present. If the resistance value is high or if there is no resistance value (when using a digital device), a breakdown can also be judged.

There are situations where no breakage is detected. Then a ground fault test is performed. At the maximum resistance one of the probes is placed on the shaft, and the other is moved across the plates. If the value is zero, there is no damage. Then use a multimeter to check the rotor in the same way. In this case, the stylus is moved along the lamellae. If it is not possible to check with a tester, a light bulb is used.

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Test with a light bulb

In the absence of the device at hand, many are interested in the question of how to check the angle grinder for possible anchor breakage. The supply wire is broken, and a light bulb is placed at the point where one wire is broken. Then rotate the shaft. By changing the brightness of the light bulb you can judge about the short circuit between the coils. If there is no burning, the following conclusions are possible:

  • the position of the brushes does not correspond to the working position, due to the triggering of the retaining spring;
  • Break the supply circuit;
  • short circuit or breakage in the stator winding.

Can be tested with a short-circuit indicator and an armature tester. This can be done by an experienced person.

Is it possible to repair the armature

Angle grinder armature repair can not be performed if there is vibration, because the balance is disturbed. Such a situation requires a replacement. Perhaps eliminate the short circuit and replace the winding.

First disassemble the motor and remove the rotor. But before that, disconnect the power terminals and remove the brushes. The rotor of the angle grinder is taken out together with the bearing and impeller for cooling.

Rewind armature

Anchors for angle grinder angle grinder can be rewound at home. To do this, you need to have certain skills with the soldering iron. To carry out the rewinding of the armature with your own hands will be required:

  • wire with a copper core that matches the previous conductor;
  • dielectric paper to insulate the winding;
  • Coil filler varnish;
  • soldering iron.

It is important before beginning to wind the armature to count the number of turns in the old winding and make the same number on the new coil.

  • Removing the previous winding. try not to spoil the surface of the body. If there is damage, grind with an emery or file;
  • inspection of the collector. the value of contact resistance lamella in comparison with the shell should not exceed 0.25 Mohm;
  • cleaning up the collector from old wires. developing slots to insert the ends of new wires
  • laying sleeves. they are made of a material that does not conduct current, such as electrical cardboard. Their size is 0.3 mm;
  • rewinding the coils. the end of the new wire is connected to the end of the lamella. Rewind in a counterclockwise direction. Fix the wires near the collector with a cotton thread;
  • Check for short circuits. measure the resistance with a tester;
  • applying varnish or epoxy to hold the winding in place. dry in an oven or use products that dry quickly.

If you can not perform such actions, you can replace the armature of the angle grinder.

armature change

Anchor replacement on the angle grinder is carried out at the same time as replacing the bearings and motor cooling impeller. To do this, you will need the following tools:

  • a new angle grinder armature suitable for your machine;
  • screwdriver and wrench;
  • a brush with soft bristles and a cloth to wipe the elements.
  • removal of the brushes;
  • unscrewing the gearbox;
  • Removing the gear cover;
  • removal of the ring which secures the small pinion to the armature;
  • removal of armature together with gear and bearing;
  • removal of the bearing with a special removal tool;
  • removal of the gear and the clamping disk;
  • wiping the main elements with a cloth.

Putting in a new part for the grinder is done in reverse order:

  • installing the retainer disk on the shaft;
  • pressing in the bearing;
  • installation of the small gear and its fixation by means of a retaining ring;
  • placing the armature in the gearbox with docking holes;
  • Fixing the gearbox in the angle grinder housing;
  • installation of brushes;
  • device inspection.

Thus, the repair of the anchor with your own hands can be performed quickly and easily. But in order to avoid such cases, it is necessary to use the device with care and not to subject it to prolonged high loads. Keeping the tool in a dry place and taking sufficient care will extend its service life.

Replacement of bearing in armature

Features of pressing a bearing on the motor armature

After you have successfully removed the bearing from the armature, you need to perform a number of necessary manipulations before reassembling the equipment. If you are installing new parts, it is essential that they match the old bearings exactly in width as well as the inner and outer diameter. It is important that during assembly no dirt or dust gets inside the product, because this can lead to corrosion, chipping and all sorts of damage. The bearing is mounted on the armature using a metal tube which should be greased beforehand. During the pressing process it is important to ensure that there is no distortion. Such nuances should also be observed:

  • Lubricate the bearings with a special thick substance. It can be moisture-proof;
  • Fill only ½ (for machines rotating up to 300 rpm) or 1/3 (for higher speed machines) of the bearing chamber with grease. Do not apply more material since all unnecessary material is ejected during the rotation process anyway.

How to disassemble the gearbox correctly: Notes

When the gearbox completely fails to work, it needs a complete disassembly to replace parts and thoroughly clean. To do the work, you need to prepare a locksmith’s vise. All work is carried out in a specific process sequence:

  • Unscrew the bolt holding the gearbox housing using a wrench.
  • Clamp the rotor body in the vise with great care.
  • Lightly tap with a hammer to remove the housing.
  • Find a convenient position of the rotor to remove the bearing. Clamp the vice once again.

Read also: Condenser for starting an electric motor

Placing a wooden bar, knock out the bearing. To remove the pinion from the gearbox axle is necessary:

  • Wrap a cloth around the rotor and secure it with the jaws of the vice.
  • Also wrap rags around the pinion, using a gas wrench, turn it counterclockwise.

5 Tricks / Hacks To Remove Armature Bearing repair

Assemble the tool with the new parts

After disassembly of the tool, necessary replacement of all destroyed parts, we will reassemble. Make sure you have all the tools, lubricants, clean rags on hand to put the finishing touches.

All previous grease should be removed and replaced with fresh grease. Use lubricants from reputable manufacturers and buy them from specialised dealers.

First assemble the rotor. Press in the bearings, mount the impeller. Before doing so, thoroughly lubricate the bearings. Using a wooden spacer, press them on top of the shaft.

Cover the collector bearing with rubber protectors. This is the same circuit, how to assemble the rotor shaft.

Then reassemble the gearbox. Start this process by placing the gear on the rotor shaft housing. When the shaft is already inside the housing, put the pinion, then the washer and the jam nut on it.

Now place the gear case together with the shaft inside the stator housing. It is necessary to press both housings after the collector bearing is already in the seat. Next check whether the rotor rotates easily on the bearings.

The final step is to put the cover back where it was. Check that the spindle shaft rotates. If you find that the rotation is light, even with the movement of your hands, you can proceed to screw the screws on. They do the fixing of the cover to the housing. Before doing so, lubricate all the screws using sealant.

Replacing the bearings in the motor

Timely replacement of electric motor bearings is the key to long and trouble-free operation. Neglecting to do so may result in serious damage. Bearings are highly stressed in operation and should be serviced or replaced at least as often as specified.

Lubricants should be changed regularly to prevent accidents. When replacing out-of-date bearings, replace and relubricate together. Typical signs of loss of lubricating properties are heating of bearing unit and reduction of rotational speed of electric motor shaft.

Before greasing, the bearing unit is thoroughly cleaned of old grease, washed with kerosene and blown with compressed air. Grease is applied by hand with a wooden spatula.

Replacing the bearings in an electric motor: Features of the procedure

In order to change a bearing, the following points must be considered:

  • Frequency of bearing replacement in the electric motor. in accordance with the regulations specified in the passport of the product. It is recommended to replace the bearings on industrial electric motors after 10,000 to 20,000 hours of continuous operation. Note that bearings on the shaft end wear more than those on the opposite side. If abnormal noise is detected in the bearing unit, the bearings must be replaced immediately.
  • Both bearings must be replaced
  • For unhindered access all or part of the motor must be disassembled

Removal of bearings by non-destructive or destructive method. To do this, the bearing is heated up and removed with a special puller or by cutting.

  • Dismantle coupling halves, fan impeller from the reverse side of the shaft.
  • Partial or complete disassembly of the motor.
  • Bearings are removed with a special puller or by gas cutting.
  • Mounting and fixing the bearings. The bearings are inserted in the heated condition and firmly secured to the shaft once it has cooled. After that, the bearings are coated with grease.
  • Assembly of an electric motor.

At the request of clients who buy our motors, we can replace the standard bearings installed at the manufacturer’s plant with their counterparts having a longer service life.

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How to remove the bearing from the armature to check its performance?

The condition of the bearing on a power tool motor should be given proper attention. If the bearing is worn beyond the allowable limit, it can overheat and cause the motor to begin to run noisily. If the bearing is not removed from the armature in time, the stationary and moving parts will contact each other in the running state. And this, in turn, threatens a serious breakdown of the electric motor. In this case the rotor or the armature must be replaced. Checking the bearings is quite easy. To do this, place the motor on a hard surface, put your hand on top of it and rotate the shaft. The rotor must move freely with no stick-slip. If you hear scratching noises or feel uneven rotation, this is the first call to remove the bearing from the armature and troubleshoot.

How to replace the bearings on a Bosch GWS 5-115 angle grinder

Every bearing has a backlash, i.e. clearances. Their presence is quite acceptable, but it is important that the figures are within the permissible limits. The backlash must be checked:

  • either radial or axial. This is done by placing the motor on a hard surface and trying to deflect the shaft with your hand in different directions. The amount of misalignment depends on the size of the part. For domestic power tool models, deviations should be barely noticeable;
  • Axial. The inspection is simpler in this case. Take the shaft by hand and pull it towards you or push it in the opposite direction to the rotor. In domestic appliance motors, the deviation should not exceed 3 mm. The closer to zero it is, the better.

If during disassembly of the electric motor you notice traces of friction of details, it means that there was a wear of bearings of the electric motor. It is necessary to immediately remove the bearing from the armature and make replacement parts. This avoids negative consequences in the form of motor failure or complete failure of the tool.

How to remove the inner bearing without a puller from the hub of the front wheel VAZ 2110

Dismantling and replacement of the c/c is required if you hear a characteristic crunch or hum, which is heard when driving from the front wheels. It is better to perform the replacement with a special device and auxiliary tools to avoid damage. To understand how to remove the bearing from the front hub half on your own, you should read the step-by-step procedure:

  • set the car on an elevated or level surface, jack up the wheel, tighten the handbrake;
  • Remove caliper, brake disc, unscrew retaining nut;
  • Use the two studs inserted in the brake disk and screwed into the hub as far as they will go, to pull the part off the shaft;
  • unscrew ball joint bolts and pull the ball joint out of the socket;
  • Remove the locking ring using the pliers;
  • use a puller to press out the upper cage;
  • Remove the mud ring with a screwdriver;

Before installing a new element, carefully clean and lubricate the seating and check for damage. Reassemble in the reverse order.

How to check the angle grinder armature for proper operation

If the armature is defective, the motor overheats, the winding insulation melts and the turns are short-circuited. Armature winding connection to manifold plates becomes unsoldered. Current flows out and motor stops working.

Standard diagnostics

Inspect the anchor before taking the diagnostic tool. It may be damaged. If the wiring is melted, the burnt insulating varnish will leave black marks or a specific smell. Bent or crumpled coils or conductive particles such as solder residues can be seen. These particles are the cause of a short circuit between the coils. The lamellae have bent edges, called roosters, to connect to the winding.

A fault in these contacts can cause the lamellas to burn out.

Other damage to the commutator: raised, worn or burned plates. There may be graphite from the brushes accumulated between the lamellae, which also indicates a short circuit.

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