How To Check The Anchor Angle Grinder

Anchor check examples

Both the anchors of professional tools and equipment of medium power can fail. Below we present to your attention a concrete example of checking the armature of a Makita GA 9050 angle grinder. To check the performance of the anchor, the Makita GA 9050 angle grinder should be diagnosed directly with the contact group of the part. Before that, you must turn on the multimeter and set the measurement mode to 200 Ohm. If you have an analog digital meter, it is better to use it than a digital one. After setting the multimeter, you can proceed directly to checking the armature.

The resistance is measured between each plate. Multimeter probes are placed on each lamella so that the groove between them is located exactly in the middle. If the part is in good condition, the resistance between each of the lamellas should be the same. The discrepancy between the indicators most likely indicates a break in contact. Of course, such a malfunction cannot be detected at home. If you notice a break in the winding outside when checking the armature, you can try it yourself. Sometimes this will save the day and the angle grinder will serve you for a while. The absence of indicators when examining the plates during the check of the armature for operability indicates their breakage.

Sometimes a malfunction can be noticed visually. In working order, all the plates of the armature contact group must be even and smooth. In the cases described, the part cannot be repaired and must be replaced. The engine brushes should be changed directly with the armature. A new part can cost a lot of money, but buying it is cheaper than purchasing a tool.

If, after passing along the contact circle, checking the anchor, you find that the resistance is the same between all the plates, its indicators are not “are jumping” and there are no visible breaks, the following check must be carried out. The measurement mode must be set to 200 kOhm. If your meter does not contain such a scale, it can be set to 20 kΩ. One probe of the multimeter is fixed to ground, and the second one must touch any of the plates. Normally, when checking the armature, the contacts should not “ring”. If you DO NOT observe such a reaction, then do not reduce the mass of your anchor. Most likely, the part is serviceable or the presence of an interturn short circuit is possible.

How to check the anchor if you have Special Tools?

In the absence of a multimeter, you can check the armature contacts using a simple 12-volt light bulb. I inserted it into the break of one of the wires; the voltage from a 12 Volt battery must be applied to the plug of the angle grinder. With the simultaneous rotation of the spindle by hand, the light should burn brightly, and not fade out. This result indicates that the anchor is working properly. The changing glow indicates a short circuit between turns. If the light does not light at all, the following breakdowns can be assumed:

  • Break in the supply circuit;
  • Hanging of the brushes in the inoperative position as a result of the actuation of the support spring;
  • Short circuit or break in the stator winding.

You can also check the performance of parts in other ways, but they require complex equipment or measuring instruments, which are not available or are little used in everyday life.

In which case, to check the anchor, you should definitely contact the specialists?

In order to check the armature for the presence of an interturn short circuit, a special measuring device is required, which is a special bracket with a coil. But this is already the work of professional craftsmen. To detect such a breakdown by checking the anchor, they can only in a service center or a power tool repair shop. A qualified technician will identify the fault with high accuracy using a Punch or the simplest transformer with a split toroidal core and one primary winding. Using the method described above, you can check the serviceability of the drill’s electrical parts.

How to check an anchor angle grinder: expert recommendations

How To Check The Anchor Angle Grinder

Despite the quality and the guarantee declared by the manufacturer, any tool is subject to wear, especially during intensive use. You are unlikely to be able to repair an angle grinder at home, but you can diagnose the cause of its breakdown yourself. Most often, such a tool is subject to wear and tear. Its breakdown can be both mechanical and caused by the failure of units and constituent elements of the electrical system. In this article, we will try to figure out in detail how to check the anchor angle grinder yourself? To determine a mechanical failure, a visual inspection must be carried out; it does not require special skills. Otherwise, you should contact the professionals.

How to check the anchor and determine the cause of tool breakage yourself?

Vibration and heating of an angle grinder during operation most often indicates the presence of a mechanical breakdown. On examination, you can find uneven wear on the brushes and their burning. Only a specialist with Special skills and technical aids can diagnose a breakdown in the electrical system when checking the armature. The main reasons for the failure of the tool in this case are:

  • Damage to the armature winding;
  • The presence of a short circuit in the turns;
  • Broken resistance between core and winding.

In order to check the anchor of the angle grinder, you need to disassemble the power tool and access directly to the part itself. Disassembly should be done carefully so as NOT to damage other parts. Fastening screws and screws Fold neatly so as not to lose. The surface of the table on which you disassemble the angle grinder must be clean, room lighting. Sufficient to clearly see all the details. In general, disassembly is not a difficult process, but it’s worth preparing. Completed it, you can start checking. The main common defects of anchors of a power tool can be determined using a multimeter in resistance mode.

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When you shouldn’t check the anchor yourself?

With NO experience or skills, and do not open the angle grinder yourself. It is also not recommended to disassemble it without special tools. This could damage the device. If you recently purchased your power tool, and it is out of order, you should contact the point of sale and show the warranty card to the manager along with the angle grinder. Disassembling a power tool under warranty at home is strictly prohibited. Otherwise, after such a check of the armature, you can NOT count on the device to be repaired at the representative offices of the company from which it was purchased.

Checking the anchor with a multimeter

In order to carry out such a check, you should disassemble the angle grinder and gain access to the anchor. The multimeter must be set in the range of 200 Ohm, and with the probes of the device touch two adjacent lamellas.

We carry out measurements on all turns of the winding, if all the readings are the same, then the anchor is in good order. If some curly resistance values ​​differ, then there is a malfunction. You should also check the body of the armature winding.

Visual inspection of breakage

Any, even the highest quality tool is prone to breakage. Especially if it is heavily exploited. In the event of a breakdown of the angle grinder, you are unlikely to be able to repair the tool yourself. However, preliminary examination can be carried out without Special Skills.

Most often the anchor breaks down in grinders. The breakage can be mechanical. Upon visual inspection, uneven wear of the brushes will be visible, as well as their burning. In addition, if the armature is faulty, the angle grinder will vibrate and heat up.

There are electrical breakdowns. These include:

  • Damage to the armature winding;
  • The presence of a short circuit in the turns;
  • Broken resistance between core and winding.

Such malfunctions can be identified using special measuring instruments, for example, a multimeter.

How to check an anchor on an angle grinder with a multimeter

Even if a man should not be a professional craftsman, but simply as a good owner repairs everything in the house himself, he cannot do without a quality tool.

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Solution to the problem

This type of diagnosis is rather complicated. You must have the skills to work with a multimeter, as well as be able to disassemble the angle grinder.

If your tool suddenly stops working, then it is better to immediately go to the workshop:

  • Even if you make sure that it was the anchor that was out of order, and establish the cause of its breakdown, you are unlikely to be able to replace it or repair it yourself. You still have to carry the tool to the workshop;
  • If the tool is still under warranty, opening the angle grinder by yourself may void the manufacturer’s warranty.

To ensure long tool life, choose products from renowned companies with extensive experience in the industry. Also, follow the rules for operating the tool, because very often they fail for this very reason.

Tips in the article “Open wiring in the interior” here.

Checking the motor armature, how to check the angle grinder:

Checking contacts with a light bulb

If there is no tester, you can get out of the situation with a simple 12 volt light bulb. The power can be any, optimally 30-40 W. The voltage from the 12 volt battery must be applied to the plug of the angle grinder, inserted a light bulb into the break of one wire. With the armature working properly, if you rotate the spindle by hand, the light should be on, and not changing the brightness. If the glow changes. This is a sure sign of an interturn short circuit.

If the light is off, then this may indicate the following:

  • The brushes may hang in the inoperative position. The retaining spring has worked.
  • There was a break in the supply circuit.
  • There was a short circuit or break in the stator winding.

There are other diagnostic methods, but they require more sophisticated equipment that is usually not used at home. An experienced craftsman will determine the breakdown with a high degree of accuracy using a “Punch” or the simplest transformer with a split toroidal core and one primary winding.

Inspection of the device from the inside

If everything is in order with the power supply, but the angle grinder does not work, you will have to open the case to gain access to the motor. As a rule, disassembly is NOT difficult. But it is necessary to adhere to simple rules that will avoid troubles during reassembly:

  • Be sure to unplug the appliance before disassembling.
  • Remove the working disc and the protective cover from the spindle.
  • Open the case in a well-lit place, on a clean table surface.
  • Remember the location of all parts and assemblies before disassembly. It is recommended to sketch or photograph the internal structure of the device.
  • Fold the screws and fastening screws in a separate place so as not to get lost.

It is best to inspect the motor under bright lighting so that all small details are clearly visible. The armature should rotate freely around its axis, properly functioning bearings should NOT make a sound during operation. There should be no traces of melted wiring on the armature, the loop windings should be intact, without breaks. You can smell the rotor. In the case of turn-to-turn closure, the insulating varnish burns and emits a persistent specific odor. But for such a diagnosis, certain experience is required.

Replacing the anchor yourself at home

Practice shows that if it is decided to replace the armature of an angle grinder, then it is best to change it together with the support bearings and the engine cooling impeller.

Replacement will require:

  • New anchor angle grinder. Must match your model. Interchangeable with other models. Unacceptable.
  • Screwdrivers, wrenches.
  • Soft brush and cloth for cleaning the mechanism.

Visual inspection from outside

Troubleshooting should start with a visual inspection of the angle grinder:

  • Carry out a general inspection of the tool.
  • Pay attention to the integrity of the power cord, the presence of voltage in the outlet.
  • Using the voltage indicator, check that the current flows to the motor manifold and the start button.
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DIY angle grinder check and repair

As Shakespeare said: “Nothing is eternal under the Moon.” Household appliances, alas, are NOT an exception. It happens that even the most reliable mechanism fails. And we must be ready to face this fact without panic, with firm confidence that there are no desperate situations. How is the angle grinder arranged, what malfunctions can there be, how to check the motor armature, determine the cause of the breakdown and troubleshoot? Knowledge of the structure of the main units of the power tool will allow the master to diagnose and repair the angle grinder with his own hands.

How to rewind anchor. Step-by-step instruction

If the balance of the armature is not violated, and the problem is only in the damaged windings, then such an armature can be restored independently, rewound the coils. Rewinding a rotor at home requires a lot of patience and care.

To rewind the anchor yourself you will need:

  • Wire for a new winding. A copper conductor with a diameter that exactly matches the old conductor is used;
  • Dielectric paper for insulation of the winding from the core;
  • Coil casting varnish;
  • Soldering iron with tin-lead solder and rosin.

Before rewinding, it is important to count the number of turns of wire in the winding and wind the same amount of new conductor on the coils.

The rewinding process consists of the following steps:

  • Dismantling of old windings. They must be carefully removed, and not damaging the metal body of the armature. If any burrs or damage are found on the body, they must be smoothed out with a file or sanded with emery. Sometimes, to completely clean the body of slags, the craftsmen prefer to bake it with a burner.
  • Preparing the collector for connecting a new wire. It is necessary to remove the manifold. The lamellas should be inspected and the contact resistance measured with a megohmmeter or multimeter in relation to the case. It should be no more than 0.25 MOhm.
  • Removing old collector wiring. Carefully remove the remnants of the wires, cut the grooves in the part of the contacts. In the future, the ends of the wires of the coils will be inserted into the grooves.
  • Installing anchor sleeves. The sleeves are made of 0.3 mm thick dielectric material, such as electrical cardboard. Cut a certain number of sleeves and insert into the grooves of the cleaned anchor.
  • Rewinding reels. The end of the new conductor is soldered to the end of the lamella and wound in successive circular movements, counterclockwise. This is called “right-handed”. Winding Repeat for all spools. Near the collector, pull the wires with a thick thread of cotton fabric (it is forbidden to use nylon, as it melts when heated).
  • Checking the quality of the winding. At the end of laying all the windings, check with a multimeter that there are no interturn short circuits and possible breaks.
  • Finishing treatment. Treat the finished coil with varnish or epoxy to hold the winding together. In the factory, the impregnation is dried in special ovens. At home, this can be done in the oven. As an option. Apply fast-drying varnishes for impregnation, applying a coating in several layers.

How to ring an anchor with a multimeter?

To perform this procedure, you will need the measuring electrical device itself and tools to disassemble the device. How to ring an anchor with a multimeter. Instructions:

  • Prepare your work surface. There should be enough space to arrange the necessary tools and remove parts from the device.
  • Disassemble the angle grinder and remove the anchor.
  • Clean the part from dirt and dust.
  • Using the recommendations in the presented, you can independently ring the anchor with a multimeter.

At the initial stage of diagnostics, the value of the measuring device is set at 200 kOhm. If your multimeter does not have such a scale, then you can limit yourself to 20 kΩ. To ring the armature, one probe of the measuring device is applied to the ground, and the second is touched to each of the plates. If no indicators appear on the scale of an analog multimeter or a digital screen, most likely there is an interturn short circuit in the armature winding. You can accurately diagnose the problem using a special device, which is available in professional locksmiths.

Checking the anchor angle grinder with a tester. Possible diagnostic results

Among the most common causes of equipment failure, the most common inter-turn closure of the armature of an angle grinder. It can be found. Call. Using a tester. The multimeter is an electrical measuring device that includes the functions of an ammeter, voltmeter and ohmmeter. They can not only check the presence of a turn-to-turn circuit in the winding of the angle grinder, but also measure the resistance between the lamellas. A simpler device is a tester. By checking the armature of the angle grinder with it, you can detect faults caused by a short circuit.

Checking the anchor with a tester. Recommendations of specialists. Features of checking the anchor angle grinder with a tester

A diagnostic procedure will help pinpoint the problem of a motor part. To check the armature of an angle grinder with a tester, the device, which is available in the arsenal of tools of many amateur electricians, will allow. With the help of the tester, you can check not only the anchors of the grinders, but also the stator windings of the second electric motors. In the picture below, you can see one of these homemade measuring instruments in action.

The indicator lights up when the tester is plugged in. A red light without the attachment of a technical device to the anchor means that the device is ready for testing. The working active surface of the measuring device has two points of contact with the investigated one. One of them. This is the generator coil, the second. Tie coil curls. When checking the armature of an angle grinder with a tester, it is necessary to substitute this surface to the groove under investigation. Make sure that the sensor does not extend beyond the armature plates at the same time on both sides.

If the electrical part is in good order or rewound, then during its check with a tester opposite each of the grooves, the indicator will glow green. If there is a malfunction in the armature of the angle grinder, in particular, a turn-to-turn circuit, a red light will be indicated on the indicator of the device in the place of its localization. Be careful when performing the diagnostic procedure to achieve correct surface contact when checking the angle grinder armature with a tester. Mechanical damage should not be excluded from the reasons for the failure of the angle grinder, which can be noticed visually without ringing the multimeter. They can be both significant and small. You may notice a breakdown on inspection by taking apart the angle grinder. It is necessary to diagnose such malfunctions before checking the armature for interturn short circuit.

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If you DO NOT have experience in disassembling a power tool or preparing to work with measuring instruments for ringing the armature with a multimeter and are NOT confident in your own strengths, do not interfere with the design of the angle grinder. DO NOT experiment to avoid damaging the angle grinder. In this case, in order to find the cause of the breakdown of the power tool and check the armature of the angle grinder with a tester, it is better to contact a service center or a qualified locksmith who specializes in repairing equipment.

What problems in the operation of the device can be detected when checking the anchor of an angle grinder with a tester

If you have sufficient knowledge to carry out the correct disassembly of the power tool, then in some cases you will be able to diagnose the cause of the device breakdown with your own hands. Checking the angle grinder armature with a tester for an inter-turn circuit will allow you to determine further actions for detecting faults or repairing equipment. If the part is intact, but the tool still does not work, seek qualified assistance. Did you check the angle grinder armature with a tester to accurately detect the cause of the equipment failure? If you have the necessary tools, you can repair equipment yourself in the following cases:

  • The winding damaged in the upper visible layers can be tried to Such an anchor will last for some time. After sealing, it must be checked or ringed with a multimeter;
  • In case of turn-to-turn closure, rewinding of the winding or replacement of the armature is required.

Breakdown diagnostics and repairs of the angle grinder can be performed under voltage. For the sake of your own safety, entrust this work to professionals.

How to replace an old gearbox with a new one

Angle grinders differ in size, power, manufacturers, but the principle of the arrangement of components is the same. The new motor armature angle grinder is selected strictly in accordance with your tool model.

    After unscrewing all the fastening bolts of the casing, housing and gearbox, Take out the gearbox with the armature from the casing. Usually the gearbox and the armature are rigidly attached to each other. To separate them, it is necessary to disassemble the gearbox.

Gearbox with armature

Impregnation instructions (including speed controller)

  • After making sure there are no problems, send the anchor in an electric oven to warm up for better epoxy flow.
  • After warming up, place the anchor on the table at an angle for better flow through the wires. Place a drop of resin on the forehead and slowly twist the anchor. Drip in the appearance of glue on the opposite frontal part.

Tilted impregnation

Air dry the anchor before polymerization

At the end of the process, grind the manifold lightly. Balance the armature with dynamic balancing and an angle grinder. Now grind finally on the bearing. It is necessary to clean the grooves between the lamellas and polish the collector. Make the final check for open and short circuits.

Testing the excitation coils

Based on the design of the collector motor, troubleshooting can be conditionally divided into checking the field coils (or permanent magnets) and the rotor windings. When repairing DC motors with magnets, pay attention to them in search of cracks, as they worsen the magnetic field strength, which reduces the overall performance of the electric motor.

Sectional view of a permanent magnet brushed motor

The excitation coils are checked with an ohmmeter, checking their conductivity, as well as with a megohmmeter, excluding breakdown to the case. Since the turn-to-turn short circuit in the turns of the excitation coil is extremely difficult to identify using only a multimeter, indirect methods are used, checking the color of the winding wires for signs of overheating or visible damage. Knowing the exact resistance of the excitation coils from the motor passport, the data can be compared with the results of measurements with an ohmmeter.

Stator excitation coils

Since the turn-to-turn circuit in the turns of the excitation coils is a rare malfunction, they are limited only to checking these windings, shifting attention to checking and repairing the motor armature. The armature of the collector motor can be conditionally divided into several parts:

  • Rotor windings with magnetic circuits;
  • Collector consisting of brushes and contact plates (lamellas)
  • Shaft with bearing.

Motor armature device

How to check the anchor angle grinder for serviceability

Types of armature malfunctions:

  • Breakdown of insulation to ground. This is the short circuit of the winding to the metal rotor housing. Occurs due to the destruction of insulation.
  • Wiring collector leads.
  • Uneven collector wear.
  • If the armature is faulty, the motor overheats, the winding insulation melts, the turns are short-circuited. The contacts connecting the armature winding with the collector plates are unsoldered. The power supply is cut off and the motor stops running.

    Types of anchor diagnostics:

    • Visually;
    • Multimeter;
    • Light bulb;
    • Special devices.

    How to check the rotor of an angle grinder with a light bulb

    • Take two wires and connect them to the lamp.
    • On a minus hold make a break.
    • Apply voltage to the wires. Attach the ends of the gap to the collector plates and twist it. If the light is on without changing the brightness, then there is a short circuit. Comments.
    • Conduct a short to iron test. By connecting one wire to the lamellas and the other to the rotor iron. Then with the shaft. If the light is on, then there is a breakdown to ground. Winding Closes to the rotor housing or shaft.

    This procedure is similar to diagnostics with a multimeter.

    How to anchor in place

    To install a new angle grinder anchor in place, take a new part, and then assemble the tool in the reverse order. The sequence of actions is as follows:

    • A fixing disc is installed on the armature shaft.
    • The bearing is installed by pressing.
    • The small gear is put on and fixed with a circlip.
    • The anchor is wound into the gearbox housing, the docking holes are aligned.
    • The gearbox mounting bolts are tightened.
    • The anchor with a gearbox is inserted into the body of the angle grinder and fixed.
    • The brushes are deposited in their places, closed with lids.

    After completing the above steps, the angle grinder is ready for use. Anchor replacement completed.