How To Check Anchor And Stator Angle Grinder

If you don’t have a tester, use a 12 volt light bulb up to 40 watts.

With a file, without damaging the insulator film, remove the impregnation residues. Count the conductors in the slot. Calculate the number of turns in the section and measure the wire diameter. Draw a diagram. Cut insulation sleeves from cardboard and insert them into the grooves.

Galvanic extension of collector plates

Reduced copper is very hard. Collector service life as new. Galvanic build-up can restore both a completely worn out collector and partially damaged plates.

Recovery quality will be the same.

  • Clean well the entire collector surface, including the insulator between the lamellas.
  • Wrap bare copper wire about 0.2 mm in diameter.
  • Wrap the armature shaft with tape, and smear the collector from the end with plasticine so that copper does not grow where it is not needed. And so that the electrolyte does not get on the iron.
  • For the tub, cut off the floor of the plastic bottle. Wrap the tape around the shaft so that it fits snugly in the neck of the bottle. Insert the anchor into the bottle.
  • Take a piece of copper bus. Its size is twice as large as the surface to be built up. Roll it up in a spiral and place it in a bottle.
  • Connect the power supply minus to the surface to be repaired, and plus to the busbar. One and a half amperes of current per square decimeter of solution. If the collector is separated from the shaft, wrap it with wire and hang it in a jar on a crossbar so that the electrolyte touches only the worn part of the lamellas. Connect bulbs of different wattage in series to regulate the amperage and prevent a short circuit on the vessel. After 24 hours, a remanufactured manifold is obtained.
  • The collector must be grooved and the plates must be cut with a drill or a hacksaw blade. Finally, test the manifold for shorts between the plates.

Electrolyte components:

  • Copper sulfate. 200 g.
  • Sulfuric acid 1.84. 40 g.
  • Alcohol. 5 g. It can be replaced with a triple amount of vodka.
  • Boiled water. 800 ml.

How to repair an anchor at home

Because of the anchor, a third of the breakdowns of the screwdriver occurs. With daily intensive operation, malfunctions can occur already in the first six months, for example, if the brushes are not replaced on time. With sparing use, the screwdriver will last a year or more.

The anchor can be salvaged if the balance is not disturbed. If during the operation of the device an intermittent hum is heard and there is a strong vibration, then this is a violation of balance. This anchor must be replaced. And you can repair the winding and the collector. Small short circuits are eliminated. If a significant part of the winding is damaged, it can be rewound. Grind worn out and heavily damaged lamellas, build up or solder. In addition, you should not undertake an anchor repair if you are unsure of your capabilities. Better to replace it or take it to the workshop.

How to check the stator of an angle grinder with a multimeter video

The stator as an element of the electric drive of the angle grinder participates in the creation of an electromagnetic field in which the rotor rotates, which creates a torque on the spindle shaft. During operation, for a number of reasons, it fails. The user can diagnose damage and repair the stator by himself.

How to check with a multimeter

  • Put a resistance of 200 ohms. Connect the test leads of the instrument to two adjacent lamellas. If the resistance is the same between all adjacent plates, then the winding is in good order. 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 two or more times higher than average, then there is a break in the winding turns. Sometimes, in the event of a break, the resistance is so great that the device goes off scale. On an analog multimeter, the arrow will go all the way to the right. And on digital it will show nothing.
  • The determination of the breakdown to ground is done in the absence of a winding break. Set 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 lamellas.

How to check the anchor angle grinder for serviceability

Types of armature malfunctions:

  • Insulation breakdown to ground is a short circuit of the winding to the metal rotor body. Occurs due to the destruction of insulation.
  • Wiring collector leads.
  • Uneven manifold 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.

    Checking the armature / rotor and stator with a multimeter / tester

    In the next video, a multimeter device, or as more commonly called a tester, is used as a tool for diagnosing the rotor and stator of an electric drive. It is used to measure various electrical parameters: resistance, current, voltage. To determine faults in the form of wire breakage, breakdown of the winding to the case, the “ohmmeter” mode is used, that is, a certain resistance value is set, which is comparable to that available in the tested circuit. In this case, with a limit of 200 ohms.

    Breakdown of the stator to the housing is determined by applying indicator probes to its housing and one of the ends of the winding. The presence of any resistance value on the indicator indicates the presence of a defect in the form of a breakdown of the winding onto the case. When diagnosing a winding break, the indicator of the device will not show anything when combining the probes with the winding leads.

    complex manipulations should be carried out when checking the rotor windings of the electric drive. A winding break can be in any connection with a separate collector lamella. Therefore, it is necessary to check the resistance between all collector lamellas by applying indicator probes to them one by one. In the absence of a break, the resistance will have the same small value in all cases. Any deviation indicates the presence of a cliff. The breakdown of the winding on the body is checked with probes when they come into contact with the collector and “iron” from a set of sheets of electrical steel. The indicator scale should not react to this action.

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    However, it is impossible to determine the turn-to-turn circuit with a multimeter. Here, a device called the indicator of short-circuited loops (IKZ) is used. details about it in the information below.

    Makita, without instruments

    In one of the Makita models in the following video, smoke emitted during operation, which is a sure sign of a burnt out rotor or stator. To determine the reasons, the author performed a complete disassembly of the angle grinder, which makes it possible to perform a good external examination of the angle grinder units suspected of malfunctioning. If there were no signs of smoke consequences on the rotor, then on the stator several places of burnt electrical insulating varnish were clearly visible.


    The stator of the angle grinder is a fixed structure in the form of a core made of sheet electrical steel. It has grooves in which the winding is placed, twisted in a certain way, its wires are located parallel to each other, to reduce eddy currents.

    check, anchor, stator, angle, grinder

    408-316 Stator for BOSCH GWS6-100 / GWS6-115 HAMMER. Photo 220V

    The winding is necessarily covered with an electrical insulating varnish in order to protect it from possible shorting of wires to each other. In the grooves of the cores between the coils, insulation is made of electrical cardboard, glass tape and other similar materials. In the vast majority of models of the angle grinder, the stator is tightly fitted inside the housing made of high-strength plastic, which protects the entire electrical part of the angle grinder.

    Visual inspection for malfunction

    The very first and easiest way to determine if the stator is faulty is to visually inspect it. For what it is necessary to get it out of the body of the power tool. Disassembly here will not present any difficulties. The main thing is to free it from all other structural elements of the angle grinder, including the rotor. This will make it possible, with appropriate good lighting, to inspect all surfaces of the stator winding. Usually, charred areas appear in the places of the cliff, which allows us to conclude that there is a defect. If visual inspection failed to identify a malfunction of the stator, you should resort to using special devices.

    How to check the stator winding of an angle grinder at home in different ways

    There are a large number of different electrical devices with which you can diagnose the stator. However, a limited number of technical means are used at home. Some are presented in the following videos.

    How to ring the stator angle grinder

    408-317 Stator for BOSCH GWS7-125 / GWS7-115 HAMMER. Photo 220V

    The stator as an element of the electric drive of the angle grinder participates in the creation of an electromagnetic field in which the rotor rotates, which creates a torque on the spindle shaft. During operation, for a number of reasons, it fails. The user can diagnose damage and repair the stator by himself.

    • Device
    • Causes of malfunction and characteristic symptoms
    • Visual inspection for malfunction
    • How to check the stator winding of an angle grinder at home in different ways
    • Checking the armature / rotor and stator with a multimeter / tester
    • On turn-to-turn circuit, indicator
    • Makita, without instruments
    • Multimeter. automatic: quickly and efficiently performs measurements

    Causes of malfunction and characteristic symptoms

    The main factors that affect stator failure are as follows:

    • the supply network does not always guarantee a stable voltage, its surges are possible;
    • during the operation of the power tool, any liquid, such as water, may enter the stator;
    • when processing some materials (concrete, wood and others), a sick amount of dust is formed, from which it is difficult to protect itself from falling on the stator winding;
    • long-term operation of the angle grinder under overload conditions, which causes the power tool to overheat;
    • during operation, do not stop the angle grinder by pulling the cord out of the socket suddenly.

    408-105 Stator for Hitachi G18SE3 and HAMMER angle grinders. Photo 220V

    Typical signs of a stator malfunction are as follows:

    • there is a persistent smell of burnt insulation of the winding wires;
    • the temperature of the body parts rises noticeably Angle grinder;
    • the electric angle grinder hums more than under normal conditions;
    • the appearance of smoke is quite real;
    • the spindle starts to rotate more slowly, or even may stop completely;
    • the opposite to the previous case, the other extreme is possible. the spindle starts to spontaneously work at increased speeds, it is peddling.

    On turn-to-turn circuit, indicator

    The principle of operation of the device for determining the turn-to-turn closure is shown in the following video. The device in the tested winding induces a magnetic field. If there are short-circuited turns in the winding, the short-circuit current causes an increased resistance to the electromagnetic field generated by the device. By adjusting the IKZ, a setting is performed, upon reaching which a light signal is triggered (the indicator lamp changes color from green to red) or a sound is heard. In addition to the main application, the author shows a way to determine the places of connection of the winding wires to the collector lamellas, in the absence of visually visible contacts.

    Continuity tester

    If visual inspection did not give clear results, it is recommended to continue the examination with a multimeter. Having set the mode switch to the ohmmeter position (200 Ohm range), it is necessary to “ring” two adjacent armature lamellas with two probes. If the resistance on all turns is the same, this means that the windings are in good order. If on some pairs the tester shows a different resistance or an open circuit. there is a malfunction in this coil.

    Broken wiring can occur between the winding and the core. Carefully examine the junction of the coils with the collector lamellas in the lower part of the armature, visually check the soldering of the contacts.

    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, make sure that current is flowing to the motor manifold and the start button.

    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. Interchange with other models. not allowed.
    • Screwdrivers, wrenches.
    • Soft brush and cloth for cleaning the mechanism.

    Inspection of the device from the inside

    If the power supply is OK but the angle grinder is not working, you will have to open the case to gain access to the motor. As a rule, disassembly is not difficult. But you need to adhere to simple rules to avoid trouble 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.
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    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 anchor, the loop windings should be intact, without breaks. You can smell the rotor. When inter-turn closure, the insulating varnish burns and emits a persistent specific odor. But such a diagnosis requires some experience.

    Features of the operation of an asynchronous motor angle grinder

    Almost all electrical appliances used in everyday life use an asynchronous electric motor. An important advantage of this type of motor is that when the load on it changes, the speed does not change. This means that if, for example, a household angle grinder is cut for a long time and without stopping, there will be no visible signs of engine overload. The rotation speed of the disc will be constant, the sound will be monotonous. Only the temperature will change, but you may not notice this if your hands are wearing gloves.

    If you are not careful, an advantage can turn into a disadvantage. Asynchronous motors are very sensitive to overheating, a significant excess of the operating temperature entails melting of the insulation on the rotor windings. At first, the motor will work intermittently, and then. when an inter-turn short circuit occurs. the motor will stop completely. It is worth overheating the engine of the angle grinder several times and, most likely, the anchor will melt. In addition, the contacts connecting the wires of the primary winding with the collector are unsoldered from the high temperature, which leads to an interruption in the supply of electric current.

    Do-it-yourself angle grinder check and repair

    As Shakespeare said: “Nothing lasts forever under the moon.” Household appliances, alas, are no exception. It happens that even the most reliable mechanism fails. And one must be ready to face this fact without panic, with firm confidence that there are no hopeless situations. How does an angle grinder work, 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.

    Multimeter application

    Now you need to check the possibility of breaking the stator windings. On the scale of the multimeter, set the switch to the resistance measurement sector. Without knowing the value of the measurement, we set the maximum value of the value for your device. Checking the performance of the tester.

    We touch each other with the probes. The arrow of the device should show 0. We carry out work, touching the conclusions of the windings. When an infinite value is displayed on the scale of the multimeter, the winding is faulty and the stator should be rewound.

    We check the possibility of a short circuit to the case. Such a malfunction will cause a decrease in the power of the angle grinder, the possibility of electric shock and an increase in temperature during operation. The work is carried out in the same way. We turn on the resistance measurement on the scale.

    Place the red probe on the winding terminal, attach the black probe to the stator housing. If the winding is short-circuited to the case, the resistance value on the tester’s scale will be less than on a good one. This fault requires rewinding of the stator windings.

    Armature Field Coil Rewinding Angle Grinder Repairing how to repair angle grinder armature part2

    It’s time to take measurements and check if there is an interturn short circuit in the stator winding. For this, the resistance value is measured on each winding.

    We determine the zero point of the windings by measuring the resistance for each of them. When the device shows the lowest winding resistance, it should be changed.

    Disassembly angle grinder

    To check the short circuit on the stator and rotor, you need to disassemble the motor of a household tool. Consider performing this operation to troubleshoot an angle grinder.

    • remove the protective cover by unscrewing one screw on the clamp;
    • unscrew 4 screws and disconnect the gearbox with the motor from the handle of the angle grinder;
    • then from the side of the gearbox, unscrew the 4 bolts and disconnect the gearbox, together with the engine rotor;
    • the stator remained in the case connected to the power and power button.

    Having disassembled and disconnected the parts necessary for checking, we proceed to their external inspection, checking for turn-to-turn closure.

    Visual inspection

    A malfunction can be detected when the tool body is heated unevenly. Touching with your hand, you feel the temperature difference in different places of the case. In this case, the tool must be disassembled and checked with a tester and other methods.

    In the event of a short circuit of the stator turns and troubleshooting, first of all, we inspect the turns and terminals. As a rule, when closed, the current flowing through the windings increases, and their overheating occurs.

    There is a greater short circuit of the turns in the stator windings and the insulation layer is damaged. Therefore, we begin to identify malfunctions by conducting a visual inspection. If no burn-throughs and damaged insulation were found, then proceed to the next stage.

    Perhaps the cause of the breakdown is a malfunction of the voltage regulator, which occurs when the excitation currents increase. To detect a problem, the brushes are checked, they must be ground evenly and not chipped or damaged. Then check with a light bulb and 2 batteries.

    Checking the stator and rotor of power tools for interturn short circuit

    It does not take much time to check the stator and rotor for turn-to-turn circuit with a multimeter. It will take longer to disassemble the engine. angle grinder, drill, hammer drill. each tool can be repaired, having identified a malfunction. It is better to break the check into several main stages, and consistently slowly perform the actions.

    Custom check

    The most accurate way is to check the stator with a metal ball and a step-down current transformer. The stator is connected to the terminals of the three phases from the transformer. After checking the correctness of the connection, we turn on our low-voltage circuit into the network.

    We throw a ball inside the stator and observe its behavior. If it “stuck” to one of the windings, it means that an interturn short circuit has occurred on it. The ball is spinning in a circle. the stator is working. A rather unscientific, but effective method of detecting an interturn short circuit on the stator.

    Rotor faults

    In the case of optimal use, the rotor does not wear out. Routine work is carried out with the replacement of brushes when they are worn out. But over time, under heavy loads, the stator heats up and carbon deposits form. The most common mechanical failure is wear or misalignment of bearings.

    The angle grinder will work, but at the same time the plates wear out quickly, and over time the engine breaks down. To avoid breakage, it is necessary to check the tool and maintain normal service conditions.

    Moisture on contact with metal causes the formation of rust. The friction force increases, the current is required more for work. Significant heating of contact groups, solder occurs, a strong spark appears.

    Checking the motor windings

    The electronic rotor tester is a standard digital multimeter. Before proceeding with the short circuit test, you should check the multimeter and its readiness for operation. The switch is set to measure resistance and touch each other with the probes. The device should show zeros. Set the maximum measurement value and check:

    • first check the rotor for open circuit. Touching the black probe to the slip ring, you need to ring the windings with the red one. The arrow of the device has gone off scale, which means that the winding has an open circuit of turns. The rotor should be rewound;
    • we measure the resistance to determine the possibility of a short circuit to the case. We attach a black probe to the slip ring, red should ring the rotor housing for a short circuit. In the case of a low reading of the resistance value and a sound signal, such an anchor must be returned for repair;
    • ringing for inter-turn closure of the rotor turns. We reinforce the probes on the armature slip rings. With a value on the scale of the device, from 1.5 ohms to 6 ohms, we checked a working device. All other values ​​on the scale indicate a malfunction of the multimeter.
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    This completes the rotor check. It should be recalled once again the main stages of determining a malfunction. Disconnect the power supply from the angle grinder or any other appliance before checking.

    Before taking measurements, visually inspect the housings, insulation and the absence of carbon deposits on the stator and rotor.

    It is necessary to clean the contact surfaces from clogging with dust and dirt. Contamination leads to increased current with loss of motor power.

    When disassembling the instrument for the first time, write down all of your steps. This will allow you to have a hint next time, to avoid the appearance of unnecessary parts during assembly. If the brush extends beyond the edge of the brush holder less than 5 mm, such brushes should be replaced.

    You can check the turn-to-turn circuit with an electronic tester, that is, a multimeter.

    Checking the anchor with a tester. expert recommendations

    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 the angle grinder. It can be detected. called. with a tester. A 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 malfunctions caused by a short circuit.

    Features of checking the anchor angle grinder with a tester

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

    When the tester is connected to the network, the indicator lights up. A red light without attaching a technical device to the anchor means the device is ready to be checked. The working active surface of the measuring device has two points of contact with the investigated one. One of them is the generator coil, the second is the coil of communication 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 sensors do not extend beyond the armature plates on both sides at the same time.

    If the electrical part is in good working order or has been 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, an inter-turn circuit, a red light will be indicated on the indicator of the device at its location. Use caution in the diagnostic procedure to ensure proper 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 with a multimeter. They can be both significant and small. You may notice a breakage on inspection by taking apart the angle grinder. It is necessary to diagnose such malfunctions before checking the armature for interturn short circuit.

    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 sure of your own strengths, you should 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 the service center or qualified locksmiths who specialize in equipment repair.

    How to ring an anchor with a multimeter?

    To complete this procedure, you will need the measuring instrument 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 place the necessary tools and parts removed from the device.
    • Disassemble the angle grinder and remove the anchor.
    • Clean the part from dirt and dust.
    • Using the recommendations in the presented video, 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 that is available from professional locksmiths.

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

    If you have sufficient knowledge to perform 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 turn-to-turn closure will allow you to determine further actions regarding the detection of faults or the repair of equipment. If the part is intact and 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 such cases:

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

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