How To Ring An Anchor Angle Grinder

Why tool failure most often affects the rotor?

During operation, the rotor is subjected to the greatest loads, namely:

  • Temperature;
  • Mechanical;
  • Electromagnetic.

In case of improper or too long operation, the breakdown of an electrical appliance may lie precisely in the armature, as the rotor is also called, which may need to be repaired or completely replaced. But before you are convinced of the malfunction of this particular part, you need to make sure whether it really is out of order.

Checking the angle grinder rotor by various methods

Some people test a broken tool with a tester. A fairly correct solution to the problem, but in this case, this measuring device, unfortunately, has little to show us.

You need to understand that the armature of a small motor of a construction tool has a winding and a magnetic circuit where the rotation shaft is located. One end ends with a pinion gear, the other with a lamella collector. The magnetic circuit has soft plates and grooves, which are covered with a special coating for insulation.

As the internal diagram of the rotor shows, in the grooves of the part there are conductors of the armature winding, there are two of them. Each of them is half a turn, the edges of which are connected in pairs in lamellas. In one groove are placed: the first turn (its beginning) and the last (end), which are closed on one lamella.

So how is an angle grinder anchor checked? Rotor malfunctions can only happen in some cases and for the following reasons:

  1. Breakage of conductors;
  2. Turn-to-turn closure;
  3. Insulation breakdown. In this case, the winding is closed to the metal base of the armature, in most cases the fault of such a breakdown is a violation of the insulating winding of the conductors;
  4. Desoldering the collector output;
  5. Unevenly worn manifold.

If the armature is faulty, this leads to overheating of the motor, which causes the insulation protection to melt, resulting in a short circuit of the turns. Further, there is an independent soldering of the contacts, which serve as a connection between the rotor winding and the collector plates. The current stops flowing and the tool motor does not function.

The stator of an angle grinder can also cause damage to the power tool.

Indicator as a way of checking turns in case of short circuit

Manufacturers assemble an angle grinder in different ways, which is why some do not show the wires that connect to the manifold. The insulation is well hidden under a bandage or opaque compound, and to check its serviceability, you can use the indicator of short-circuited turns. The device is easy to use and small in size.

To determine the short circuit, a diagnostics for the absence of open circuits is first carried out. To do this, you need a tester that measures the resistance between the lamellas. The resistance indicator should not be higher than half, if this is the case. That is, an open circuit. When the norm is displayed on the monitor, go to the next stage.

The resistance measuring device has a sensitivity adjustment function, which is also used for diagnostics. We look at two bulbs and adjust the instrument so that the red lights up. We apply the indicator to the winding, while slowly turning the armature. If the light is on, it indicates a short circuit.

Testing and diagnostics methods

How to check if the angle grinder rotor is working properly? It is simply necessary to check the place of engine breakdown in case of its malfunction. After all, it is this procedure that will help to understand which part of the mechanism is working and which is no longer. Diagnostics is carried out in several ways:

  • Visual;
  • Using a multimeter;
  • A light bulb;
  • Special devices.

Sometimes even a visual inspection is enough to understand that a short circuit has occurred. In this case, the details will show, for example, an unprotected winding, wires where the insulation will be melted. You should also pay attention to charred varnish or its smell after engine overheating.

Loss of contact also occurs due to the collection of dust (graphite from brushes) on the lamellas. It is not difficult to notice it, as well as to clean the anchor from such fine debris.

A device called a “multimeter” also helps to establish a breakdown of an electrical device. It is enough to set the resistance to 200 Ohm and put the probes on two adjacent lamellas. The resistance between all the plates will be the same during the normal functioning of the part. If the indicator is less than 1 Ohm, then the matter is in the closure of the turns. When the indicator is more than one, this means a break in the winding turns. The device can even go off scale, since the resistance in the latter case can be very high. Using an analog multimeter, the arrow will swing to the right to the very end, the digital measuring device will not show anything.

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A multimeter is, in fact, the same tester that determines the resistance in the right places of power tools.

When there is no device for determining and calculating resistance, you can use a simple 12 volt 40 W light bulb. Connect two wires to the light bulb. Where there is a minus, you need to make a break. Next, we apply voltage. We apply the ends of the wire at the break to the collector plates and scroll it. When, with such manipulation, the light is on without changing the brightness, then there is no short circuit.

Another test method concerns the breakdown of the current to ground. To do this, we connect one wire with the lamellas, and the second with the iron of the armature. After we carry out the same manipulation with the shaft. In the event of a malfunction in the part, the light will glow.

In any of the ways, you can check the stator of the angle grinder, which can also be the cause of breakdown or heating of the motor.

How to check the rotor of an angle grinder

Angle grinder is a construction tool used in cutting and edging various hard materials such as stone, metal, wood, etc.

The rotor is a part of the motor of an angle grinder that rotates during the working process, driving other components and parts of the electric tool. The quality of the cutting and grinding performed by the tool and the durability of the device depend on the work of this important part.

Control of the rotor operation is carried out in two ways. By preventive inspection and by determining the cause of the malfunction, if a breakdown has already happened.

Choke check of interturn closure

The rotor diagnostic tool helps to calculate the winding interturn short circuit. An inductor is a transformer with a primary winding and a magnetic gap cut in the core.

With the interaction of the armature (placed in the gap) and the choke, the winding works as a secondary, transformer. If, with the device turned on and the rotor lying on a metal plate, vibration or a magnetic effect is visible, there is a short circuit. Free movement of the plate along the turns indicates the full serviceability of the armature.


Short-circuited turns indicator. Used for diagnostics of closed anchors. This type of rotors is characterized by the lack of access to the junction of the winding with the lamellas. The tester has two LEDs. Red and green. By rotating the armature connected to the tester, you can determine the presence of a breakdown in the winding by the lit red LED.

How To Ring An Anchor Angle Grinder

How to check and troubleshoot an anchor angle grinder?

  1. Breakdown reasons
  2. Verification methods
  3. How to troubleshoot?
  4. How to rewind at home?
  5. Precautions
  6. Professional advice

Angle grinder anchor is a rotating element of the electric motor, which is the “core” of the entire structure of the device. The unit consists of a shaft. A metal axis of rotation, a wire winding, a collector. A set of contact plates representing the ends of the winding turns and a cooling screw. The armature interacts mechanically with the front and rear bearings, the angle grinder gear unit and graphite brushes; electromagnetically with a stator. The outer part of the electric motor. Voltage is applied to the armature winding through the sliding contact of the brushes with the collector plates. Lamellas.

The transfer of current is carried out in rotation mode, which creates conditions for friction and heating. These conditions carry the prerequisites for potential malfunctions.

Machine groove

The rotor angle grinder is installed in the lathe. Since the collector consists of copper plates, and copper is a viscous metal, it is necessary to select the optimal rotational speed in the range from 600 to 1200. The cutter is set in half a division. At the moment the “knife” touches the collector, a longitudinal passage is made with the removal of a thin layer of metal. The best effect can be achieved with 2-3 passes. of them can damage the structural integrity of the reservoir. Take breaks between the aisles to let the copper cool down. Otherwise, the lacquer insulation between the lamellas may melt.

For grooving with the help of available tools, you will need a vice, a drill and several types of sandpaper. The angle grinder armature is removed from the housing, while one part of it remains connected to the angle grinder gearbox. The gearbox housing is fixed in a vice, the other end of the rotor shaft is clamped in the drill chuck. The “lips” of the vise and the drill must be on the same mowing line with the axis of the anchor shaft.

Turn on the drill with the trigger button fixed in continuous operation mode. Grind the collector with sandpaper without pressing. Use a minimum of 3 types of grit size. From coarse to finer. Finishing should be zero grit sandpaper.

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Winding repair

Angle grinder armature rewinding is a job that requires the appropriate skills and special precision. To achieve the best end result, it is worth contacting the appropriate specialist.


Put this device into resistance measurement mode. Put one of the probes (polarity does not matter) on one of the plates. Apply another dipstick to the rest of the lamellas in turn. A sound signal, depending on the multimeter model, will notify that there is a breakdown between the “winding traces”.

How to troubleshoot?

Visual inspection and testing will help determine the nature of the malfunction and understand if replacement or repair at home is possible. Angle grinder rotor malfunctions are divided into two types: repairable and non-repairable. The first type includes faults associated with a violation of the insulation of the winding, damage to the collector and the iron base. The second type of breakdowns are factors of deterioration of the balance of the armature as a whole and its shaft. It is almost impossible to restore the rotor in this case.

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 needed, 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 a simple 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

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? A visual inspection is necessary to determine a mechanical failure; 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 of 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, it is necessary to disassemble the power tool and access directly to the part itself. Disassembly should be done carefully so as not to damage other parts. Fold the mounting screws and screws carefully so as not to lose. The surface of the table on which you disassemble the angle grinder must be clean, the room lighting must be sufficient so that all the details can be clearly seen. In general, disassembly is not a difficult process, but it’s worth preparing. After completing it, you can start checking. The main common defects of anchors of a power tool can be determined using a multimeter in resistance mode.

Anchor check examples

Anchors of professional tools and equipment of medium power can fail. Below we present to your attention a specific example of checking the armature of a Makita GA 9050 angle grinder. The power tool is equipped with a powerful 2000-watt collector motor. 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, at home, such a malfunction cannot be detected. If you notice a break in the winding outside when checking the armature, you can try to solder 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 anchor for operability indicates their breakage.

Sometimes a malfunction can be noticed visually. In working order, all plates of the contact group of the armature must be flat 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.

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If, after walking along the contact circle, checking the anchor, you find that the resistance is the same between all the plates, its indicators do not “jump” and there are no visible breaks, you must carry out the following check. 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, while the other 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 your anchor will not short to mass. Most likely, the part is serviceable or the presence of an interturn short circuit is possible.

How to check an anchor if you don’t have special tools?

In the absence of a multimeter, you can check the armature contacts using a simple 12-volt light bulb. Having inserted it into the break of one of the wires, voltage must be applied to the angle grinder plug from a 12 Volt battery. With the simultaneous rotation of the spindle by hand, the light should burn brightly without dying out. This result indicates that the anchor is working properly. The changing glow indicates a short interturn circuit. If the light does not light at all, the following breakdowns can be assumed:

  • Rupture of the supply circuit;
  • Hanging of the brushes in the inoperative position as a result of the actuation of the retaining 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 that are not available or are little used in everyday life.

When you shouldn’t check the anchor yourself?

Without experience or skills, you should 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 cannot count on the device to be repaired at the representative offices of the company from which it was purchased.

Checking, repairing and replacing the anchor do-it-yourself angle grinder

The angle grinder anchor is most exposed to thermal, mechanical and electromagnetic loads. Therefore, it is a common cause of tool failure, and as a result, it often needs repair. How to check the anchor for operability and fix the element with your own hands. In our article.

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

  • Take two wires and connect them to the lamp.
  • Make a break on the negative wire.
  • 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 brightness, then there is no short circuit.
  • Conduct a short to iron test. Connect 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. The winding closes to the rotor housing or shaft.

This procedure is similar to diagnostics with a multimeter.

Collector bore

Over time, the brush develops on the collector. To get rid of it, you must:

    Grind the manifold using longitudinal turning cutters, i.E. Through cutters.

Straight through cutter

Do not forget to clean the rotor from swarf to avoid short circuiting.

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.

: IKZ at work. : Winding left and right

After winding, weld the leads of the sections with the collector cock. Now check the winding with a tester and short-circuit indicator. Start impregnation.