How to test the angle grinder stator: Checking the Angle Grinder Stator with a Multimeter. CTLN.RU
When a man is not a prof prof prof master, but simply as a good owner fixes what remains to do our client in the family by himself, he can not do without high-quality tools.
A large selection of grinders, screwdrivers and other tools are available on our website http://m-online.kiev.ua/category/158-bolgarki.aspx.
Even any, the most high-quality tool is prone to failure. Particularly if it is actively exploited. If the passage of a breakdown angle grinder, to fix the tool you are unlikely to get without assistance from others. But the preparatory inspection is an option to carry out and without special abilities.
Often the electric grinders have a burned-out armature. Breakage you like mechanical. Upon visual inspection, you will see uneven wear and tear of the brushes, and additionally their burning. Even today, with a faulty armature angle grinder will vibrate and heat.
There are electronic breakdowns. Among such tools are:
Detect such faults of course through special measuring devices, for example, multimeter.
To be able to conduct such a test, you should disassemble the angle grinder and get access to the anchor. Multimeter should be put into a range of 200 ohms, and the feelers of the device touch the 2 adjacent lamellae.
Carry out measurements on all turns of the winding, if our client is similar readings, then the armature is serviceable. If the resistance values on any turns are different, then that is where the problem is. The armature winding housing should also be checked.
How to check the collector motor multimeter. The winding of the stator and the rotor
This type of diagnosis is difficult. You need to be able to use a multimeter and also disassemble the angle grinder.
If your tool suddenly stopped working, it is better to go to the shop:
- When you make sure that the armature is out of order, and establish the cause of his breakdown, to replace it or repair without the aid of others, you are doubtful you will get. Indifferently have to carry the tool to the shop;
- if the tool is still under warranty, opening the angle grinder yourself could void the manufacturer’s warranty.
To ensure the long life of the tool, choose products from reputable companies with extensive experience in the industry. Also observe the rules of operation of the tool, because they often go out of order for this reason.
Tips on the text of the article “Open Wiring in the Interior” here.
Check the motor armature, how to check the angle grinder:
How to Test a Power Tool Armature at Home
Self-checking the motor armature can easily be done at home. This will allow you, firstly, to restore the tool’s performance, and secondly, not to overpay a specialist for a fairly simple operation. All you need for testing is a screwdriver and a multimeter. In addition, you can buy a special device to determine the inter-turn short circuit.
Visual inspection of your tool
- When the motor is running, you can see very strong sparking on the manifold.
- If you try to start the angle grinder (power drill, circular saw, etc.), it will not start.) There is a hard voltage drop (the lights blink).
- Sharp jerks during electric start-up.
- There is a distinctive smell of burning wiring coming from the tool body.
- The tool is not picking up its previous power.
Either way, if there is nothing wrong with the brushes, you can’t do without disassembling the tool. At this stage the most important thing is not to do more damage. Particular attention should be paid to the correct selection of a screwdriver, as damaged screws will be difficult to unscrew, and the check will turn into a painful locksmith’s work. In some tools different length fasteners are used. Their location should be memorized (it is better to write them down or sketch them).In order to successfully assemble the power tool after its diagnosis and repair, we recommend that beginners take photos of each stage of disassembly. It helps a lot if you forget which part is how before you checked it.
Preparing the motor armature for inspection
Once the armature has been removed from the housing it is advisable to prepare it for diagnosis. The procedure is to thoroughly clean the graphite buildup off the collector blades. If this is not done, further testing may be inconclusive.Scale can be removed with a rag and alcohol. If the blades have a thicker than average layer of carbon deposits, they must be removed with fine grit emery paper. Make sure that there are no visible abrasion grooves on the collector. This will reduce the contact between the lamellae and the brushes and will also accelerate their wear and tear.
Visual Inspection of Anchor Before Checking
- Collector lamellae. They should not show any heavy wear.
- Motor armature winding. Look for wire breaks or visible signs of burning.
- Contacts. The entire winding is soldered to the collector lamellae. These points should be checked for continuity.
Checking the armature with a multimeter
Checking a motor armature with a multimeter involves two steps. The first thing to do is to test it for a breakdown. To do this, set the multimeter to the circuit test mode with a beep.
Next, use one feeler gauge on the collector lamellae and the other on the armature body.
The second stage of checking the armature with a multimeter is to measure the resistance between the adjacent windings. To do this, the device is set in resistance mode at the lowest threshold (usually 200 ohms).
Next, the probes are applied to the adjacent collector blades, and the readings are recorded on the screen. When measuring the resistance between all neighboring lamellae should be the same. If it doesn’t, then the armature is faulty.
This is also indicated by a complete absence of resistance on any of the windings.
Checking the armature for a short circuit
Before you check the motor armature for an inter-turn short circuit, it is necessary to get a special device. It costs a penny, and there is plenty of information about it on the Internet.The essence of checking the armature is to apply the same tool to all sections of the body. The fault is determined by the LED indicator.
Stator test (tagalog)
Replacing the armature and reassembling the tool
The faulty armature is either rewound or replaced with a new one. Fortunately, today you can find suitable parts even for the cheapest Chinese tools in online stores. Before installing a new or reconditioned armature, it is advisable to check it according to the algorithm described above.If all is normal, put everything back together and work. When replacing the motor armature, it is also recommended to install new brushes. They are cheap.
How to check the angle grinder with a multimeter?. Kvazar-wp
In the household of any home handyman, not to mention professionals, there is almost always an angle grinder (angle grinder), popularly referred to as an “angle grinder”. The tool is popular, loved and respected, so any malfunction is perceived very painfully.But before you go to the specialized department for a new angle grinder, it is worth trying to figure out the breakdown on your own. Having disassembled the angle grinder, you can visually detect some mechanical damage, but the defects of the electrical part should be checked with special tools, one of which is a multimeter. Below we will look at how to check the angle grinder multimeter.
What causes an angle grinder to malfunction
Most often, the tool will stop working when the armature (rotor) is damaged. When opening the housing, you can see the burning and uneven wear of the brushes. Indirect signs of such a breakdown are tool heating and vibration during work.
Electrical faults are more difficult to detect. These include:
Also fairly common causes of tool failure can be:
- breakage of wires in the power cable and failure of the switch. the angle grinder does not turn on;
- Short circuits in the rotor windings and defective electronics cause the tool to run only at low speeds;
- sparking due to worn carbon brushes or heavy wear of the motor collector;
- The appearance of smoke occurs when there are short circuits in the stator or rotor windings, as well as during excessive use (when the air cooling ducts are clogged with dust).
As you can see, many breakdowns are caused by faults in the electrical part of the tool. You should therefore be able to detect them before you decide to send the tool to a repair shop.
How to test the armature with a multimeter
You need to know how the rotor works and how it works in order to do the test. Its main structural parts are:
- A circular-shaped core, which is a set of plates made of electrical steel;
- the winding, wound in a certain way into the grooves of the core.
Following a special scheme, in each of the slots lay two conductors of the winding. Each of the conductors is half a coil. Its ends are connected in pairs on the lamellae. The end of the last coil and the beginning of the first coil are positioned in the same groove and shorted to one lamella.
Before checking the armature with a multimeter, it should be carefully inspected for various damages:
- melted wiring;
- of burnt insulating varnish;
- Deformation of the coils;
- the presence of conductive particles (such as solder residue) which frequently cause short circuits;
- curvature of bent edges of lamellas (cocks), connecting them to the winding, leading to the burnout of the lamellas;
- Accumulation of graphite from deteriorating brushes between the lamellae, which also causes short circuits.
Step by step instructions
Directly checking the armature with a multimeter is as follows:
- Insert the test leads of the device into the appropriate jacks.
- Set the resistance measurement mode. Measuring range. 200 Ohm.
- Use the styli to touch each of two adjacent blades one by one, recording the results on the multimeter display. You have to test each pair of neighboring plates in series.
Deciphering the results
Deciphering of the results of testing the armature with a multimeter:
- When the resistance between all pairs of neighboring blades is the same, then the armature winding is considered to be in good order.
- If the resistance is less than 1 ohm or close to zero, then there is a short circuit between the coils.
- If the resistance exceeds the average value by a factor of two or more, look for a break in the winding winding turns. When the resistance is very high, the screen of the digital device will not show anything at all, while on the analog device the arrow will go off-scale.
Checking the condition of the stator
The stator is the stationary part of the electric motor that creates the electromagnetic field in which the rotor rotates. The cause of failure is often either a short circuit or a breakage in the winding (coil) of the stator.
Signs indicating stator breakage:
- appearance of smoke;
- smell of burning insulation;
- overheating of the angle grinder housing;
- The shaft stops rotating or slows down;
- Rapid, spontaneous revolving.
You can also check the stator with a multimeter:
- The probe connectors are inserted into the corresponding sockets on the body of the tester.
- Set the device into the resistance measurement mode. The measuring range is from 20 Ohm to 200 Ohm.
- Take the probes one by one to the windings and record the readings on the screen.
Deciphering the results
The results of the testing may be as follows:
- The tester registers the same resistance everywhere. the stator coil (winding) is serviceable.
- In some points, the resistance is different. there is a short circuit in the winding, or there is a breakage of one of the turns.
So with even the simplest multimeter in your possession you can determine the nature of the problem with your angle grinder and make an informed decision as to whether it is worth repairing it or whether you should buy a new one Although, for diagnostics it is still better to give the tool in a workshop, where there are more opportunities and devices for an expert opinion.
Now you know how to check the angle grinder with a multimeter.
Question: What is the correct name for the moving part of the motor “rotor” or “armature”??
Answer: As far as the angle grinder is concerned, both terms are used in relation to the rotating part of the electric motor.
Question: What multimeter is better to use for wire tapping on the angle grinder?
Answer: You can use both types equally well. analog and digital. Both instruments are equally effective in showing the value of the parameters of interest. But nonprofessionals are more likely to use the digital.
Question: Can I rewind the rotor winding at home if a multimeter wire check revealed a winding defect??
The most accurate way is to test the stator with a metal ball and a step-down current transformer. The stator is connected to the three phase leads from the transformer. After checking the connection, connect our under-voltage circuit to the mains.
Throw the ball inside the stator and watch how it behaves. If it is “stuck” to one of the windings, it means that there was an inter-turn short circuit. The ball rotates in a circle. the stator is in good condition. Rather unscientific, but effective method of interturn fault detection on the stator.
How to check the motor armature at home?
Electric motor armature refers to the rotating part, on which the dirt collects, soot forms. If something is wrong, you can do some home diagnostics at home, both visually and with a multimeter. There must be no chips, scratches or cracks on the rubbing surfaces. If any are found, corrective action is taken.
The motor armature is not subject to wear and tear under normal operating conditions. Replace only the brushes, measuring the permissible length. But with prolonged loads, the stator windings begin to heat up, resulting in fouling.
Mechanical influences can cause the motor armature to warp if the bearings are damaged. The motor will work, but the gradual wear of the lamellae or plates will lead to its final failure. But preventative maintenance is often enough to save expensive equipment and you can use it for a long time.
Negative factors affecting the motor armature include moisture on metal surfaces. Critical is prolonged exposure to moisture and rust. Increased friction due to red buildup and dirt, causing increased current loading. The contact parts will heat up, the solder may flake off, creating occasional sparks.
The Metabo PowerMaxx BS BS cordless screwdriver is designed for normal use and can be serviced, but at a reasonable price. You can solve the problem yourself by reading the following question: How to check the motor armature at home. A device that measures resistance and tools are needed for diagnosis.
How the fault is diagnosed?
Checking the motor armature begins with identifying the fault itself. Complete failure of this unit occurs due to crumbling brushes of the collector, the destruction of the dielectric layer between the plates, as well as due to a short circuit in the electrical circuit. If there is sparking inside the device, it is concluded that the current collectors are worn or damaged.
Sparking of brushes begins because of a gap at the contact with the collector. This is preceded by a fall of the device, high load on the shaft when jammed, as well as a violation of the integrity of the solder on the winding leads.
Failure on a running electric motor manifests itself by typical conditions:
- Sparking is the main symptom of a malfunction.
- Rumble and friction as the armature rotates.
- If you notice vibrations during operation.
- Direction of rotation reversal as armature travels less than a revolution.
- Melting plastic odor or intense heating of the housing.
What to do if a malfunction occurs?
Electric motor armature speed is kept constant. May not appear at idle speed. Under load, friction is compensated by an increase in current flowing through the windings. If you notice deviations in the operation of the angle grinder, drill, or starter, disconnect the power supply.
Continued use of the appliance can cause a fire or electric shock. The first thing to do is to inspect the body of the product, assess the wiring for integrity, absence of melted parts and damaged insulation. To the touch check the temperature of all parts of the device. Try to rotate the armature by hand, it should move easily, without sticking. If the mechanical parts are intact and there is no contamination proceed to disassembly.
Diagnosis of internal parts
Motor armature windings must be free of carbon deposits, dark spots or anything that looks like overheating. The surface of the contact parts and the gap area must be free of ashes. Fine particles reduce motor power and increase current. It is not advisable to disassemble appliances with the plug plugged in for safety reasons.
It is recommended that you film the disassembly process to avoid complications during the reverse process. Or you can write down every step of your actions on a sheet of paper. Some wear of brushes, lamellae is permissible. But if there are scratches, find out the reason for them. A crack in the housing could be the cause, and this can only be seen under load.
Working with an ohmmeter
Sparks can occur due to loss of electrical contact in one of the lamellae. To measure the resistance it is recommended to put probes on the side of current collectors. Turning the motor shaft, watch the dial readings. The screen should show zero values. If even a few ohms slip by, it is a sign of fouling. If the reading is infinite, a break in the circuit will be judged.
No matter what the result, the next step is to check the resistance between each adjacent lamella. It must be the same for each measurement. In the event of abnormalities, all connections of the coils and the contact surface of the brushes should be inspected. The brushes themselves should have uniform wear and tear. If there are chips and cracks they must be replaced.
The coils are connected to the core by wiring that may have peeled off. The solder often cannot take the impact of a fall. In starters, current through the contacts can reach 50A, which leads to burning of poor connections. Visually inspect for damage. If no fault is detected, then the resistance between the lamellas and the coil itself should be measured.
If you do not have an ohmmeter?
If you do not have a multimeter, you will need a 12 volt power supply and a light bulb of the appropriate voltage. No problem for any motorist with this set. Connect the plus and minus terminals of the electric appliance to the plug. An incandescent bulb is placed in the gap. Visualize the result.
The armature shaft is turned by hand and the lamp illuminates with no jumps in brightness. If fading is observed, it is judged that the motor is defective. Most likely an inter-turn fault has occurred. Complete loss of glow indicates a break in the circuit. Causes can be non-contact of brushes, breakage in the winding or lack of resistance in one of the lamellae.
Causes of fault and symptoms
The main factors that affect stator failure are as follows:
- Power supply network does not always guarantee a stable voltage, its jumps are possible;
- During operation of the power tool some liquid, e.g. water, may get inside the stator;
- When processing some materials (concrete, wood, etc.) a large amount of dust is generated, which is difficult to protect against getting on the stator winding;
- Prolonged operation of the angle grinder in conditions of overload, which is the cause of overheating the power tool;
- during the operation of the angle grinder should not stop it abruptly pulling the cord out of the socket.
408-105 Stator for Hitachi G18SE3 and HAMMER angle grinder. 220Volt photo
Characteristic signs of stator failure are the following:
- there is a persistent smell of burned wire insulation of the winding;
- the temperature of the body parts of the angle grinder rises appreciably;
- the electric angle grinder drive is more noisy than in normal conditions;
- smoke formation is quite real;
- the spindle begins to rotate more slowly, or may even stop altogether;
- the opposite extreme of the previous case is possible. the spindle starts to work at higher speeds, it goes out of order.
How to check the stator of an angle grinder. causes of failure, tools for checking
The stator is the stationary part of the electric motor, designed to create the electromagnetic field in which the rotor (the moving part of the motor) rotates. Possible causes of malfunction of angle grinders, or “angle grinders” include an open or short circuit in the winding (coil) of the stator.
Factors causing stator failure:
Signs by which you can recognize that the stator is defective
- A burning smell of insulation appears.
- The case overheats.
- Smoke appears.
- The rotation of the shaft slows down or stops.
- Unintentional loosening of the shaft, the tool sharply gathers maximum speed.
Winding wires are coated with a protective layer of insulating varnish. Overheating causes the shaft to overheat and is destroyed. This causes a short circuit in the windings. The lacquer emits a peculiar smell. Short-circuiting just one of the wires will permanently damage the angle grinder.
Rules to avoid overheating of the angle grinder motor:
- Turn off the unit after working at reduced speeds, not immediately, but after about one minute.
- Take frequent breaks when working under load at reduced speed.
It is often possible to avoid replacing a faulty stator by rewinding the. Rewinding a damaged stator coil of the angle grinder can be done on your own, but it is still recommended to have this work done by a specialist.
Checking with the short circuit indicator
A winding breakage or short circuit in a winding can be detected with the short circuit indicator (IC). Other names are as short-circuit indicator or electrical machine winding fault indicator.
- of the power supply unit;
- housing with LCD display, sockets for connecting accessories;
- connecting wires;
- large induction sensor;
- Small induction sensor.
The principle of operation of the indicator is based on the induction of an impulse electromotive force in the tested winding. In the presence of short-circuited coils the magnetic field impulse of the short circuit current flowing through them is registered.
Procedure for testing the stator of an angle grinder with the IDWI machine:
- Inspect the inter-turn indicator. Make sure that there is no external damage and that the connection wires and sensors are intact.
- Connect power supply.
- Press the power button and make sure the unit is in good condition.
- If the winding defect indicator has been out in the cold for a long time, keep it at room temperature for at least 2 hours.
- Turn off the power angle grinder.
- Choose the large or small sensor from the two sensors, depending on the size of the stator.
- If the passport of the angle grinder does not specify the rated voltage per coil of the winding, it must be determined by the formula: The rated voltage of the entire coil divided by the number of turns.
- Turn on the device.
- Set on the indicator the amplitude of the impulse test voltage which is larger than that received during the calculation.
- Hold the sensor against the surface of the winding and check all the slots one after the other after waiting 3-4 seconds. If a short circuit is detected the instrument will beep and the corresponding inscription will appear on the display.
- If no short-circuited turns are detected, then set the next (higher value) amplitude on the device and make sure that there is a safety margin of winding insulation.
- Turn off the instrument.
Using the winding fault indicator it is possible to check the insulation condition between the stator and rotor coils as well as between the stator winding and the angle grinder body. If you have no possibility to buy a ready made device you can make a simpler indicator of short circuits by yourself.
Checking with a multimeter
Check the stator with a multimeter to see if it is in good working order. It is a universal measuring device. It can measure several electrical quantities: voltage, current, resistance. The device consists of a housing with a display, a switch and sockets, and two cords with probes (plus and minus). always connect the minus probe to the lower slot and the plus probe to the middle or upper one, depending on the current in the tested device.
To check the stator of the angle grinder, you need to set the multimeter to a resistance value of 20 to 200 ohms and take turns to bring the feelers of the measuring device to the windings. If the resistance is the same everywhere, then the coil is fine. If the device shows a different resistance at some points, then there is a short circuit or breakage of one of the coils in the winding. Use an ohmmeter to check the stator in the same way. Its only difference from a multimeter is that this device can only measure resistance.
Analyser for checking armatures and stators of electrical machines
Another device with which you can verify the stator of angle grinder is a device for verifying the armatures and stators of electric machines PUNS 5. The device has light and sound alarms, makes it possible to detect winding short circuits, open circuit, measure insulation resistance of coils.
The unit operates in two modes. “armature” and “stator”. Mode change is made by means of a switch. The device is equipped with a handy attachment for mounting and fixing the motor to be tested. It consists of two legs attached to the shaft. The paws move freely along the shaft, allowing you to change the distance between them and check the motors of different sizes. This is checked by means of two feeler gauges. The presence of open or short circuits in the stator winding is indicated by special red LEDs and an audible signal. For more details on the test procedure, please refer to the instruction manual of the device.
It is relatively easy to carefully check the stator of an angle grinder. But this can only be done using special instruments. Therefore, if visual inspection confirmed that the cause of angular grinder failure is a spoiled stator, further testing and repair is better to perform in a specialized workshop.
AG100 8S/8D. Replacing Rotor, Stator, Capacitor, Switch
Construction and electrical diagram of the angle grinder
Over the many years of existence of such a tool as an angle grinder, its appearance, as well as the internal structure has not changed much. To repair the angle grinder with your own hands, you need to know the structure of its mechanical part, as well as the electrical.
If you look at the figure below, you can see what parts consist of the angle grinder.
- The wheel for adjusting the machine’s spindle rim.
- The electric motor, consisting of the rotor and stator.
- Start button. Soft starter sometimes connected to it.
- Shock-resistant plastic body.
- Button for locking the spindle (used when changing tools).
- Safety clutch. Protects motor from overload if tool jams.
- Protective guard. It protects the tool and the user from flying particles of machined material, and prevents personal injury if the tool, such as the abrasive disc, breaks.
- Nut that clamps the tool. Unscrewed with special tool wrench. There are also quick-release nuts that can be unscrewed without a wrench.
- The gear case and the gearbox itself. Consists of a set of gears that transmit the rotary motion from the rotor to the spindle with the tool.
The illustration below shows an electrical diagram of an angle grinder.
The electrical part of the angle grinder has the following elements:
- Electric cable with a plug for connecting to the power grid;
- start button;
- Electrical brushes (carbon or graphite);
- armature (rotor).
The following illustration shows the connection diagram of an angle grinder, namely its motor.
All components of the electric motor perform certain functions.
- The rotor is the shaft on which the coils and the collector are mounted. The rotor, rotating in the magnetic field of the stator, transmits rotary motion to the gearbox of the angle grinder.
- Collector. Represents a part of the rotor, to which all control cables are connected. The electrical signals from the control box to the motor are routed through the collector. It is to the collector that the electric brushes are connected.
- The electric brushes. Their main task is to transmit the electric current from the power cable to the collector.
- stator. Represents a coil with a specific number of turns. The task of the stator is to create a magnetic field, which, interacting with the armature, sets the latter in motion.
The main troubles of the angle grinder and their causes
According to statistics, most cases of failure of the angle grinder are related to the electrical part of the machine. Some failures may be minor, which allows you to repair the angle grinder with your own hands. But, for example, if the burnout of the motor windings angle grinder repair can only produce a specialist.
The angle grinder does not turn on
The reasons why the angle grinder does not turn on may be the following:
- the electrical plug is faulty;
- The electrical cable is defective;
- the start button is broken;
- The contact between the power cable and the button is broken;
- breakage of the contact wire of the electric brush;
- heavy wear of the electric brushes;
- rotor or stator winding failure.
the angle grinder does not develop speed
The reasons why the angle grinder does not turn on, can be different.
- Breakdown of the speed control unit. To check this version, connect the motor of the machine directly, without the regulator, and check the operation of the device.
- A damaged electrical cord due to constant bending or mechanical damage. A damaged wire becomes warm under load and the engine speed starts to drop.
- The collector is contaminated with dust. Impurities must be removed with alcohol.
- Problems with brushes. They may be worn out or have a short contact wire as shown in the following photo.
The brush is half worn out, but still fully functional. A short contact wire prevents the spring from holding the electrode against the collector. This situation can also be the reason why the angle grinder stopped working normally.
The motor is warm
If an angle grinder is heating, it could be due to.
- Improper operation of the machine. As a result of overloads, the electric motor can become very hot, which often leads to the burnout of the windings.
- Destruction of bearings, located on the armature. As a result, the rotor clings to the stator, motor operation is hindered, and the windings overheat. The problem can be solved by replacing the bearings.
- The ventilation ducts through which air flows to cool the motor are clogged. The ventilation ducts must be cleared of dust.
- Breakage of the impeller, which is used for cooling the motor. It is installed on the rotor, on the opposite side with respect to the collector. If the impeller is broken, it must be replaced with a new one.
- Interwinding of stator and rotor windings. It is necessary to rewind the coils or replace these parts with new ones.
How to rewind at home, steps of rewinding
Repairs begin by removing the defective old winding. Use pliers (pliers, round pliers) to release the old winding from the slots of the stator.
Important: be sure to take data on the number of windings and wire diameter of the coils to be removed. Clean the stator surface from old burnt insulation, wash and dry it.
Then the stator coils are rewound. It can be carried out on a special made template or directly into the slots of the stator core. This depends on the depth and width of the space to lay the wire.
Important: determine the beginning and end of the winding, the direction of laying the wire. If making a template do not forget to give an allowance for insulation and the width of the future coil (about 3-5 mm).
place the wound coil in the stator, making sure that the beginning and the end of the winding wire are positioned as described above. The winding is secured in the stator maintaining all the gaps (see the following videos for fastening options). The stator is heated in the furnace to approximately 80°C to 110°C. Using a brush, paint or pre-prepared epoxy resin and hardener is applied. When applying the impregnation it is important to achieve the deepest possible penetration.
Practical tips for rewinding stator windings are given in the following videos.
Rewinding the windings directly on the core
The following video describes in detail how to repair the stator of an angle grinder. The author shows all the steps of the work and argues his choice of rewinding directly on the “iron”. This model has wide grooves, and it will be difficult to fit the coil tightly into them. As a guide device the author uses a plate that is bent at the height of the corresponding extreme point of the winding laying in the grooves. The surface of the plate is covered with insulating tape to prevent damage to the wire insulation and fixed on the core with the same tape. This rewinding process is rather cumbersome. With a large number of coils, you should record your actions, for example, with the appropriate notes on paper. This will help to avoid mistakes.
After winding is complete and the guide plate is removed, the coil may loosen its stacking due to residual stress, individual turns may fall out of the overall mass. In this case, tying with yarn from natural material (synthetics should not be used) will keep the winding tight. The use of various wedge objects allows to lay the coil tightly in the grooves. However, the author does not welcome their use, as this negatively affects the quality of impregnation.
It is not always possible to choose the right pattern
In the following video, the author warns those doing the rewinding with their own hands about the difficulties of selecting a pattern. It is not always possible to choose the right one. Guaranteed quality rewinding gives a much more time-consuming, but reliable method directly on the “iron”.