Rewinding the stator of a grinder
Stator rewind angle grinder can now be done independently. For this you need to stock up only with the necessary knowledge. If the master has the necessary tools, repair skills and a certain amount of knowledge in the field of electrical engineering, the question of how to fix the malfunction of this tool with your own hands is quite easy.
Stator winding circuit.
Causes and signs of stator failure
Manual grinders, popularly called "angle grinders", can fail for various reasons. The most common problem is the breakage of the stator turns, which occurs due to an excessively strong load on the device. Now, such a malfunction can be corrected independently. correctly rewind the stator.
There are frequent cases when the failure of the electrical part of the device becomes the cause of the breakdown. Various factors lead to this:
- water entering the surface through which current flows;
- power surges;
- sharp pulling out the plug from the outlet;
- high overloads and, as a result, overheating.
There is an opinion that it is impossible to rewind the stator yourself. In fact, it’s enough to understand the design of the device. If you have experience with such work and the necessary knowledge, you can repair a three-phase start-up device at home. Given the preparatory work, the process can take several hours.
Wire winding circuit.
Often the engine fails due to a break in the magnetic circuit, violation of the winding or the anchor manifold. With increasing voltage, an abrupt increase in the strength of the spark is noted. Usually this is observed on only one brush. This phenomenon leads to the destruction of the insulation of the wires on the stator coil. If, when turned on, the drive accelerates very quickly and gains speed, this indicates a stator short-circuit.
Sparks that occur during the operation of the collector signal the occurrence of violations in the balancing of the armature. Checking the operation of the collector can be done in this way: when turned on, the sound should amplify gradually with increasing voltage. No vibrations should occur. If resonance is observed, the angle grinder electric motor needs repair.
The grinding tool consists of three important components:
The anchor is a rotating element with a winding and creates the torque of the electric motor. On the stator, divided into sectors, there is the same winding. The current through the carbon brush passes through the winding, enters the anchor. Then the current passes to other brushes until all parts of the stator are involved. When electric current passes through the winding, a magnetic field constantly interacting with the stator arises. Thus, an electric motor is driven. There are several characteristic failures of the “angle grinder” launch device:
- burning or rupture of the winding;
- a short circuit between the turns of the winding;
- destruction of insulation.
Scheme of an eccentric orbital sander.
You can rewind the winding with your own hands, without contacting a specialist. You only need to disassemble the device first. But if you are not completely confident in your abilities, then contacting a specialized workshop will be the most reasonable step. First of all, the casing shifts. To do this, the screw fixing it is unscrewed. After that, you can see all the details of the angle grinder, with the exception of the gearbox hidden under the metal cap. The screws that secure the metal plate are loosened. Now all the mechanical parts are clearly visible. Only after this can you move on to rewind the stator.
Better than a well-made repair can only be the correct operation, in which there will be no breakdowns at all. In order for the “angle grinder” to work longer, the following simple rules must be observed:
- In no case do you need to exceed the amount of grease and the timing of its addition or replacement.
- After the tool has been operating at reduced speed, it is strictly forbidden to immediately turn it off. If you leave it to work for at least 1 minute, you can avoid overheating.
- Do not allow long-term operation of the tool at reduced speeds under load.
A refurbished stator will allow the grinder to operate normally for a long time.
To rewind the stator, you will need special tools:
- hammers: wooden, metal;
- pliers and pliers;
- steel brush;
- electric drill;
The first and most important step is to clean the stator from contamination. The old winding is removed from the grooves. All this can be done with a steel brush. Cleaning is carried out manually using steel brushes, electric drills. It is also necessary to remove the old insulation. To facilitate the task, transformer oil can be used. It is necessary to warm it a little and lower the launching device into it. Such a measure will soften the damaged insulation and simplify its removal. For cleaning, a mild caustic solution (temperature. 80ºС) mixed with compressed air is also used.
After treatment, the stator should be washed well with water and dried. The condition of the stator and steel bags must be well checked. Then pull the studs tightening the core, the grooves are cleaned from burrs. Insulation resistance is measured with a megger. Parts of the core, thrust washers and grooves are varnished. Washers and slots must be insulated.
The accompanying note, where the main data is displayed, can facilitate further work:
- phase connection diagram and their number;
- coil and phase resistance;
- number of grooves and their sizes;
- winding section, coil pitch along grooves;
- The method of isolating the groove, the number of interlayer gaskets and their sizes.
Then the remaining frontal winding is removed and a new one is wound. There is a special template for making a winding. It is fixed on an axis holding 2 large-size plates made of metal.
When working, it is important to get a strictly defined number of turns. it should be identical to the number of turns of the old winding. The wire must be wound so that the seal is maximized. Coils are placed in the stator. From the same material from which the winding for the coils is made, conclusions are drawn. Their tips need to be insulated with cambrices. tubes made of plastic.
Before installing the coils, it is necessary to check that the groove boxes are symmetrical. They must close the winding. If this does not happen, when inserting the wires of the coils, temporary inserts are placed. This simple measure avoids damage.
The coil is mounted above the groove, which is located below the bore. Coil conductors are installed using a special plate. The wires located in the groove should never cross over. They need to be laid in the same way, in the same sequence as the winding. Conductors must be installed strictly in parallel.
To perform the next operation, the stator needs to be slightly rotated. only one division. Coils from the same group fit into the groove. After laying, lay the interlayer gaskets. Screw the terminals onto the external circuit so that they are parallel to the external circuit. The underside of the coils is mounted in the same way. The operation is repeated until the grooves of this step are full.
When the winding is finished, the ends can be plugged. The dimensions of the sleeves depend on the size of the stator. The thickness of the sleeve is usually 0.2 mm, but the length should be greater than the size of the launcher. Most often, this value is about 1.5 mm. For the manufacture of liners using special cardboard. A film must be wound on it (it must be heat-resistant). The entire resulting structure is wrapped with tape. Coils with sleeves must be installed in the grooves of the stator. After that, you can check whether the anchor is moving correctly. The coil is completely ready. It remains only to wrap with kiper tape, and on top to cover with a layer of varnish. After the varnish has dried, the device is completely ready for use.
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How to rewind the stator with your own hands?
When it comes to rewinding the stator, in the vast majority of cases, repair of the tool is implied. As an example of the execution of the aforementioned process, the stator can be rewound to an angle grinder.
The indicated process of replacing the windings in one of the parts of the electric motor can be carried out in domestic conditions. This can be explained by a complete repetition of the burned winding. That is, exactly the same conductor is selected, with exactly the same insulation.
What is the reason for the breakdown?
The following are the most common causes that, one way or another, can lead to stator failure:
- rupture rupture due to overvoltage;
- electrical circuit of adjacent turns;
- partially burnt winding;
- violation of isolation.
Video: How to Rewind Stator Angle Grinder Video
As a rule, several symptoms from the above list are present at once. Also, equipment failure occurs, with a significant increase in the load on the tool.
Any violation of the operating rules, technically can lead to damage to the tool. However, if the worst has happened, this does not mean that you have to buy a new angle grinder.
After all, it is much cheaper to replace the electrical winding (or its burned part) and continue to operate the equipment.
Preparing for rewinding. removing the old winding
Indeed, before rewinding, it is necessary to prepare the stator. To do this, pre-stack it in hot oil. As a result, the insulation (often used electrotechnical varnish) softens.
Removal is carried out using a metal brush.
After removal, it becomes clear which wire was wound at the factory. With a piece of this wire, we go to the market and buy exactly this one (according to technical characteristics).
Naturally, it is forbidden to change the metal of the conductor. That is, if the winding was made with a copper wire, you should not choose a thicker, but aluminum. Our task is to restore the burned-out winding as reliably as possible.
You have to rewind manually. Conclusions must be made exactly as they were before the initiation of the rewinding process.
The specialist will tell you how to independently rewind the electric motor in a working tool:
Repair angle grinder: 4 main components for repair
In order to repair an angle grinder, it is enough to study the basics of technology and know the design features of the device There is no doubt that every electric tool may stop working sooner or later. Most often this is due to the fact that the operating conditions were not met. Not included in the list of exceptions and angle grinder. If suddenly you had such a nuisance, you can not immediately contact the workshop, but try to figure it out on your own, especially since most of the problems are easily solved.
Repairing an angle grinder is not a simple matter; you need to know all the subtleties and reasons why the machine may fail. For example, repairing an asynchronous motor or a sparking collector, this is not always possible for an ordinary person. And then you have to turn to the master. In order to understand what the angle grinder consists of, you need to know how this technique works. With the help of electricity, an engine runs that transmits rotation to the shaft thanks to the gear. At the end of the shaft, a cutting or grinding wheel is installed.
The quality of work of an angle grinder depends on the number of revolutions per minute. A professional tool is capable of speeds of 1000 rpm.
The first thing to do in case of breakdown is to disassemble the device and clean it, in most cases the angle grinder starts to work.
The body of the angle grinder is made of durable plastic. Its main task is to keep all components in place and transfer the physical strength of a person at the time of work
If this did not happen, you need to understand exactly where the breakdown occurred. The composition of the angle grinder may vary depending on the model, but the main parts are the same.
When parsing, we can see 4 components:
- The case, which consists of 2 parts;
- Electrical component.
The engine makes the gear move, which in turn drives the cutting element.
It is not strange in most cases, the breakdown of grinders occurs due to the accumulation of dust and as a result of the departure of the power button. Therefore, first you need to determine the integrity of the electric drill, its lamellas and the battery. All this is not so difficult, it is enough to know how the device is arranged. If you once studied the structure of a vacuum cleaner or a washing machine, then this will seem a trifle to you, and a special video can help.
Anchor to an angle grinder: how to check the motor anchor at home
If you are sure that the anchor is broken, you will need to get an electric motor.
Disassembly of the motor should be carried out as carefully as possible. Disconnect all brushes and terminals from the power supply.
Do not forget that before changing the winding, it does not matter which Bosch, Sparky, Makita, Interskol power tool you need to manually establish the causes of the breakdown of the grinding machine. For this, the winding and gearing scheme will help you, as well as a special indicator. We take out the rotor, and with it the thrust bearings and cooling impeller. All this is a single whole subject. If you notice that most of the wiring is damaged and the balance is upset, then it is better to replace this component completely. The fact that the balance is disturbed can be indicated by the appearance of a hum and vibration in the mechanism.
Do not attempt to repair an angle grinder if you do not have basic knowledge in working with a soldering iron. In such a situation, it is better to take the device to the workshop and consult a professional
If the balance of the anchor is not disturbed, and the problem is only in the winding, then the anchor must be restored. The work will consist in rewinding the reel on its own, everything should be done carefully with patience and accuracy. If the balancing of the angle grinder is intermittent, then first you need to check it with a tester. In the event that the groove shows different data, it will not be possible to repair the electric motor itself. But to replace it will help replacement.
In order to replace the rewind in the anchor you will need:
- New wires for winding should be copper conductors, the diameter of which will correspond to the previous wires;
- Dielectric type paper for insulating the winding;
- Varnish to fill the coils;
- Soldering iron with solder and rosin.
Before rewinding, you need to count the turns of the wire and apply the same amount in the new winding.
Step-by-step instruction: how to rewind the electric motor at home
If the problem does not concern the starter, gear, but you find the problem in the winding, then here you have to purchase copper and enlist the help of a collector puller. To begin with, the tester runs the circuits, a multimeter will help you ring, and in order to check the operation of the device, use a short-acting transformer. So you can pick up the necessary actions and tools to subordinate the angle grinder.
The rewinding process is a painstaking task and will require patience and skills.
The process itself consists of the following actions:
- Elimination of the old winding. It must be carefully removed and the metal body of the anchor itself will not be damaged. If you find scratches or burrs, they need to be smoothed out using a sandpaper or a soldering iron. Sometimes, in order for the body to be completely cleaned, a burner is used.
- Preparing to connect new wires. It is not necessary to remove the collector itself. You will need to inspect the lamella and measure the resistance of the existing contacts with a multimeter in relation to the case. The indicator should be approximately 0.25 megohms.
- Elimination of old wires. Residues must be carefully removed and cut through the grooves in the contacts. In the future, they will be needed to insert the wires of the coils.
- Installation of sleeves. The sleeves are made of cardboard of the electrical type, this is a material whose thickness is not more than 3 mm. The required amount is cut and inserted into the slots of the anchor.
- Rewind The end of the wiring must be soldered to the end of the lamella and wound in a circle counterclockwise. The same action is repeated in relation to all the tubs.
- Quality checking. After all the windings are done, using a multimeter to check for short circuits or breaks.
- Final processing. The finished coil is treated with epoxy resin or varnish. At home, the finished work is dried in the oven. You can use varnish that dries faster.
It might seem like a daunting job. We hasten to assure you that there is not, but it will take a lot of time and effort to do this.
How to check the stator for interturn short circuit with a multimeter
An anchor is the part that most often accumulates a large amount of dirt. If the angle grinder has malfunctions, they can be detected by yourself using a multimeter or in other words an ammeter.
The check begins with finding the faulty component. If your device is completely out of order, this may be evidence of the scattering of brushes or a broken layer of dielectric that is located between the plates. If you observe sparking inside, this means that the current collectors are damaged in the angle grinder.
Checking the stator for interturn circuit with a multimeter does not require much time
Regardless of what result you get during the examination, you need to check the resistance. It should be the same for each measurement.
If the indicators show a deviation, this indicates a violation of the connection of the coils and poor fit of the brushes.
Pay attention to the brushes, their wear should be the same, and if there are scratches, they must be replaced with new ones. If you did not find any malfunctions, then you need to measure the resistance of the lamella and coil.
DIY angle grinder repair (video)
As you can learn from our article, angle grinder is not a complex structure, because it consists of only 4 parts. But revealing the true cause of the breakdown is quite difficult, and as it turned out most often, this is a careless attitude to the tool. To avoid this, take care of your tool, but if the device is out of order, take the time and follow our instructions to bring it into working condition.
Attention, only TODAY!
Rewind the stator.
If the bearings at the anchor of the power tool are not timely replaced, the anchor begins to touch the rotor and local heating occurs at the point of contact. Typically, such heating occurs from the side of the “broken” bearing around the entire circumference of the armature and at one point of the stator. Since the temperature is distributed over the anchor over a larger area, and on the stator in one place, the stator is usually the first to fail. From increased temperature, the insulation burns in the groove and the wire, touching the metal groove, closes to the body.
Another cause of stator failure can be normal overheating. When the tool runs under heavy load for a long time. In either case, the stator coils must be rewound or the entire stator replaced.
If for rewinding the anchor certain knowledge and skills are required, as well as a lathe for grooving the collector after winding. And a balancing machine for dynamic balancing of the armature after winding, impregnation and grooving. That stator rewind is available to anyone who has the desire and enamel wire. You just need to carefully disassemble the burned stator and count the number of turns in each coil. Often, the number of turns in both coils is the same. The exception is only a small percentage of engines with several operating modes. For example, mixers. Also, when unwinding the coils, we notice the direction of winding and the number of wires soldered to one output. The stator of a more powerful tool can be wound in 2 wires.
After disassembly, measure the diameter of the wire. The wire is measured without enamel. Next, we see which wire was used in the stator, copper or aluminum. If there was aluminum, and you want to wind with copper, then you need to find out the cross section of the burned wire according to the table, or by the formula. And multiply it by a factor of 0.7-0.8. So we find out the cross section of the copper wire. Now again, according to the table, we translate the section into diameter. Copper wire will always be thinner than aluminum.
After we know the diameter of the wire, the number of turns, the direction of winding and the number of wires soldered to the output, it is necessary to check the stator slots and prepare the sleeves. The grooves must be clean, with no sharp edges or burrs. Old sleeves must be removed, and possible deposits of the burnt wire cleaned. We make new sleeves from electric cardboard (pre-finished), taking into account the direction of the fibers, and protecting the edges from breaks with adhesive tape. The length of the sleeve should be 4 mm longer than the length of the stator iron.
We make winding by fixing two metal plates on the stator to form the frontal parts. We isolate the outgoing ends of the wire with cambrics. We follow the direction of winding and carefully consider the turns. After winding, we seal the wire in the grooves. To do this, use a screwdriver, or a metal rod wrapped in preshpan. We fix the frontal parts of the coil with braid or a harsh thread and bind together, so that the coil fits tightly in the grooves and does not vibrate. And also so that the wires do not fluff.
When both coils are wound, sealed and tied, you can begin to impregnate.