As Shakespeare said: "Nothing lasts forever under the Moon." Household appliances, alas, is no exception. It happens that even the most reliable mechanism fails. And we must be ready to meet this fact without panic, with a firm conviction that there are no desperate situations. How is the bulgarian arranged, what kind of malfunctions, how to check the motor's armature, determine the cause of the failure and fix the problem? Knowing the device of the main components of the power tool will allow the master to perform diagnostics and repair of the angle grinder.

Features of the asynchronous motor of the Bulgarian

Virtually all electric 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 of rotation does not change. This means that if, for example, long and without stopping the stone with a domestic bullet, there will be no noticeable external signs of engine overload. The rotation speed of the disk will be constant, the sound is monophonic. Only the temperature will change, but you can not notice this if your hands are clothed in gloves.

Inattentive attitude, the advantage can turn into a disadvantage.Asynchronous motors are very sensitive to overheating, a significant excess of the operating temperature entails a fusing of the insulation on the rotor windings.Initially, the motor will work intermittently, and then - when there is an inter-turn short circuit - the engine will stop altogether. It is worth several times to overheat the engine of the Bulgarian and it is most likely that the anchor will melt. In addition, contacts that connect the wires of the primary winding with the collector are soldered off from the high temperature, which leads to an interruption in the supply of electric current.

How to determine the malfunction of the anchor of a Bulgarian

The signs of breaking the anchor bolgarki are: increased sparking of the brushes on the engine collector, vibration of the motor at low speed, rotation of the working shaft in different directions.If such symptoms are present, the instrument should be discontinued - this is dangerous.Suspicions are easy to verify with simple tests.

Visual inspection from the outside

Search for a malfunction should begin with a visual inspection of the Bulgarian:

1. Conduct a general examination of the instrument.
2. Pay attention to the integrity of the power cord, the presence of voltage in the outlet.
3. Using the voltage indicator, make sure that the current flows to the engine collector and start button.

Inspection of the device from the inside

If the food is ok, but the bulgarian does not work, you will have to open the case to gain access to the motor. As a rule, disassembly is not difficult. But it is necessary to adhere to simple rules that will avoid troubles during the reassembly:

1. Be sure to disconnect the appliance from the mains before disassembling.
2. Remove the working disk and protective cover from the spindle.
3. Carry out opening of the case in a well-lit place, on a clean table surface.
4. Remember the location of all parts and assemblies before disassembling. It is recommended to draw or photograph the internal device of the device.
5. Screws and screws fasten in a separate place so that they are not lost.

To inspect the motor is best under bright lighting, so that all small parts are clearly distinguishable. The anchor should rotate freely around its axis, properly working bearings should not produce sound during operation. At anchor there should be no traces of fused wiring, the windings of the circuit must be intact, without breaks. You can smell the rotor. In the interturn closure, the insulation lacquer burns and produces a stable specific odor. But for such diagnostics a certain experience is necessary.

Chime of chains tester

If visual inspection does not give clear results, continue the examination is recommended using a multimeter. After setting the mode switch to the position of an ohmmeter (200 Ω range), two proximity probes should be pierced by two probes. If the resistance at all turns is the same, this means that the windings are in good order. If, on some pairs, the tester shows another resistance or an open circuit, there is a malfunction in this coil.

A wiring gap may occur between the winding and the core. It is necessary to carefully examine the connection points of the coils with the collector lamellae at the bottom of the armature, visually check the soldering of the contacts.

Checking contacts with a light bulb

If there is no tester, you can get out of the situation with a simple 12 volt light bulb. Power can be any, optimally 30-40 watts. Voltage from the battery of 12 volts must be applied to the fork of the bulgarian, inserting a light bulb into the break of one wire. With a working anchor, if the spindle is rotated by hand, the bulb should be lit, without changing the brightness. If the glow changes - this is a sure sign of inter-turn short circuit.

If the bulb does not burn, then it can talk about the following:

1. Possible hang of the brushes in the non-working position. The spring was activated.
2. There was a break in the supply circuit.
3. There is a short circuit or a break in the stator winding.

There are other ways to diagnose, but they require more sophisticated equipment, which is usually not used at home. An experienced wizard will determine the failure with a high degree of accuracy, using a "punch" or a simple transformer with a cut toroidal core and one primary winding.

When can I save the anchor and restore it myself?

If the armature damage is established with guaranteed accuracy, the part must be removed from the motor.Disassembly of the motor must be done with special care, after removing the brushes and disconnecting the power terminals.The rotor is withdrawn together with the bearing bearings and the impeller of the motor cooling, they form a single whole with it.

If the armature is damaged most of the wiring and as a result of overheating, the balancing is broken, it is better to replace it entirely. On the violation of balancing said increased vibration and uneven hum while the mechanism works.

How to rewind the anchor - step by step instructions

If the balance of the armature is not broken, and the problem is only in the spoiled windings, then such an anchor can be restored independently by rewinding the coils.Rewinding the rotor at home requires a lot of patience and accuracy.

The master must have skills in working with a soldering iron and devices for the diagnosis of electrical circuits. If you are unsure of your abilities, it is better to take the engine for repair to the workshop or replace the entire anchor yourself.

To self-rewind the anchor you will need:

• wire for a new winding. A copper conductor with a diameter exactly matching the old conductor is used;
• Dielectric paper for insulation of the winding from the core;
• varnish for filling coils;
• soldering iron with tin-lead solder and rosin.

Before rewinding it is important to count the number of turns of the wire in the winding and rewind the coils with the same number of new conductors.

The process of rewinding consists of the following steps:

1. Dismantling of old windings.They must be carefully removed without damaging the metal armature body. If any burrs or damage are found on the case, they must be ironed with a file or sanded with sandpaper. Sometimes, to completely clean the body of the slag, the craftsmen prefer to burn it with a burner.
2. Preparing the collector to connect a new wire.It is not necessary to remove the manifold. It is necessary to inspect the lamellae and measure the resistance of the contacts with respect to the body with a megger or multimeter. It should be no more than 5 MOhm.
3. Delete the old wiring on the manifold.Carefully remove the remnants of wires, cut through the grooves in the part of the contacts. In the future, the ends of the wires of the coils will be inserted into the grooves.
4. Installation of sleeves for the anchor.The sleeves are made of dielectric material of thickness, mm, for example, of electrical cardboard. Cut a certain number of sleeves and insert them into the grooves of the cleaned anchor.
5. Rewind coils.The end of the new conductor is attached to the end of the lamellae and wound by successive circular motions, counterclockwise. This laying is called "stowing right". Winding Repeat for all reels. Near the collector, pull the wires with a thick thread of cotton fabric (kapron should not be used, as it melts when heated).
6. Checking the quality of the winding.At the end of stacking of all windings, check the multimeter for the absence of interturn closures and possible breaks.
7. Finishing.The finished coil should be treated with varnish or epoxy to hold the winding. At the factory, the impregnation is dried in special furnaces. At home it can be done in the oven. As an option - to apply for impregnation quick-drying varnishes, applying a coating in several layers.

Replacing the anchor yourself at home

Practice shows that if it is decided to replace the anchor bolgarki, then it is best to change it together with the bearing bearings and the impeller of the engine cooling.

To replace it you will need:

1. The new anchor of the USM. Must match your model. Interchange with other models is unacceptable.
2. Screwdrivers, spanners.
3. Soft brush and rag for wiping the mechanism.

How to remove the anchor

The replacement of the anchor begins with disassembly of the Bulgarian. The following steps are performed:

1. The screwdriver unscrews the brush assemblies from both sides. Brushes are extracted.

   For removal, you need a wide flat screwdriver

2. Four screws securing the gear housing are twisted.

   Remove the case carefully

3. Carefully open and remove the cover of the gearbox to gain access to the inside of the gear mechanism.

   Disassembly of the gearbox requires a puller

4. Removes the retaining ring, which fixes the small gear at the anchor.
5. The anchor retainer is released from the fastening, the anchor is pulled out together with the small gear and the bearing.
6. The gear, bearing and anchor fixation disc are removed, wiped with rags. The bearing is removed by a special puller.

   The puller is operated by rotating the stop screw

Video: replacing bearings on a bulgarian

How to put the anchor in place

To replace the new anchor bolgarki should take a new part, and then assemble the instrument in reverse order. The follower is:

1. The fixing disk is mounted on the armature shaft.
2. The bearing is installed by pressing.
3. A small pinion is attached and fixed by a lock ring.
4. The anchor is wound in the gear housing, the connecting holes are aligned.
5. The bolts fastening the reducer.
6. The anchor with the reducer is inserted into the housing of the Bulgarian and fixed.
7. Brushes are deposited in their places, closed with lids.

After performing these actions, the Bulgarian is ready to work. The anchor has been replaced.

Video: how to check the Bulgarian

The ancient Sufi wisdom says: "A man who can come out with dignity from a difficult situation is able to understand. But the wise is the one who does not get into this situation. "Observing the rules of operating household appliances, not allowing overheating of the engine, it is possible to avoid breakdowns and troubles in the work of the Bulgarian. The maintenance and storage of the tool in cleanliness and dryness will prevent its mechanisms from contamination and oxidation of current-carrying elements. Timely maintenance of the tool is guaranteed to eliminate unpleasant surprises during operation.