The armature of the electric motor refers to the rotating part where dirt collects, soot forms. In case of malfunctions, you can diagnose at home visually and using a multimeter. There should be no chips, scratches or cracks on rubbing surfaces. If any are found, measures are taken to eliminate them.
Typical faults
The armature of the electric motor is not subject to wear under normal operating conditions. Replace only the brushes, measuring the allowable length. But under prolonged loads, the stator windings begin to heat up, which leads to the formation of soot.
Due to mechanical influences, the armature of the electric motor may warp if the bearing assemblies are damaged. The engine will work, but the gradual wear of the lamellas or plates will lead to its final failure. But to save expensive equipment, it is often enough to carry out preventive maintenance and the device can be used for a long time.
Negative factors affecting the motor armature include moisture on metal surfaces. Critical is the prolonged exposure to moisture and the appearance of rust. Due to the red clusters and dirt occursincrease in friction, this increases the current load. The contact parts get hot, the solder may peel off, creating an intermittent spark.
The service center can help, but this will require certain costs. You can deal with a breakdown on your own, having familiarized yourself with the question: how to check the armature of an electric motor at home. For diagnostics, you will need a device that measures resistance and tools.
How is a fault diagnosed?
Checking the armature of the electric motor begins with the definition of the fault itself. The complete failure of this assembly occurs due to crumbling collector brushes, destruction of the dielectric layer between the plates, and also due to a short circuit in the electrical circuit. In the event of sparking inside the device, they conclude that the current collectors are worn or damaged.
Sparking brushes starts due to the appearance of a gap at the point of contact with the collector. This is preceded by a fall of the device, a high load on the shaft during jamming, as well as a violation of the integrity of the solder on the winding leads.
A malfunction with a running electric motor manifests itself in typical conditions:
- Sparking is the main symptom of a malfunction.
- Hum and friction as the armature rotates.
- Perceptible vibration during operation.
- Change the direction of rotation when the anchor passes the trajectory of less than a turn.
- The appearance of the smell of melting plastic or strong heating of the case.
What to do if the listed deviations in work appear?
The frequency of rotation of the motor armature is kept constant. At idle, the malfunction may not appear. Under load, friction is compensated by an increase in current flowing through the windings. If deviations in the work of the grinder, drill, starter become noticeable, then you need to remove the voltage supply.
Continued use of appliances may result in fire or electric shock to persons. First of all, it is recommended to inspect the body of the product, evaluate the wiring for integrity, the absence of melted parts and damage to the insulation. The temperature of all parts of the device is checked by touch. They try to rotate the anchor by hand, it should move easily, without jamming. If the mechanical parts are intact and there are no impurities, proceed to disassembly.
Diagnosis of internal parts
The armature winding of the electric motor should not have carbon deposits, dark spots, similar to the consequences of overheating. The surface of the contact parts and the gap area must not be clogged. Small particles reduce motor power and increase current. Do not disassemble appliances with the plug connected to the network in order to work safely.
It is recommended to film the disassembly process to avoid the difficulty of the reverse process. Or you can write down on a piece of paper each step of your actions. Some wear of brushes, lamellas is allowed. But if scratches are found, the cause of their origin should be found out. Perhaps thiscontributed to a crack in the body, which can only be seen under load.
Ommeter operation
Sincere could be due to the loss of electrical contact in one of the lamellas. To measure the resistance, it is recommended to put the probes on the side of the current collectors. Rotating the motor shaft, observe the readings of the dial. The screen should show zero values. If the numbers skip even a few ohms, then this indicates soot. When an infinite value appears, they judge an open circuit.
Regardless of the results, the next step is to check the resistance between each adjacent lamella. It should be the same for every measurement. In case of deviations, it is necessary to inspect all coil connections and the contact surface of the brushes. The brushes themselves should have uniform wear. In case of chips and cracks, they must be replaced.
The coils are connected to the core by wiring that may have peeled off. Solder often does not withstand shock from falls. At the starter, the current through the contacts can reach 50A, which leads to burnout of poor-quality connections. External examination determines the location of damage. If no malfunction is found, then the resistance is measured between the lamella and the coil itself.
If there is no ohmmeter?
If you don't have a multimeter, you will need a 12 volt power supply and a light bulb for the appropriate voltage. Any motorist with such a set will not have problems. The positive and negative terminals are connected to the plug of the electrical appliance. An incandescent lamp is placed in the gap. Resultobserved visually.
The armature shaft is rotated by hand, the lamp burns without jumps in brightness. If attenuation is observed, a faulty engine is judged. Most likely, there was an interturn short circuit. The complete disappearance of the glow indicates a break in the circuit. The reasons may be a non-contact of the brushes, a break in the winding or the absence of resistance in one of the lamellas.
How to "revive" a faulty device?
Repair of the armature of the electric motor is started only after full confidence in the failure of the unit. Scratches and chips on the lamellas are removed with a circular groove on the surface. Carbon deposits and soot can be removed with cleaning agents for contact electrical connections. Broken bearings are repressed and replaced with new ones. It is important to balance the shaft during assembly.
Rotation should be easy and without noise. Damaged insulation is restored, you can use ordinary electrical tape. Suspicious connections should be soldered again. In case of problems with the armature coils, it is recommended to resort to rewinding, which you can do yourself.
Coil recovery
You can rewind the armature of an electric motor in a garage, you just need to be careful when applying each turn. Copper wiring is selected similar to the wound one. The cross section cannot be changed, this will lead to a violation of the high-speed modes of the engine. Dielectric paper is required to separate the windings. Coils are varnished at the end.
You will need a soldering iron and the skills to use it. Connection points are processedacid, rosin is used to apply tin-lead solder. When dismantling the old winding, the number of turns is counted and the same amount of new winding is applied.
The case must be cleaned of old varnish and other inclusions. A file, sandpaper or burner is suitable for this. Sleeves are made for the anchor, the material is electrical cardboard. The resulting blanks are placed in grooves. Wound coils should be done with right turns. The conclusions from the side of the collector are rewound with a nylon thread.
Each wire is soldered to the corresponding lamella. The assembly should end with regular measurements of the resistance of the contact connections. If everything is normal and there are no short circuits, you can check the operation of the electric motor under voltage.
