CC BY
2УДК 621.75 Aliev N.A., Agayev R.A.
Aliev N.A.
Associate Professor Azerbaijan State Oil and Industry University (Baku, Azerbaijan)
Agayev R.A.
Master student Azerbaijan State Oil and Industry University (Baku, Azerbaijan)
INVESTIGATION OF PROBLEMS THAT MAY ARISE IN AN ASYNCHRONOUS MOTOR, THEIR DIAGNOSIS AND REPAIR PROCESS
Abstract: in order to ensure the normal and efficient operation of enterprises, it is important to carry out timely repairs along with proper maintenance of electrical equipment during operation. In order to carry out repair work in a short time, with quality and with little expenditure, in addition to the high level of organization of repair work, there must be highly specialized specialists. The long-term experience of enterprises' electrical repair shops and electrical repair plants shows that the electricity coming for repair more than 80% of its equipment are transformers, electrical machines and switching devices. In the article, the problems that may arise in the asynchronous motor, issues related to diagnostics and repair work were considered.
Keywords: stator winding, insulation, protection, insulation classes, effect of temperature.
In the process of working of electrical equipment, their gradual wear and tear occurs. Under the concept of physical wear is understood the change in the state of its surface as a result of residual deformation under the influence of dimensions, shape, mass of a technical object or a constantly acting load, or due to the disintegration of the top layer during friction. By referring to electrical equipment, physical wear and
tear are divided into mechanical, electrical and spiritual wear and tear. Mechanical wear of electrical equipment occurs as a result of long-term variable or constant (fixed) effects on its individual parts or assembly points. As a result, their original form changes or their quality deteriorates. The repair of electrical equipment is carried out in industrial enterprises according to the planned preventive maintenance system (PQT) adopted by the state. The periodicity and volume of repairs is determined by the PQT system, depending on the operating modes, the technical condition of the electrical equipment and the operating conditions.
Thus, PQT is a system of organization and technical measures, the implementation of which ensures long-term and accident-free operation of electrical equipment. There are three main systems of PQT organization in electrical equipment industrial enterprises: centralized, decentralized and mixed. During the centralized system, several repair services specialize in the types and operations of electrical equipment. These services are subject to the chief energy officer of the enterprise. The staff who maintain the electrical equipment of the workshop or substation only perform control and minor current repairs. A decentralized system is characterized by the absence of specialized maintenance services. All electrical repair works are performed by the personnel of electrical repair shops or brigades. This staff is administratively subordinated to the relevant superiors, for example, the workshop supervisor. During the current repair, after a comprehensive inspection of the electrical equipment, they eliminate minor defects, adjust the mechanisms, and carry out repairs that are small in volume (for example, recharging the fuses with the replacement of the fusible filling, cleaning the burnt contacts of the devices, replacing the broken brushes), the normal operation of the electrical equipment, until the next planned repair. , they perform work that can provide. (Fig. 1).
Figure 1. The structure of the repair cycle (TS): A - fundamental repair, C - current repair, O - average repair, d - maintenance period.
Current maintenance is usually carried out without disassembling electrical equipment during short-term downtime of production equipment. Maintenance that prevents excessive wear and tear of the most responsible parts and components of electrical equipment is considered average. In this case, they change individual details, eliminate defects in the insulation of the front parts of the windings of electric motors, repair brush holders (change springs and flexible connections), polish the contact rings of electric motors with a phase rotor, etc. They plan the repair of electrical equipment depending on the inter-repair periods, repair cycles and their structures. Before repair, they carefully examine the windings, paying special attention to the places where the windings come out of the stator slots. Lubricated parts of the wheels are wiped with gasoline-soaked lubricant. Slight damage to the insulation of the loop (peeling, mechanical damage, wire stripping, etc.) is covered with insulating varnish or air-drying treatment, in which case the varnish is applied either by brush or spray. The brands of lacquers and enamels recommended for covering the edges are given in the table. The place where the wires are twisted is soldered with POC-40 solder or welded with a carbon electrode. During welding, one clamp of the transformer is connected to the winding, and the second - to the carbon electrode. The voltage in the arc should be 16...18V (Fig. 2)
—M
Figure. 2 With the wiring of the spool groups of the output wirescombining: a-copper wire twists, b-twisting of copper wire 1 with aluminum 2, welding of c-copper 2 and aluminum 1 wires, d-isolation of the bend with a linoxin pipe.
Since the windings of the phase rotors of asynchronous motors have an internal connection, the insulation resistance of the windings is measured by connecting the clamp marked "ground" of the megohmmeter to one of the outputs of the winding and the clamp marked "line" (Fig. 3).
Figure 3. Measurement of insulation resistance of windings of electric motors.
If the insulation resistance is less than 5MOm when the temperature is 150C, the winding of electric motors should be dried. It is recommended to carry out the drying of electric motors in the conditions of the maintenance department for electrical equipment in the workshops of the farm or enterprise.
Conclusion. One of the most important issues in electric cars is the issue of diagnostics. Any fault in asynchronous motors should be diagnosed first. After that, it
is necessary to carry out repairs according to the malfunction. In this article, all these issues are investigated and various methods are developed.
СПИСОК ЛИТЕРАТУРЫ:
1. T. Ahonen. Monitoring of Centrifugal Pump Operation by a Frequency Converter, Doctoral Thesis, Lappeenranta University of Technology, 2011, p. 134;
2. L. Szychta, "Analysis of efficiency characteristics of squirrelcage inductionmotor for pump applications," 14th International Power Electronics and Motion Control Conference EPE-PEMC 2009, pp. 73 - 78;
3. N.S. Mammadov, "Methods for improving the energy efficiency of wind turbines at low wind speeds", Vestnik nauki, Issue 2, Vol. 61, №4, April 2023;
4. Al-Khalifah, M., Mcmillan, G. Control valve versus variable speed drive for flow control. ISA Autom. Week 2012, 60, 42-46;
5. Kiata, E., Ngasop, N., Justin, N.S.J., Djalo, H. Fuzzy Adaptive Control by Reference Model of a Submerged Electric Pump: Application to Photovoltaic Water Pumping. Glob. J. Eng. Sci. 2023, 10, 861-869;
6. Sul, S. Control of Electric Machine Drive Systems, John Wiley & Sons: Hoboken, NJ, USA, 2011, pp. 291-294
