In the context of the inevitable use of calculation and simulation in the design of traction electrical equipment in industrial environments, the issue of technological purity in manufacturing traction drive units is becoming increasingly relevant. Specifically, precise production of charge-welded units, hardening, and tempering of materials for elements of the supporting structures of traction motors are crucial. One of the most pressing issues in the serial production of traction electric drives, from the perspective of mechanical and strength tests, is to determine the cause of vibration in the rotating components of the electric drive. This vibration can be of both mechanical and electromagnetic nature, especially when considering the power supply characteristics of the traction motor gear unit (hereinafter referred to as MGU) using voltage converters with pulse width modulation (PWM). The purpose of this work is to conduct experimental studies to establish the causes of increased vibration activity in the MGU sample. Research has shown that vibration in motors featuring charge-welded housings can be substantially intensified by structural resonance.

The article analyzes and evaluates the components of traction motor-gear units of electric trains operating on regional lines at speeds of up to $160 \mathrm{~km} / \mathrm{h}$, focusing on the durability and performance of these components. It was found that the most worn parts of the electric motors and gear units are the bearing holes in the motor shield and the gearbox housing, which are subjected to significant stress and wear over time. Based on the simulations conducted, the critical wear limits were determined, taking into account various factors such as load, speed, and environmental conditions. These limits were found to depend significantly on the material of the bearing shields, which can be restored to their original condition using advanced electrophysical methods, thereby extending the service life of the components and improving the overall reliability of the trains.

The article examined and assessed the parts of traction motor-gear units (referred to as MGUs) and their components within suburban-type electric multiple units (EMUs) subject to vibrational strength analysis. It was found that the bearing shields of the MGUs are the most heavily loaded and worn parts. By measuring the vibration levels of different types of bearing shields, the maximum allowable loads and single impacts were determined. The primary emphasis was placed on investigating the potential impact of the motor's magnetic field on the vibration resilience of the MGUs. Relationships have been identified that enable the analysis of the correlation between the magnetic field waves in the air gap of an asynchronous motor, the radial magnetic force waves impacting the stator, and the bending deformation waves of the stator yoke. These relationships have been applied in multiphysics finite element analysis program to develop a prototype of the MGU. This model, grounded in the provided motor geometry, material characteristics, and the configuration of the current in the stator winding, facilitates the simultaneous exploration of interconnected electromagnetic and mechanical processes across diverse components of the electric machine. Moreover, it considers the rotor's rotation influenced by magnetic forces. The outcomes of the simulation have facilitated the assessment of the radial magnetic force's magnitude impacting the stator, as well as the form and frequency of its deformation waves, crucial for devising active methods to mitigate vibrations.

At present, the continuous development of suburban and regional railway communication creates the prerequisites for continuous improvement of the reliability of traction electric drive systems, taking into account the constant increase in loads on actuators. In electric rolling stock, the predominant use of traction electric drives often results in difficult accessibility and maintenance of the actuators once they are installed. Intensive traffic gave impetus to the mass introduction of an asynchronous traction electric drive. The traction electric drive consists of various functional components, and the phenomena taking place within the drive exhibit diverse physical characteristics. These factors necessitate evaluating the present condition of the electrical and mechanical elements of the equipment and monitoring its state during operation. It is recommended to conduct comprehensive tests and acceptance trials during the manufacturing process, particularly for new products and during the inspection phase of mass production.

In the presented work, a description of the methodology for determining the vibromechanical state of the rotating units of the traction electric drive of the motor bogie of a suburban electric train is proposed. The study contains the determination of the level of eccentricity of the motor rotor and the flange of the traction gear unit, which causes imbalance, followed by the determination of the influence on the bearing supports both for dynamic modes, using the example of starting a motor bogie from a place, and under single shock loads. On the basis of the calculated traction and energy characteristics of the traction electric drive, an algorithm for controlling the traction and braking modes of paired motor-gear units (MGU) was created. The level of vibration velocity in the areas of bearing supports is determined as a verification indicator of the reliability of the MGU design, in terms of resonance and the influence of a possible imbalance of the motor rotor for clockwise and counterclockwise rotation.

Vibration diagnostics is one of the effective tools for solving a wide range of problems of detecting defects in electrical machines, preventing failure of parts, extending the service life and increasing the overhaul periods of their operation. Simultaneously occurring electromagnetic and mechanical processes during operation significantly complicate the collection and analysis of vibration parameters due to the presence of a large number of harmonic and random components in the experimental data signal. Preservation of electrical safety, reliability and durability of the operation of electromechanical equipment of electric drives based on asynchronous motors in transport remains an urgent task of electrical systems. The determining factor in the effective functioning of diagnostic systems is the establishment of a one-to-one correspondence between the parameters of diagnostic features, determined from the results of current measurements of the machine characteristics, and the type of defects that have arisen. These can be design errors, violations of the technological process of production, maintenance and repair of electrical machines, as well as intensive non-repair operation, all this leads to various kinds of defects.

The problem of the influence of torsional vibrations of the traction motor frame as a source of additional dynamic loading of the gear casing is indicated. The paper presents the amplitude-frequency characteristic of torsional vibrations of the traction motor frame and considers the dynamic moments that occur on the gear casing during torsional vibrations of the traction motor. The criteria for the technical condition and the degree of development of defects in the method used are fully focused on the corresponding standard values of vibration levels adopted for traction geared-motor units. In this diagnostic method, such a structural element of the structure is considered defective, the vibrations of which exceeded the general norm for the unit, this is a sign of a defective condition.

The goal is a model-experimental study of the vibration that occurs in the nodes of the motor-gear unit (hereinafter referred to as MGU) installed on the motor bogie of an electric train under operating conditions. Vibration measurement was carried out experimentally on a motor stand using vibration sensors of the SKF CMXA 80 type, installed on the casing of the traction gearbox and the frame of the traction motor. For measurements, a system was used that allows continuous recording of the vibration transducer signal over eight channels. Experimental data on the parameters of vibrations that occur on the bearing shield of the output shaft of the MGU were obtained by simulating the departure of a motor bogie by instantaneous load shedding. A pattern has been established that the vibration level under skid conditions in three coordinates X, Y, Z has sharp bursts of activity. During the MGU operation in the traction mode, it was found that a sharp increase in the amplitude of harmonics with frequencies that are multiples of the gear frequency is associated with the coincidence with the natural frequency of the MGU case. When switching to the coast down mode in the frequency range of about 1.5 kHz, a random vibration is recorded on the MGU body, the RMS acceleration value of which exceeds 50 $\boldsymbol{\mathrm{m}/\mathrm{s}^{2}}$ , which is comparable to the acceleration value when passing the skid.

The article provides an analysis of the procedure for conducting and results of research tests of a traction geared motor box (hereinafter GMB). The traction GMB is provided for installation on a motor trolley as part of an asynchronous electric drive of a suburban electric train. Railway transmission systems operate in an environment with various sources of mechanical and electromagnetic excitations, where the possible unstable operation of the traction motor is one of the most critical indicators. This paper describes the structure and functionality of the physical test equipment and a model of a coupled system with a complete electrical circuit, including a rectifier, a DC link, a traction inverter, a motor-gear unit, and a system of mechanical connections, including flexible damper couplings and shock absorbers. This approach makes it possible to determine the intrinsic resonant frequencies of the GMB design, as well as the level of vibration activity of the GMB under dynamically changing loads. The obtained cascade characteristics of vibration activity correspond to both a long-term steady-state mode and transient mechanical disturbances during start-up, a change in rotation speed and the transition of the GMB to the run-out mode.

The goal is a model-experimental study of the vibration that occurs in the nodes of the motor-gear unit (hereinafter MGU) installed on the motor bogie of an electric train under operating conditions. Vibration measurements were carried out experimentally on a motor bench controlled by a traction inverter. Experimental data on the parameters of vibrations that occur on the bearing shield of the output shaft of the MGU were obtained by simulating the departure of a motor bogie by instantaneous load shedding. A pattern has been established that the vibration level under skid conditions in three planes has sharp bursts of activity.

The article deals with the problem of experimental determination of the mechanical reliability indicators of motor-gear unit of motor coaches of suburban electric trains. The range of natural frequencies of the casing is compared with the frequencies of disturbing influences. The problem of the influence of torsional vibrations of the traction motor frame as a source of additional dynamic loading of the gear casing is indicated. The value of the rigidity of fastening the casing to the traction motor depends significantly on the method of fastening. If the technology of joining the traction motor and the gearbox is not observed, the range of natural frequencies of the oscillatory system of the casing may change, while the occurrence of resonance phenomena is also possible. The paper presents the amplitude-frequency characteristic of torsional vibrations of the traction motor frame and considers the dynamic moments that occur on the gear casing during torsional vibrations of the traction motor. To reduce the level of dynamic loads on the gear housing, which contribute to the occurrence of failures, the design of the housing with shock-absorbing fastening to the frame of the motor bogie, which provides increased vibration protection of the system, is considered.

One of the most pressing issues for the serial production of traction electric drives in terms of mechanical and strength tests is the determination of the cause of vibration of the rotating units of the electric drive, which can be of both mechanical and electromagnetic nature, especially taking into account the peculiarities of supplying the traction geared motor box (hereinafter GMB) from a voltage inverter with pulse-width modulation (PWM). The purpose of this work is to conduct experimental studies of vibration activity on a GMB sample powered by a two-level voltage inverter at the stage of acceptance tests.

In according to the widespread use of an asynchronous electric drive in transport, research is currently being carried out aimed at improving the dynamic and static performance of the drive. In addition, more and more attention is paid to reducing the level of vibration and acoustic noise, due to the fact that the traction electric drive units to the end customer, such as a traction converter, a geared motor unit, a top-level control unit, are supplied from different manufacturers, which requires a separate preliminary check and testing of operating modes. No less relevant is the issue of increasing the level of vibration when the GMB is powered from a voltage inverter with PWM. The purpose of this work is to perform experimental studies of the vibroactivity of the GMB, powered by a two-level voltage inverter at the stage of acceptance tests.

A methodology has been developed that introduces a generalized approach to the synthesis of physical-simulated energy equipment through the creation of closed automatic control systems that link and synchronize the physical and virtual part of the research object. Within the framework of the methodology, a substantiation of the load generation type in virtual-physical tests is provided, an improved method for creating virtual-physical objects for energy equipment tests with several power units is proposed and practically implemented. Virtual vehicle models with combined energy equipment (CEE) have been created, which include vehicle, wheels, power drive, electric motors. The models reflect the CEE properties characteristic of the mechanical and electrical environment. The adequacy of the models is confirmed by comparison with experimental data.

Transition to a low carbon emission transport is supported in all European countries, including Latvia. In this paper, a specific case of converting diesel bus into electric bus is analyzed. During its processing and development, real ready-made porotypes with field tests, and computer evaluation models are used.

Electric traction is one of the most promising technologies that can lead to significant improvements in vehicle performance, energy utilization efficiency, and pollution emissions. This paper presents various solutions for the power traction motors of hybrid electric vehicle (HEV), that is the most promising technology that has the advantages of high performance, high fuel efficiency, low emissions and long operating range [1]. The paper describes the development of the simulation model for a hybrid electric traction using MATLAB Simulink. Simulation results are presented below.

In a stage of development of the project and during the exploitation of transmission line (TL), the specialists have to solve one of the most complicated problems — insulation failures llashover rate (IFFR). The main indicator of the IFFR of TL is the minimization of the probability of outages, which is irreversible destructions of the isolating TL designs. When using valid normative documents, for an assessment of IFFR, it is necessary to use the data of the designs of a standard type with typical geometrical parameters of lines. For atypical constructions of TL towers, this method is not appropriate. The methodology of establishment of IFFR of TL metal construction offered in this research makes the procedure of designing metal constructions easier, including also atypical TL tower constructions due to the synthesis of computer modelling included in the methodology.

Book and Electronic Proceedings, Latvia, Riga, October 13–16, 2011,– pp. 45–45. 7. Sļiskis O., Miesniece S., Ketners K., Vanzovičs E. Application of ATP/EMTP Program for Solving of Some High-Voltage Engineering Problems // Abstract Book and Electronic Proceedings, Latvia, Riga, October 11–14, 2010,– pp. 137–140. 8. Sļiskis O., Miesniece S., Ketners K., Vanzovičs E. Zibensizlādes raksturīgie parametri pārspriegumaizsardzības skaitliskos uzdevumos // RTU zinātniskie raksti, 4. sēr., Enerģētika un elektrotehnika. – 26. sēj., 2010, 46.–49. lpp.

This article presents sequenced methodology for simulation lightning discharge process on high voltage (HV) transition towers. The tower surge impedance is deeply related to geometric shapes. Tower could be represented as inductance connecting shield wires to ground, constant-impedance transmission line, variable-impedance transmission line, or radiating structure. Many experimental and theoretical studies of tower response have been initiated. Scientists Wagner and Hileman found the transient impedance of a cylinder to an impressed surge at the top of the tower. Sargent and Darveniza noted that a cone has constant transient impedance and derived average impedance of cylinder. Chisholm, Chow and Srivastava found that impedance depends on direction of injection, with vertical injection to cylinders and cones agreeing with and horizontal injection matching experiments using this geometry [1, 2]. As a method to obtain surge wave propagation of overhead HV transmission, like towers, analytical calculated and numerical methods, based on the electromagnetic field theory are used. With this purpose, were used Comsol Multiphysics and ATPDraw software.