In the case of electric or tram traction vehicles, the energy for propulsion purposes, as well as all other purposes, is processed and delivered via traction substations. Knowledge of the course of traction substation...In the case of electric or tram traction vehicles, the energy for propulsion purposes, as well as all other purposes, is processed and delivered via traction substations. Knowledge of the course of traction substation loading, especially at the stage of its design, is an extremely important issue because of the choice of the processing equipment of the main circuit or protection devices. In the range of investigations of railway traction substation B in vicinity of Cracow （Poland）, the measurements of current load in hours 4：00 a.m.-8：00 p.m. were realized. The measurements for the analysis were chosen from those realized between 6：00 a.m.-8：00 a.m. （the morning rush time）. Due to the sampling of 2 h summit with a frequency of 2 kHz, the recorded data set contains 1.44 ~ 107 elements. Therefore, the necessary transformation of data was to lower frequency 1 Hz, 10 Hz and 50 Hz. The results of the analysis presented below indicate the effect of such conduct on the obtained results for the parameters of time series models. In view of the unsatisfactory effects of the polynomial approximation, there is a need to seek a more efficient approximation method for achieving the optimum compatibility with the measured process. Continued research should lead to the formulation of procedures, which will determine an acceptable accuracy of the expected variability of traction substation loads.展开更多
The impulsive components induced by bearing faults are key features for assessing gear-box bearing faults.However,because of heavy background noise and the interferences of other vibrations,it is difficult to extract ...The impulsive components induced by bearing faults are key features for assessing gear-box bearing faults.However,because of heavy background noise and the interferences of other vibrations,it is difficult to extract these impulsive components caused by faults,particularly early faults,from the measured vibration signals.To capture the high-level structure of impulsive components embedded in measured vibration signals,a dictionary learning method called shift-invariant K-means singular value decomposition(SI-K-SVD)dictionary learning is used to detect the early faults of gear-box bearings.Although SI-K-SVD is more flexible and adaptable than existing methods,the improper selection of two SI-K-SVD-related parameters,namely,the number of iterations and the pattern lengths,has an adverse influence on fault detection performance.Therefore,the sparsity of the envelope spectrum(SES)and the kurtosis of the envelope spectrum(KES)are used to select these two key parameters,respectively.SI-K-SVD with the two selected optimal parameter values,referred to as optimal parameter SI-K-SVD(OP-SI-K-SVD),is proposed to detect gear-box bearing faults.The proposed method is verified by both simulations and an experiment.Compared to the state-of-the-art methods,namely,empirical model decomposition,wavelet transform and K-SVD,OP-SI-K-SVD has better performance in diagnosing the early faults of a gear-box bearing.展开更多
The traction motor is the power source of the locomotive.If the surface waviness occurs on the races of the motor bearing,it will cause abnormal vibration and noise,accelerate fatigue and wear,and seriously affect the...The traction motor is the power source of the locomotive.If the surface waviness occurs on the races of the motor bearing,it will cause abnormal vibration and noise,accelerate fatigue and wear,and seriously affect the stability and safety of the traction power transmission.In this paper,an excitation model coupling the time-varying displacement and contact stiffness excitations is adopted to investigate the effect of the surface waviness of the motor bearing on the traction motor under the excitation from the locomotive-track coupled system.The detailed mechanical power transmission path and the internal/external excitations(e.g.,wheel–rail interaction,gear mesh,and internal interactions of the rolling bearing)of the locomotive are comprehensively considered to provide accurate dynamic loads for the traction motor.Effects of the wavenumber and amplitude of the surface waviness on the traction motor and its neighbor components of the locomotive are investigated.The results indicate that controlling the amplitude of the waviness and avoiding the wavenumber being an integer multiple of the number of the rollers are helpful for reducing the abnormal vibration and noise of the traction motor.展开更多
The locomotive traction motor is described as a rotor-bearing system coupling the kinetic equations of the traction shaft and its support bearings with the determination of their elastic deformations in this study.Und...The locomotive traction motor is described as a rotor-bearing system coupling the kinetic equations of the traction shaft and its support bearings with the determination of their elastic deformations in this study.Under the effect of excitations induced by the dynamic rotor eccentric distance and time-varying mesh stiffness,the elastic structure deformations of the shaft and support bearings are formulated in the vibration environment of the locomotive.In addition,the nonlinear contact forces between the components of the rolling bearing,the lubricating oil film,and radial clearance are comprehensively considered in this study.The results indicate that the elastic deformations of the shaft and bearings can change the dynamic responses of the traction motor and its support bearings.There are large differences between the ranges of the rotor motion calculated by the rigid and the flexible traction motor models when the intensified wheel-rail interaction is considered.With the increase of the rotor eccentricity,the results underscore the role of the elasticity of traction shaft and support bearings in dynamic researches of the traction motor.The critical value of the initial eccentric distance for the rub-impact phenomenon decreases from 1.23 mm to 1.15 mm considering the flexible effect of the shaft and bearings.This dynamics model of the traction motor can provide more accurate and reasonable simulation results for correlational dynamic researches.展开更多
While modeling a power supply system for an electric railway traction, knowing equivalent circuits of locomotives supplied this way is an essential issue. In alternating current traction, it is important to diagnose i...While modeling a power supply system for an electric railway traction, knowing equivalent circuits of locomotives supplied this way is an essential issue. In alternating current traction, it is important to diagnose inter alia processes taking place in transformers installed on electric vehicles. This article presents specific phenomena occurring during the work of mono-phase, multi-winding, multisystem （systems AC： 50 Hz, 16.7 Hz） laboratory traction transformer. It also shows difficulties encountered during the process of identifying multi-port equivalent scheme＇s elements of the described device, in which a construction defect occurs.展开更多
The paper presents a mathematical model ofbrushless DC machine induced by permanent magnets. Its construction uses the classical model of permanent magnet synchronous machine and induced model of power inverter using ...The paper presents a mathematical model ofbrushless DC machine induced by permanent magnets. Its construction uses the classical model of permanent magnet synchronous machine and induced model of power inverter using the serraphil form. The results of the computer simulation were presented for such states： startup, work under active constant load and the behavior of the machine in terms of exponential and stepping change of the power inverter＇s control angle.展开更多
Wear is a major cause of bearing failure,however,compared with other impact failures,smooth wear is often neglected because of its slow gradualness.In a locomotive,under the effect of the intensified wheel-rail intera...Wear is a major cause of bearing failure,however,compared with other impact failures,smooth wear is often neglected because of its slow gradualness.In a locomotive,under the effect of the intensified wheel-rail interaction and gear mesh,the surface wear can increase the radial clearances of motor bearings,trigger abnormal vibration and noise,and adversely affect the efficiency and safety of the traction motor.In this study,considering the mechanical structure of the traction motor,a locomotive-track spatially coupled dynamics model with traction power transmissions(LTMM)is adopted to provide accurate dynamic loads and obtain the dynamic responses of the system.From the perspective of contact stress and relative skidding at the roller-race interface,the causes and evolution of motor bearings surface wear are analyzed.The results indicate that the wear of inner races of motor bearings is uniform.The outer races of the driving/non-driving end bearings(DB or NDB)are worn in the loaded/main loadbearing regions.The increasing surface wear can increase the internal dynamic forces(e.g.,the centrifugal force of rotor and unbalanced magnetic pull)induced by the instantaneous eccentricity of the rotor,intensify the interactions between the roller and races,and deteriorate the vibrations of the traction motor and its neighboring components in the locomotive.In addition,the effects of the friction coefficient at the roller-race interface and track random irregularity are analyzed.This study offers a theoretical basis in service life prediction and design of the motor bearings.展开更多
文摘In the case of electric or tram traction vehicles, the energy for propulsion purposes, as well as all other purposes, is processed and delivered via traction substations. Knowledge of the course of traction substation loading, especially at the stage of its design, is an extremely important issue because of the choice of the processing equipment of the main circuit or protection devices. In the range of investigations of railway traction substation B in vicinity of Cracow （Poland）, the measurements of current load in hours 4：00 a.m.-8：00 p.m. were realized. The measurements for the analysis were chosen from those realized between 6：00 a.m.-8：00 a.m. （the morning rush time）. Due to the sampling of 2 h summit with a frequency of 2 kHz, the recorded data set contains 1.44 ~ 107 elements. Therefore, the necessary transformation of data was to lower frequency 1 Hz, 10 Hz and 50 Hz. The results of the analysis presented below indicate the effect of such conduct on the obtained results for the parameters of time series models. In view of the unsatisfactory effects of the polynomial approximation, there is a need to seek a more efficient approximation method for achieving the optimum compatibility with the measured process. Continued research should lead to the formulation of procedures, which will determine an acceptable accuracy of the expected variability of traction substation loads.
基金Project(51875481) supported by the National Natural Science Foundation of ChinaProject(2682017CX011) supported by the Fundamental Research Foundations for the Central Universities,China+2 种基金Project(2017M623009) supported by the China Postdoctoral Science FoundationProject(2017YFB1201004) supported by the National Key Research and Development Plan for Advanced Rail Transit,ChinaProject(2019TPL_T08) supported by the Research Fund of the State Key Laboratory of Traction Power,China
文摘The impulsive components induced by bearing faults are key features for assessing gear-box bearing faults.However,because of heavy background noise and the interferences of other vibrations,it is difficult to extract these impulsive components caused by faults,particularly early faults,from the measured vibration signals.To capture the high-level structure of impulsive components embedded in measured vibration signals,a dictionary learning method called shift-invariant K-means singular value decomposition(SI-K-SVD)dictionary learning is used to detect the early faults of gear-box bearings.Although SI-K-SVD is more flexible and adaptable than existing methods,the improper selection of two SI-K-SVD-related parameters,namely,the number of iterations and the pattern lengths,has an adverse influence on fault detection performance.Therefore,the sparsity of the envelope spectrum(SES)and the kurtosis of the envelope spectrum(KES)are used to select these two key parameters,respectively.SI-K-SVD with the two selected optimal parameter values,referred to as optimal parameter SI-K-SVD(OP-SI-K-SVD),is proposed to detect gear-box bearing faults.The proposed method is verified by both simulations and an experiment.Compared to the state-of-the-art methods,namely,empirical model decomposition,wavelet transform and K-SVD,OP-SI-K-SVD has better performance in diagnosing the early faults of a gear-box bearing.
基金This work was supported by the National Natural Science Foundation of China(Grant Nos.52022083,51775453,and 51735012).
文摘The traction motor is the power source of the locomotive.If the surface waviness occurs on the races of the motor bearing,it will cause abnormal vibration and noise,accelerate fatigue and wear,and seriously affect the stability and safety of the traction power transmission.In this paper,an excitation model coupling the time-varying displacement and contact stiffness excitations is adopted to investigate the effect of the surface waviness of the motor bearing on the traction motor under the excitation from the locomotive-track coupled system.The detailed mechanical power transmission path and the internal/external excitations(e.g.,wheel–rail interaction,gear mesh,and internal interactions of the rolling bearing)of the locomotive are comprehensively considered to provide accurate dynamic loads for the traction motor.Effects of the wavenumber and amplitude of the surface waviness on the traction motor and its neighbor components of the locomotive are investigated.The results indicate that controlling the amplitude of the waviness and avoiding the wavenumber being an integer multiple of the number of the rollers are helpful for reducing the abnormal vibration and noise of the traction motor.
基金National Natural Science Foundation of China(Grant Nos.52022083,51775453,and 51735012).
文摘The locomotive traction motor is described as a rotor-bearing system coupling the kinetic equations of the traction shaft and its support bearings with the determination of their elastic deformations in this study.Under the effect of excitations induced by the dynamic rotor eccentric distance and time-varying mesh stiffness,the elastic structure deformations of the shaft and support bearings are formulated in the vibration environment of the locomotive.In addition,the nonlinear contact forces between the components of the rolling bearing,the lubricating oil film,and radial clearance are comprehensively considered in this study.The results indicate that the elastic deformations of the shaft and bearings can change the dynamic responses of the traction motor and its support bearings.There are large differences between the ranges of the rotor motion calculated by the rigid and the flexible traction motor models when the intensified wheel-rail interaction is considered.With the increase of the rotor eccentricity,the results underscore the role of the elasticity of traction shaft and support bearings in dynamic researches of the traction motor.The critical value of the initial eccentric distance for the rub-impact phenomenon decreases from 1.23 mm to 1.15 mm considering the flexible effect of the shaft and bearings.This dynamics model of the traction motor can provide more accurate and reasonable simulation results for correlational dynamic researches.
文摘While modeling a power supply system for an electric railway traction, knowing equivalent circuits of locomotives supplied this way is an essential issue. In alternating current traction, it is important to diagnose inter alia processes taking place in transformers installed on electric vehicles. This article presents specific phenomena occurring during the work of mono-phase, multi-winding, multisystem （systems AC： 50 Hz, 16.7 Hz） laboratory traction transformer. It also shows difficulties encountered during the process of identifying multi-port equivalent scheme＇s elements of the described device, in which a construction defect occurs.
文摘The paper presents a mathematical model ofbrushless DC machine induced by permanent magnets. Its construction uses the classical model of permanent magnet synchronous machine and induced model of power inverter using the serraphil form. The results of the computer simulation were presented for such states： startup, work under active constant load and the behavior of the machine in terms of exponential and stepping change of the power inverter＇s control angle.
基金supported by the National Natural Science Foundation of China (Grant Nos. 52022083, 51775453, 51735012)
文摘Wear is a major cause of bearing failure,however,compared with other impact failures,smooth wear is often neglected because of its slow gradualness.In a locomotive,under the effect of the intensified wheel-rail interaction and gear mesh,the surface wear can increase the radial clearances of motor bearings,trigger abnormal vibration and noise,and adversely affect the efficiency and safety of the traction motor.In this study,considering the mechanical structure of the traction motor,a locomotive-track spatially coupled dynamics model with traction power transmissions(LTMM)is adopted to provide accurate dynamic loads and obtain the dynamic responses of the system.From the perspective of contact stress and relative skidding at the roller-race interface,the causes and evolution of motor bearings surface wear are analyzed.The results indicate that the wear of inner races of motor bearings is uniform.The outer races of the driving/non-driving end bearings(DB or NDB)are worn in the loaded/main loadbearing regions.The increasing surface wear can increase the internal dynamic forces(e.g.,the centrifugal force of rotor and unbalanced magnetic pull)induced by the instantaneous eccentricity of the rotor,intensify the interactions between the roller and races,and deteriorate the vibrations of the traction motor and its neighboring components in the locomotive.In addition,the effects of the friction coefficient at the roller-race interface and track random irregularity are analyzed.This study offers a theoretical basis in service life prediction and design of the motor bearings.
