Conductive grease has been considered as a potential solution in addressing electric erosion issue inside motor bearings.Understanding the conductive grease performance,especially the electric and tribological behavio...Conductive grease has been considered as a potential solution in addressing electric erosion issue inside motor bearings.Understanding the conductive grease performance,especially the electric and tribological behaviour is crucial for its application.This paper combines bulk grease characterization and contact film study considering both electrical and tribological loading conditions.The results show that the electric performance for the selected conductive grease sample is electric field dependent,including both frequency and voltage amplitude.Its film impedance inside the contact area is closely related to the external electric field,running condition,and lubrication regime.The following film impedance calculation tells that not only bulk grease electric parameters,but the contact parameter,lubricant film contour and lubrication condition should be considered when performing the overall bearing electrical modelling.展开更多
In modern rail transportation,inverter drive systems have been extensively used due to their excellent speed control capabilities.However,in recent years,premature failure problems caused by bearing voltage and curren...In modern rail transportation,inverter drive systems have been extensively used due to their excellent speed control capabilities.However,in recent years,premature failure problems caused by bearing voltage and current phenomena have been frequently reported in electric motors,with electrical bearing failures making up a considerable percentage.The purpose of this review is to provide a comprehensive overview of facets relating to the electrical erosion of bearings in an electrical environment represented by railway vehicles.First,the origins of the phenomenon as well as typical bearing electrical failure modes are discussed.Next,we introduce the distinctive features of the electrical environment of railway traction motor bearings,including output voltages with high common-mode components and systems with complex grounding configurations.Then,we classify the fundamental mechanisms for generating bearing voltages/currents into four groups,and present their modeling processes,including equivalent circuit establishment and parameter determination methods.Furthermore,we summarize the strategies frequently used to protect bearings,and describe a typical solution to suppress electrical bearing failures in railway vehicles.Finally,we present a case example to illustrate a research procedure for systematic investigation of inverter-induced bearing currents in rail transportation.展开更多
文摘Conductive grease has been considered as a potential solution in addressing electric erosion issue inside motor bearings.Understanding the conductive grease performance,especially the electric and tribological behaviour is crucial for its application.This paper combines bulk grease characterization and contact film study considering both electrical and tribological loading conditions.The results show that the electric performance for the selected conductive grease sample is electric field dependent,including both frequency and voltage amplitude.Its film impedance inside the contact area is closely related to the external electric field,running condition,and lubrication regime.The following film impedance calculation tells that not only bulk grease electric parameters,but the contact parameter,lubricant film contour and lubrication condition should be considered when performing the overall bearing electrical modelling.
基金supported by the National Key R&D Program of China(No.2018YFB1201804)the National Natural Science Foundation of China(Nos.52293424,51827810,and 51977192).
文摘In modern rail transportation,inverter drive systems have been extensively used due to their excellent speed control capabilities.However,in recent years,premature failure problems caused by bearing voltage and current phenomena have been frequently reported in electric motors,with electrical bearing failures making up a considerable percentage.The purpose of this review is to provide a comprehensive overview of facets relating to the electrical erosion of bearings in an electrical environment represented by railway vehicles.First,the origins of the phenomenon as well as typical bearing electrical failure modes are discussed.Next,we introduce the distinctive features of the electrical environment of railway traction motor bearings,including output voltages with high common-mode components and systems with complex grounding configurations.Then,we classify the fundamental mechanisms for generating bearing voltages/currents into four groups,and present their modeling processes,including equivalent circuit establishment and parameter determination methods.Furthermore,we summarize the strategies frequently used to protect bearings,and describe a typical solution to suppress electrical bearing failures in railway vehicles.Finally,we present a case example to illustrate a research procedure for systematic investigation of inverter-induced bearing currents in rail transportation.
