Short-circuit Faults Analysis And Risk Prediction Between Laminations Of Large Motors Core

As the intelligent production industry enters a rapid development stage,the safe service and effective perception of products have become a critical issue now.Large-scale induction motor is one of the key component of the industrial manufacturing system,and its operational reliability will directly affect the safety and economy of the entire production line.As one of the main component of the motor,the stator core may cause a wide range of silicon steel sheets to burn out or even shutdown accidents once it fails,which is causing substantial economic losses and personnel dangers.Therefore,the accurate analysis of the degradation and failure status of the key structure of the motor,the prediction of the deterioration trend,the optimization of the structure and the establ ishment of a scientific and reasonable maintenance mechanism are the essential elements to ensure safety,improve service quality,and reduce maintenance costs.The fault mechanism between laminations and the main development modes in the gradual change process are studied,and an analytical calculation method that can calculate the electrical parameters of the core fault domain in the gradual change process under different failure development modes is proposed.Considering the skin effect of the alternating magnetic field in the silicon steel sheet,the analytical formula and the complex power expression of the silicon steel sheet magnetic field are derived,and the equivalent of the silicon steel sheet under the two development modes of initial failure and complete failure is established based on circuit theory.The eddy current loss and induced voltage composed of multiple laminated sheets in the fault domain are calculated,and the influence of the number of fault sheets on the electrical parameters of th e fault zone is quantitatively analyzed.Thoroughly consider the influence of frequency and magnetic flux on the skin depth perpendicular to the direction of punching and rolling,and make reasonable corrections to the original anisotropic conductivity and permeability calculation formulas.Moreover,a fast simulation method for inter-chip failures--Considering the homogenization modeling method of the core lamination under the short-circuit faults between laminations is proposed.A uniform and continuous structure of equivalent electrical conductivity and magnetic permeability in the macroscopic view is used instead of the actual laminations to construct a three-dimensional eddy current field calculation model for inter-chip failure;And calculate the resistance,axial conductivity,magnetic permeability,eddy current induced current,Conductivity,permeability,eddy current induced current and eddy current loss of the core fault domain in the gradual process under different fault development modes;comparison with the eddy current test results,Compared with the experimental results of eddy current testing,the rationality and applicability of the built simulation calculation model are verified.Analyzed the fault source of the silicon steel sheet in the fault domain,the environment and the working principle of the current motor sheet fault detection system.The detection method is a combination of low-frequency excitation and eddy current detection,and the ARM-based embedded system design is used as the background,using u IP for protocol Ethernet communication.Short-circuit faults between laminations detection system using LM3S8962 microprocessor is designed.The induced voltage in the core fault domain in the gradual process of different failure development modes is detected,and the analytical calculation method of induced voltage is verified experimentally.The influence of the axial thermal conductivity of the core fault domain in the gradual process under different failure development modes is stu died.Moreover,by using a combination of experimental detection and simulation calculation,the equivalent heat transfer model and three-dimensional temperature field model of the core fault domain are established;Calculate the axial thermal conductivity and temperature rise of the core fault domain in the gradual process under different failure development modes;Measure the temperature rise of the prototype under rated conditions to verify the accuracy of the model;The development trend of the temperature rise in the laminated fault domain and the harm to the winding insulation and the iron core laminated are discussed in depth.By studying the current fault state evaluation methods and maintenance mechanisms,a core failure degree evaluation and risk prediction mechanism based on trend prediction is proposed;Using the combination of potential risk prediction and reliability state intelligent perception,the gray prediction model and reliability state evaluation model for calculating the development tre nd of the electrical parameters of the core fault domain in the gradual process under different failure development modes are established respectively;Combining the data and simulation parameters provided by the enterprise,the current state of the core fault domain is classified into the fault diagnosis and the degree of fault,and the risk that may appear in the future is predicted,at the same time,it also provides a data reference for the enterprise to formulate a reasonable and effective maintenance mechanism.