Analysis On Stator-rotor Loss And Temperature Characteristics In Generators Under 3D Static Air Gap Eccentricity

Air gap eccentricity is one of the common mechanical failures of generators.If the eccentricity is small,it will not affect the normal operation of the generator.If the radial eccentricity exceeds 10%,it will affect the normal operation of the generator.In severe cases,the motor will be destroyed The paper,the temperature as well as the core loss variations of the stator and rotor core before and after the radial rotor eccentricity,the axial rotor eccentricity,and the hybrid rotor eccentricity of synchronous generator are detailed studied.The research results of this paper reveal the influence of 3D static air gap eccentricity fault on the stator and the rotor core temperature,which will be beneficial for the preventive insulation manufacturing process of generator windings in actual production.In the meantime,it can also lay a foundation for the monitoring on the radial rotor eccentricity,the axial rotor eccentricity,and the hybrid rotor eccentricity.The paper primarily focuses on three aspects: theoretical analysis,ANSYS numerical simulating calculation and experiment verification.First,the hysteresis loss and the eddy current loss under normal conditions and three types of eccentricity cases are analyzed,and the loss expressions for each working condition are derived,respectively.Then the three-dimensional finite element model of the CS-5 generator is established to calculate the loss and the temperature change of the stator and the rotor cores under different conditions.Finally,the stator and the rotor core temperatures under the three types of air gap eccentric cases were measured on the CS-5 fault simulation generator.The finite element calculation data and the experimental results generally follow the theoretical analysis.It is shown that the temperature of the stator and the rotor core under the radial eccentricity is higher than that in normal condition.With the increase of the radial eccentricity,the temperature will be also increased.However,the axial eccentricity will generally decrease the stator and the rotor temperature.The severer the axial eccentricity is,the more the temperature will be decreased.In the case of the 3D hybrid eccentricity,the temperature changes little,but still presents an increasing trend.