Material Properties and Natural Frequency of Stator Core of Large Turbo-Generator

Techniques for vibration reduction and design of stator core require knowledge of its modal frequencies, which depend on the geometry shapes, dimensions and material properties. The material properties of stator core are mainly related to its laminated process and assembly as well as the operating temperature of turbo-generator. It is found that the generally accepted value of material properties is not valid for the stator core with laminated silicon steel slice and operating at about 110-120 Celsius. This paper simply summarizes the method of determining elastic properties of stator core material, considers these as uncertainty variables obeying Gaussain distribution and changing in the possible range, and then applies to Six Sigma Analysis method for the calculation of the modal frequencies of stator core.