Выпуск: 11 , Том: 17 , Год издания: 1981

A method of diagnosing and predicting the thermal condition of heat-liberating defects in the cores of stators of powerful generators based on mathematical treatment of test results in the absence of closed circuits in the laminations of the electrical steel of the cores with the use of the тА│StatorтА│ infrared images was developed. The problem of finding the temperature field of the core is solved by two methods, analytically without taking into consideration the piecewise-continuous character of the surface of the bore and numerically for the practically actual geometry of the core. The conditions of heat exchange corresponding to stand tests and steady service conditions are considered. An algorithm is proposed and its numerical solution on the computer for detection of defects in a large ferromagnetic cylinder with a piecewise-continuous boundary is given. The problem is solved by the finite-difference method for an equation of parabolic type with second-order boundary conditions. The results of calculations and measurements were approximated by spline functions and a defect is localized in comparison of these approximations.