The eddy-current damping of synchronous machines with solid cylindrical rotors

This thesis is concerned with calculating the eddy-currents losses and their associated damping which are induced in the solid conducting parts of synchronous generators when they are subjected to abnormal operation. Eddy-current flow in solid rotor is presented in two dimensions and solutions, which are obtained in terms of one component of magnetic vector potential, are sought for the case where the surface of the rotor is subjected to a time-varying sinusoidal field. A theoretical investigation has been carried out on the eddy-current damping in a cylindrical screen in superconducting generators. Solutions are obtained, in two dimensions, for different screen parameters. Experimental investigations of eddy-current damping for two different rotors are presented. The eddy-current damping is calculated with different rotors configuration. In this study it is found that the best method for measuring the damping is the logarithmic decrement method. A numerical finite element technique which is available as an electromagnetic package called PE2D has been used to obtain the eddy-current loss and its distribution in the superconducting screen model. The same method has been used to study the effect of slots, wedges and damper strips on the eddy-current loss and its distribution in solid rotors of conventional design.(DX89577)