Analytic calculation of turbo generator end winding inductances using Neumann’s formula

This paper presents an analytic method to determine the end winding inductances of turbo generators. The model of the end winding, to which the inductance calculation using Neumann´s formula is applied, consists of the stator coils and the exciter winding in the rotor. In the model, both the stator bars and the rotor bars are replaced by serially connected straight filaments. The effects of field affecting components in the end face of the active component of the machine are considered by adopting two different approaches, where on the one hand tangential and on the other hand perpendicular flux is assumed. Virtual air gap conductors are used in order to consider the field characteristics in the area near the air gap. Regarding these additional conductors the inductances calculated are considerable larger than those without consideration.