Loss-at-source thermal modelling in salient pole alternators using 3-dimensional finite difference techniques

A method of calculating the temperature rise in the core, conductors, insulation, and cooling air of the stator and rotor of a salient pole alternator is described, with emphasis on the development of a finite-difference model of sufficiently reduced complexity to allow reasonably economic computation. The electrical losses arising in each metal element of the 3-D mesh are derived from loss-at-source computations described elsewhere, while thermal properties and convection coefficients are obtained by experiment or from standard characteristics. The results of temperature rise predictions are presented and compared with measured values