Computation of end-winding inductances of rotating electrical machinery through three-dimensional magnetostatic integral FEM formulation Flavio Calvano Dip. di Ingegneria Elettrica, Universita ` di Napoli “Federico II”, Naples, Italy Giorgio Dal Mut and Fabrizio Ferraioli Ansaldo Energia, Genova, Italy Alessandro Formisano Dip. di Ingegneria Industriale e dell’Informazione, Seconda Universita ` di Napoli, Aversa (CE), Italy Fabrizio Marignetti Dip. di Ingegneria Elettrica e dell’informazione, Universita ` di Cassino e del Lazio Meridionale, Cassino, Italy Raffaele Martone Dip. di Ingegneria Industriale e dell’Informazione, Seconda Universita ` di Napoli, Aversa (CE), Italy Guglielmo Rubinacci Dip. di Ingegneria Elettrica, Universita ` di Napoli “Federico II”, Naples, Italy, and Antonello Tamburrino and Salvatore Ventre Dip. di Ingegneria Elettrica e dell’informazione, Universita ` di Cassino e del Lazio Meridionale, Cassino, Italy Abstract Purpose – The paper aims to illustrate a numerical technique to calculate fields and inductances of rotating electrical machines. Design/methodology/approach – The technique is based on an integral formulation of the nonlinear magnetostatic model in terms of the unknown magnetization. The solution is obtained by means of a Picard-Banach iteration whose convergence can be theoretically proved. Findings – The proposed method has been used to build a model of a large turbine generator. In particular, the influence of end effects on flux linkages has been computed. It has been demonstrated that the 2D solution underestimates the flux linkages as well as the no load voltage of 2 per cent, while the leakage fluxes are computed by the 2D solution with errors as high as 20 per cent. Originality/value – The method is advantageous in comparison to standard methods. Keywords Numerical techniques, End winding inductances, Synchronous machine, Windings, Electrical equipment Paper type Research paper The current issue and full text archive of this journal is available at www.emeraldinsight.com/0332-1649.htm COMPEL: The International Journal for Computation and Mathematics in Electrical and Electronic Engineering Vol. 32 No. 5, 2013 pp. 1539-1551 q Emerald Group Publishing Limited 0332-1649 DOI 10.1108/COMPEL-04-2013-0135 Computation of end-winding inductances 1539