Resistive losses constitute a big part of the total loss in a generator, especially in low speed generators where frequency-dependent losses are low. The resistive losses in the winding are proportional to the length of the winding. In this paper, a computer-based program for generator design, using a two-dimensional finite-element method, is used to verify a theoretically-derived result, that the length of the armature winding is minimal for a specific generator geometry. A shorter armature winding might imply only a negligible improvement of the overall efficiency. The result of the computer-based design program is compared with the theoretically-derived results. A rough estimation of the relation between the length of the armature winding and the overall efficiency is included in the paper, as well as data from two existing generators. (C) 2005 Elsevier Ltd. All rights reserved.