The use of aluminum (Al) alloy substances is analyzed in this paper in order to obtain a lighter and less costly winding design without dimensional changes in electrical machines. The determination of aluminum alloy winding material, which has an electrical conductivity close to that of copper (Cu) but has a lower density, is the basis of this study. In this context, various aluminum alloy substances have been investigated. Windings with these aluminum alloy materials for a 300 kVA synchronous alternator have been modeled with the Ansys Maxwell 2D software program. The performances of tempered and annealed alloy windings have been analyzed with respect to that of a copper winding. The analysis results show that the aluminum winding losses are close to copper winding losses under nominal operating current values. Among the aluminum alloy winding models, aluminum 1350 and aluminum 2041 have the closest loss values. On the other hand, there is very little difference between aluminum alloy windings in terms of winding weight, while the weight of the aluminum winding is 70% lower compared with that of the copper winding. It is suggested to wind turbine manufacturers that windings be formed with the aluminum 1350 and aluminum 2041 series to provide performance comparable with that of copper windings.