Analytical calculus and computational models of multiphysics problems were used in order to solve an overheating problem and simultaneously increasing reactive power in a generator group of a hydroelectric power plant (HPP). All of them present the same geometrical, mechanical and electromagnetic characteristics. A method of iteration using finite elements analysis (FEA) called simplified virtual laboratory (SVL) was used to find a solution from an accurate, reliable and fast process. Models of electromagnetics, computational fluids flow (CFD), heat transfer and stress analysis were done. Finite elements models were used to evaluate different aspects and to develop the final solution