Abstract
DC motors with independent excitation, used in electric drives, are often controlled in classical way because of simplicity. In such case, field is maintained constant until the maximum voltage available. This paper underlines by simulation the potential gain given by an optimisation device that allows operation at reduced field for low torques and speeds. The DC drive train thus optimised becomes comparable to an optimised asynchronous one, if we don't take into account the problems due to the brushes. In order to establish by simulation such comparison, a DC and an AC motors were modellised and validated on test bench. Simulation results performed on actual use cycles are given in this paper.