To design actuators or motors requires analyzing a lot of parameters such as length, temperature, efficiency, weight, etc. To obtain the optimum results for given specifications the solution is to analyze globally all the free parameters in one go, with an optimization algorithm based on the "Prodesign" software which includes an optimization module developed by INPG in Grenoble (France). A comparison between the parametrical study and the finite element design is made with two different examples. The first one is a reluctance actuator and the second one is a brushless DC motor intended for a new intra-cardiac blood pump