A novel motor design methodology and optimization is proposed, which is applied to a SRM. It greatly reduces the finite element analysis use. A multi physics study is realized in order to couple the thermal, magnetic and electric motor analysis. Then, the information obtained with this study allows creating different behaviors maps in order to evaluate the motor in all operating area. With the joule and iron losses, the thermal network obtains a temperature map for each current and angular speed. Then, the electric model uses the parameters obtained on reluctances network and the phase resistance variation obtained on thermal lumped parameter. Finally, the optimal motor obtained is validated on FEA. To sum up, the motor design is obtained using multi physics analysis taking into account different operating points, i.e. it is a range operation optimization. In addition, reducing FEA computation time is achieved with the methodology proposed.