SWITCHED RELUCTANCE MOTORS (SRM) ARE ATTRACTING MUCH ATTENTION BECAUSE OF THEIR SPECIAL ADVANTAGES. GENERATED HEAT BY LOSSES CAN REDUCE THE LIFE TIME OF SRMS. THEREFORE, OPTIMAL DESIGN BASED ON THERMAL MODELING HELPS TO IMPROVED THEIR PERFORMANCE AND INCREASE THEIR LIFE TIME. IN THIS PAPER, A LUMPED THERMAL MODEL OF SRM IS BASED ON THE ANALOGUE OF CONDUCTIVE AND CONVECTIVE THERMAL RESISTANCES IS PROPOSED. THIS MODEL CAN BE USED TO DESIGN THE MOTOR OPTIMALLY AND INVESTIGATE THE INFLUENCES OF DIMENSIONS UPON THE PERFORMANCE.