Interior Permanent Magnet Synchronous Motor (IPMSM) produces two kind of torque that Magnetic and Reluctance torque. The permanent magnet linkage flux ${Psi}_a$ and d-axis and q-axis inductances have an important influence on the torque characteristic of IPMSM. Thus their accurate prediction is essential for predicting performance aspect such as the torque and flux-weakening capabilities. In this paper, the influence of barrier width on the ${Psi}_a$ and $L_d$, $L_q$ is calculated by FEM analysis. Predictions are validated by comparison the average torques, using Maxwell Stress Tensor method.