Cogging torque prediction by superposition of torque due to pole transition over slot

In this paper, an effective method for predicting cogging torque developed in high precision permanent magnet motors used in data storage devices is presented. The torque component due to transition of magnet polarity over slot opening is studied in details, numerically and analytically, to gain in depth understanding of the torque development mechanism. The resultant cogging torque has good agreement with numerical simulation by finite element methods