This paper, authored by Z. Q. Zhu and David Howe, investigates the influence of various design parameters on the cogging torque in permanent magnet machines. The study highlights that the combination of slot and pole numbers significantly affects the cogging torque, influencing the optimal skew angle, magnet arc, and the number of auxiliary teeth/slots. A factor, proportional to the slot and pole numbers and inversely proportional to their smallest common multiple, is introduced to indicate the "goodness" of the combination, with higher values generally corresponding to larger cogging torque. The paper also explores the impact of stator slot opening width, magnet thickness, magnetization distribution, skewing, and magnet disposition on cogging torque. The authors use analytical and finite element methods to predict cogging torque, providing insights into the optimal design parameters for minimizing cogging torque. Key findings include the preference for an odd number of slots in 2-pole motors and the importance of the magnet pole-arc to pole-pitch ratio in reducing cogging torque.This paper, authored by Z. Q. Zhu and David Howe, investigates the influence of various design parameters on the cogging torque in permanent magnet machines. The study highlights that the combination of slot and pole numbers significantly affects the cogging torque, influencing the optimal skew angle, magnet arc, and the number of auxiliary teeth/slots. A factor, proportional to the slot and pole numbers and inversely proportional to their smallest common multiple, is introduced to indicate the "goodness" of the combination, with higher values generally corresponding to larger cogging torque. The paper also explores the impact of stator slot opening width, magnet thickness, magnetization distribution, skewing, and magnet disposition on cogging torque. The authors use analytical and finite element methods to predict cogging torque, providing insights into the optimal design parameters for minimizing cogging torque. Key findings include the preference for an odd number of slots in 2-pole motors and the importance of the magnet pole-arc to pole-pitch ratio in reducing cogging torque.