Reduction of cogging torque helps in reducing the motor noise generated due to electromagnetic causes.

Shape of Magnet

• Magnet shaping will change the airgap flux profile and hence the harmonics.
• Elimination or reduction of certain harmonics will lead to lower cogging torque.

Size of Slot Opening

• Smaller slot opening offers lower change in magnetic circuit reluctance and hence reduce the cogging torque.

Number of Pseudo Slots

• Pseudo slots increase the effective number of teeth as seen by airgap flux.
• Number of pseudo slots per tooth resulting in fractional slot/pole system help to lower the cogging torque.
• Mechanical stability and production feasibility need to be considered while deciding the number of pseudo slots and its dimensions.