Effect of Motor Design Parameters on Cogging Torque – Part 2
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.