This paper presents sizing approaches to improve output torque performance in PM motor when partial stator body is removed. As the output torque performance is directly proportional to the electric loading, Q, modification on stator geometry affects the output torque performance and special procedures have to be taken to restore the desired output torque capability. Influences of split ratio, tooth body width, airgap and magnet thickness of  magnet in PM motor with asymmetry stator design are carried out and the performance verification are referred to the back-emf, average output torque, torque ripple as well as cogging torque. From the investigation using 2D-Finite Element Analysis, optimum size of tooth body width and optimum number of coil turns result better output torque while other sizing approaches result no significant change as quick saturation took place.

This article presents the simple basic sizing approaches to decrease overall weight of motor and improve magnetic characteristics in PM motor. A review on various stator design in PM motor i.e. radial-flux or axial-flux with slotted or non-slotted is presented. As magnetic and electric loading influence the electromagnetic motor performance, modification on stator body are included in investigation for a desired electromagnetic torque performance. Influences of tooth body width sizing and additional stator slots sizing in PM motor equip with hemicycle stator design are carried out. Two designs are included, both having similar semi-circle stator but different in additional slot tooth within and over 180 ○ i.e. Design 2 and 3 respectively. For optimization using 2D-Finite Element Analysis, optimal tooth body sizing and additional stator tooth result the weight significantly reduce by 44%, 5.9 Nm output torque and 30% torque ripple.

<p>This paper presents a basic approach to reduce an overall weight of selected PM motor. The approach is not based on normal sizing step by keeping the overall design in symmetry dimension, but by introducing semi-circle stator design. The investigation takes 12-slot/10-pole motor as a subject due to it symmetric winding disposition. Two designs are included, both having identical semi-circle stator but different in rotor configuration. Design 1 has a standard rotor design that equipped with 10-pole while Design 2 has a semi-circle rotor design following the stator design. This inherently result an even number of pole i.e. 5. From the investigation using 2D-Finite Element Analysis, an overall weight in PM motor can be theoretically reduced by having asymmetric design dimension. However, motor torque performance would deteriorate and unwanted noise may exist due to high cogging torque and high output torque ripple. A proper design procedure that includes parameter optimization and intelligent switching for optimum current excitation is required to restore the desired torque.</p>