*2.3. Main Dimensions*

Referring to Figure 1 and Table 1, the maximum value of outer diameter (*Do*) and maximum value of axial length (*L*) are obtained from space constraints. Shaft diameter (*Dsh*) is obtained from the shaft's standard sizes that are based on output torque value. The values of outer diameter (*Do*) and axial length (*L*) can be changed during design within their maximum values. However, keeping them at their maximum values results in the maximum output torque of SRM design. The shaft diameter (*Dsh*) is kept constant during design process. The air gap length (*g*) is assumed to have the commonly used value of 0.5 mm that can be obtained often in practical implementation. The rest of the dimensions are modified to reach the requirements of design.

#### *2.4. Variables Dimensions Limits*

The limits of variables are determined by the application and the available space. In this paper, outer diameter (*Do*), axial length (*L*), shaft diameter (*Dsh*), and air gap length (*g*) are kept constant by making their maximum and minimum limits at the same value. The remaining limits are set by the previous experience. Table 2 shows the maximum and minimum limits values of all the variables.

**Figure 1.** The lamination dimensions considered in the optimization process.



**Table 2.** Limits of variables.

