Winding Factor Equation for Main Pattern of Single-Layer Fractional-Slot Distributed Windings

The winding factor is important to compare windings, to estimate the performance of electrical machines and to find the origin of electromagnetic NVH excitations analytically. Besides the available calculation methods, it is applicable to find calculation equations valid for the winding factor of all spatial harmonics in the case of symmetrical windings. There are such calculation equations for integral-slot and double-layer fractional-slot windings. However, there is no valid equation for single-layer fractional-slot distributed windings. This article reviews the already suggested equations in literature in a coherent notation and then derives a new one for the most applicable single-layer fractional-slot distributed windings.