Experimental Determination of Conductor Lay and Impact on AC Loss in Volume Manufactured Machines using X-Ray Computed Tomography

The volume manufacture of power-dense electrical machines results in a random conductor lay throughout the stator winding and stator slots, which is unknown and varies from slot-to-slot. The AC losses of such windings are sensitive to the specific conductor lay present within the stator slot. However, limited data is currently available regarding the actual conductor lay observed in ‘as manufactured’ windings. This paper presents the novel application of X-ray Computed Tomography to characterize the conductor lay in a wound prototype plastic stator. Preliminary results indicate that limited strand transposition occurs in the stator active length, compared to the significant strand transposition present in the end winding region. Variability in strand compaction in the stator slot is also identified as a contributary factor to the variability observed in AC losses.