THREE-PHASE DOUBLE-LAYER FRACTIONAL-SLOT (Q=15/13) LAP WINDING FOR ELECTRICAL MACHINES

FIELD: electrical and electromechanical engineering; three-phase squirrel-cage induction motors and synchronous generators. ^ SUBSTANCE: proposed three-phase double-layer symmetrical fractional-slot winding has number of slots per pole per phase q = 15/13 of 6p = 78c coil groups; it is 2p = 26c lap winding placed in z = 90c slots. Coil groups are numbered 1G through 78G (c), coils being grouped in number series 2 1 1 1 1 1 2 1 1 1 1 1 1; slot pitch ys = 4; even-numbered groups of each phase are differentially connected to odd-numbered ones. Groups 1G through 13G of first of similar groupings repeating 6c times have coil turn number (1 - x)wc for double-coil groups 1G and 7G, (1 - x)wc for groups 4G, 10G, 11G, and wc for remaining groups with starts of phases I, II, III running from starts of groups 1G, 27G, 53G, respectively, where c = 1 and 2; wc is turn number in completely filled up slot at optimal value of x = xopt = 0.32. ^ EFFECT: improved harmonic content of mmf and reduced differential dissipation. ^ 1 cl, 4 dwg