FRACTIONAL-SLOT NINE-PHASE WINDING FOR AC ELECTRICAL MACHINES Russian patent published in 2004 - IPC

FIELD: electrical and electromechanical engineering. SUBSTANCE: proposed fractional-slot winding intended for nine-phase squirrel-cage induction motors of variable-speed ac drives supplied with power from semiconductor frequency changers is double-layer lap winding with m = 9 phases, m = 18 zones at q = 5/4 slots per pole per phase, 2p = 4 and p = 2 in z = 18pq = 45 slots. It has 18p = 36 coil groups of concentric coils placed in z = 45 slots arranged in row 2 11 1 and numbered 1G through 36G: with phase number m = 9 and zone number m = 2m = 18 double-coil groups 1G + 4(c) have slot pitch Yni = 9 and 7 with turn number w_c and (1-x)w_c; each coil of single-coil groups with slot pitch Yin = 8 has w_c turns for groups 2G + 4(c) and (1-x)w_c turns for groups 3G + 4(c). Series-interconnected in first phase are groups 1G, 10G, 19G, 28G with even-numbered groups differentially connected relative to odd-numbered ones, starting phase lead running from starting lead of group 1G and its finishing lead, from starting lead of group 28G; groups of each next phase are alternating at interval of 20 numbers within 36 groups relative to groups of first phase, where 2w_c is turn number in each phase, x = 0.20, and value c in coil group numbers varies in range of 0 to m 1 = 8. EFFECT: reduced differential dissipation due to eliminating conspicuous fractional-order harmonic component in winding mmf. 1 cl, 3 dwg