GB889420A - - Google Patents

Abstract

889,420. Interaction pumps; linear motors; winding layouts. ENGLISH ELECTRIC CO. Ltd. June 3, 1958 [June 4, 1957], No. 17803/57. Class 35. In a polyphase linear or arcuate motor or interaction pump the ends of the wound stator cores have a reduced number of slot windings to produce a graded reduction of M.M.F. and additional matching windings are provided at the points where the windings are reduced and, if desired, at the ends of the windings to prevent the abrupt changes in M.M.F. giving rise to pulsating flux components. The matching conductors produce alternating M.M.F.'s which maintain the magnitudes of the M.M.F.'s on either side of the junctions or ends substantially in proportion to the ampere-conductors per unit length of the core on either side of the junction, i.e. the working flux has a travelling component only. As shown for an interaction pump, in which the central portion of a distributed threephase winding has a whole number of poles, and the end portions a single pole wound with half the number of ampere - conductors per unit length, matching conductors 17, 18 serve to prevent flux pulsations at the junctions between the central and end portions, and matching conductors 19, 20, if these are employed, maintain the M.M.F.'s at the outer ends of the winding substantially at zero value. As shown, the matching conductors carry the current flowing in the third phase, those at 17 and 18 being in reverse, and their M.M.F. is equal to half the peak ampere-turns per pole produced by the central portion of the stator winding. In a modification, the conductors 17, 18, 19, 20 are replaced by conductors of all three phases. The matching conductors may be placed in special slots (not shown), or mutually cancelling conductors may be omitted to leave room in the existing slots. Grading may take place in several steps.