Patent GB-1162718-A (GB)
Title: Motor with Multiplex Wave Wound Disc Armature
IPC: H02K23/54
Filed: 1966-12-01
Abstract: 1,162,718. Dynamo-electric machines having planar airgaps. DURA CORP. 1 Dec., 1966 [27 Dec., 1965], No. 53888/66. Heading H2A. A disc armature motor includes a wave winding on the disc armature having at least four layers of conductor segments, and commutation means electrically connected to the winding, the winding and the commutation means being of multiplex form and providing more than two current paths through the winding. Preferably, the winding comprises four layers of generally radially extending conductor segments, the conductor segments being identical and arranged in identical patterns in each layer, the span of one turn being an odd integer, and the number of pole pairs being an even number when the multiplicity factor (i.e., duplex, triplex &c.), is an even number and being an odd number when the multiplicity factor is an odd number. The Figure shows schematically an eight-pole, duplex, singly re-entrant, retrogressive, wave wound disc armature. The radially-extending lines represent generally-radially-extending conductor segments of substantial width mounted in four axially-spaced parallel planes forming four layers, separated by insulating material. The heavy lines represent conductor segments in the front outside layer on which commutation is directly effected, and are thus shown connected to a symbolic commutator ring 180 engaged by four brushes 182 to 188. The brushes are located on the pole axes 190. Four current paths are established in the winding: between positive brush 182 and negative brush 188; negative brush 188 and positive brush 186; and so on back to brush 182. For this preferred construction, an equation relating the number of pole pairs, the span number (n) of one turn, the winding multiplicity factor (m), and the total number of armature conductor segments in all layers, must be satisfied, and in the equation the winding multiplicity factor (m) must have a negative sign for a progressive winding but a positive sign for a retrogressive winding. Also, the winding is singly re-entrant if n is not divisible by m, and is multiply reentrant, with the number of re-entrances equal to m, if n is divisible by m. Though the conductor segments are arranged in identical patterns in each layer, the inside layers are reversely positioned relative to the outside layers. Connections are made sequentially between a segment in one layer and a segment in another layer in the following order: front outside layer, rear outside layer, rear inside layer, front inside layer (Fig. 3, not shown). The total number of armature conductor segments is 140. In another example the motor again has eight poles, and the conductor segments are again arranged, retrogressive, duplex winding commutated by four brushes, but the total number of conductor segments is 60. In a further example, the motor has ten poles, and 96 conductor segments arranged in four layers in a triply re-entrant, retrogressive, triplex winding commutated by four brushes. The invention relates to axial air-gap motors, having permanent magnet stators, of the type described in Specification 1,072,991.