Patent GB-219015-A (GB)
Title: Improvements in and relating to the armature windings of dynamo electric machines
IPC: H02K27/02
Filed: 1924-07-10
Abstract: 219,015. British Thomson-Houston Co., Ltd., (Assignees of Compose Franþaise pour l'Exploitation des ProcÚdÚs Thomson- Houston). July 10, 1923, [Convention date]. Void [Published under Sect. 91 of the Act]. Windings. - An armature winding for dynamo-electric machines, and particularly for alternating-current commutator motors, comprises two separate windings interlaced with one another and so connected to the commutator that adjacent segments belong to different windings, equipotential connections being made between points on one winding at one end of the armature and points on the other winding at the other end of the armature. The windings provide a double drum system having the characteristic of a simple ring winding that the voltage between adjacent commutator segments is that induced in a single conductor. Fig. 1 shows a bipolar machine having an even number of sections in two layers 1, 2, 3 - - 12 and 1<1>, 2<1>, 3<1> - - 12<1> forming two separate windings 1, 6<1>, 11 - - 8<1> and 2, 7<1>, 12 - - 9<1>, shown in full and dotted lines respectively, interlaced and connected to alternate commutator segments. Equipotential points in the two windings, such as the junctions of conductors 1, 6<1> and 7<1>, 12 or 6<1>, 11 and 12, 5<1> may be connected, a point in one winding at one end of the armature being always connected to a point in the other winding at the other end. To ensure that the connected points are magnetically symmetrical, the number of slots per pole is made integral and the field form under the two poles is identical. The equipotential connecting plates may be placed on a low-permeability or non-magnetic spider, between the arms of which the connections pass and the arms may be surrounded by closed conducting spirals for magnetic screening. For small machines in which the plates are directly fitted to the shaft, holes are bored in the plates adjoining the shaft for the passage of the equipotential connections. The Specification also describes a bipolar sixslot winding with three sections in both ranges of each slot of similar nature to the winding shown in Fig. 1. For multipolar windings the number of winding sections per pole and the number of slots per pole must both be integral. If b be the number of sections per pole, for a series-parallel wave winding, a uniform pitch of either b+1 or b-1 is employed and in an interlaced multipolar winding alternate positive and negative winding pitches are employed with a corresponding displacement which is always the same and equal to either +1 or -1. Thus, the pitches would be b-1 and -(b+1) or b+1 and -(b-1). Fig. 9 shows a 4-pole, 16-slot, series-parallel winding with one section per slot, i.e. in which b-1 = 3. Two kinds of equipotential connectors may be used simultaneously, viz., (i) those joining points at opposite ends of the armature, and located under unlike poles, such as the junctions of conductors 1, 4<1> and 5<1>, 8; and (ii) those joining points under like poles, such as the junctions of conductors 4<1>, 7 and 12<1>, 15 or 1, 4<1> and 9, 12<1>, these being of the ordinary type located at one end of the armature. The Specification also describes a 4-pole, 16-slot interlaced winding with one section per slot and alternate positive and negative winding pitches of value 3 and 5, this giving a winding with eight paths and adapted for two kinds of equipotential connectors as described in connection with Fig. 9.