Abstract: A plug in commutator has a hub body (1) of nominally cylindrical cross section. Ribs (4) are formed on the circumferential periphery of the hub body (1) each rib extends longitudinally and is equiangularly spaced to define grooves (5). The ribs are of cylindrical section and so form substantially hour glass sectioned grooves (4). Each groove (4) accommodates a portion of a conductive segment (2) which has opposing radially extending surfaces oversized and shaped corresponding to the shape of the adjacent groove surfaces. At least a part (11) of the oversized portion is of swallow tailed shape to be resiliently deformable and is sized to leave a small gap 5' between the bottom of the groove and the bottom of the segment (2). The commutator is assembled by slotting a preformed segment (2) one into each groove (5). The resiliently deformable part acts to prevent displacement of the segment (2) and to relieve stresses imposed on the hub body (1).

Abstract: A method for assembling a high current commutator and winding to form an armature includes positioning end portions of pairs of conductors against a connection portion of a segment on the commutator. A support member is engaged with the connection portion while a connection member, such as an electrode or sonotrode, applies energy to fuse together the stack formed by the connection portion and the conductor ends together. The connection member and the support member are then disengaged from the stack after the stack is fused together. The apparatus for assembling the armature includes connection member and the support member. The support member confines the securing energies to the stack thus allowing the commutator segments, connection portions and a core of the commutator to be made lighter.