A wedge placed between adjacent coils in a generator comprises a wedge body having a generally triangular portion to be positioned at a radially inner location, and a radially outer portion. The radially outer portion includes ends that will be spaced at axial ends of the wedge when the wedge is positioned within a generator. The ends have a first surface spaced a first distance from an apex of the triangle. The end walls extend above the first surface at each of two spaced positions axially inwardly of the ends of the wedge. The end walls are connected to side walls that extend near circumferential edges of the wedge. An open pocket is formed within the wedge body at locations between the side walls and axially between the end walls.