Low pressure drop lattice area reinforcement for section plate support for cores of generators

Section plates in a generator frame are spaced longitudinally or axially one from the other and have ventilation openings for flowing a cooling gas. The ventilation openings comprise in each section plate a plurality of alternating right-side-up and upside-down triangles extending across the bottom of the section plate. The bases of the triangular openings are formed by the housing or wrapper plate enabling free flow unbounded by additional ligaments through the openings in the section plate, reducing the pressure drop and windage losses, while increasing machine efficiency.