Staggered cooling holes for enhanced heat transfer in air-cooled motors

摘要

A method for fabricating a stack of motor laminations comprises forming cooling holes in each of the motor laminations and stacking the motor laminations with respective ones of the cooling holes in the laminations at least partially coincident to form a staggered cooling passage by having at least some of the cooling holes extending further into the cooling passage than others of the cooling holes. In one embodiment, the cooling holes can be perturbed cooling holes which are radially displaced from another cooling hole, azimuthally displaced from a hole axis, having an asymmetrical shape, being a different size from another cooling hole, or being shaped so that the rotation and stacking of a subsequently applied lamination results in a situation wherein adjacent cooling holes are not precisely aligned.