Patent ID: 8593021

Claim:
A gravity-fed coolant drainage system comprising: an electric machine including a rotor substantially circumscribed by a stator and an air gap defined between the rotor and the stator; a module housing including a first axial end and a second axial end, an inner wall and at least one end cap, the module housing least partially defining a machine cavity and at least partially enclosing the electric machine within the machine cavity; a drain pan coupled to the module housing and including a drain outlet the drain pan configured and arranged to permit liquid coolant to flow toward the drain outlet, the drain pan extending across a region radially outward from each axial end of the stator to near the first axial end and the second axial end of the module housing; a first set of drain holes extending through the module housing and located near the first axial end of the module housing, the first set of drain holes in fluid communication with the machine cavity and the drain pan, the first set of drain holes angularly spaced apart along the first axial end of the module housing; and a second set of drain holes extending through the module housing and located near the second axial end of the module housing, the second set of drain holes in fluid communication with the machine cavity and the drain pan, the second set of drain holes angularly spaced apart along the second axial end of the module housing, the first set of drain holes and the second set of drain holes angularly spaced apart along an angular span of the module housing to provide gravity-fed drainage paths from the machine cavity over a range of rotation of the module housing so that a liquid coolant pooling level inside the machine cavity remains below the air gap.