Stack of laminations for a stator having cooling channels

A method for operation of an electric machine cooling system, comprising:

• operating an oil pump to generate a turbulent flow of oil through a plurality of oil channels in a stack of a plurality of stator laminations that are located radially outward from a plurality of teeth in the plurality of stator laminations;
• wherein each of the plurality of oil channels are formed by sequentially arranged holes in the stack of the plurality of stator laminations;
• wherein three or more of the sequentially arranged holes a different shape and/or area;
• and
• wherein two or more of the sequentially arranged holes have radially offset positions.

An electric machine cooling system comprising:

• a stack of a plurality of stator laminations with a first portion of the plurality of stator laminations each including a plurality of holes that are arranged radially outward from a plurality of teeth, wherein the plurality of holes includes:
• a first set of holes and a second set of holes having different areas;
• and
• a third set of holes having a different radial position in relation to the second set of holes;
• wherein a plurality of oil channels are formed by an alignment of holes in adjacent stator laminations in the first portion of the plurality of stator laminations;
• and
• wherein a second portion of the plurality of stator laminations have a smaller outer diameter than the first portion of the plurality of stator laminations and form an inlet to the plurality of oil channels.