A rotor assembly with a cooling mechanism having first and second channels is provided. The rotor assembly includes a shaft having a hollow portion and a rotor core having at least one rotor stack positioned at least partially around the shaft. The rotor core has a first end and a second end. The rotor stack forms an interior cavity which is only partially filled with a permanent magnet so as to define a gap in the rotor stack. The first channel is configured to direct fluid flow in a generally radial direction from the hollow portion of the shaft. The second channel is at least partially defined by the gap in the interior cavity of the rotor stack and is configured to direct the fluid flow from the first channel to at least one of the first and second ends of the rotor core.