Patent ID: 7800266

Claim:
An electric motor comprising: a wound rotor having a shaft, a rotor core, a commutator and windings wound about the rotor core and connected to the commutator; a stator confronting the rotor; brush gear connecting the commutator to motor terminals; first and second bearings for rotatably supporting the rotor, and; an oil stopper fitted to the shaft between the commutator and the first bearing for preventing oil migrating along the shaft from the first bearing reaching the commutator; wherein the oil stopper has a body portion for fixedly mounting to the shaft and an oil collecting portion and is of high temperature material; wherein the oil collecting portion of the oil stopper extends radially outwardly from the body portion and has an annular cavity with an opening facing towards the first bearing, where the opening is spaced from the shaft and the diameter of the outer edge of the opening is greater than a diameter of a radially outer surface of the bearing.