an electric motor has a wound rotor having a shaft , a rotor core , a commutator and windings wound about the rotor core and connected to the commutator . the motor has a stator confronting the rotor ; brush gear electrically connecting the commutator to motor terminals ; first and second bearings for rotatably supporting the rotor , and an oil collector 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 . the oil collector is of high temperature material , preferably a metal such as brass , aluminum and steel . the oil collector returns the collected oil to the first bearing .