Investigation on excessive commutator and brush wears in DC traction machines

The paper presents an experimental investigation on excessive brush and commutator wear in DC traction machines. An advanced computer measurement system is employed for data acquisition so that all measured data are recorded continuously in revenue raising services. The measured parameters include the mechanical vibration of the motor and its carbon brushes, a video camera image of sparking at the brush-commutator interface, transient currents of armature winding and carbon brushes. The paper reveals the relationship between harmonic currents and mechanical vibrations in DC traction motors. It concludes that the mechanical resonance of a motor at a certain locomotive speed is a major cause for the excessive brush and commutator wear.