Brush Wear Process Involved by Arc Discharge during Commutation Process in Fuel-Immersed DC Motor: Brush Development for Attaining Low Wear Amount

Regarding an experimental DC motor equipment immersed in ethanol or gasoline, driving the motor in ethanol proved to raise the arc energy occurred after the commutator separation and to cause large amount of brush wear. Furthermore, the wear mechanism was found from observation of the brush sliding-surface with a scanning electron microscope as follows: first, the brush binder was damaged due to arc discharge and graphite particles were subsequently released from the binder part. As a solution method for reducing the amount of the brush wear, we paid the attention to the binder material in consideration of various properties and then developed the brush employing thermal plastics as the material.