Carbon Brush Belt Sander 1200W PBS12001-SP-53 [INGCO]

Carbon brushes work by reducing the damage to the motor.
Also by arrying the current back and forth between the stationary and moving parts of the motor.
Sold by pair in our retail shop Brickhardware in Port Louis
Function
Electrical current is transmitted from the rotating shaft via contact with the carbon brush.  The contact spots should be evenly distributed on the surface of the brush to maintain brush balance and avoid damage to the commutator/slip ring surface.
 
How are Carbon Brush maintained?
Look at  carbon brush stability. 
Check the clearance between brush holders and the brush to ensure it is stable and slides properly.
Check the distance between the brush holder and commutator slip ring
Ensure the brush holder is adjusted correctly and at the proper angle.
Check whether commutator wear and the presence of copper dust.
Dust leads to high brush wear, machine pollution, grooving of commutators/slip rings and brush side gulling. The best way to prevent this is with regular motor cleaning to ensure air filters provide clean air to the motor.