Special attention should be paid to the installation and operation of carbon brush holders, as the correct installation and use of carbon brushes determine their service life. The distance between the lower edge of the carbon brush holder and the surface of the commutator or collector ring should be maintained within a range of 2-4 millimeters. If the distance is too small, the brush holder is prone to scratching the commutator or the collector ring is too large. Carbon brushes are prone to shaking and causing damage. Ensure that the carbon brush operates within the surface of the commutator or collector ring and does not approach the edge of the collector ring. If the carbon brush is installed improperly in a cold state, the carbon brush may not fully contact the surface of the collector ring after the motor shaft expands in a hot state. Grind the curved surface of the carbon brush to match the commutator or collector ring.
Due to the gap between the electric brush and the carbon brush holder, as well as the slight deformation of the fixed components of the carbon brush holder (such as the brush rod) under stress, the curvature radius of the electric brush section will be slightly larger than that of the commutator or collector ring. Therefore, during the operation of the motor, not all of the cross-sectional area of the electric brush is in contact with the commutator or collector ring, but only a part of the area. Therefore, it is necessary to perform arc grinding on the carbon brush to make it basically match the commutator or collector ring. In practical operation, the contact area between the arc surface of the electric brush and the commutator or collector ring should not be less than 75% of the cross-section of a single electric brush.
