Serial Number

Description of work status

Effect evaluation

01

The working surface of the carbon brush is dense and bright

Operating normally

02

The working surface of the carbon brush is slightly loose

Operating normally

03

The working surface of the carbon brush has fine lines

May be affected by dust

04

The working surface of the carbon brush is textured and grooved

Low loads, or affected by dust and grease

05

Working face grooves and textures of carbon brushes

Low loads are more severe, and grease has a large impact

06

The working surface of the carbon brush is laminated

Incorrect commutator position leads to difficulty in commutation

07

The working surface of the carbon brush slides in or out with corrosion

Difficult rectification, large sparks, insufficient spring force

08

There are ablation marks on the working surface of the carbon brush

Overload or intermittent contact

09

The working face of the carbon brush is in layered contact

Motor winding causes voltage surge

10

The working face of the carbon brush has a double working face

Motor carbon brush installation tilt

11

Slip marks appear on the working surface of the carbon brush

Copper sintering, copper pulling phenomenon

12

The edges and corners of the carbon brush are damaged

The commutator is bulging, seriously misaligned, and the vibration is very large under light load or no-load

Illustrate: The appearance of the commutator, the normal operation of the carbon brush, and the formation of an oxide film on the surface of the commutator are more important. In a suitable working environment, an oxide film will be formed on the working surface of each carbon brush. 

The oxide film contains metal oxides, graphite deposits, and an appropriate amount of water. The working surface of the carbon brush and the appearance of the commutator are the basis for judging whether the motor is working normally. 

Usually, the oxide film on the rectifying surface is uniform and the color is slightly bright, from copper brown, black, blue and red, the most critical thing is the uniformity of the oxide film.