1. Fair status:

Light film
The surface film of commutator is well-proportioned, which means the running status of generator and carbon brush is satisfactory, shade of colour of film is subject to depth of film, it should be well-proportioned

2. Fair status:

Dark black film
It shows commutator runs well, color of film is much more dark black than picture 1,and quite well-proportioned as well.

3. generic status:

Light dark sheet senary mark is mixed
Commutator is not in the good status, it experientially appears that the result of generator runs under this status is satisfactory, its mixed sheet relates on armature group.

4. bad status:

Stripe mark but commutator without abrasion
Usually that generator is operated in low load, the number of carbon brush is too much or material of carbon brush quality is incorrect. air and environment is also important factor.

5. bad status:

Asymmetrical film
Different password and switch of consistent color. Commutator is under smudgy or deviant physical status.

6. bad status:

Film with black section
Black section is probably abiogenetic or well-regulated distributing, the reason may be aroused from commutator short of circularity or defects of device operation, axletree, linker and so on.