Serial Number

Description of the state of the oxide film

Cause Analysis

01

Striped oxide film, different width and color, no commutator wear

High air humidity, high oil vapor and corrosive gases, low electrical load on carbon brushes

02

There are intermittent traces of oxide film on the surface of the commutator, but the commutator is damaged

Running for too long will cause damage to the commutator

03

Black oxide film, uneven color spots showing no downwind distribution

Uneven rectification or unclean operating environment

04

Black oxide film with regular or irregular color spots on one or more rectifiers

The commutator is not concentric, the main shaft of the motor jumps or the main bearing of the motor is damaged, causing the motor to vibrate

05

Black mottled oxide film with typical lace

The surface of the commutator is raised, causing the commutator piece to bulge, which causes the carbon brush to jump

06

Colored spots in the middle or edge of the commutator

Incorrect grinding of the commutator or difficulty in commutation

07

Alternating shiny and dull streaks of the commutator

Double windings bypass the same convex slot, causing uneven current distribution of two rows of parallel wires

08

Rough spots appear in bipolar

Wrongly welded riser, or fairing link

09

Ablation streaks appear on the edges or in the middle of the bus bars on the surface of the commutator

Difficulty rectifying causes sparks

10

Porous oxide film, bright, dense or dotted

The resistance is too large to cause the destruction of the oxide film

11

Black spots appear on the edge of the bus bar along the direction of rotation

The motor is stopped for a long time or the load is insufficient for a short time stop

12

Ablation streaks on the sliding end of the bus bar and the sliding end of the next bus bar

The commutator appears bulging

13

Dark markings

The commutator is undercut, which may be caused by the commutator plane point

14

Conspicuous dark markings with commutator edge ablation

Mica bulge

15

Dark markings

Undercut of commutator segment edge

16

Unusual metal wear on the bus bars of the commutator

Abnormal wear caused by misalignment of carbon brushes, unsuitable carbon materials and contamination, etc.

17

Low commutator, raised mica, pulled copper

The fairing is installed incorrectly, causing vibration or collision