Yale MPB040E Manual page 104

Brush and Commutator Inspection
Problem
Heavy streaks and fine
grooves indicate the be-
ginning of damage to the
commutator.
Grooves and lines that
have followed the heavy
streaks and fine grooves
shown above. The arma-
ture must be removed
from the motor so the
commutator can be re-
paired. A commutator
with this condition will
cause the brushes to
wear rapidly.
6
Table 2. Commutator Problems
Possible Cause
• Operation of the
motor in dirty and
abrasive condi-
tions.
• Continuous opera-
tion of a motor with
a light load.
• Brush pressure is
too low.
• Worn brushes.
• Operation of the
motor in dirty and
abrasive condi-
tions.
• Continuous opera-
tion of a motor with
a light load.
• Brush pressure is
too low.
• Worn brushes.
0620 YRM 0294
Illustration