Yale MPB040E Manual page 105

0620 YRM 0294
Problem
Grooves that are the
width of the brushes.
A condition called copper
drag occurs when copper
from the commutator bar
is pulled into the slot be-
tween the commutator
bars. This condition will
cause a short circuit be-
tween the commutator
bars if it is not corrected.
The brushes will wear
rapidly.
Table 2. Commutator Problems (Continued)
Possible Cause
• Operation of the
motor in dirty and
abrasive condi-
tions.
• Wrong type of
brushes for this
motor and opera-
tion.
• Brush pressure is
too high.
• Operation of the
motor in dirty and
abrasive condi-
tions.
• Brush holder is not
adjusted electri-
cally correct for the
motor.
• Wrong type of
brushes for this
motor and opera-
tion.
• Brush pressure is
wrong (too high or
too low).
Brush and Commutator Inspection
Illustration
7