Yale MPB040E Manual page 127

0620 YRM 0294
PROBLEM
Electrical burns on commutator bars
on opposite sides of the commutator
(see Table 2).
Copper wears rapidly at the edge of
the commutator bars (see Table 2).
Burning/Overheating
1. Flashover causes burning of
the commutator bar.
2. Open circuit in winding cau-
ses deep burning of adjacent
commutator bars.
3. Overheating causes damage
to varnish insulation (see Ta-
ble 2).
Commutator bars are either too high
or too loose, both of which can
cause damage to brushes (see Ta-
ble 2).
POSSIBLE CAUSE
Open armature winding.
Motor has been stalled.
Operation in a dirty or abrasive en-
vironment.
Wrong type of brushes for this mo-
tor and operation.
Motor has been too hot. Wrong lift
truck for the application. Motor has
been stalled. Open armature wind-
ing. Open field coil.
Motor has been stalled.
Motor has been too hot.
Troubleshooting
PROCEDURE OR ACTION
Replace armature.
Use correct operating techniques.
Clean commutator
quently.
Replace brushes with correct type.
Use correct lift truck for the appli-
cation. Use correct operating tech-
niques. Replace armature or resur-
face commutator in a lathe. Re-
place field coil.
Use correct operating techniques.
Use correct lift truck for the opera-
tion.
more fre-
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