Yale MPB040-E, Manual

Page: 127 / 130

PROBLEM POSSIBLE CAUSE PROCEDURE OR ACTION
Electrical burns on commutator bars
on opposite sides of the commutator
(see Table 2). Open armature winding. Replace armature.
Motor has been stalled. Use correct operating techniques.
Copper wears rapidly at the edge of
the commutator bars (see Table 2). Operation in a dirty or abrasive en-
vironment. Clean commutator more fre-
quently.
Wrong type of brushes for this mo-
tor and operation. Replace brushes with correct type.
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).
Motor has been too hot. Wrong lift
truck for the application. Motor has
been stalled. Open armature wind-
ing. Open field coil. 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.
Commutator bars are either too high
or too loose, both of which can
cause damage to brushes (see Ta-
ble 2). Motor has been stalled. Use correct operating techniques.
Motor has been too hot. Use correct lift truck for the opera-
tion.
0620 YRM 0294 Troubleshooting
29