(d) Inspect the bearing for wear, scoring, pitting, and damage. Replace if defective.
(e) Inspect the cover plate for cracks and warpage. Replace if necessary. Replace the cover plate gasket.
(f) Inspect the commutator end frame for breaks, cracks, and warpage. Replace if broken or damaged.
(3) Armature.
(a) Inspect the armature for wear, pitting, and scoring. Replace if worn or damaged.
(b) Inspect the armature windings and see that they are properly pressed into the core slots and tightly
soldered to the commutator risers. Replace the armature if the coils are loose or unsoldered.
(c) Inspect the commutator for rough spots, discoloration, pitting, scoring, and high mica. If the commutator
is rough, pitted, or worn, mount the armature in a lathe (preferable on the shaft bearing seats, if the
lathe is so equipped). Otherwise, mount the armature on the shaft centers (fig. 104). Take light cuts
until the commutator is completely cleaned. Remove all burrs by holding No. 00 sandpaper lightly
against the commutator while the armature is turning in the lathe.
(d) Use a dial indicator to measure the commutator out of round (fig. 105). Repeat the turning procedure if
Figure 104. Turning commutator down.
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