Inspection: Brush (+); Inspection: Armature; Test For Coil Grounding; Commutator Outside Diameter - Mitsubishi 6M60-TL Service Manual

Inspection: Brush (+)

(1) Brush length
• If either brush (+) is shorter than the limit, it must be replaced.
(2) Contact surface of armature's commutator and brush
• If the commutator contact surface of either brush is rough or un-
evenly worn, rectify it with emery paper (#300 to 500).

Inspection: Armature

(1) Test for coil short circuit
• Hold an iron rod parallel with the armature.
• Slowly rotate the armature by hand.
• If the iron rod vibrates or is pulled toward the armature, the coil is
short-circuited and the armature must be replaced.

(2) Test for coil grounding

• Check that continuity does not exist between the commutator
and the core (or shaft).
• If continuity exists, the coil is grounded and the armature must
be replaced.

(3) Commutator outside diameter

• If the measurement is out of specification, replace the armature.
(4) Runout of commutator periphery
• If the reading exceeds the specified limit, rectify the commutator
of the armature, making sure the outside diameter stays within
specification.
(5) Condition of commutator surface
• If the surface is rough or has stepped wear, rectify it with emery
paper (#300 to 500).
• After rectifying the surface, check the extent of commutator
runout.
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