TM 5-3740-214-14
ELECTRICAL PARTS GROUP (Continued)
Figure 5-243. Armature Test
(f) Check the armature for shorts. Use a growler (open core transformer).
(1) Rotate the armature slowly on the growler.
(2) Hold a hacksaw blade over the armature while it is turning. When a shorted winding comes under
the hacksaw blade, it will vibrate.
(3) If shorts are found in the commutator, brush the dust and grit from between the slots and check the
commutator again.
(g) Check for grounds in the armature. Use a 110 volt test lamp and test leads.
(1) Connect one lead to the commutator.
(2) Connect the second test lead to the armature shaft.
(3) If the light lights, there is a grounded wire.
(4) Clean the slots in the commutator and test for grounds.
(h) If there are any opens, shorts or grounds, replace the armature.
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