d. Electrical components are checked for cracked or broken conditions.
Insulation breakdown, shorts, and grounds are checked with an ohmmeter.
(1) Inspect relay contact surfaces for severe burning or pitting. Minor
burning and pitting is permissible. Do not use a file to clean surfaces. Relay
should be replaced if severe burning or pitting has occurred.
(2) Inspect electrical terminal studs for burning or pitting and damaged
threads.
If studs are defective, replace the necessary assembly or component.
(3) Check brushes and springs for cracks, excessive wear, and
conformance to repair standards. Replace springs as necessary. If any of the
brushes are defective, replace entire set.
e. The armature is checked for conformity to repair standards.
A growler
is used to check the armature for grounds and shorts.
(1) Figure 19 shows the test probes of the growler when checking for
armature grounds. The probes are connected to a lamp and high voltage source. By
touching one of the test leads to the armature core and the other to the commutator
bar riser, the continuity is checked. Test all commutator bar risers in this
manner. If the light glows at any time, the armature is grounded.
Figure 19.
Armature ground checks.
OS 010, 6-P17
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