Starter Inner Components Inspection: Armature

1. Verify that there is no continuity between the commutator and the core at each segment using an ohmmeter. If there is continuity, replace the armature. See Fig 1.
2. Verify that there is no continuity between the commutator and the shaft using an ohmmeter. If there is continuity, replace the armature. See Fig 2.
3. Place the armature on V-blocks, and measure the runout using a dial indicator. If not within the specification of, runout 0.002" (0.05 mm) maximum, repair using a lathe or replace the armature. See Fig 3.
4. Measure the commutator diameter. If not within the minimum specification, standard commutator diameter 1.16" (29.4 mm), minimum commutator diameter 1.13" (28.8 mm), replace the armature. See Fig 4.
5. Measure the segment groove depth of commutator. If not within the minimum specification, undercut the grooves to the standard depth. Standard depth is 0.016-0.023" (0.4-0.6 mm), minimum depth 0.008" (0.2 mm). See Fig 5.

Fig 1: Checking For Continuity Commutator To Core

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Fig 2: Checking For Continuity Commutator To Shaft

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Fig 3: Measuring Run-Out

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Fig 4: Measuring Commutator Diameter

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Fig 5: Measuring Segment Grove Depth

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