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d. INSPECTION
• BRUSH LENGTH
Measure the brush length.
1
If the measurement is less than the service limit, replace the
breaker assembly or brush assembly as an assembly.
2
Standard
3
9.75 mm (0.384 in)
4
5
6
• ARMATURE
Check the armature for discoloration or damage, and replace it
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with a new one if necessary.
8
Check the armature shaft for burrs, and correct it with a fine
emery paper if necessary.
9
Check the commutator surface for rust or damage, and correct
it with a fine emery paper if necessary.
10
11
12
Armature short-circuit test:
13
Place the armature on a V-block and hold a hacksaw blade
close to the armature core.
14
Check the armature by turning the core. If the hacksaw blade
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attaches to the core or if it vibrates, it indicates the short-circuit
in the armature.
16
Replace the armature with a new one.
17
18
19
Test without using armature tester:
1) Check for continuity between the segments. If an open
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circuit exists between any two segments, replace the
armature.
• If the resistance between the given segments is extremely
low compared to the resistance between the other
segments, there can be a short-circuit between the
segments caused by blockage with brush particles.
Remove the brush particles and recheck. If the resistance
is still extremely low, replace the armature with a new
one.
14-48
Service limit
5.5 mm (0.22 in)
514
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