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ST–10
2. Check of commutator continuity
Check continuity between each adjacent segment of the
commutator, using an ohmmeter.
If no continuity exists between any adjacent segments, re-
place the armature.
Check of commutator
1. Check each contact surface of the commutator segments
with the brushes for burning.
If the surfaces are dirty or burnt, correct the commutator
surfaces, using abrasive paper (No. 400) or a lathe.
2. Check of commutator for circle runout
Support the armature at its both ends on a Vee block.
Check the commutator for circle runout, using a dial
gauge.
Circle Runout Limit:
If the circle runout exceeds the allowable limit, turn down
the commutator on a lathe.
At this point, care must be exercised to ensure that the
commutator diameter is not less than the minimum re-
quirement diameter of 27 mm.
3. Measurement of commutator diameter
Measure the commutator diameter by means of a microm-
eter or vernier calipers.
Standard Diameter:
Minimum Diameter:
If the commutator diameter is less than the minimum diam-
eter, replace the armature.
4. Check of commutator undercut
Measure the insulator groove depth between commutator
segments.
Minimum Depth:
If the insulator groove depth becomes less than the limit
value, replace the commutator.
0.05 mm
28 mm
27 mm
0.2 mm
JST00032-00028
JST00033-00029
JST00034-00030
JST00035-00031
JST00036-00032
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