Nanni 5.280HE Workshop Manual page 122

03-M Series, WSM
Armature Coil
1. Check the continuity across the commutator and armature coil
core with resistance range of circuit tester.
2. If it conducts, replace the armature.
3. Check the continuity across the segments of the commutator with
resistance range of circuit tester.
4. If it dose not conduct, replace the armature.
Commutator and Mica
1. Check the contact of the commutator for wear, and grind the
commutator with emery paper if it is slightly worn.
2. Measure the commutator O.D. with an outside micrometer at
several points.
3. If the minimum O.D. is less than the allowable limit, replace the
armature.
4. If the difference of the O.D.'s exceeds the allowable limit, correct
the commutator on a lathe to the factory specification.
5. Measure the mica undercut.
6. If the undercut is less than the allowable limit, correct it with a saw
blade and chamfer the segment edges.
Factory spec.
Commutator O.D.
Allowable limit
Factory spec.
Difference of O.D.'s
Allowable limit
Factory spec.
Mica under cut
Allowable limit
(1) Segment
(2) Depth of Mica
(3) Mica
S-105
DIESEL ENGINE
W1156507
30.0 mm
1.181 in.
29.0 mm
1.142 in.
Less than 0.02 mm
0.0008 in.
0.05 mm
0.0020 in.
0.50 to 0.80 mm
0.0197 to 0.0315 in.
0.20 mm
0.0079 in.
(a) Correct
(b) Incorrect
W1155802
KiSC issued 08, 2012 A