Jacobsen SXG323, Service Manual

Page: 134 / 230

CHAPTER 13. ELECTRICAL ACCESSORIES
133
13
armature coil core. If there is no continuity, the
armature coil is normal.
2) Inspection of armature coil for short circuit
• Turn the armature coil on a armature coil tester
while holing a piece of iron closely above the
armature. If the iron piece does not vibrate nor is
attracted to the armature, the armature is nor-
mal.
Note:
The armature coil surfaces should be cleaned
ahead of time.
3) Inspection of the commutator
• Inspect the commutator surfaces for dirt, burn-
ing, damage, etc. Minor damage can be correct-
ed with sandpaper of #400 or higher no.
• Inspect the commutator for run-out with a dial
gauge on a V-block.
• Measure the commutator diameter with vernier
calipers.
• Measure mica depth against segment top.
4) Inspection of field coils for short circuit
• Inspect for continuity across the lead from termi-
nal C and field coil brush. If there is continuity,
the coils are normal.
5) Inspection offield coils for grounding
Inspect continuity across the field coil brush and
field coil. If there is no continuity, the coils are
normal.
Fig. 13- 20
Standard value
0.02 mm
Usable limit
0.05 mm
Standard value
30 mm
Usable limit
29 mm
Standard value
0.5-0.8 mm
Usable limit
0.2 mm
Fig. 13- 21
Fig. 13- 22
Fig. 13- 23
Fig. 13- 24
Fig. 13- 25