Komatsu 4D98 Series Shop Manual page 154

f0. Alternator
(4
(4
(e)
Rotor coil continuity test
Check electrical continuity between slip
rings using a tester.
Not continuity:
Open circuit of rotor coil
Replace the rotor.
Rotor coil resistance at 20°C: 3.45Q
Rotor coil insulation test
Check electrical continuity between the
slip ring and the rotor core or shaft using
a tester.
1 Continuity:
1
Short-circuiting of rotor coil
Replace the rotor.
Checking ball bearing
Check the rear ball bearing. If rotation is
unsmooth or abnormal noise is gener-
ated, replace the ball bearing.
(3) Stator
(a) Stator coil continuity test
Check electrical continuity between two
respective terminals using a tester.
Not continuity:
Open circuit of stator coil
Replace the stator.
Stator coil resistance at 20%:
0.108Wphase
Resistance between terminals
U and V: 0.216Q
Fig. 11
Fig. 12
Fig. 13
III
_ Tester
Fig. 14
1 O-8