Komatsu 4D98 Series Shop Manual page 155

(b) Stator coil insulation test
Check electrical continuity between one
of the stator coil terminals and the stator
core using a tester.
-Continuity:
Short-circuiting of stator coil
Replace the stator.
(4)
(6)
Brush
Measure the brush length. If wear ex-
ceeds the limit (6 mm), replace with a new
brush holder assembly. The wear limit line
is indicated on the brush.
Standard: 18, Wear limit: 6 (mm)
Caution on Brush Lead:
1) Temperature of soldering iron:
300°C - 350°C
Always use the non-acidic paste.
Check of IC regulator
Prepare the connection for test setup as
shown in Fig. 17, using a variable resistor,
two 12V batteries, an ohmmeter and a
voltmeter.
(a) Jigs required
@ Variable resistor (Rv): 0 - 300Q
12w (1)
@ Resistor (Rl): 1OQ 3W (1)
@ Battery (BAT1 , BAT2): 12 V (2)
@ DC voltmeter (4 measurement
points): 0 - 50 V, Class 0.5 (1 set)
(b) Measurement procedure
(Refer to Fig. 17.)
@ Measure voltage at Vl (BATl). If
the measured value is between 10
V and 13 V, the battery is accept-
able.
@ Measure voltage at V3 (voltages of
BAT1 + BAT2). If the measured
value is between 20 V and 26 V,
both batteries 1 and 2 are accept-
able.
Fig. 15
Fig. 16
E F
L
BAT1
Fig. 17 Test circuit for IC regulator alone
1 o-9