Komatsu 830E-AC Shop Manual page 256

Stator Test 2: Check For Grounded Stators
1. Set the DMM to the ohms scale and zero the
meter.
2. Connect one DMM lead to the (B-) terminal on
the alternator, and connect the other meter lead
to each phase lead P1, P2, and P3 (Figure 10-
15).
3. If the resistance reading is other than OL (out of
limits) at any connection, the stator is grounded
to the shell. Replace the stator.
4. Connect one DMM lead to the (B-) terminal on
the alternator, and connect the other DMM lead
to each phase lead P4, P5, and P6.
5. If the resistance reading is other than OL (out of
limits) at any connection, the stator is grounded
to the shell. Replace the stator.
THERMAL SWITCH TEST
If the alternator is not operating properly, check the
thermal switch. This switch is a normally closed (NC)
switch which must have continuity between the wires
from the switch.
D10-26
Initial Test
1. Disconnect the wiring harness plug from the
regulator.
2. If necessary, remove the cover from the drive
end housing.
3. Check for continuity between pin B (phase 1) of
the wiring harness plug and the phase lead
(diode) connection (2), shown in Figure 10-16.
This connection is just left of the 11 O'clock
position when looking at the alternator from the
drive end.
a. If continuity exists, there is a problem with
the alternator and not with the thermal
switch.
b. If there is no continuity, the thermal switch is
probably faulty.
1. Pin B (Phase)
Battery Charging Alternator
FIGURE 10-16.
2. Phase Lead
Connection
D10003 07/06