Mitsubishi L3E Service Manual page 133

ELECTRICAL SYSTEM
Figure 139 Checking diodes
Figure 140 Checking field coil for continuity
Figure 141 Checking field coil for insulation
Service Manual Mitsubishi L-Series diesel engines
Version 08/2004
ALTERNATOR AND DYNAMO
33.7.1 Inspecting the diodes
Check each built-in diode in the rectifier for continuity
as follows:
1. Connect a circuit tester (ohm meter) across the
lead wire and case of the diode to be tested. The
diode is considered as normal if its resistance is
large in either direction and small in the reverse
direction.
2. If there is equal resistance in both directions, the
diode is suspected to be defective.
Replace the rectifier assembly.
3. Check every diode for continuity.
33.7.2 Inspecting the field coil
1. Check continuity between slip rings. If there is no
continuity, the field coil is suspected to be broken.
Replace the field coil.
2. Check for continuity between a slip ring and shaft
(or core). If any continuity is found, the field coil is
suspected of grounding. Replace the field coil.
ENGLISH 133 / 155