ELECTRICAL SYSTEM
117
2b. Check the stator for resistance across the
AC leads. The resistance should fall
between the valves specified by the engine
manufacturer. See Figure 7.36.
2c. With the engine stopped and the stator
lead unplugged from the voltage regulator /
rectifier, check the resistance from each of
the stator leads to ground (engine block).
2d. The meter should indicate no continuity.
See Figure 7.37.
Figure 7.36
Probes to output wires show
normal resistance through
stator windings: GOOD
Figure 7.37
Stator lead
Ground
2e. Interpretation: If the ohm meter indicates
no continuity between the two stator leads,
there is a fault in the stator windings. If the
ohm meter indicates continuity between
either stator lead and ground, the stator
windings are shorted to ground.
NOTE: If there is an intermittent charging sys-
tem problem, perform these tests when the
engine is cold, and again when the engine is hot.
NOTE: Low voltage readings may also result
from poor test connections or low engine RPM.
3. If the stator is good, test the amperage out-put
from the regulator / rectifier.
3a. Attach a DC shunt with DVOM or an
ammeter capable of reading up to 25
amperes of DC current. The most accu-
rate point to take a reading will be at the
battery ground cable.
3b. The altenator should produce the rated
current at the rated RPM under an electri-
cal load.
3c. Connect a load tester between the battery
terminals.
3d. With the engine running at the rated RPM,
energize the load tester to draw amperage
from the system.
3e. Read the amperage on the meter.
See Figure 7.38.
NOTE: Output varies with load. A fixed-load
battery tester can be used to apply enough load
to test the charging system out-put.
Figure 7.38
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