Electrical System
i02418531
Alternator
-
Test
1.
Put the positive lead
“
+
”
of a suitable multimeter
on the
“
B+
”
terminal of the alternator. Put the
negative
“
-
”
lead on the ground terminal or on the
frame of the alternator. Put a suitable ammeter
around the positive output wire of the alternator.
2.
Turn off all electrical accessories. Turn off the fuel
to the engine. Crank the engine for 30 seconds.
Wait for two minutes in order to cool the starting
motor. If the electrical system appears to operate
correctly, crank the engine again for 30 seconds.
Note:
Cranking the engine for 30 seconds partially
discharges the batteries in order to do a charging test.
If the battery has a low charge, do not perform this
step. Jump start the engine or charge the battery
before the engine is started.
3.
Start the engine and run the engine at full throttle.
4.
Check the output current of the alternator. The
initial charging current should be equal to the
minimum full load current or greater than the
minimum full load current. Refer to Specifications,
“Alternator and Regulator” for the correct minimum
full load current.
Table 12
Fault Conditions And Possible Causes
Current At Start-up
The Voltage Is Below Specifica-
tions After 10 Minutes.
The Voltage Is Within Specifica-
tions After 10 Minutes.
The Voltage Is Above Specifica-
tions After 10 Minutes.
Less than the specifications
Replace the alternator. Check the
circuit of the ignition switch.
Turn on all accessories. If the volt-
age decreases below the specifi-
cations, replace the alternator.
-
Decreases after matching
specifications
Replace the alternator.
The alternator and the battery
match the specifications. Turn on
all accessories in order to verify
that the voltage stays within
specifications.
Replace the alternator.
The voltage consistently ex-
ceeds specifications.
Test the battery. Test the alternator
again.
The alternator operates within the
specifications. Test the battery.
Replace the alternator. Inspect the
battery for damage.
5.
After approximately ten minutes of operating the
engine at full throttle, the output voltage of the
alternator should be 14.0 ± 0.5 volts for a 12 volt
system and 28.0 ± 1 volts for a 24 volt system.
Refer to the Fault Conditions And Possible Causes
in Table 12 .
6.
After ten minutes of engine operation, the charging
current should decrease to approximately 10
amperes. The actual length of time for the
decrease to 10 amperes depends on the following
conditions:
• The battery charge
50
UENR0617
This document has been printed from SPI2. NOT FOR RESALE.