Komatsu 830E-AC Shop Manual page 251

Bench Test 2: Full Load Test
1. With the load set to the rated output (listed on
the nameplate) ± 10%, operate the alternator at
5000 rpm.
2. Compare the test results to Table 10-6, and take
the appropriate action, as stated in the table.
Table 10-6: FULL LOAD TEST
Amps Volts
HIGH LOW The test bench battery is dis-
charged or defective. Allow the
battery to charge or replace the
battery.
HIGH NORMAL The charging system is good.
HIGH HIGH Stop the test. The regulator and/
or field coil replaced. Go to Static
Testing.
LOW LOW The alternator and/or regulator
must be repaired or replaced. Go
to Bench Test 3.
LOW HIGH Stop the test. The alternator is
defective, the bench is not work-
ing properly, or the alternator is
wired improperly to the bench.
Bench Test 3: Regulator Bypass Test
Perform this test only when directed by other tests.
1. Bypass the regulator by installing a jumper
between pin A (F-) and pin F (F+).
FIGURE 10-10. PIN CONNECTION
IDENTIFICATION
D10003 07/06
Diagnosis
Battery Charging Alternator
2. Set up the load on the alternator the same as
Bench Test 2.
3. Note whether the amps increased to within ±
10% of the rated output when connecting pin A
(F-) to alternator ground (B-.)
4. Note whether the amps decrease when discon-
necting pin A (F-) from the alternator ground.
Compare the test results to Table 10-7, and take
the appropriate action, as stated in the table.
Limit the time the terminal is connected to a few
seconds. Doing so can protect the charging sys-
tem from excessive voltage increase.
Table 10-7: REGULATOR BYPASS TEST
Connect Disconnect
Amps increase Amps decrease The alternator is
No change
No change
Diagnosis
good. Replace the
regulator only if low
amps/low Volts are
indicated by Bench
Test 1 or 2.
The alternator must
be repaired. Go to
Static Testing.
D10-21