Bypass Test - Komatsu 930E-2 Shop Manual

Table 13-1. TROUBLESHOOTING
AMPS VOLTS
Charging system is OK. Battery
is not yet fully charged. Wait for
charging system to bring to full
HIGH LOW
charge: AMPS should fall and
VOLTS should stabilize within
normal range.
Watch until AMPS fall, or VOLTS
exceed normal range. If AMPS
fall and VOLTS remain normal,
HIGH NORMAL charging system is OK. If VOLTS
exceed normal, regulator and/or
field coil should be replaced
(Go to Static Tests).
Stop test. Regulator and/or field
HIGH HIGH coil should be replaced.
(Go to Static Tests.)
Make sure voltmeter leads are
a t ta c he d a t a l te r na to r . I f
connections are OK, alternator
and/or regulator must be repaired
or replaced. Bypass regulator
LOW LOW (See Figure 13-3). If VOLTS
and/or AMPS rise, alternator is
OK and regulator should be
replaced. If no effect, repair
alternator.
(Go to Static Tests.)
LOW NORMAL Charging system is OK.
Stop test. If battery and voltmeter
LOW HIGH check OK, regulator and/or field
coil must be replaced.
Table 13-2. VOLTAGE REGULATOR
SYSTEM FACTORY
VOLTAGE SETTING
27.5
24
28.0
ON-VEHICLE TEST

Bypass Test:

Disconnect plug between alternator and regulator and
momentarily touch "F-" terminal from alternator plug
to ground.
M13003 04/01
DIAGNOSIS
NORMAL
RANGE
27.2 - 27.8
27.7 - 28.3
Niehoff Alternator Overhaul Manual
FIGURE 13-2. VOLTAGE STEP ADJUST
1. Low
2. Medium
CAUTION!
USE HIGH SETTING ONLY FOR:
• EXTREME COLD
• INTERMITTENT SERVICE
• MAINTENANCE - FREE BATTERIES
CHECK BELT TENSION BEFORE ADJUSTING
VOLTAGE. TO ADJUST VOLTAGE, MOVE LINK TO
OTHER POST.
System voltage may rise above 32 volts on a 24
volt system, during regulator bypass test.
Possible damage to sensitive electronic compo-
nents could occur.
Refer to the "On Vehicle Troubleshooting Guide"
for an alternative to the bypass test.
FIGURE 13-3.
1. F+ Stud (some units have F+ Stud & Phase taps)
3. High
M13-7