Preliminary Checks; Test Set-Up; On Vehicle Test - Komatsu 930E-2 Shop Manual

ON-VEHICLE TEST
Equipment:
Belt Tension Gauge
Voltmeter, 0 - 40 Volt range
Ammeter, 0 - 400 Ampere range

Preliminary Checks:

1. Check Belt Tension.
Use Belt Tension Gauge to measure belt tension:
Poly V Belt Adjustment (20 lbs./strand):
240 lbs. maximum for 12 groove Poly V-belt.
2. Check Battery.
Batteries must be in good condition and fully
charged. If any battery condition is marginal, it
should be replaced with one known to be in good
condition.
For split battery pack, dual voltage systems, bat-
tery rest voltages should agree within 0.3 V.
When "12V" battery voltage is more than 0.3 V
lower than "24V" battery voltage, check the "12V"
battery circuit to verify adequate charge.
Polarity of battery and alternator must agree;
reverse polarity will damage the alternator.
The alternator is NEGATIVE ground.
3. Check electrical connections in charging circuit.
Make sure all connections are clean, tight, and
free of corrosion. Battery connections are espe-
cially important.
4. Check Energize circuit.
If alternator is not charging, check for voltage at
the alternator energize terminal. Refer to Figure
13-1 for energize terminal location on the outside
of the control box. Check for battery voltage at the
"E" terminal with engine running.

Test Set-up

5. Discharge Battery as Follows:
a. Disable fuel system.
b. Turn all lights and accessories "ON". Crank the
engine for 10 – 15 seconds to discharge bat-
tery, then stop cranking engine.
c. Turn all lights and accessories off.
d. Enable fuel system.
6. Determine setpoints of regulator.
The setpoint of the alternator is 28V.
"Normal" range is within ± 0.2V of setpoint.
M13-6
1. Alternator
2. Voltmeter
7. Attach meters as indicated by Figure 13-1, be sure
Test Procedure
8. Start engine. Accelerate to high idle.
If voltmeter reading exceeds 32V for 24V system,
stop engine immediately and refer to Table 13-1.
9. Watch meter reading.
Niehoff Alternator Overhaul Manual
FIGURE 13-1.
3. Ammeter
4. Battery
to measure voltage and amperage at alternator,
not at batteries or intermediate point.
If an in-line ammeter is used, disconnect battery
ground cable before connecting ammeter. Then
reconnect battery ground cable. Ammeter con-
nections must carry rated output of alternator.
If battery is sufficiently discharged, amps should
be high within +/- 10% of output specified by
performance curve (refer to SPECIFICATIONS,
alternator RPM = engine RPM x pulley ratio).
Volts should be within or below the "normal"
range as battery approaches full charge. Amps
should fall as Volts rise. When amps and volts
stabilize, note readings and refer to Table 13-1.
M13003 04/01