Ingersoll-Rand 070008 Maintenance Manual Download Page 84

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Electrical Maintenance

2. Use the Service Test Mode to run the unit in

low speed cool. The evaporator fans should
run at approximately 1180 rpm with the EFLC
contactor energized and the engine running in
low speed. The evaporator fans should run at
approximately 1770 rpm in the correct
direction with the EFHC contactor energized
and the engine running in low speed. If it does
not run, go to step 7. If it runs backwards, go
to “If Fan Runs Backwards” on page 82.

3. Check for AC voltage between the T1, T2,

and T3 terminals on the fan harness side of the
EFLC (low speed) contactor. Approximately
345 Vac should be present between each pair
with engine running in high speed. If the
voltage is acceptable, go to the next step. If
not, go to step 6.

4. Turn the unit off and check the resistance on

the three pairs of wires (ET1-ET2, ET2-ET3,
and ET1-ET3) at the fan side of the contactor
for fan being tested. The resistance should be
approximately 10.4 ohms on each pair. If not,
go to the next step.

5. Check the continuity of the ET1, ET2, and

ET3 wires from the EFLC contactor to the fan.
If all three wires have good continuity, the fan
motor is probably faulty.

6. Check the T1/L1, T2/L2, and T3/L3 circuits

(including any contactors) back to the AC
generator for continuity. If the T1/L1, T2/L2,
and T3/L3 circuits all have good continuity,
test the AC generator.

7. Check for AC voltage between the T1, T2,

and T3 terminals on the fan harness side of the
EFHC (high speed) contactor. Approximately
230 Vac should be present between each pair
with engine running in low speed. If the
voltage is acceptable, go to the next step. If
not, go to step 10.

8. Turn the unit off and check the resistance on

the three pairs of wires (ET11-ET12,
ET12-ET13, and ET11-ET13) at the fan side
of the contactor for fan being tested. The
resistance should be approximately 5.8 ohms
on each pair. If not, go to the next step.

9. Check the continuity of the ET11, ET12, and

ET13 wires from the EFHC contactor to the
fan. If all three wires have good continuity, the
fan motor is probably faulty.

10. Check the T1/L1, T2/L2, and T3/L3 circuits

(including any contactors) back to the AC
generator for continuity. If the T1/L1, T2/L2,
and T3/L3 circuits all have good continuity,
test the AC generator.

Ground Fault Detection Module

The ground fault detection module trips and sets
the Ground Fault Alarm Code 518 if it detects a
ground fault (short between the generator phase
outputs and unit chassis). Check the AC circuits
between the AC generator and the AC Loads (fan
motors, battery charger, heaters) for a ground fault
if the Ground Fault Alarm Code 518 is set. To
check for a ground fault, check for continuity
from the AC circuits to a chassis ground.

Base Controller Fuses

A number of fuses, located on the base controller,
protect various circuits and components. The base
controller (see Figure 153) is located inside the
control box. Refer to the SR-4 Microprocessor
Control System Diagnostic Manual TK 55533 for
a complete list of the size and function of the
fuses.

Fuses

Fuse

Size

Function

2A Circuit for REB

15A

Power to On/Off Switch

40A

Fuel Solenoid/Starter Circuit

None No Fuse - Alternator Excite Circuit

60A

Preheat Circuit