SECTION 2 600H, 700HH, 750, 750H, 750HH, 825, 900H, 1050 USER MANUAL
51
2.18 HYDRAULIC FAN DRIVE
SYSTEM
Refer to Figure 2-6. The compressor is equipped with
a hydraulically driven fan to provide cooling airflow
for the compressor fluid, engine coolant, charge air,
fuel, and hydraulic fluid. If equipped, cooling airflow is
also available to provide aftercooled discharge air.
The system includes a fan and vane motor
positioned in front of the main cooler pack and
provides the cooling airflow for the main cooler
assembly. This fan also acts as the cooling airflow
mechanism for aftercooled service air as well.
The fan motor is driven by dual pumps which are
coupled together and driven by the engine's auxiliary
gear drive. A variable displacement piston pump
drives the fan motor while a fixed displacement gear
pump pulls all the fluid from the reservoir and helps
to maintain a positive pressure at the inlet of the
piston pump. This arrangement allows a smaller fluid
reservoir as well as more favorable inlet conditions to
the piston pump.
The fan is automatically varied depending on the
ambient, compressor, engine coolant, charge air,
and package discharge temperature. This provides
fuel savings by only running the fan as much as
needed to maintain proper operating temperatures.
Additionally, load on the engine at startup is reduced
assisting in cold starts and thermal cycling/shock is
eliminated.
516
3509-3 262-3 Sensor Supply Voltage 1 : Voltage Above Normal
3509-4 262-4 Sensor Supply Voltage 1 : Voltage Below Normal
3510-3 2131-3 Sensor Supply Voltage 2 : Voltage Above Normal
3510-4 2131-4 Sensor Supply Voltage 2 : Voltage Below Normal
527 630-2 268-2 Calibration Memory : Erratic, Intermittent, or Incorrect
Table 2-1: Cross Reference for Diagnostic Codes and Event Codes from CAT trouble shoot guide
(KENR 6848)
Flash Code
SPN
(1)
/
FMI Code
Diagnostic Code
or Event Code
Description of Code
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