9
2
−
7
62-11389
2.3 CONDENSING SECTION
The condensing section (see Figure 2
−
1 & Figure 2
−
2)
consists of an engine-generator drive package,
compressor, condenser fans, condenser coil, radiator,
refrigerant controls, defrost air switch, piping, wiring,
and associated components.
The engine-generator drive package (see Figure 2
−
3)
includes the engine, generator, air cleaner, muffler,
coolant system, fuel system, oil filter system and engine
sensors.
2.3.1 Engine
The engine is a four cylinder diesel which gives excellent
fuel economy and has easy starting characteristics. It is
equipped with spin-on lube oil and fuel oil filters for
easier filter changes. The fuel filter may also be
equipped with a thermostatically controlled fuel heater.
The engine cooling system consists of the radiator (which
is mounted with the condenser coil) and coolant overflow
bottle. The system is also fitted with an electronic battery
charger which converts generator or standby alternating
current to direct current for battery charging. Refer to
Section 2.8 for engine data.
2.3.2 Engine Air System
The air cleaner prolongs the life and performance of the
engine by preventing dirt and grit from getting into the
engine and causing excessive wear on all operating parts.
It is the responsibility of the operator to give the air cleaner
equipment regular and constant attention in accordance
with the instructions. An optional air cleaner service
indicator may be connected to the intake manifold. Its
function is to indicate when the air cleaner requires
replacement. (Refer to section 8.5.9.)
2.3.3 Engine Controls:
a. Engine Speed Control Unit (ENSCU)
The ENSCU (see Figure 2
−
6) is a microprocessor
based unit which controls the fuel supply to, and speed
of, the engine in accordance with the position of the
Main Power Switch and speed relay.
The unit has an LED which may be used to diagnose
failures within the electronic speed control system.
Refer to Section 9.5 for information on diagnostic
failures.
The ENSCU sends engine speed information to the
microprocessor to be displayed in the Unit Data and
recorded in the DataLink data recorder. The ENSCU is
mounted on the air cleaner bracket.
LED
Figure 2
−
6 Engine Speed Control Unit
b. Fuel/Speed Actuator (FSA)
The FSA combines the fuel shutoff solenoid and speed
control solenoid into one component. Fuel supply to the
injectors and engine speed is controlled by varying rod
position in accordance with the signal from the ENSCU.
The FSA is located on the front of the injection pump.
c. Engine Speed Sensor (ENSSN)
The ENSSN provides the ENSCU with information on
the speed at which the engine is running. The ENSSN is
located in the gear case cover above the oil filter.
d. Engine Oil Pressure Switch (ENOPS)
The ENOPS is normally open and closes on pressure
rise to signal to the microprocessor the engine has
sufficient oil pressure for operation. There is a 15
second delay after the engine starts to allow the oil
pressure to build up before the microprocessor looks at
the input from this switch. The switch is located in the oil
filter mounting assembly.
e. Engine Coolant Temperature Sensor (ENCT)
The ENCT provides the microprocessor with engine
coolant temperature information to be displayed,
recorded in the DataLink data recorder and used to
control the refrigeration system. The sensor is located
on the starter side of the engine near the #4 Injector.
f. Engine Oil Level Switch (ENOLS)
The ENOLS provides the microprocessor with engine
oil level information to be displayed, recorded in the
DataLink data recorder and used to control the
refrigeration system. The switch is located in the oil pan,
just to the right of the lube oil fill & dipstick.
2.3.4 Generator (GEN)
The generator is directly bolted to the engine and sup-
plies nominal 460V/3Ø/60Hz power when the engine is
in high speed and nominal 300V/3Ø/45Hz power in low
speed.
2.3.5 Compressor
The compressor assembly includes the refrigerant com-
pressor, suction and discharge service valves, high
pressure switch, compressor discharge temperature
sensor and the suction and discharge pressure trans-
ducers. The compressor draws refrigerant gas from the
evaporator and delivers it to the condenser at an in-
creased temperature and pressure. The pressure is
such that refrigerant heat can be absorbed by the sur-
rounding air at ambient temperatures.
2.3.6 Unloaders
The compressor is equipped with unloaders as standard
equipment. Unloaders are used as a compressor ca-
pacity control to unload the cylinder banks during peri-
ods of reduced cooling loads. This provides closer tem-
perature control and reduces the power required to
operate the compressor; thus reducing fuel consump-
tion.
a. Major Working Parts
Solenoid and valve system.
Spring loaded piston type bypass valve.
Spring loaded discharge check valve (located on the
valve plate).
