Sullair 375H - 2.10 Electrical System, Functional Description; 2.11 Compressor Shutdown & Warning System

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375 John Deere Standard and Aftercooled/Filtered Operator’s Manual and Parts List
SECTION 2
ELECTRICAL SYSTEM, 2.10
FUNCTIONAL DESCRIPTION
The electrical system consists of the basic electrical
elements required to operate the compressor and also has
a system feature that automatically shuts down the
compressor when a malfunction occurs. The system’s
components include: an engine starter, battery, alternator/
voltage regulator, and a fuel solenoid. It also has a
compressor discharge temperature switch that will shut the
compressor down if the compressor temperature exceeds
250° F (121° C). It has an engine water temperature
switch set to shut down the compressor when the coolant
temperature reaches 230° F (110° C) and an oil pressure
switch that will shut down the compressor if the engine oil
pressure goes too low. An underspeed sensor shuts down
the compressor if the engine speed falls below 1500 rpm
and a low fuel level switch shuts down the engine when
fuel level is low to prevent running the engine dry (out of
fuel). The engine is also equipped with an ECM (electronic
control module).
COMPRESSOR SHUTDOWN 2.11
& WARNING SYSTEM,
FUNCTIONAL DESCRIPTION
The Shutdown System and Annunciator Module (SSAM)
continuously monitors the status of the compressor. In the
event of a shutdown condition, the SSAM will shut down
the compressor and display (ashing) the appropriate
code on the instrument panel annunciator light. The
display will continue ashing until the ignition switch is
turned OFF. The shutdown codes are:
One ash: high compressor discharge temperature•
Two ashes: high engine coolant temperature•
Three ashes: low engine oil pressure•
Four ashes: low engine speed•
Five ashes: low fuel level•
The SSAM also provides startup logic for the compressor.
When the ignition switch is in the ON position, the
annunciator light will illuminate for 30 seconds. During this
30 second period, pressing the ignition switch will engage
the engine starter. The low engine speed switch is inactive
during this startup time interval. By the end of these 30
seconds, the annunciator light goes out and the engine
START cycle is disabled. At this time the system runs all
safety checks including low fuel level.
The engine is equipped with an electronic speed control
and has a shutdown protection/diagnostic capability. A
variety of sensors and a speed control module interface
with the ECM. These sensors include the following: oil
pressure, coolant temperature, intake manifold, fuel
temperature, timing cranking; and a remote shutdown
switch. The engine speed control module consists of the
module and a pressure transducer. The pressure
transducer senses the compressor control pressure and
as the control pressure increases, the speed control
module decreases the engine speed by lowering the
output voltage to the ECM.