SHAFT CONTROL UNIT
A shaft control unit (SCU) is located in each main
The EOOW/LU is tested by the console operator or
engine room on the DDG-51 class ships. The SCU
maintenance person. The tests on the EOOW/LU consist
provides the interface between the propulsion plant and
of a lamp test of the indicators on the A2 panel and an
the ship's DMS. It also provides the interface between
LED and audible alarm test of the AN/USH-26 tape unit.
the propulsion plant and other control locations in the
The lamp test of the A2 panel is conducted by
CCS and the bridge. The SCU controls the propulsion
depressing the LAMP TEST push button on the A2
p l a n t for its respective shaft, including auxiliary
panel. The CONSOLE TEMP HIGH and UPS IN USE
machinery such as bleed air, fuel service, propeller
i n d i c a t o r s should light when the push button is
hydraulics, and lube oil. Signal conditioners and A/D
depressed. The audible alarm and the LED test is
converters are apart of the standard electronic modules
(SEMs) that are located in the A2 section of the SCU.
conducted by setting a three-position toggle switch on
The SCU performs the same function as the PLCC on a
the AN/USH-26 unit to the TEST position. When the
DD-963, DDG-993, or CG-47 class ship.
switch is placed in the TEST position, the audible alarm
circuits sound the audible alarm and illuminate the
The SCU is another important console on the
LEDs labeled HOT and OVERTEMP. You will use these
DDG-51 class ships. Any malfunction that occurs to the
tests to make sure the audible alarm and lamp circuits
SCU is immediately reported to the EOOW.
are functioning properly.
Maintenance of the SCU is the responsibility of the
GSEs; therefore, the EOOW will contact you, the GSE,
to correct the problem.
The EOOWLU uses the machinery control system
(MCS) to monitor the engineering systems. It also uses the
The SCU is tested by the console operator or
data multiplex system (DMS) to communicate with the
maintenance person. The tests on the SCU consist of a
other consoles. Planned maintenance is conducted on the
lamp test of the indicators and an audible alarm test of
MCS according to the MRCs. Although the MCS and
the siren, horn, bell, and buzzer.
DMS are different from the control systems on other gas
turbine-powered ships, the basic troubleshooting and
The audible alarm test is conducted by depressing
maintenance procedures are the same. Control and other
each AUDIBLE ALARM TEST push button on the
electronic circuitry is located on circuit card assemblies.
SCU. This action causes the audible alarm circuits to
Computer interface within the console is extensive.
sound the appropriate alarm. The volume of the audible
alarms is adjusted by a variable potentiometer located
Therefore, the maintenance person must read the technical
b e l o w the test push buttons. The operator or
maintenance person uses this test to make sure the
Malfunctions that occur in the EOOW/LU are the
audible alarm circuits are functioning properly.
responsibility y of the GSEs. As a GSE, you must handle
T h e lamp test of the SCU is conducted by
any problems that arise. Since many different systems
d e p r e s s i n g the LAMP TEST push button on the
are monitored from the EOOW/LU, you will have to
t h r u s t / a u x i l i a r y panel. When the push button is
understand the problems that are presented. Always
depressed, all indicators will light, all LED meters
refer to the manufacturer's technical manual when you
segments will light to indicate frill scale, and the digital
perform maintenance on the EOOW/LU.
displays will indicate all 8s. You will use this test to
Use of the technical manual is essential when you
make sure the lamp circuits are functioning properly.
a r e troubleshooting any problem or fault in the
EOOW/LU. The console contains circuits that interact
w i t h the circuits in other electronic systems and
consoles. Consequently, it will be impossible for you to
The SCU uses the MCS to monitor and control its
troubleshoot the EOOW/LU without using the technical
associated engineering systems. It also uses the DMS to
manual. Troubleshooting a problem or fault in the
c o m m u n i c a t e with the other consoles. Planned
EOOW/LU is the same as troubleshooting a fault in the
maintenance is conducted on the MCS according to the