Two resistance temperature detectors (RTDs) are
not have a remote control mode, therefore, there is no
provided in the jacket water outlet line from the diesel
LOCAL/REMOTE indicator on the EPCC for this
switchboard.
engine. One detector provides a signal to the EPCC to
provide continuous display and to actuate a HIGH
TEMPERATURE audible and visual alarm. The second
Shore Power Monitoring and Control
detector supplies a signal to an indicator mounted on the
diesel engine gauge board. A temperature switch is also
The EPCC can monitor the seven breakers
located in the diesel engine jacket water outlet piping.
connected to shore power. At the EPCC, the operator can
The switch energizes a high temperature alarm on the
trip all seven breakers by using the TRIP lever. Current
from the shore power source is monitored on a meter
local switchboard.
that reads up to 3,000 amperes. Each of the seven
A pressure transducer, located at the discharge of the
breakers can handle 400 amperes. The status of each
jacket water pump, provides a signal to the EPCC for
breaker is indicated at the EPCC by an illuminated blue
demand display readout. The expansion tanks have both
light indicator. The EPCC only controls the transfer of
a liquid level gauge and a low level alarm. The low level
shore power to ship's power. The transfer of ship's
alarm energizes an audible and visual alarm at the EPCC
power to shore power can only be accomplished by the
when the level drops to 7 1/2 gallons.
3SA switchboard.
The EPCC controls the flow of seawater to the
Engine Fuel Service System
jacket water system by opening or shutting the
motor-operated valve leading from the seawater chest.
A dual-illuminated indicator on the EPCC monitors the
The EPCC provides for remote monitoring of the
SSDG's fuel service system. Alarms at the EPCC
OPEN or SHUT condition of the seawater valve. The
activate when the fuel tank level is beyond the high level
discharge of seawater, after it has picked up heat from
of 90 percent of tank capacity or lower than the low level
the jacket cooler, is routed to the overboard valve. The
of 20 percent of capacity. Engine fuel discharge pressure
EPCC has the control and monitoring functions
and manifold pressure are monitored by the EPCC
associated with this discharge.
through the SCS. Engine fuel discharge pressure is
displayed on edgewise meters on the EPCC front panel.
Supervisory Control System
To avoid transient alarms, the SCS provides a 16-second
delay on the level indicating alarms. We will take a
The program module for the SCS monitors the
closer look at the SCS later in this chapter.
electric plant for failures or degradation of performance.
The program either initiates corrective action or alerts
Auxiliary Fuel Service System
the operator to take corrective action. The supervisory
control is executed during the allotted 50-millisecond
The EPCC controls the suction valves for each of
interval of every 200-millisecond program cycle when
the six auxiliary fuel tanks. The EPCC operator can
the supervisory control mode switch is in the AUTO
control which tank is used to supply SSDG No. 4 or
position. When executed, this function reads the
SSDG No. 1 since they each have two tanks. The SSDGs
SHORE POWER indicator, the supervisory control
No. 2 and No. 3 share two day tanks; therefore, the
mode, and each SSDG control mode. If the electric plant
EPCC operator can only open or close the tanks. The
is on shore power, i f the supervisory control mode is off,
EPCC operator cannot transfer fuel to the day tanks.
or if all SSDGs arc in the local control mode, control is
This transfer must be done locally in auxiliary room
returned to the executive control program. Otherwise,
No. 2.
the status of each SSDG is established, and a bit pattern
is generated to identify the SSDG status and those
Jacket Water System
SSDGs operating in parallel. Each SSDG status is
recorded in a 16-bit computer word and updated each
The jacket water system provides cooling water to
program cycle. You should refer to the appropriate
the jacket of the diesel engine and acts to cool the
technical manual for a detailed discussion on the SCS.
lubricating oil. Each engine is served by its own jacket
Now that you have read about the PCC and EPCC
water system. The water is circulated through each
controls for FFG-7 class ships, let's take a look at the
system by a centrifugal pump that is a part of the diesel
controls at the ACC.
engine.
