400-Hz/208-V AC Distribution System
Scheduled maintenance of the LCAC control
Primary power (400 Hz/208 V ac) is provided nom
systems includes the procedures you must perform for
either external shore power or the two APU-driven
preventive maintenance and performance tests. You will
g e n e r a t o r s . Generator power and shore power is
discover that you must accomplish these procedures on
distributed through the craft using the same busses.
a scheduled or condition monitoring basis.
After the generators are started and power is available,
the generators can be placed online by depressing the
You can find the appropriate scheduled
appropriate switch on the C&C keyboard. The power
maintenance actions in the technical manuals for the
control relays are energized and route power to the main
specific equipment items. Remember, the scheduled
line contractors to energize the aft busses, port and
maintenance instructions in these technical manuals are
starboard. The forward busses are controlled
not intended to duplicate the instructions furnished in
a u t o m a t i c a l l y through relay contacts of the line
the PMS. In the case of conflicts, the PMS
contractors. An isolation power supply wired between
documentation takes precedence.
the battery switchboard and the switchboard control
panels provides isolation between the ac and dc power
MAINTENANCE REPAIR LEVELS
For the LCAC, the maintenance repair levels are
28-V DC Power Distribution System
divided into the following four categories:
All 28-V dc power is provided from two sources:
(1) the storage batteries and (2) the transformer/rectifier
2 Enhanced organizational
(T/R) units. The storage batteries are made up of two
12-volt batteries connected in series. The T/R units
convert 400 Hz/208 V ac to 28 V dc. The 400-Hz load
4. Specialized repair facilities
centers are energized from the APU-driven generators
or from 400-Hz external shore power. The No. 1 and No.
T h e s e repair levels are part of the source,
2 primary dc busses are cross connected through the
maintenance, and recoverability (SMR) codes for each
emergency dc power panels. The reverse current relays
part, subassembly, and module. The SMR codes are
function to prevent damage to the T/R units if a T/R unit
identified and explained in the Coordinated Shipboard
should fail. When shore power or generator power is
Allowance List (COSAL) for the LCAC. Let's briefly
unavailable, the battery serves as the emergency dc
look at each of these levels.
Now that you have read about the LCAC propulsion
control system and the associated components and
systems, let's look at some important aspects involving
Organizational maintenance includes the type of
the maintenance of these systems.
maintenance actions that are performed on the LCAC
craft, afloat. Organizational maintenance consists of all
t h e maintenance actions required to maintain the
LCAC SYSTEMS MAINTENANCE
operational status of the LCAC during deployment.
As with all equipment and systems, the propulsion
control systems and related equipment on the LCAC
Enhanced Organizational Maintenance
must be monitored for effective and safe operation.
Monitoring these systems is also a way of providing
Enhanced organizational maintenance includes the
early warnings concerning potential trouble areas.
maintenance actions that are normally performed on the
In this section, we will talk about the general
LCAC craft, ashore. This level of maintenance normally
consists of craft system troubleshooting, component
maintenance and troubleshooting routines you will
replacement, or part manufacturing. The LCAC craft
e n c o u n t e r with the LCAC control systems and
unit, ashore, is normally a complete repair facility. The
equipment. For detailed information concerning the
procedures you should use for removing and replacing
only maintenance actions that are not performed at this
facility are those that require a depot or specialized
s p e c i f i c parts, we recommend you consult the
appropriate technical manuals.