today's Navy, we will also tell you about some important
housing, a core, a cover plate, and a seawater inlet/outlet
safety considerations you should keep in mind
plate. Each intercooler is shared by two turbochargers
whenever you are working with or around GTEs or your
with an air elbow and hose attached to the air inlet
ship's electric plant equipment.
shutdown assembly with bolted flanges. The air is
cooled by circulating seawater through the core of the
intercoolers.
GAS TURBINE ENGINES
The air shutdown housing is mounted between the
As we mentioned earlier, the Allison 501-K17 is
intercoolers and serves as a plenum chamber for the
the most widely used GTE on board the Navy's gas
intake manifold. The air shutdown assembly is
turbine-powered ships for electric power generation.
mounted in the shutdown housing. It consists of a
This is why we will use the Allison 501-K17 as a
spring-actuated damper (valve) pivoted over the air
standard model as we discuss the general maintenance
outlet to the intake manifold and a shutdown solenoid.
and repair requirements that are fairly common to
The solenoid actuates a latch mechanism to release
most of the GTEs. Remember, even though we may
the valve plate when an emergency shutdown signal
use the Allison 501-K17 as our standard example, you
is received. The emergency shutdown solenoid can be
should be aware that the maintenance requirements
actuated by a signal from the Halon interlock, the
will be applicable to more than one type of prime
e n g i n e overspeed circuitry, or the remote
mover. Wherever necessary, we will indicate the
EMERGENCY STOP push button at the EPCC. A
specific procedures that apply to a particular prime
manual trip cable is also provided at the machinery
mover. To maintain your engine in peak performance,
space access.
you will perform these routine procedures quite
The two roots-type blowers are connected in tandem
frequently.
and mounted to the air box between the cylinder banks.
The two three-lobed rotors rotate in opposite directions
NOTE
to provide supercharged air to the engine. The helical
designed lobes are used because fewer lobes are needed
The contents of this section are provided for
to provide a greater airflow capacity in a smaller size
training purposes only and are not intended to
without sacrificing the smoothness of flow.
replace the authorized maintenance and repair
You have now read about the basic construction,
procedures for your ship. For the authorized
functions, and operations of the electric plants installed
maintenance practices and specifications for
on gas turbine-powered ships. In the remainder of this
your ship, always consult the appropriate
chapter, you will read about some of the important safety
MRCs and technical publications.
requirements and practices you must observe whenever
you are preparing to perform or supervise maintenance
Before continuing with this section, you should take
of these plants. You will also read about some of the
time to refresh your memory concerning the safety
more common routine maintenance procedures for these
precautions you should follow whenever you plan to
plants. As a GSM, you will need to be aware of these
perform maintenance on any GTE prime mover.
procedures and your responsibilities for performing
them correctly.
SAFETY PRECAUTIONS
Chapter 2 of this TRAMAN told you about some
ROUTINE MAINTENANCE AND
of the safety precautions you should use whenever
REPAIRS
you are handling fuels or other hazardous petroleum
products. In the following paragraphs, we will focus
In this section, we will briefly discuss some of the
on the safety precautions you should take whenever
common shipboard maintenance practices and repair
you are performing, supervising, or preparing to
procedures that you, the GSM, will be expected to
perform maintenance on any section of a GTE prime
perform on your ship's electric plant. First, we will take
mover.
a look at some of the more common maintenance
responsibilities you will encounter for your ship's GTE.
Remember, these precautions are general. You
Next, we will tell you about some maintenance
should always follow the authorized guidelines and
responsibilities you will likely have concerning other
specifications for your ship. In fact, the most important
areas of the electric plant. Because it is so important in
safety rule you can follow is to adhere conscientiously
