On the CG-, DD-, and DDG-993 class ships, the
No. 2 GTGS is located in main engine room (MER)
GTGS module receives carbon dioxide (C02) from the
No. 2. The No. 3 GTGS is located in the generator room.
fire-extinguishing system. On the DDG-51 class ships,
In each ship class, the engine arrangements and
t h e GTGS module receives Halon from its
relative locations of the GTGSs separate each GTGS by
at least three watertight bulkheads. his placement of
the GTGSs reduces the chance of total loss of electric
ALLISON 501-K34 VERSUS
power resulting from battle damage.
THE ALLISON 501-K17
If you have not recently reviewed chapter 3 of the
Monitoring and Control
Gas Turbine Systems Technician (Electrical) 3/Gas
Turbine Systems Technician (Mechanical) 3, Volume 2,
In each ship class, the GTGSs can be started and
NAVEDTRA 10564, you should at least make certain
monitored either locally at the local operating panel
you understand the basic design and operational features
(LOCOP) mounted on the generator end of the unit or
of the Allison 501-K17. In this section, we will discuss
remotely from the SWBD or the EPCC in the CCS. The
some basic design differences between the Allison
LOCOP contains the electronic controls that sequence
501-K17 and the newer K34 model found on the
and monitor the operation of the GTE. Control of the
DDG-51 class ships. After studying the information in
generator voltage, frequency, and circuit breaker is
this section, you should have a better understanding of
available at either the EPCC or the switchboard.
the design changes in the newer engine and how these
changes make the KI7 and the K34 different.
In discussing the differences between the two
engines, we will describe the basic changes to the
Each GTGS is a module consisting of a GTE, a
equipment in terms of design and location. We will only
reduction gear assembly, and a generator. These main
briefly mention the changes to equipment operating set
components are mounted on a common base with the
points or parameters, as these changes are minimal. In
associated engine controls and monitoring devices. The
fact, we will mention them only to give you a basis for
GTE and the reduction gear assembly are housed in an
comparison. Remember, all equipment set points and
parameters are listed in your ship's EOSS and in the
applicable technical manuals.
On the CG-, DD-, and DDG-993 class ships, each
generator has a remotely mounted generator control
Engine Foundation and Enclosure
unit. The lube oil cooler for each gas turbine/reduction
gear system is mounted under the module base.
Let's first look at the changes made to the engine
foundation and its enclosure because most of the
On the DDG-51 class ships, the configurations for
the generator control unit and the turbine lube oil cooler
configuration changes from the Allison 501-K17 to the
are somewhat different from those on the other ship
K34 model are in these areas.
classes. We will point out these configuration
In the Allison 501-K34, the foundation and
differences later in this chapter.
enclosure for the engine are larger to provide more space
for the internal and external equipment additions and
In all ship classes, each GTGS has its own seawater
modifications. Actually, the size of the original
cooling system, lube oil system, and start air system.
Each GTGS module receives cooling and emergency
equipment on the older engine did not change. The
engine foundation for the K34, however, had to be made
cooling water from the seawater service system, fuel
from the engine room's fuel oil (FO) service system, and
longer to accommodate both the additional equipment
gas turbine cleaning and rinsing solution from the water
and the relocation of the LOCOP.
wash system. It also receives starting air from the bleed
(low-pressure) air system and high-pressure air systems
new equipment items. Notice also that the location of
and signal air from the ship's service air system (SSAS).
some of the equipment on the K34 is different from that
On the DD- and DDG-class ships, the GTGS
on the K17. Notice on the K34 how several new pieces
module is cooled by air supplied from the intake system
of equipment are located on the generator end of the
foundation. Refer to figure 7-1 as we describe the design
through a single electric fan. On the CG-47 class ships,
and location of some of these new items. Remember, the
cooling air is supplied from two fans.