SHIP'S SERVICE GAS TURBINE
Until now our discussion has centered on the
the equipment is usually required to log
propulsion uses of GTEs. This means we have
parameters not otherwise observed. Most often
covered only part of the job tasks of GSs. On the
these monitors are GSs in the junior paygrades
larger gas turbine ships, such as the DD,
(E-5 and below). You will need to be able to
and CG classes, GSs must maintain the ship's
quickly identify any impending casualty to the
service gas turbine generator sets (SSGTGSs).
GTGS to prevent loss of the ship's electrical
These ships use four different gas turbine
power. To do this, you must first understand how
generator sets (GTGSs). The model 104 is found
the set is constructed, how its systems function,
on the DD-class ships, the model 119 on
and how to operate it.
ships, and the model 139 on CG-class ships.
After reading this chapter and completing the
The model 170 GTGS is found only on the USS
associated nonresident training course (NRTC),
Paul F. Foster (DD-964). It is very similar to the
you should be ready to begin qualification as an
model 104. Except for the 51 class ships,
engine-room equipment monitor and as an EPCC
all of the GTGSs use the Allison 501-K17 GTE
operator. You should also be able to identify and
as a prime mover. The 51 class ship uses
describe a majority of the GTE and generator
the Allison 501-K34, a modified version of the
components. You should be able to understand
K17. In this chapter we refer to the Allison
the operations of the various engine systems and
501-K17 (K34) as the GTE, the engine, or the
the generator control and monitoring equipment.
prime mover. Although the engine is the same on
You should understand the procedures for
all sets, many differences exist between the units.
starting, stopping, and motoring a gas turbine
generator (GTG) locally or from the SWBD. You
Models 104 and 170 GTGSs are 2000-kW GTGSs;
should also be able to understand frequency and
models 119 and 139 are 2500-kW GTGSs. Models
voltage control functions.
104, 119, and 170 have solid-state local operating
control panels (LOCOPs) that use analog meters;
The EOSS gives you the correct procedures for
the model 139 incorporates a digital LOCOP with
operating this vital piece of machinery. Always
light-emitting diodes (LEDs) used to display
use the EOSS when actually operating any
engineering equipment. Using the EOSS will
operating parameters. Models 119 and 139 use a
brushless exciter that replaces the brushes and slip
prevent you from missing any steps/procedures
that could result in damage to a valuable piece
rings found on the 104 and 170. Many other
differences exist between these GTGSs. We will
of ship's equipment.
discuss most of these in detail in this chapter.
Model 170 incorporates features from each of the
NOTE: Directions in this chapter relate to an
other three models. It will not be discussed
observer standing at the exhaust end of the GTGS
looking toward the generator (aft looking
separately in this chapter.
Normally the GTGS is not attended while it
is in operation. It is controlled either at the
switchboard (SWBD) or the electric plant control
GENERAL DESCRIPTION OF THE
console (EPCC). The EPCC operators are the
watches that monitor the electric plant. They are
responsible for taking action to prevent loss of
Ship's service electric power is provided by
the electrical load during a generator casualty.
three 2500-kW GTGSs on the CG-class ships. On
Neither control station can monitor all the
parameters of the operating GTGS. For this
electric power is provided by three 2000-kW
reason, a monitor who makes hourly rounds of