flexible couplings, a distance piece, and an aft
system, the water wash system, and the bleed air
system. In this section, we will present a more
adapter, which mates with the reduction gear
high-speed pinion. The forward and aft adapters
detailed description of these systems for the
LM2500 GTE.
are connected to the distance piece by the
flexible couplings. The flexible couplings allow
START AIR SYSTEM
for axial and radial deflection between the GTE
and the ship's drive system during operation.
The start air system provides compressed air
Inside the aft adapter and the aft flexible
to rotate the engine starter through the accessory
coupling is an axial damper system which has a
drive. The starter rotates the GG for starting,
cylinder and piston assembly. The damper
motoring, and water washing. The system uses
assembly prevents excessive cycling of the
either engine bleed air or HP air on the CG-, DD-,
flexible couplings. Antideflection rings restrict
class ships. The FFG-class ships use HP
radial deflection of the couplings during shock
air as the primary start system and diesel-driven
loads.
start air compressors (SACs) and engine bleed air
as secondary start air systems.
The start air system (fig. 2-40) has a pneumatic
turbine starter and a starter (air regulating) valve.
ENGINE SYSTEMS
The starter is mounted on the aft side of the TGB
(AGB). The starter valve is line-mounted behind
Engine control systems were discussed briefly
in chapter 1 of this TRAMAN. They consist of
the starter. The starter drives the GG through the
the start air system, the fuel and speed-governing
gearbox during the start cycle. It drives it until
system, the synthetic lube oil system, the ignition
the GG reaches or exceeds self-sustaining speed.
Figure 2-40.--LM2500 GTE start air system.
2-33
