regulated at 22 psig (motoring position). The last valve
control circuits to select a lead pump and a standby
in the GTE start air flow is the starter air valve. This
pump. Pump control is then a function of lube oil header
pressure and time.
valve is controlled either manually or automatically at
the PACC, if GTE control is transferred to the PACC.
Lube oil pump control is transferred to the PACC
The last valve in the GTGS start air flow is the starter
by depressing the control transfer switch at the PLCC.
air valve that is controlled by the GTGS's system.
The PACC commands are sent over the serial data bus
Emergency start air is started by depressing the
to the PLCC. The PLCC pump control circuitry then
i n i t i a t e s the proper signals to the pump motor
EMERGENCY push button on the PACC. This action
controllers.
causes air from the high-pressure storage flasks to be
available for GTE starts. The high-pressure air is
reduced and enters the GTE start air system upstream of
Air System
the motor air regulator valve.
There are two main air systems associated with the
Masker Air System.-- The masker air system causes
GTEs and the GTGSs: (1) the bleed air system and (2)
the start air system valves to line up to one of two
the high-pressure air system. The bleed air system and
possible states depending on whether masker air is on
high-pressure air system are interconnected by piping
or off and if the air system is in automatic control mode.
and valves. These systems are monitored and controlled
For the first condition (masker air on) after a start
at the PACC. Control is available continuous y and
sequence, the start air system valves will automatically
simultaneously at both the PACC and the PLCC.
align to allow masker air to the masker air belts. For the
second condition (masker air off) after a start sequence,
BLEED AIR SYSTEM.-- We will look at the bleed
the masker transfer valve will remain in the start
air system in terms of its four distinct subsystems:
position. Both valve alignments can be performed
1. Starter air
manually from the PACC.
2. Masker air
Prairie Air System.-- The prairie air system controls
consist of a prairie air supply valve. The PACC control
3. Prairie air
operates prairie air in both engine rooms from one
4. Anti-icing air
ON/OFF push-button indicator. If one of the prairie air
supply valves fails to respond to a command, the failure
Located in each bleed air line for each GTE is a
is shown by a lack of illumination of both sections of
motor-operated bleed air valve. The position of the GTE
the indicator push button.
bleed air valve can be controlled manually at the PACC
as long as GTE control is transferred to the PACC. This
Anti-icing Air System.-- The anti-icing system
valve can be controlled automatically by the start/stop
includes a bleed air injection system and an electrical
sequence logic circuits. There are status indicator lights
intake heater system. The bleed air injection system is
on the PACC that show the position of the bleed air
used to increase the intake combustion air temperature
valves.
for the GTEs and GTGSs. The electrical heater system
is used to prevent ice formation on the stack intake
The GTGS No. 3 has a bleed air isolate valve that
louvers and blow-in doors. The intake heater controllers
can isolate the GTGS No. 3 bleed air from the rest of the
must be in the ON position for the PACC push buttons
ship's system. The ISOLATE push button, located on
to operate the heaters.
the PACC, is illuminated when the valve is closed and
No. 3 GTG is isolated. On the CG-47 class ship, the
The bleed air injection system anti-icing system
G T G S solenoid-operated bleed air valves can be
monitoring is available at the PACC for each GTE and
controlled from a bleed air valve control panel in CCS.
GTGS. The injection of bleed air is manually controlled
by operating personnel.
Starter Air System.-- The starter air system has
three operating modes available at the PACC: (1)
HIGH-PRESSURE AIR SYSTEM.-- The high-
normal, (2) emergency, and (3) motor.
pressure (HP) compressed air system provides HP air to
Normal start air is used during a normal start
the weapons systems, aviation equipment, gas turbine
sequence. The start air for the GTE is controlled by the
starting, and backup for the ship's service air system.
motor air regulator valve. This valve is controllable at
This system consists of two vertical reciprocating air
compressors, various storage flasks, two dehydrators,
the PACC and provides one of two functions: valve
opened nonregulated (start position) and valve opened
and a piping distribution system.
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