condition, the upper display lamp will go out, the
communication systems provide audible and visible
signaling devices to safeguard machinery and
lower display lamp will come on, and a steady alarm
tone will sound.
STANDBY MODE.-- The STANDBY mode is
used to acknowledge an alarm. During an alarm
SYSTEM (CKT F)
condition, the mode switch is shifted to STANDBY to
silence the audible alarm. The upper display lamp will
Circuit F provides a means of detecting and
stop flashing and remain on, and the lower display
warning of the presence of overtemperature or smoke
lamp will come on and remain on. When the alarm
in compartments requiring continual supervision; that
condition is cleared, the lower display lamp will begin
is, ammunition spaces, flammable stowage areas,
flashing, and the upper display lamp will go out. The
living spaces, or other spaces designated by ship's
alarm module sends a signal to the tone generator and
design. This system is classified as semivital readiness
a steady tone will sound on the loudspeaker. The mode
switch is then returned to the NORMAL mode to
silence the alarm.
Figure 9-16 illustrates a high-temperature alarm
circuit using a mercury thermostat as the sensing
CUTOUT MODE.-- The CUTOUT mode is used
device. This system is of the supervisory closed-
when maintenance needs to be performed on a line. In
circuit type, whereby each detector line and associated
this mode, power is disconnected to the individual
relay coils on the high-temperature alarm switchboard
line, the upper display lamp will go off and remain off,
form a closed circuit, which is under continuous check
and the lower display lamp will come on and stay on.
for grounds, open circuits, low temperature, or the
There is no audible signal associated with this mode.
normal function of the system.
The position of the mode switch disconnects power
from the sensor circuit to allow maintenance to be
The presence of smoke or a rise in the temperature
within the compartment to a predetermined temper-
ature (105°F, 125°F, or 150°F) will create a bridge on
TEST MODE.-- The TEST mode is used to
the line that will actuate an alarm module in the
simulate an alarm condition. In this mode, the upper
high-temperature alarm switchboard. The nameplate
display lamp will flash continuously, a wailing tone
on the alarm signal designates the compartment in
will sound, and the lower display lamp will remain off.
which the alarm condition exists.
Power supplies furnish operating power to the
An extremely low temperature in a compartment
alarm modules, their sensors, and to a common circuit
or open circuit in the line will result in a failure of the
board in the common alarm section. The power
supervisory current, causing a supervisory alarm on
supplies consist of one transformer and one bridge-
type diode rectifier for each 10 alarm modules. The
output voltage is approximately 6.3 volts rms.
GAS TURBINE AND DIESEL GENERATOR
A power failure alarm will sound if a primary
HIGH-TEMPERATURE ALARM AND
power failure occurs. A battery in the alarm
FLAME DETECTION SYSTEM (CKT 1F)
switchboard operates the power failure alarm upon
loss of primary power. The battery is float charged by
Circuit IF provides a means for alarm signals to
a taper charger while primary power is applied. The
indicate high temperatures and detection of flame
alarm switchboard is inoperative unless the battery is
within the acoustical module enclosures for gas
connected. A power failure is indicated when the
turbine and diesel generators. This system is classified
upper and lower module lamps are out, and a pulsating
as semivital readiness class 1.
tone is heard from the alarm speaker.
To serve each gas turbine, two temperature
switches are located in the acoustic cell and three
ELECTRICAL ALARM, SAFETY, AND
flame detectors are located at critical points about the
gas turbine. A manual push button is located adjacent
to the enclosure access. In addition, door switches are
The following sections will describe the various
installed at the enclosure access and vent fan control
alarm and warning systems that you, as an IC
switches are provided at the local operating station and
Electrician, will be involved with. These interior
at the propulsion control console (PCC).