Figure 2-7.--Signal conditioner block diagram and typical signal conditioner unit.
and shuts it off when inlet air temperature reaches
is transmitted to the signal conditioner to alert the
85 to 95F. The thermostat turns on the blower
operator of fire in the module. On the LM2500
motor at 125F and secures it at 145F.
GTE of the twin-shaft ships and on the Allison
501-K17, it also activates the fire stop sequence
and releases fire-extinguishing agents to extinguish
FIRE DETECTION AND
the fire.
EXTINGUISHING SYSTEMS
The signal conditioner (fig. 2-7) is contained
in a metal box. The box is attached to the
All LM2500 GTE modules have some method
for detecting and extinguishing a fire in the
underside of the base enclosure on the LM2500
enclosure. The sensors used to detect a fire are
GTE. On the Allison 501-K17 GTE, the unit is
located in the alarm terminal box on the generator
identical on all classes. The detection system has
end of the base. Identical detector cards (one
three ultraviolet (UV) flame detectors, a flame
for each UV sensor) are located in the signal
detector signal conditioner, and two resistance
conditioner. The detector card amplifies, rectifies,
temperature elements (RTEs) used as temperature
and filters the current pulses from the UV
switches. The use of these sensors and the fire-
sensor. This provides an output voltage level
extinguishing systems vary with ship classes.
proportional to the UV light level at the UV
Figure 2-6 shows a block diagram and an
sensor. The signal conditioner processes the
exploded view of a UV flame detector. This
input from the UV flame detector and completes
detector senses the presence of fire in the enclosure
the alarm control circuitry outside of the gas
and generates a photoelectric signal. This signal
2-7
