TM 11-5855-217-12
tion, and only infrared light is projected from
the searchlight. When the power switch is at
a. General. When the 28-volt dc source is con-
VISIBLE, the IR filter drive motor retracts the
nected to the searchlight set, dc power is dis-
IR filter away from the xenon lamp (A, B, and
tributed but is not available to the searchlight
until the power switch is placed in either the
from the searchlight.
INFRARED or VISIBLE position. When the
power switch is at INFRARED or VISIBLE, the
c. Reflector. The reflector collects the light
lamp igniter operates, causing the xenon lamp to
emitted by the xenon lamp and directs it into a
ignite. After ignition, the 28-volt dc operating
beam. The focus drive motor is used to change
circuit is applied to the xenon lamp to sustain the
the shape of the reflector and deflect a portion of
the light beam upward. The reflector does not
volt dc circuit is also used to operate the IR filter
move but is held rigidly to its mount while being
and focus drive motors and provide power to the
slightly deformed by the deflector mechanism.
blower motor in the air-to-air heat exchanger.
d. Focus Drive Motor. The focus drive motor is
b. Infrared Filter. The static position (power
used to change the shape of the reflector assembly
switch set to OFF) of the IR filter is that it com-
and the position of the xenon lamp, thereby chang-
pletely surrounds the xenon lamp (D, E, and F,
ing the beam width. The normal unchanged con-
figuration of the reflector assembly with the
at INFRARED, the IR filter does not change posi-
xenon lamp located at its focal point will cause the