Transformer A1T1 provides 115 V to chopper assembly A1XA1 which is used to produce the 30 KV pulse
ignite voltage for the xenon lamp A2DS1.
When main contactor A1K1 is energized, approximately 80 VDC is applied between the anode and cathode
of xenon lamp A2DS1. The 80 VDC is also used to energize AC ignite relay A1K2, through the voltage regula-
tor network consisting of dropping resistor A1A2R1 and 50V regulating zener diode A1A2CR2 in parallel with
isolating diode A1A2 CR1 and capacitor A1A2C1. The voltage regulator network along with the DC resistance
of the ignite relay A1K2 and capacitor A1A2C1 form an auto start-up circuit to ignite the xenon lamp automati-
cally when remote control panel STANDBY/ON/IGNITE switch A3S1 is positioned to on. The auto start-up cir-
cuit functions when ignite relay A1K2 is energized and capacitor AlA2C2 begins to charge. Capacitor A1A2C2
after approximately 40 ms or 1RC time constant causes the voltage across ignite relay A1K2 to drop below
20 VDC, de-energizing the relay. Capacitor A1A2C2 will stay charged as long as the main contactor A1K1 is
energized and will discharge through resistor A1A2R5 when the main contactor A1K1 is de-energized.
The searchlight is controlled from the remote control panel (A3) which consists of STANDBY/ON/IGNITE
switch A3S1, POWER ON lamp A3DS2 and VARIABLE BEAM WIDTH control switch A3S2. The STAND-
BY/ON/IGNITE switch is a two position STANDBY/ON switch with a momentary IGNITE position. With
STANDBY/ON/IGNITE switch A3S1 in STANDBY, POWER ON lamp A3DS1 is off and main contactor relay
A1K1 and elapsed time meter/blower fan relay A1K3 are maintained de-energized by removal of ground
return through switch A3S1. With main contactor relay A1K1 de-energized, main DC operating and ionization
power is removed from the anode of xenon lamp A2DS1. During STANDBY, capacitor A1C1 is charged to 80
VDC by the 80 VDC supply and 115 VAC is provided from A1T2 for operation of blower fans A1B1 and A2B2
through contacts 1 and 4 of de-energized relay A1K4. Relay A1K4 is maintained de-energized through time
out timer A1TMR for approximately 18 minutes to apply 115 V to operate the blower for cooling. If the search-
light remains in STANDBY for longer than 18 minutes, relay A1K4 will energize and blower power will be cut
off.
When remote control panel STANDBY/ON/IGNITE switch A3S1 is positioned to ON main contactor relay
A1K1 energizes. With A1K1 energized, 80 VDC is initially applied to the anode of xenon lamp A2DS1 on the
searchlight head assembly. The 80 VDC is also applied through resistor A1A2R1, diodes A1A2CR1 and
A1A5CR2 and capacitor A1A2C1. Diode A1A2CR2 is a 50V zener diode which will hold the voltage to igniter
relay A1K2 at 50V. Igniter relay A1K2 energizes and remains energized for approximately 40 ms or 1RC time
constant of capacitance of A1A2C1 and the DC resistance of igniter relay A1K2. During this period 115 V is
applied to chopper assembly A1A1 which produces pulses that are applied to the primary winding of high
voltage transformer A2T2. The secondary winding of high voltage transformer A2T2, in conjunction with
capacitor A2C1 and spark gap A2A2, then produces 6KV pulses which are applied to step up transformer
A2T1 resulting in approximately 30KV pulses. The 30KV pulses are then applied to the cathode of xenon
lamp A2DS1. The 30KV pulses arc across the lamp to the anode allowing the 80 VDC from capacitor A1C1 to
discharge through the lamp and ionize the xenon gas. The anode return for the 30KV pulses is via capacitor
A2C4. As soon as the xenon lamp is conducting, the 20 VDC operating voltage then provides current for
xenon lamp A2DS1 operation through shunt resistor A1R1. Capacitor A2C3, and A1C2 are rf decoupling
capacitors, while diodes A1CR3 through A1CR2 are spike suppressors.
Momentarily holding the STANDBY/ON/IGNITE switch in IGNITE will apply +24 VDC to ignite relay A1K2 ter-
minal 1 forcing it to energize. Energizing the relay will again apply 115 V to the chopper assembly as in the
ON position. The IGNITE position is provided as a manual means of igniting the lamp especially during very
cold weather or where normal lamp aging requires additional ignite pulses.
Once the xenon gas is ionized by the high voltage (30KV) pulse the xenon lamp will conduct at the main DC
operating (20 VDC) levels. The xenon lamp will continue to conduct as long as the main DC operating voltage
is applied to the anode.
The searchlight beam width is controlled via the remote control panel VARIABLE BEAM WIDTH switch A3S2
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