Power Circuits

TM11-5895-932-14&P

(4) The electrical circuit that is set up when the

b. Internal circuits are 45 identical switches and

operator presses the alarm switch results in

components used for controlling the alarm and items

energizing the coil in S2 (alarm switch). Current flow

common to all circuits such as power.

is now routed through limiting resistor, R2, through

(1) Following an alarm ground, generated by

the coil of S2, which holds the armature and switch

the closing of a switch, left side of figure 5-2,

S2 in the locked position, and through diode CR2 to

through the main connector pin 1, the following

ground. This condition holds until the alarm ground

action occurs: diode CR1 and CR2 are forward

on the input to the alarm panel is removed by

biased; one path of current flows through CR1,

clearing the trouble which caused the alarm.

indicating lamps (part of S2), voltage dropping

(5) To test the lamps on the alarm panel, switch

resistor R1, to the negative power supply connected

S1 is provided. When the switch is pressed, a ground

at pins 57 through 60 of the main connector. The

is connected to the input of all 45 alarm switch

indicating lamps are part of switch S2 and cause the

circuits. They are all similar to circuit #1 shown.

segment on the front panel representing the alarm to

Diodes CR3 and CR135 are forward biased and

light, signaling the alarm condition.

(2) The other current path is through diode

current flows through each individual lamp from the

CR2 through the relay contacts to pin 46 of the main

negative power supply.

connector . This path provides an interuptable

5-4. Power Circuits

output ground (at pin 46) which goes to the audible

NOTE

alarm. The other side of the audible alarm (not

Main ac power is first distributed through

shown) is connected to the -48 vdc supply. The

the distribution box located near the door.

current path is from the negative 48 vdc supply to

Power for operation of the patch and test facility are

the audible alarm; to pin 46 on the alarm panel;

provided as follows: alternating current (ac) is

through the normally closed switch contact of S2;

provided through power distribution boxes located

through forward biased diode CR2; to pin 1 on the

in the main room and crypto vault (fig. l-l); direct

main connector on the alarm panel.

current (dc) is provided by the dc power supply

(3) As the result of the alarm ground input to

located in bay 1.10. Schematic and wiring diagrams

the alarm panel, the indicator lamps light and the

for power distribution are provided by figures 5-3,

audible alarm sounds. The operator responding to

5-4, 5-5, and 5-6.

the alarm, presses the alarm switch (lighted panel

segment) on the alarm panel front. This action

silences the audible alarm and sets the alarm switch

into the manual lock, or latch position.

5-5