Figure 4-36.--Block diagram of the complete alarm system.

any tube in the assembly becomes defective. A failure

the system will give multiple alarm warnings when

in any loop circuit will actuate the alarm and cause a

trouble develops in that loop. In addition, as trouble may

neon indicating lamp to light on the associated computer

also develop in the alarm circuits, the circuits are so

amplifier, or amplifiers, and any tube failure in the

arranged as to give alarm warnings when they

computer control assembly will cause a similar

themselves become defective. This is accomplished in

indicating lamp to light on the computer control

each alarm circuit by using normal tube current to

assembly panel.

energize an alarm relay. (See fig. 4-34). Therefore, if

trouble develops within that circuit to reduce tube

The ship's 400-Hz supply alarm (not shown in fig.

current, the relay will de-energize and actuate the alarm.

4-35) is actuated in the event of failure of any phase of

the ship's 3-phase, 400-Hz supply, or a drop supply

Figure 4-35 shows in block form the points at which

voltage below 104 volts. Undervoltage detection

each loop in the system is alarmed. This figure does not

circuits and associated relays in the system control

show every alarm that will give warning, but merely the

place in the loop where the initial alarm will occur. The

assembly (fig. 4-24) actuate the alarm, disconnect the

complete alarm system may be divided into four

compass from the ship's supply line, and operate the

separate systems: the follow-up alarm system, the

standby supply as a generator. The ship's supply

indicating light (green) on the control panel goes out and

compass control alarm system, the ship's 400-Hz supply

the standby supply light (red) comes on, showing that

alarm system, and the voltage regulator alarm system.

the ship's 400-cycle supply has failed and that the

The follow-up alarm system consists of two alarm

compass is operating on the standby supply.

circuits in each follow-up amplifier. As the three

The voltage regulator failure alarm gives a visual in-

follow-up amplifiers are identical, the alarms in each are

dication of a tube failure in the differential amplifier and

identical. The alarm circuits are the preamplifier tube

for an out-of-tolerance input voltage. A voltage in excess

failure alarm and the follow-up error alarm. Two neon

of 122 volts or less than 108 volts will actuate the alarm.

indicating lamps on each amplifier are provided to give

a visual indication of the source of trouble when an

Figure 4-36 shows a block diagram of the action of

alarm is actuated.

the complete alarm system. The flashing lamps in the

compass failure annunciator are actuated by flasher

The compass control alarm system consists of nine

units in the system control assembly (fig. 4-24).

computer loops and four torque loops. These 13

computer and torque loops have associated with them

Starting Control Systems

11 type 1 and 2 type 2 computer amplifiers, with alarm

circuits. Also, each of the compass control signals pass

To aid in starting and operating the master compass,

through the computer control assembly. An alarm circuit

two auxiliary control systems are provided; the starting

is employed that will actuate the compass alarm when

system and the fast-settling system.

Figure 4-36.--Block diagram of the complete alarm system.

4-33