Fignre 4-24.--System control assembly.

SYSTEM CONTROL ASSEMBLY.-- The

VOLTAGE REGULATOR.-- Because a supply

voltage fluctuation even as low as 2 volts can cause

system control assembly (fig. 4-24) is mounted at the

compass errors, a voltage regulator was developed for

top of the rear section of the control cabinet and includes

the Mk 19 Mod 3A system. This regulator is designed

switches, a time delay and circuits, and a stepping relay

to be installed in the bottom of the control cabinet and

for cycling the events automatically. These components

provides an output of 115 volts, 400 Hz ac regulated

are required for starting and operating the compass

within 0.75 volt for an input of 115 volts 7 volts. The

system. They operate in conjunction with the switches,

regulator unit (fig. 4-25, view B) is a single chassis

indicators, and relays on the control panel (fig. 4-22) and

containing a diode rectifier circuit, a dc reference circuit,

elsewhere in the system in performing starting and

a differential amplifier, and a corrector circuit. The

control functions.

corrector circuit includes a magnetic amplifier, a

FOLLOW-UP AMPLIFIERS.-- Mounted below

servomotor and gear train, a variable autotransformer,

and a buck-boost transformer. The buck-boost

the system control assembly are the roll, pitch, and

transformer aids or opposes the line voltage with a

azimuth follow-up amplifiers. The three follow-up

voltage supplied from the autotransformer.

amplifiers are identical and interchangeable.

An alarm indicator tube is provided to indicate a

DC POWER SUPPLY.-- Below the follow-up

tube failure and an out-of-tolerance input voltage. In

amplifiers is the dc power supply unit (fig. 4-25, view

addition, the unit contains a magnetic amplifier balance

A) containing the power supply component (metallic

control, a nominal voltage adjustment control, an

rectifiers, filters, and so forth), a monitoring meter, and

automanual switch, and an ac voltmeter to indicate the

an associated selector switch. The unit operates from the

regulated output voltage.

115-volt, 4(X)-HZ, 3-phase supply and furnishes all dc

voltages required for the operation of the various

ADDITIONAL COMPONENTS.-- In addition to

amplifiers and relays in the system.

the components and assemblies previously mentioned,

Fignre 4-24.--System control assembly.

4-19