Figure 3-5.--ACO drawout switch unit.

Panel 3 is supplied with 250 volts dc from one of

the fleet, the ABT is located separate from the

two 450-volt, 3-phase, 60-Hz motor generators. Two

switchboard itself.

stop-start switches, power available indicator lights

for each source, and a voltmeter are located on panel

The normal power supply is from the forward

3. The motor generators obtain their power from the

ship's service distribution switchboard. The

450-volt, 60-Hz, 3-phase bus.

alternate power supply comes from the after

ship's service distribution switchboard. The

emergency power supply comes from the forward

PANEL 4.-- The 450-volt, 400-Hz, 3-phase power

emergency distribution switchboard. The bus

for panel 4 is received from a motor generator or a

may also be energized by a casualty power

static power supply. The 120-volt, 400-Hz, 3-phase

terminal installed on the board, which, in turn,

power is received from a bank of transformers. A

receives its power via portable cable from a

voltmeter, a frequency meter, and an ammeter are

remotely located riser nearby.

also installed on panel 4 for monitoring by watch

standers and maintenance personnel.

PANEL 2.-- The 120-volt, 3-phase, 60-Hz bus

located in panel 2 receives its power from panel

ACO Section

1 via a bank of three 450/120-volt, 60-Hz, single-

phase transformers located in panel 2. This

The ACO section (panels 5 and 6) permits isolation

panel disseminates both 120-volt, single-phase,

of damaged portions of certain IC systems and, in

60-Hz, and 120-volt, 3-phase, 60-Hz power to

addition, allows transfer control of certain systems

various IC and FC systems as required. A

from one station to another. Drawout switch units

voltmeter, an ammeter, and a megohmmeter are

(fig. 3-5) are used, with each unit incorporating the

installed on the front of panel 2 for monitoring

associated JR switch, fuse holders, synchro overload

by watch standers and maintenance personnel.

transformers, and overload indicators.

PANEL 3.-- Panel 3 is supplied with 120

The switches found on these panels are for the

volts dc from the 450-volt supply of panel 1 via

repeater and control circuits of the gyrocompass,

two remotely located rectifiers. A switch on the

wind indicating, propeller revolution, propeller order,

front of panel 3 allows the operator to select

engine order, and underwater log systems.

either of the two rectifiers. Indicator lights on

the panel indicate which of the two rectifiers is

Through the proper manipulation of switches,

in operation.

either the main or the auxiliary gyrocompass may be

Figure 3-5.--ACO drawout switch unit.

3-7