APPENDIX I
GLOSSARY
AUTOMATIC CONTROL SYSTEM.-- Controls the
ALARM ACKNOWLEDGE.-- A pushbutton that must
PHM during takeoff, landing, and all foilborne
be depressed to silence an alarm.
operations.
ALTERNATING CURRENT (ac).-- An electrical
AUXILIARY POWER UNIT (APU).-- The APU
current that constantly changes amplitude and
system provides ac power to the LCAC and also
polarity at regular intervals.
provides bleed airflow to start the main propulsion
engines. The system consists of a gas turbine
AMBIENT TEMPERATURE.-- The surrounding
generator set, a GCU, an electronic sequencing unit,
t e m p e r a t u r e , such as the air temperature, that
a relay, a current transformer, and built-in test
surrounds a conductor in a compartment or piece of
equipment.
equipment.
BATTERY.-- A device for converting chemical energy
AMBIENT PRESSURE.-- The surrounding pressure,
into electrical energy.
such as the air pressure, that surrounds a conductor
in a compartment or piece of equipment.
BINARY SIGNAL.-- A voltage or current that carries
information in the form of changes between two
AMPERE (amp).-- A unit of electrical current or rate of
possible values.
f l o w of electrons. One volt across 1 ohm of
B I T . -- Abbreviation for binary digit. A unit of
resistance causes a current flow of 1 ampere.
information equal to one binary decision, or the
ANALOG SIGNAL.-- A measurable quantity that is
designation of one of two possible and equally
continuously variable throughout a given range and
likely values or states (such as 1 or 0) of anything
that is representative of a physical quantity.
used to store or convey information.
BLEED AIR.-- Air bled off the compressor stages of the
ANALOG-TO-DIGITAL CONVERSION (A/D or
GTEs. See BLEED AIR SYSTEM.
ADC).-- A conversion that takes an analog in the
form of electrical voltage or current and produces a
BLEED AIR SYSTEM.-- This system uses as its source
digital output.
compressed air extracted from the compressor stage
of each GTE or GTG. It is used for anti-icing, prairie
ARMATURE.-- The moving element in an electro-
air, masker air, and LP gas turbine starting for both
mechanical device, such as the rotating part of a
the GTEs and GTGs.
BRIDGE CONTROL UNIT (BCU).-- The console
AUTOMATIC BUS TRANSFER (ABT).-- Normal
located on the bridge of the DDG-51 class ships that
and alternate power sources are provided to vital
has equipment for operator control of ship's speed
loads. These power sources are supplied from
and direction.
separate switchboards through separate cable runs.
BRIDGE WING DISPLAY UNIT (BWDU).-- Part of
U p o n loss of normal power supply, the ABT
the SCE. Displays actual port and starboard shaft
automatically disconnects this source and switches
rpm and standard orders. One BWDU is mounted
the load to the alternate source.
on the port and one on the starboard bridge wing.
AUTOMATIC
PARALLELING DEVICE (APD).--
BUBBLE MEMORY.-- A read-only device used
The APD
automatically parallels any two
sparingly and considered nonvolatile. This type of
generators
when an auto parallel command is
memory is found in the consoles on the DDG-51
initiated by
the EPCC.
class ships.
BULKHEAD-MOUNTED ELECTRONICS
AUXILIARY CONTROL CONSOLE (ACC).-- The
ENCLOSURE (BMEE).-- Contains the gas turbine
console in the CCS that is used to monitor the
auxiliary systems on FFG-class ships.
e l e c t r o n i c s that interface with the propulsion
AI-1
