AMETEK Compact i/iX Series Software Manual - Manual (Page 62)

User Manual – Rev H California Instruments
62 Avionics Software
4.2 –B787 Power Groups
The following twelve power groups are covered in the Boeing 787B3-0147 directive:
Category reference:
- For ac equipment: 115V L-N, 235V L-N
- For dc equipment: Type 1 through Type 5, and Type 6 for Rev B and C
Definitions:
AC Power Sources: Variable frequency primary AC power will be supplied by either a 230V L-N
(400V L-L) or 115V L-N (200V L-L) nominal, 360-800 Hz nominal, three-phase, four wire, Y (wye)
connected system. The neutral of the system is connected to the current return network and the
current return network is considered to be the fourth wire. Phase rotation is in the order A, B, C. The
current return network is also referred to as the airplane electrical power return and grounding
protection path.
Variable frequency single-phase AC power is obtained by connection to any one line and the current
return network.
This system includes multiple, engine driven power-generation channels. The output characteristics
of these individual electric power channels will remain within the limits specified herein, but will not
necessarily be identical.
Ground Handling Equipment: Ground Handling Equipment has a constant frequency and these
tests are kept separate from the variable frequency AC tests.
Type I DC Power: Type I DC power will be supplied by a 28 volt (nominal), two-wire, Transformer
Rectifier Unit (TRU) powered by the primary AC system, without battery backup. The negative
terminal of the TRU is connected to the current return network and the current return network is
considered to be the second wire.
Type II DC Power: Type II DC power normally will be supplied by the Type I DC power sources. A
24 volt (nominal) storage battery system will be an alternative backup source of Type II DC power.
Type III DC Power: Type III DC power will be supplied by a 24 volt (nominal) storage battery system
with backup by a battery charger.
Type IV DC Power: Type IV DC power will normally be supplied by a 28 volt (nominal) converter
regulator (Power Supply Assembly) powered by dedicated Permanent Magnet Generators (PMGs) on
one or more engines. Backup sources of power for the converter regulator include: Type I DC power,
the standby system main battery and the RAM air turbine generator.
Type IV DC power is provided exclusively for the Fly-By-Wire flight control system and dependent
equipment.
Type V High Voltage DC Power: Type V High Voltage DC (HVDC) power will be a +/-270 volt
(nominal) system supplied by a two-wire, Auto-Transformer Rectifier Unit (ATRU) system powered by
a variable frequency 230V L-N (400V L-L) nominal primary AC system.
The voltage of the two output terminals of this system with respect to ground will be +270 and –270
volts respectively. All +/-270 volt equipment shall be connected between the +270 and –270 volt
terminals.
Note: The Type V HVDC system nominal voltage has been initially defined at +/-270V. The nominal
voltage may change by as much as +/-20V.
Type VI High Voltage DC Power: Type VI DC power will be a +/-130 volt (nominal) system supplied
by a two-wire, Electric Brake Power Supply Unit (EBPSU) system powered by either the Type I DC or
Type III DC power system.