02-24-30
FALCON 7X
PAGE 2
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CODDE 1
ISSUE 2
ATA 24 – ELECTRICAL POWER
SYSTEM PROTECTIONS
DGT97831
DASSAULT AVIATION Proprietary Data
ACTIVE PROTECTIONS
Active protections include:
-
Load shedding of some loads when electrical power sources can not supply all airplane
loads.
-
Generator under/over voltage, current output limitation through automatic disconnection of
the corresponding generator to the bus by the GCU.
-
A shear shaft in the generator to prevent damage to the accessory gearbox in case of
generator seizure. A damper in the generator shaft prevents vibration.
-
Bus short-circuit (or undervoltage) through automatic isolation of the bus by the
corresponding PDCU.
-
Fuses in the PPDB to protect SPDB feeder cables,
-
Conventional mechanical Circuit Breakers in the PPDB,
-
Conventional mechanical Circuit breakers and Electronic Circuit Breaker (SSPC) in the
SPDB.
-
Static dischargers (12) evacuate static currents and prevent severe damages in case of
lightning attachments. Static dischargers are installed on the trailing edge of each wing
and horizontal stabilizer.
LOAD SHEDDING LOGIC
In flight, main load-shedding logics are:
-
PFCS loads: never load shedded,
-
In case of one generator overload: cabin loads are load-shedded,
-
If one generator fails: RH cabin loads are load-shedded until RH battery is sufficiently
charged,
-
If two generators fail: Cabin and Galley loads are load-shedded,
-
If three generators fail: SPDB loads and Cabin and Galley loads are load-shedded.
On ground, the auto load-shed system is disabled, allowing normal operation of all cabin
facilities: with only one generator there is not automatically load shedding of cabin and
galley load.
ELECTRONIC CIRCUIT BREAKERS (SSPC)
The Solid State Power Controller (SSPC) modules are designed to provide overload
protection in the same manner as a conventional thermal circuit breaker. Their overcurrent
protection logic is however not only based on a predetermined threshold, but on various
thresholds which depend on the duration of the overcurrent.
Their status can be modified by software from the cockpit or by connecting to the SPDB.
