Basic Flashcards
(27 cards)
Basic AC and DC system
115VAC and 28V DC
all power is routed through 5 circuit breaker panels. 4 cockpit, one in aft equipment bay.
AC power sources
2 IDGs
1 APU
1 ADG
EPU
what is an IDG and its numbers
two components
integrated drive, and electrical generator
Provides 115 Vac to 6 AC busses
what is an CSD and the switch lights associated
the constant speed drive speed is maintained at 12000rpm to maintain a constant 400HZ. A Fault light will indicate one of the following : high oil temp, low oil pressure. The DISC light will indicate the IDG has been disconnected either manually or automatically. Cannot be reconnected for either reason while airborne.
When can he IDG be tripped either automatically or mannually
over/under voltage
over/under frequency
generator or buss over current
what kind of protection does the GCU provide?
System protection
Voltage regulation
Buss priority
what are the external AC power switch lights and the meanings
The AVAIL light means the AC is plugged in and providing the correct phase, volts and frequency. When in use switch light is selected by the pilot it will connect the power to BUS 1 and BUS 2
what is the external service panel
Ext service push button outside may activate certain AC power to service persons. may be disconnected by flight crew by selecting the switch off on the panel
when is the ADG automatically deployed and what are its limits
AUTO when all AC power is lost last power source was internal weight off wheels sensed parking break released
manual option available through deploy handle
wet (hydraulic speed controlled) limit VMO
Dry (counter weights) 250 KIAS
improper configs can cause deployment on ground
can only be retracted by maintenance
how could ADG deploy on ground
master off - weight on wheels not detectible
gens reset
last power was internal only
parking break not on
Ground ops DC power is limited to how many minutes and why
5 Mins because display fans are AC and displays will over heat
What are the TRU types and max continuous amps
TRU 1 & 2
TRU ESS 1 & 2
SERV TRU
max continuous 5 min
How long can the aircraft run on only DC while on the ground
5 min . cooling fans are AC for display fans
Name the 5 TRUs and max output
TRU 1 and 2 ESS TRU 1 and 2 Service TRU 100 AMP max continuous Transforms 115VAC to 28VDC
Name the 10 DC busses
2 Busses Main Essential Buss Service Buss 2 Utility Busses Emergency Buss Batt buss APU and Batt Direct Buss
What are the types of DC Buss ties and their functions.
DC Buss tie 1 and 2 used for main TRU 1 and 2 failure. This will automatically load shed Utility Buss 1 and 2 to prevent over loading. The main DC buss tie will automatically or manually close when TRU 1 or 2 fail. The ESS tie is only manually used and will connect the system to the ESS buss and Bat Buss if TRU 1/2 fail. Both cannot be used at once.
What are the Lead acid DC batteries used for?
APU Start and DC backup during flight in the event of AC and ADG failure. 30 min only
What route does the DC power take from the Batteries in the event of a total power loss?
The emergency Tie contractor allows electricity to flow to the Battery bus and ESS buss. power can last for 30 min
The Batteries are charged by which busses
AC utility Buss 1 and 2
What does a White CHARGER message indicate?
Anytime their associated buss (UTIL bus 1 and 2) are powered but the batteries are not charging
What does the DC Bat master switch do when turned on? No AC vs With AC
No AC power: Connects Battery Buss to Battery and APU Direct busses (uses battery power).
With AC power: Arms the Battery Buss to be powered by the direct busses although is actually powered by the ESS TRU and the Batteries are not being used.
What does DC SERV buss switch do when on
Connects SERV buss to APU Direct buss.
IDG Fault switch light illuminates when?
IDG is disconnected from accessory gear box. Now APU powers corresponding BUSS
AC XFER switch light illuminates when
ESS Buss is not being powered by Buss 1. for one of the following situations:
- ESS buss is not being powered by anything
- ESS buss is beings charged by Buss 2
- ESS buss is being charged by the ADG
- Manually selected to charge ESS buss by buss 2
