Electrical Flashcards
(109 cards)
What type of power to most of our generators produce
AC
What type of power does the aircraft use
115VAC and 28VDC electrical power
What’s our primary source of electrical power
- AC electrical power
- supplied by 2 engine driven integrated drive generators
What’s a transformer rectifier unit (TRU) do?
Converts 115VAC to 28VDC power
What does the AC power center (ACPC) do?
Distributes power to all AC buses during normal operations
What’s an IDG?
It’s an “integrated drive generator. It consists of a constant speed drive and a generator. It’s the aircrafts primary source of AC power.
What are our alternate electrical sources
The Auxiliary Power unit (APU) and Air Driven Generator (ADG)
GCU fault protection
- Over/under voltage
- over under frequency
- generator phase sequence…
Electricity generation altitude limitations
Engine IDG’s = 41,000
APU. = 41,000
ADG…
Integrated drive generators
- Consists of a generator and a constant speed drive
- Constant speed drive takes variable N2 and produces a constant 12,000RPM generator speed. This creates a consistent electrical output.
When will the IDG FAULT switch light illuminate?
The IDG FAULT switch light illuminates on the overhead panel when there’s either high IDG oil temperature or low IDG oil pressure.
QRH checklist types
Command, response type
What’s the correct response to a request to confirm something with the other pilot?
Either “I agree” or “no’”
What happens when you hit the IDG fault switch on the overhead panel
The disconnect solenoid moves, which allows the disconnect plunger to engage the IDG worm shaft and disconnects the IDG by spreading the jaw tooth clutch.
IDG critical temperatures
At 168ºC IDG oil temp, the fault light will come on
At 186ºC the hot IDG oil will melt the disconnect solenoid sauter point and disconnected the IDG automatically
What are the different AC buses?
Bus1
Bus2
Ess bus
Serv Bus
AC BUS 1 power priority
- 1st from IDG 1
- 2nd priority is to get electricity from APU generator
- 3rd priority is IDG 2
- 4th priority is external ground power
What’s the ground power priority?
Lowest power priority. You have to turn off APU and engine to get ground power to work.
AC BUS 2 power priority
1st is IDG 2
2nd is APU generator
3rd is IDG 1
4th is External power
AC Essential bus power and faults
- Gets is power from AC BUS 1, and therefore its generally powered by IDG 1.
- If the AC BUS 1 loses power, AC BUS 2 will automatically power the AC ESS BUS
- The AC ESS XFR switch light illuminates any time the AC BUS 1 has failed and is being powered by AC BUS 2. If it doesn’t automatically switch to being powered by by AC BUS 2, pressing the switch light will manually switch to AC BUS 2
AUTO XFER inhibit switch light
- FAIL: illuminates when a bus fault or generator overcurrent is detected by the GCU. The affected generator is taken offline. The GCU automatically inhibits the auto transfer system on the affected side.
- Pressing the switch light turns off the Bus 1/2 respectively. Hitting it again turns the bus back on.
AC external power switch light
- AVAIL means the ground power is connected and is the correct voltage, frequency, and phase
- IN USE means that the aircraft systems are being actually power by ground power
Ground power control panel and plug in location
… I’ll get back to it…
AC external service switch
-Looks like the internal switch light. Pressing the external switchlight only powers the SERV bus.