AC/DC Power Flashcards
How man IDGs (integrated drive generators)
2 - 115VAC, 400 Hz, 40 KVA
APU Electrical power is
1 generator 115VAC, 400Hz, 40 KVA
Other power source
1 RAT (ram air turbine) puts out 115VAC, 400Hz, 15KVA
How man inverters
1 - 250v
How man IDG to power aircraft
1 IDG can power both AC buses on ground and in flight
APU power
Can power both AC buses on ground and in flight up to 33,000 feet
IDG (integrated drive generator)
- Primary AC power
- One on each engine
- AUTO - system logic controls contractor
- OFF - opens contractor
- DISC - mechanically disconnects the CSD (constant speed drive) from IDG
- Flight crew cannot reconnect the IDG (MX function only)
- Amber light when accompanied by an EICAS oil message indicates IDG disconnect is required
APU (auxiliary power unit)
- Secondary power source
- Batt 1 and 2 or Batt 1 and the DC GPU required to start
- Batt 1 is used to control the APU FADEC
- Batt 2 is isolated from the network during APU start to exclusively power the APU START BUS
- 22.5 VDC mini for APU START
- 18.0 VDC min required to close the battery contactor
- Mini BATT 2 temp for start is -20c
AC GPU power (ON)
Turn on 3 ways
- AC GPU panel (only powers ground service bus)
- Opposite FWD Lav (only powering the ground sec/bus)
- Cockpit on overhead panel
GPU Power when?
- CAS Message MASTER CAUTION
- AVAIL light
- IN USE powering AC system
AC electrical power priority
- Onside (IDG)
- Inside (APU)
- Outside (GPU)
- Cross-side (Other IDG)
Inverter powers
Powers the AC STANDBY BUS when normal AC power is available
RAT (ram air turbine) Power below 130 Knots
- Provides power only to AC ESS
- BATTS will provide power to DC ESS and AC STANDBY
- As airspeed decreases, load shedding occurs until AC ESS is no longer powered
RAT (ram air turbine) will deploy
- Will deploy with no altitude or airspeed restriction
- Automatically deploys if both AC buses lose power during flight to supply the ESS buses
- Manual deployment is available if necessary
- Deploys in 8 seconds (aircraft batteries provide power)
DC electrical power consists of
- 3 TRUs (transormer rectifier units) 28DC, 300A
- 2 Batteries 24VDC, 27 AH
- 1 DC GPU - 28VDC