AC/DC Power

Question 1

How man IDGs (integrated drive generators)

Answer 1

2 - 115VAC, 400 Hz, 40 KVA

Question 2

APU Electrical power is

Answer 2

1 generator 115VAC, 400Hz, 40 KVA

Question 3

Other power source

Answer 3

1 RAT (ram air turbine) puts out 115VAC, 400Hz, 15KVA

Question 4

How man inverters

Answer 4

1 - 250v

Question 5

How man IDG to power aircraft

Answer 5

1 IDG can power both AC buses on ground and in flight

Question 6

APU power

Answer 6

Can power both AC buses on ground and in flight up to 33,000 feet

Question 7

IDG (integrated drive generator)

Answer 7

• 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

Question 8

APU (auxiliary power unit)

Answer 8

• 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

Question 9

AC GPU power (ON)

Answer 9

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

Question 10

GPU Power when?

Answer 10

• CAS Message MASTER CAUTION
• AVAIL light
• IN USE powering AC system

Question 11

AC electrical power priority

Answer 11

• Onside (IDG)
• Inside (APU)
• Outside (GPU)
• Cross-side (Other IDG)

Question 12

Inverter powers

Answer 12

Powers the AC STANDBY BUS when normal AC power is available

Question 13

RAT (ram air turbine) Power below 130 Knots

Answer 13

• 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

Question 14

RAT (ram air turbine) will deploy

Answer 14

• 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)

Question 15

DC electrical power consists of

Answer 15

• 3 TRUs (transormer rectifier units) 28DC, 300A
• 2 Batteries 24VDC, 27 AH
• 1 DC GPU - 28VDC

Question 16

TRUs (transformer rectifier units) Do what

Answer 16

• Primary DC power source
• Convert 115VAC into 28VDC
• Each works in isolation from the other

Question 17

Batteries

Answer 17

• 2 24V SLAB (sealed lead acid batteries

Question 18

Batteries charge by

Answer 18

AC power source thru the TRUs

Question 19

Min volts to close battery contactor

Answer 19

18 Volts min

Question 20

Min battery power from battery during electrical emergency

Answer 20

Provides power for 10 min

Question 21

Electrical power distribution done by

Answer 21

ICC (integrated control center)

• 4 in various electrical bays
• Line-replaceable (plug-n-play like computer motherboard)

Question 22

SPDAs (secondary power distribution assemblies)

Answer 22

• Electrical load management unit
• Receives power from ICCs
• Distributes power according to system logic

Question 23

DC Hot BUS 1 Powers

Answer 23

• Engine 1A/2A Fire Extinguisher
• Engine Fuel Shutoff Valve 1
• Hydraulic Shutoff Valve 1
• Engine 1 oil level indication
• Courtesy/Service light
• DC ceiling lights

Question 24

DC Hot BUS 2 Powers

Answer 24

• Engine 1B/2B Fire Extinguisher
• Engine Fuel Shutoff Valve 2
• Hydraulic Shutoff Valve 2
• Engine 2 oil live indication
• CMC
• Panel Refuel
• Water and Waste System

Question 25

Minimum voltage for normal operations?

Answer 25

- 22.5V

Question 26

How to disconnect IDG manual?

Answer 26

-Switch must be held in DISC position for at least 1 second.

Question 27

Why would and IDG be disconnected manual or automatically?

Answer 27

- Do to low oil pressure - Or high oil temperature If auto and not fought the shaft will shear

Question 28

What is the lowest batter voltage we can accept before calling MX?

Answer 28

- 21.0 volts, we can charge the batteries using the table and time. Need to check battery temperature on status page.

Question 29

Power priority is?

Answer 29

- IDG outside - APU inside - AC GPU outside - Opposite IDG crossside (plane does not like to cross)