AC/DC Power Flashcards Preview

E-Jet EMB175 > AC/DC Power > Flashcards

Flashcards in AC/DC Power Deck (29):
1

How man IDGs (integrated drive generators)

2 - 115VAC, 400 Hz, 40 KVA

2

APU Electrical power is

1 generator 115VAC, 400Hz, 40 KVA

3

Other power source

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

4

How man inverters

1 - 250v

5

How man IDG to power aircraft

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

6

APU power

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

7

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

8

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

9

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

10

GPU Power when?

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

11

AC electrical power priority

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

12

Inverter powers

Powers the AC STANDBY BUS when normal AC power is available

13

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

14

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)

15

DC electrical power consists of

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

16

TRUs (transformer rectifier units) Do what

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

17

Batteries

- 2 24V SLAB (sealed lead acid batteries

18

Batteries charge by

AC power source thru the TRUs

19

Min volts to close battery contactor

18 Volts min

20

Min battery power from battery during electrical emergency

Provides power for 10 min

21

Electrical power distribution done by

ICC (integrated control center)
- 4 in various electrical bays
- Line-replaceable (plug-n-play like computer motherboard)

22

SPDAs (secondary power distribution assemblies)

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

23

DC Hot BUS 1 Powers

- 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

24

DC Hot BUS 2 Powers

- 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

25

Minimum voltage for normal operations?

- 22.5V

26

How to disconnect IDG manual?

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

27

Why would and IDG be disconnected manual or automatically?

- Do to low oil pressure
- Or high oil temperature

If auto and not fought the shaft will shear

28

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

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

29

Power priority is?

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