SkyWest ERJ175 Electrical

Question 0

Min. Batt Temp.

Answer 0

-20C

Question 1

Min. Batt Voltage

Answer 1

22.5 V

Question 2

One or both Battery less than 22.5 V
Determine lowest battery voltage
IF between 21.0 and 22.5 volts

Answer 2

Recharge the batteries prior to T/O, through and AC source (including engines during taxi) for:
Batt temp. > = 0C 30mins
 > = -5C and < 0C 35mins
 > = -10C and < -5C 40mins
 < -10C 50mins

Question 3

One or both Battery less than 22.5 V
Determine lowest battery voltage
IF Below 21.0

Answer 3

IOR

Do Not Depart

Question 4

AC system composed of

Answer 4

2 integrated drive generators (IDG)
1 Auxiliary Power Unit APU
1 Invertor
1 Ram Air Turbine (RAT)
1 AC external power unit

Question 5

DC system composed of

Answer 5

2 NiCd batteries
3 transformer rectifier units (TRU)
1 DC external power unit

Question 6

Both IDG and APU generator are rated at?

Answer 6

40 kVA (40,000 amps)
115 VAC
400 Hz
Three phase

Question 7

In flight the RAT is used as an emergency generator powering the?

Answer 7

ESS BUSSES

When both AC bus 1 and 2 are not powered

Question 8

A static inverter (AC/DC inverter) converts 28v DC from the batteries to 115 VAC to supply the STANDBY AC BUS when?

Answer 8

An AC power source is not available

Question 9

RAT generator is rated at?

Answer 9

15 kVA (15,000 amps)
115 VAC
400Hz
Three phase
8 secs after deployment

Question 10

The RAT electrical power drives the AC Motor-driven Pump (ACMP 3A) for primary flight control tasks. This includes?

Answer 10

high lift system actuation and power for essential avionics, communication and battery recharging.

Question 11

What airspeed is required to ensure the RAT continues supplying AC/DC ESS BUSES? At speeds below this, the RAT may only supply the AC ESS BUS, and the batteries will automatically provide electrical power to the DC ESS BUSES and the STANDBY AC BUS through the static inverter (AC/DC inverter). As airspeed decreases, load shedding occurs and the AC ESS BUS is no longer powered.

Answer 11

130 kts

Question 12

The DC electrical system comprises:

Answer 12

Three transformer rectifier units (TRU)s;

Two batteries

Question 13

On ground, a DC ground power unit (DC GPU) can be connected to the airplane supplying power to only?

Answer 13

APU START BUS.

Question 14

The TRU, rated at ____, are used as a primary source of the DC electrical system, converting 115VAC power from the AC BUSES into 28v DC power.

Answer 14

300A

Question 15

In certain conditions, batteries #1 and #2 are used to backup what buses?

Answer 15

DC ESS BUSES

AC STBY BUS

Question 16

Battery #2 also supplies the _________, during APU starting.

Answer 16

APU START BUS

Question 17

__________ power up the airplane and are also used as a backup for the DC essential electrical system.

Answer 17

Two NiCd 22.8 VDC, 27 A batteries

Question 18

The batteries are constantly charged by any AC source through the ?

Answer 18

TRUs, including the AC GPU and the RAT.

Question 19

In an ELECTRICAL EMERGENCY, batteries are capable to supply airplane essential systems for at least_____, even if the RAT is failed.

Answer 19

10mins

Question 20

Whenever the battery temperature reaches ____for at least ____, the associated indication becomes red and the EICAS WARNING message BATT 1 (2) OVERTEMP is triggered.

Answer 20

70C for 2sec

Question 21

The minimum battery #2 temperature for APU starting is?

Answer 21

-20°C

Question 22

On ground, if the airplane is powered only by the batteries for _______, a horn will sound to alert the ground personnel.

Answer 22

more than 5 mins

Question 23

The DC GPU is used when the battery is no longer available or the battery #2 temperature is below -20°C.
A suitable DC GPU should be able to supply the airplane systems with at least_____ and no more than_____, when under use. The voltage may be checked on the synoptic page on MFD.

Answer 23

24VDC

29VDC

Question 24

What is on the AC ESS bus

Answer 24

AC fuel pump 2A
Hydraulic pump 3A
1 flap channel
1 slat channel

Question 25

What is on the AC STBY BUS (powered by static inverter)

Answer 25

Engine 1 Exciter 1A and Engine 2 Exciter 2A