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Mesa CRJ-900 > Electrical > Flashcards

Flashcards in Electrical Deck (31):
2

The aircraft engine driven(IDG) and APU generators are rated at?

40 KVA

3

The engine driven (IDG) generators have an Overload rating of?

45 KVA for 5 minutes

60 KVA for 5 seconds

4

The main aircraft generators supply power to how many AC buses?

4

5

Power for the 28v DC systems is supplied by?

4 TRU's

(Transformer Rectifier Units)

6

The APU battery is rated at?

24v and 43 amp hours

7

The main battery is rated at?

24v and 17 amp hours

8

TRU 1 normally supplies which bus?

DC BUS 1

9

TRU 2 normally supplies ?

DC Bus 2 and DC UTIL Bus

10

ESS TRU 1 and ESS TRU 2 normally supplies?

DC ESS BUS

11

The ADG supplies AC power to?

1.  3B hydraulic pump

2.  ESS AC BUS

3.  Slats/Flaps

4.  Pitch Trim channel 2

12

The Main battery is kept in a charged condition by a charger that is powered from which bus?

AC Bus 1

13

The APU battery is kept in a charged condition by a charger that is powered from which bus?

AC Service Bus

14

The IDG provides a means of converting

variable engine speed to a contant generator speed of 12,000 rpm

15

Fault protection for each generator is provided by?

Generator Control Units (GCU's)

16

The priority for allowing power to AC Bus 1 would be?

  1. Gen 1
  2. APU
  3. Gen 2
  4. External AC

17

IDG 2(GEN 2) normally powers:

AC Bus 2

Service Bus

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18

Each TRU is rated for how much current?

120 amps

19

Which DC Bus ties have automatic operation?

  • MAIN TIE
  • CROSS TIE
  • ESS TIE
  • TRU CONTACTOR CONTROL
  • ESS TRU TRANSFER

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20

The ADG will auto deploy when?

  • AC Bus 1 and AC Bus 2 falls below 50 volts
  • weight on wheels system indicates aircraft is airborne
  • Any aircraft generators were online for at least 3.45 seconds prior to the loss of power on AC Buses 1 and 2

21

An Amber IDG fault light / caution light indicates?

  • Low IDG oil pressure and / or high IDG oil temp

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22

An AUTO XFER fail light(amber) on the Electrical panel indicates:  

Generator over current or a bus fault

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23

An AC ESS XFER light(white) on the Electrical panel indicates:

AC Bus 1 is no longer powering the AC ESSENTIAL Bus

24

What happens when you switch on the DC SERVICE switch?

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  • With no AC power, the SERV BUS is powered directly from the APU BATT DIR BUS via the service bus contactor
  • SERVICE CONFIGURATION message appears on DC synoptic page
  • Service bus contactor not represented on the DC synoptic page

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25

What happens when you turn on the Battery Master switch?

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  • Connects the main battery to the battery bus through the main battery direct bus
  • Connects the APU battery to the battery bus throught the APU battery direct bus

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26

With the Battery Master switch left on, is there anything you should be concerned about?

  • Yes, the CRT displays have a 5 minute limitation of being left on without the AC system providing power to the cooling fans
  • You can run down the Main and APU batteries if left on too long

27

How many DC buses does the CRJ have?

9 buses in total

DC EMER BUS not shown

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28

What happens when TRU 1 fails?

  • Main Tie contactor automatically closes
  • TRU 2 powers DC BUS 1
  • DC UTIL BUS is load shed(turned off)
  • Status Messages saying TRU 1 has failed and Main Tie has closed

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29

What happens when TRU 1 and TRU 2 fail?

  • DC MAIN TIE and CROSS TIE automatically close
  • ESS TRU 2 powers DC BUS 1, DC BUS 2 and DC SERV BUS
  • DC UTIL BUS is unpowered
  • Status messages saying MAIN and Cross TIE's have closed and TRU 1, 2 failed

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30

What happens when ESS TRU 1 fails?

  • DC ESS TIE automatically closes allowing ESS TRU 2 to power the DC ESS BUS
  • DC ESS TIE CLSD status message displayed 

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31

Which DC Bus Tie does not have automatic operation?

Service Bus Contactor

  • It gets activated by the DC SERVICE switch on the Overhead when there is no AC power on the airplane

32

What are the nine DC buses?

  • DC Bus 1
  • DC Bus 2
  • DC ESS Bus
  • DC SERV Bus
  • DC UTIL Bus
  • DC BATT Bus
  • MAIN BATT DIR Bus
  • APU BATT DIR Bus
  • DC EMER Bus