ELECTRICAL

Question 0

WHAT DOES THE BATTERY MASTER DO?

Answer 0

ON – Connects the APU & MAIN BATTERY DIRECT BUSES to the DC BATT BUS provided no external power is in use.
Two NiCad batteries (MAIN and APU), located in the aft equipment bay, store and provide a source of DC power.
The MAIN is a 17 ampere hour, 24 volt Battery.
The APU is a 43 ampere hour, 24 volt Battery.
OFF - Disconnects the APU & MAIN BATTERY DIRECT BUSES from the DC BATT BUS.

Question 1

WHAT DOES THE DC SERVICE BUS DO?

Answer 1

DC SERVICE
ON – Connects DC SERVICE BUS to the APU BATTERY DIRECT BUS.
Dome light
LAV lights
Passenger Cabin lights
External NAV lights
OFF – Disconnects DC SERVICE BUS from the APU BATTERY DIRECT BUS.

Question 2

DESCRIBE THE DC EMERGENCY BUS.

Answer 2

Connected directly to the APU BATT DIR BUS & the DC BATT BUS and is continuously powered. It provides power to the:
L & R Engine and APU fire bottle squibs
L & R Engine HYD SOV’s
L & R Engine and APU Fuel SOV’s
Emergency Lights
Note: Only displays on the DC Synoptic page when faulted or loss of one or more power sources.

Question 3

DESCRIBE THE DC BATT BUS AND DC ESS BUS.

Answer 3

Both supply the equipment for safe flight.
Normal power from ESS TRU and TRU 2, Backup power can be provided from SERV TRU (ESS TIE).
If all 5 TRU’s fail, both busses are powered from the APU & MAIN BATTERY DIRECT BUSES

Question 4

DESCRIBE THE EXT DC SWITCHLIGHT.

Answer 4

AVAIL – External power is connected to the aircraft (but not online), and operating within limits.
IN USE – Indicates external power is powering the DC busses.

Question 5

DESCRIBE THE EXT AC SWITCHLIGHT.

Answer 5

AVAIL – External power is connected to the aircraft (but not online), and operating within limits.
IN USE – Indicates external power is powering the busses.
External power is only useable if engine and APU generators are not online.

Question 6

DESCRIBE THE IDG 1 & 2 SWITCHLIGHT.

Answer 6

FAULT – Indicates an oil system fault with the generator, either high oil temperature or low oil pressure (HOT LOP).
DISC – Indicates the selected disconnect was successful.
The IDG will automatically disconnect when an over-temp or over-torque condition occurs.
Once disconnected, the IDG cannot be reset until on the ground and engine is shutdown.

Question 7

DESCRIBE THE AC ESS XFER SWITCHLIGHT.

Answer 7

ALTN – AC ESS BUS is “looking” at AC BUS 2 for power because AC BUS 1 is not able to power it.
Transfer is automatic during an AC BUS 1 failure.

Question 8

DESCRIBE THE AUTO XFER SWITCHLIGHT.

Answer 8

FAIL – Indicated BUS is isolated and may only be reset by removing all AC power and turning the BATTERY MASTER off.
OFF – Indicates the automatic AC BUS tie operation is inhibited.

Question 9

DESCRIBE GEN 1 & 2 SWITCHES.

Answer 9

ON – Selects generator online if serviceable.
OFF/RESET – Removes generator from line and/or resets the GCU if there has been a fault.
The GCU will automatically trip off and remove a generator from the BUS system for:
Over/Under Voltage
Over/Under Frequency
GEN or BUS over current

Question 10

DESCRIBE TIE 1 & 2 SWITCHES.

Answer 10

CLOSED – Indicates that the corresponding DC BUS has been automatically or manually tied to the SERV TRU during an abnormal condition.
When in use the corresponding DC Utility BUS is load shed.

Question 11

DESCRIBE THE ESS TIE SWTCH.

Answer 11

CLOSED – Indicates the DC ESS BUS & DC BATT BUS have been manually tied (there is no automatic operation of the essential tie contactor) to the SERV TRU in the event of a failure of ESS TRU 2.
CAUTION: In the event of TRU 1 & 2 FAIL (resulting in the closing of both TIE 1 & 2) and the ESS TIE is closed, power will be lost to DC BUS 1 & 2 and cannot be restored. REMEMBER: THREE STRIKES AND YOU’RE OUT!

Question 12

WHAT BATTERIES ARE THERE IN THE CRJ 200?

Answer 12

The MAIN is a 17 ampere hour, 24 volt Battery.

The APU is a 43 ampere hour, 24 volt Battery.

Question 13

WHAT WILL CAUSE THE GCU TO AUTOMATICALLY TRIP OFF?

Answer 13

The GCU will automatically trip off and remove a generator from the BUS system for:
Over/Under Voltage
Over/Under Frequency
GEN or BUS over current

Question 14

WHAT SYSTEMS ARE POWERED WHEN THE DC SERVICE SWITCH IS IN THE ON POSITION?

Answer 14

Dome light
LAV lights
Passenger Cabin lights
External NAV lights

Question 15

WHAT ARE SOME OF THE SYSTEMS THAT YOU WILL LOSE IF THE DC EMERGENCY BUS FAILS?

Answer 15

L & R Engine and APU fire bottle squibs
L & R Engine HYD SOV’s
L & R Engine and APU Fuel SOV’s

Question 16

Name the different TRU’s and what the power sources are on the CRJ 200.

Answer 16

TRU 1 - AC BUS 1
TRU 2 - AC BUS 2
SERVICE TRU - AC SERVICE BUS
ESS TRU 2 - AC BUS 2
ESS TRU 1 - ESS AC BUS

Question 17

Name the different AC BUS’s on the CRJ 200 and the default/redundant power sources.

Answer 17

AC BUS 1 - GEN 1, APU, GEN 2, EXT POWER.
AC BUS 2 - GEN 2, APU, GEN 1, EXT POWER.
ESS AC BUS - AC BUS 1, AC BUS 2 ( COMMANDED OR AUTO).
AC SERVICE BUS - AC BUS 2, APU BATT ( WHEN COMMANDED).
UTILITY BUS 1 - AC BUS 1.
UTILITY BUS 2 - AC BUS 2.