Electrical System

Question 1

What buses are powered when the BATTERY MASTER is selected on?

Answer 1

Left and Right Essential

Question 2

What buses are powered when BATTERY MASTER and MAIN BATTERY switch are selected on?

Answer 2

Left and Right Essential and Right Main

Question 3

What buses are powered when the BATTERY MASTER, MAIN BATT, and AUX BATT switches are selected on?

Answer 3

Left and Right Essential and Right Main

Question 4

With the BATT MASTER, MAIN and AUX BATT switches on, what must be selected to power the left main bus?

Answer 4

MAIN BUS TIE

Question 5

When do the AC generators come on line?

Answer 5

Engine running and condition levers in the MIN to MAX range

Question 6

What buses are powered the APU generator powered?

Answer 6

All DC Buses

Question 7

What buses are owered with the DC external power?

Answer 7

All DC Buses

Question 8

What will happen if the DC External power voltage exceeds 31.5 volt?

Answer 8

DC External power is automatically disconnected from the system

Question 9

What buses are powered with the AC external power?

Answer 9

All AC and DC buses

Question 10

What controls the 4 bus ties?

Answer 10

DC Logic

Question 11

What is the maximum DC generator load, ground and in flight?

Answer 11

0.7 ground and 1.0 in flight

Question 12

What is the purpose of the TRU’s?

Answer 12

Convert 3 phase 115 volt variable frequency AC to 28 volt DC

Question 13

What is the maximum TRU load?

Answer 13

200 amp each

Question 14

What is the minimum TRU voltage?

Answer 14

25 volts, below 18 volts caution light indicates a TRU failure

Question 15

What is the maximum AC generator load ground or in flight?

Answer 15

Temps below 10 C is 1.0 and above 10 C limited to .33

Question 16

What does a battery load indication of +1.05 indicate?

Answer 16

Overcharging by 5% over maximum charge rate

Question 17

What is the maximum output rating of the DC generators?

Answer 17

300 amps

Question 18

What is the maximum output rating of the TRUs

Answer 18

200 amps

Question 19

When does the BBPU - Breaker Bar Protection Unit react to a main bus fault?

Answer 19

High generator output over 450 amps

Question 20

What does the BBPU do when it detects a main bus fault?

Answer 20

Opens the ties and isolates the affected bus

Question 21

How many inverters are there?

Answer 21

three

Question 22

What is the purpose of the inverters?

Answer 22

Converts 28 volt DC to 115 volt single phase AC

Question 23

What are the step down transformers for?

Answer 23

Convert 115 V AC to 25 V AC

Question 24

What is the indication of a failure of the 26 V AC or the 115 V AC bus?

Answer 24

Caution light illuminates for 26 V AC but no indication for the 115 V AC failure

Question 25

What will happen if an inverter fails?

Answer 25

Parallel control box disconnects failed inverter and related caution light comes on and the remaining inverters provide necessary power

Question 26

What is the indication of a fault on the battery temperature display sensor and the over temperature sensor?

Answer 26

Amber light comes on at the 60 degree point, over temperature SENSOR FAIL light comes on

Question 27

Will all buses be powered if DC generator fails?

Answer 27

Yes, DC Logic closes appropriate (Main) bus tie

Question 28

Will all buses be powered if both DC generators fail?

Answer 28

Yes, DC Logic closes appropriate bus ties and power comes through the TRUs

Question 29

What action should be taken as per the QRH with a double DC generator failure?

Answer 29

1 and 2 Generator Reset, Batteries off, Master off, Land as soon as possible

Question 30

What will occur if a subsequent TRU fails after losing both DC generators?

Answer 30

Total power failure, loss of cabin pressurization, battery on, descend and land as soon as possible

Question 31

Will all buses be powered if a TRU fails?

Answer 31

Yes, DC Logic closes appropriate bus ties

Question 32

Will all buses be powered if both TRUs fail?

Answer 32

Yes, DC Logic closes appropriate bus ties

Question 33

Will all buses be powered if an AC generator fails?

Answer 33

Yes, Other AC Gen takes up the load

Question 34

Which battery is the Hot battery bus connected to?

Answer 34

Main (Right) Battery

Question 35

Can the BBPU disconnect the main bus tie if the main bus tie switch is on?

Answer 35

Yes