ELECTRICAL SYS

Question 1

AC GENERATORS (type and power)
APU GEN

Answer 1

2 oil-cooled, 30/45kVa, 115Vac, 3-phase, 400 HZ generators

APU - 35kVa, 115Vac, 3-phase, 400HZ

Question 2

GCUs regulate/protect against what?

Answer 2

regulate generator output, protect against over voltage, undervoltage, feeder fault, and underfrequency

Question 3

Underfrequency protection

Answer 3

WOW - GCUs remove main generators from the AC system if Nr < 94%

WoffW - protection disabled, generators remain online until Nr < 80%

Minimum of 97% Nr required for GCU to reconnect the generators

Question 4

Electrical bus load shedding priority

Answer 4

1. Backup hydraulic pump - major load on #1 AC PRI
2. Mission power / T/R De-Ice- major load on AC SEC
3. M/R De-Ice - only system one the AC Monitor

Question 5

Which AC buses (primary, secondary, or monitor) can be powered if you only have one generator and the APU?

Answer 5

Only 2/3 of the buses.

Question 6

Which AC buses (primary, secondary, or monitor) can be powered if you only have one generator?

Answer 6

Either the #1 AC primary or the AC secondary bus (backup pump or mission power). The monitor bus is dropped.

Question 7

Which AC buses (primary, secondary, or monitor) can be powered if you only have the APU?

Answer 7

Only the #1 AC primary bus will be powered. (backup pump)

Question 8

How many converters do we have and what do they supply?

Answer 8

two converters that supply 28Vdc by converting 115Vac from the #1 and #2 AC primary buses

Question 9

Our primary source of DC power comes from what? What do we use it for?

Answer 9

the 24Vdc battery - used for APU starts, and is a secondary power source for the DC essential and battery buses

Question 10

With ____% charge, the battery can run for how long during the day/night?

Answer 10

80% charge - 11 min day, 9 min night

Question 11

The battery analyzer / conditioner monitors and provides what?

Answer 11

fault conditions, battery charge, internal temp., cell conditions, battery charging capability

Question 12

Where does the battery analyzer / conditioner receive power from?

Answer 12

receives power from the #2 AC primary bus and DC charging power from the #2 DC primary bus

Question 13

What is the difference between a single and a dual converter failure?

Answer 13

Single converter fail - the operating converter picks up the load dropped by the failed converter

Dual converter fail - battery becomes emergency power source to the utility bus, battery bus, and the DC essential bus (if charge > 35%).

Question 14

Battery charge at ____% indicates [BATTERY LOW CHARGE]

Answer 14

40%

Question 15

The DC essential bus will be dropped when battery charge is ____%. What will you no longer be able to do?

Answer 15

35%, slew the stab

Question 16

If battery charge reaches ____% you will no longer be able to fire the CADs.

Answer 16

30%

Question 17

External power system includes a ___-amp circuit breaker that places a ___-amp draw.

Answer 17

4-amp, 2-amp

Question 18

External power is monitored for:

Answer 18

phase rotation, overvoltage, undervoltage, underfrequency, and over frequency

Question 19

The #1 AC generator powers which buses?

Answer 19

AC secondary, #1 AC primary, AC essential

Question 20

The #2 AC generator powers which buses?

Answer 20

2 AC primary, AC monitor

Question 21

The #1 converter powers which buses?

Answer 21

1 DC primary, DC essential, battery bus

Question 22

The #2 converter powers which buses?

Answer 22

2 DC primary bus

Question 23

In a dual converter failure, what can you expect to lose?

Answer 23

DTU 1&2 (util mode)
AFCS computer and control
Jettison power
Aux fuel and fuel management
Backup pump operation
Pilot / copilot mission displays
Engine anti-ice/start-bleed valve open (18% torque)
Rast probe
#1 EGI (AFCS functionality)

Question 24

If you lose all DC power or your DC ESNTL bus where the battery dies after 11 or 9 minutes, what can can you expect to lose?

Answer 24

SAS/Boost
Lights
#2 EGI
Stab man slew capability

Question 25

What happens if you lost the BAT BUS?

Answer 25

APU fire detection capability
Fuel prime boost pump (no more APU)
Backup attitude indicator charge (lose after 9 min)