Ch. 2 - Electrical and Lights

Question 1

AC power generators/APU

DC power converters

Battery power

Answer 1

30/45 kVA (35 kVA for APU), 115-volt AC, 3 phase, 400 hz

28 volt dc

24 volt dc, 5.5 amp

Question 2

GCU is/does what?

Answer 2

Generator control unit

• Connects generator to AC bus system
• regulates generator output

Protects against:

-overvoltage, undervoltage, feeder fault, underfrequency

Question 3

When does the GCU remove the generators from the bus system?

Answer 3

Ground: below 94% NR

Air: below 80% NR, reconnects above 97% NR

Question 4

External power is monitored for:

Answer 4

• phase rotation
• overvoltage
• undervoltage
• over frequency
• under frequency

Includes a 4 amp circuit breaker with a 2 amp draw so that the ship can sense the load to provide power.

Question 5

What are the 5 ac electrical buses?

Answer 5

1 and #2 AC Primary

AC essential
AC secondary
AC Monitor bus

Question 6

The No. 1 generator normally power the :

Answer 6

1 AC primary

AC Essential
AC Secondary

Question 7

The No. 2 generator normally powers the :

Answer 7

#2 AC primary
AC Monitor bus

Question 8

If both generators are on the APU is?

Answer 8

Not connected

Question 9

If electrical power demand exceeds the capacity of the generator operating normally, the electrical bus loads are redistributed to available generators as follows:

aka Three little pigs

Answer 9

1. Backup pump, will always be powered if required (#1 AC primary bus)
2. Mission power is the next priority (AC Secondary bus). Bus also has tail rotor deice
3. Main rotor deice has lowest priority (AC Monitor bus)

Question 10

Ext pwr is automatically removed when ____________

Answer 10

APU or main generator is brought online

Question 11

With ______ charge the battery will last _____ at night and _____ at during the day

Answer 11

80%
9min
11min

Question 12

What are the D.C. Buses?

Answer 12

No. 1 and No. 2 DC primary bus
D.C. Essential bus
Battery utility bus
Battery bus

Question 13

If only on battery power; the DC essential bus will get dropped at _______

Answer 13

35% charge

Question 14

The battery utility bus receives power from the ________

Answer 14

Battery regardless of position.

Will connect to the dc essential and battery bus if in the ON position and battery is the only source of power.

Question 15

With no other source of DC power, and battery below _____ the power may be insufficient to do what?

Answer 15

30%

Blow the fire extinguisher CADs

Question 16

The batt low charge appears at ____

Answer 16

40% power

Question 17

Battery fault caution means that the ______

Answer 17

Battery has an overtemperature or cell dissimilarity. Battery is disconnected from the charging circuit.

Question 18

Search light can be moved ?

Answer 18

120* forward and 360* about its axis

Question 19

When you turn the search light off will it re-stow?

Answer 19

No. It will remain in current position

Question 20

The rescue light can be operated from the crew hover panel only when?

Answer 20

The cockpit switch is in OFF or FWD.

Question 21

What is the primary source of electrical power, and where can it be supplied from?

Answer 21

Alternating Current (ac) power
Main generators, APU generator, or external power.

Question 22

Where is DC electrical power supplied from?

Answer 22

two converters that convert 115-vold ac power to 28-vold dc power

Question 23

When does the #1/#2 GEN caution appear?

Answer 23

1. Respective generator is not supplying power to the buses
2. Respective Generator is selected off
3. A failure of the generator, GCU, contactor control relay, or a wiring fault has occurred.

Question 24

When does the #1/#2 GEN BRG caution appear?

Answer 24

When the generator main bearing is worn or has failed

Question 25

When does the APU GEN caution appear?

Answer 25

1. Failure of the APU-driven generator, GCU, contactor control relay, or wiring fault
2. APU generator selected ON, APU started, but has not reached operating limits.

Question 26

What are the two converters powered by?

Answer 26

The #1 and #2 AC primary buses

Question 27

The 24-volt dc battery is the primary source of power for _______ and the secondary source of power for the ____ and ____.

Answer 27

APU Starting

DC essential bus, Battery bus

Question 28

What does the battery analyzer/conditioner do?

Answer 28

It monitors the battery system for:

• fault conditions
• battery charge
• internal temperature
• cell conditions
• provides a battery-charging capability.

Question 29

If the converters are operating and the BATT switch is ON, the charging circuit of the analyzer/conditioner receives power from what?

Answer 29

the No. 2 AC Primary bus and DC charging power from the No. 2 DC Primary bus.

Question 30

What does the #1 Converter power?

Answer 30

1 DC primary bus

DC essential Bus
Battery Bus

Question 31

What does the #2 Converter power?

Answer 31

2 DC Primary Bus

Question 32

What happens if a single converter fails?

If both converters fail?

Answer 32

The operating converter will pick up the load of the buses powered by the failed converter via automatic bus switching

The battery provides a source of emergency electrical power to the Battery Utility bus, the Battery bus (if the switch is on) and the DC Essential bus
Both Flight and Mission displays will be lost

Question 33

Can the Pilot override the Copilot when controlling the searchlight on the collective?

Answer 33

Yes

Question 34

In the event of total loss of AC power, what cockpit lights do you have?

Answer 34

Lower console secondary lights, Utility lights, and the glareshield lights