Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

King Air C90 > Electrical > Flashcards

Electrical Flashcards

1
Q

System voltage & battery

A

28-VDC, dc power provided by one 34 amp-hr, air cooled, 20 cell, nickel cadmium battery & two 250 amp starter/generators connected in parallel

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What bus is the battery always connected to?

A

Hot battery bus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

How does the battery provide power to the whole system?

A

Battery switch closes a bus tie and a battery relay

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

The airplane utilizes a ________ system

A

Multi-Bus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

How many buses are there? What are they?

A

5

L/R generator Bus, Center Bus, Triple-Fed Bus, and battery emergency bus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is the triple fed bus powered from?

A

Battery and both generator buses

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is the center bus fed from?

A

Two generator buses and the battery, connecting both components when the bus ties are closed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is provided to isolate a fault in the system?

A

High current (Hall Effect) sensors, bus tie relays, and current limiters

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

The DC power distribution is commonly called a _________ system

A

Triple-fed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are the 3 DC power sources available?

A

One 24 volt, 34 amp-hr, nickel cadmium battery

Two 28 volt, 250 amp starter/generators

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What happens when the battery switch is turned on?

A

Bus tie relays close

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

How is the battery power routed?

A

Battery relay to the triple fed bus, and through the battery bus tie relay to the center bus and to both starter relays

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What 3 buses are tied together by the center bus?

A

Generator bus, hot battery bus, and the battery

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

How is the electrical system protected from excessively high current flow?

A

The bus tie system

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

With no power applied to the electrical system, how many bus tie relays are left open?

A

All 3

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Why is the coil circuit of the bus tie relay latched open?

A

To prevent the bus tie relay from closing

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

When the bus tie relay has been opened by excessively high current flow through the Hall Effect sensor, how can it be reset?

A

Momentarily activating the BUS SENSE switch to RESET

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Momentarily activating the BUS SENSE switch to TEST connects bus voltage to ________ current sensor test circuits.

A

All 3

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Manually closing the generator bus tie relays will connect the generator buses to what bus?

A

The center bus, providing power to the whole system

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Can a generator bus tie relay be manually closed if a fault opened the tie?

A

No, the BUS SENSE switch must be activated to RESET to reset the tie.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is bypassed during a cross-generator engine start?

A

The high current sensors and current limiters

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What happens if an over current situation causes a current limiter to open?

A

It causes bus isolation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What is the protection for the triple-fed bus?

A

60-amp current limiters

24
Q

When will triple-fed bus isolation occur?

A

If all 3 of the limiters are opened

25
Q

Why is load shedding beneficial?

A

Electrical system automatically will remove excess loads

26
Q

What happens, during load shedding, when both generators are offline?

A

The generator bus ties open and the bus loads are shed

27
Q

What is the best choice to make if load shedding occurs during flight?

A

To land as soon as practicable, unless it can be remedied, and one generator be brought back online.

28
Q

Is the lead acid battery air cooled?

A

No

29
Q

The starters are dual purpose, ________ units.

A

Engine driven

30
Q

A series starter winding is used during _________ operation and a shunt field winding is used during ________ operation.

A

Starter, generator

31
Q

What is the regulated output of the generator?

A

28.25 +- 0.25 volts with a maximum continuous load of 250 amps.

32
Q

During an engine start, the battery is connected to the _________ by the starter relay.

A

Starter/generator

33
Q

Normally one engine is started on ______ power, and the other is ______ started.

A

Battery, cross

34
Q

During a cross generator start, the generator control panel closes what relay?

A

Cross-start, which allows for a bypass of the generator bus, current limiter, and bus tie relay.

35
Q

When a starter is selected, what happens to the bus tie sensors?

A

They are disabled to prevent them from opening their respective bus tie relays.

36
Q

Is the generator system self exciting or require external power for operation?

A

Self-exciting

37
Q

How many generator control units is the generator operation controlled through?

A

2

38
Q

What are some functions of the Generator Control Unit (GCU)?

A

Voltage regulation, over voltage protection, paralleling/load sharing, reverse-current protection, cross-start relay activation

39
Q

What happens if the generator output voltage is within 0.5 volts of the aircraft bus voltage?

A

GCU sends a signal to the line contractor, which will close and connect the generator to the aircraft bus and will close both generator ties to connect the center bus and the generator buses.

40
Q

During single-generator operation, what does the GCU do to the line contractor?

A

Opens it and isolates the inoperative generator from its bus.

41
Q

What provides over voltage protection to prevent excessive generator voltage from being applied to aircraft equipment?

A

The GCU

42
Q

What is the max voltage of the generator output before being detected by the over-excitation circuits?

A

32 volts

43
Q

What happens during an over-excitation from a generator?

A

The GCU over-excitation circuit will disconnect generator from electrical system.

44
Q

What is paralleling/load sharing?

A

Averages the output of the both generators to equalize the loads

45
Q

When does paralleling of the GCU become operative?

A

When both generators are online

46
Q

What percentage are the GCUs designed to balance loads to?

A

2.5%

47
Q

What is reverse current protection provided by?

Ex: When shutting an engine down, enough power isn’t provided so it begins to pull from elsewhere.

A

The GCU.

48
Q

During cross-starts, what sensors are disabled to prevent bus isolation?

A

The Hall Effect sensors

49
Q

How is AC power provided to avionics and engine instruments?

A

By 2 inverters

50
Q

What are the 2 levels of power that inverters can provide?

A

115 volts, 400Hz for avionics and 26 volts, 400Hz for the engine instruments, and some avionics

51
Q

What is the standard rated output of an inverter?

A

250 volt-amps (optional: 300 amps)

52
Q

Where are the inverters located?

A

The wing, outboard of each nacelle

53
Q

What is the purpose of an inverter?

A

To change AC power to DC power

54
Q

What are indications of an inverted failure?

A

Getting INVERTER annunciator, erratic behavior, or loss of AC powered instruments (torque gage), or AC avionics

55
Q

Switches that have a white ring around them receive power from which buses?

A

The center bus and the triple-fed bus

King Air C90 (6 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions