Electrical Flashcards

1
Q

Conditions for auto transfer

A

PWR selector on BATT
One MAIN GEN ON
MAIN GEN contactors open

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2
Q

Indication of auto transfer

A

“6 pack” lights on the electrical panel
Observer light illuminates

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3
Q

What checklist to use in auto transfer

A

MAIN GEN failure

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4
Q

What charges the main battery in auto transfer

A

AUX GEN >70Np

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5
Q

Can APU be started in auto transfer

A

No because central bus is isolated. Must take out of auto transfer before APU start

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6
Q

TRNSFER FAIL light will indicate

A

AUX Bus failed to transfer to EDC’s. Electrical system is powered by battery only

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7
Q

How is backup battery being charged

A

EDC 2

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8
Q

Backup battery powers standby gyro when

A

EDC 1 drops below 19v

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9
Q

How long can backup battery support standby gyro

A

30 min

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10
Q

What must be on for inverters to work

A

Radio masters

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11
Q

If you lose 115vac on inverter 1 what happens to the inverter, if 26vac

A

Inverter 2 will pick up inverter 1 automatically in the event of 115vac, 26vac must be switched manually

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12
Q

GPU amps and volts required

A

24 volts, 1600amps min 1800 recommended

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13
Q

Can GPU voltage be read in the cockpit

A

No only amps

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14
Q

Can GPU charge the main battery

A

No

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15
Q

What is on the hot battery bus

A
  1. Auto transfer
  2. Clock/Chronograph
  3. Coutesy lights
  4. DC indication 1 & 2
  5. Fire extinguisher left and right
  6. Forward entry door
  7. Fuel shutoff valve left and right
  8. Hydraulic shutoff valve blue and green
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16
Q

If Emergency Transfer happens and APU is available can it be used to power systems

A

Yes, the system should be placed into normal mode prior to an air start of the APU

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17
Q

How do you prevent a reset to normal operation after emergency transfer

A

Emergency mode must be selected prior to turning off both generators

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18
Q

Is the battery connected to the hot battery bus

A

Yes during normal operations the power source that powers central DC bus, powers the hot battery bus and charges the battery

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19
Q

Is there any protection for overvoltage while on GPU

A

Yes, an overvoltage relay protects the central DC bus if external power exceeds 32VDC

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20
Q

When can APU gen provide electrical power to aircraft

A

95% RPM

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21
Q

When does the generator switches from starter to generator

A

50% Nh

22
Q

How many volts are the inverters

A

28VDC converted to 115AC and 26AC

23
Q

What generators is EDC busses connected to normally

A

Right generator

24
Q

If one EDC fail how can you tell which on failed

A

Tq and T6 gauges
EDCI 1 # 1Engine
EDC 2 # 2Engine

25
Q

When does AUX generator turn on

A

Np 70%

26
Q

What is the EDC

A

The emergency DC, it contains all the essential equipment because it is always powered

26
Q

What is the EDC

A

The emergency DC, it contains all the essential equipment because it is always powered

27
Q

Functions of GCU

A
  1. Initiates starting cycle
  2. Cancels starting cycle at 50% Nh
  3. Regulates generator output
  4. Overvoltage protection
  5. Overcurrent protection
  6. Reverse current protection
  7. Generator field over exiting protection
  8. Load sharing
28
Q

Functions of AUX GCU

A
  1. At 70% Np connects generator to AUX DC BUS and disconnects DC BUS 3 form DC BUS 2 and connects it to AUX DC BUS
  2. Voltage regulation
  3. Overvoltage protection
  4. Undervoltage protection
  5. Overcurrent protection
  6. Generator field over exiting protection
  7. Load sharing
  8. Underspeed protection when Np drops bellow 70%
29
Q

Generator Specification

A

MAIN GEN = 28VDC 400A (600A during start)
AUS GEN = 28VDC 150A
APU = 28VDC 400A

30
Q

Battery Specification

A

MAIN BATT = 24VDC 36A/H Nick-cad
BACKUP BATT = 24VDC 5A/H sealed led acid

31
Q

The EMB 120 Electrical system supplies

A

28VDC and 26/115 AC

32
Q

The EMB 120 has how many generators

A

5

33
Q

The EMB120 has how many batteries

A

2

34
Q

When using GPU can APU gen be used

A

No power source priority

35
Q

During the engine start phase, the starter generator is powered from

A

Central DC bus

36
Q

Can you start the engines in electrical transfer mode

A

No, no supply to Central DC BUS

37
Q

The main generators are connected to the electrical system by

A

Main generator contactors

38
Q

The EMB 120 has how many inverters

A

2

39
Q

The No 1 and 2 inverters is powered through

A

DC Bus 1 inverter 2
DC Bus 2 inverter 1

40
Q

With total generator failure the main battery will last

A

Approximately 30 minutes

41
Q

APU generator is identical to

A

Main generator

42
Q

Are the AUX generator identical to Main GEN

A

No

43
Q

The APU generator may be used with the battery for engine start

A

True

44
Q

The primary reason for Auto transfer

A

Both main generator failure

45
Q

During normal operation AUX GEN power

A

DC bus 3 and RB DC 3

46
Q

The back up battery will automatically supply electrical power to the standby attitude indicator when

A

EDC 1 drops below 19V

47
Q

The aircraft batteries located

A

Left nose compartment

48
Q

During engine start the primary purpose of the back up battery is

A

To prevent transients affecting certain instruments

49
Q

In total electrical emergency the backup battery’s primary purpose is

A

To power the standby gyro only