Electrical

Question 1

Conditions for auto transfer

Answer 1

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

Question 2

Indication of auto transfer

Answer 2

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

Question 3

What checklist to use in auto transfer

Answer 3

MAIN GEN failure

Question 4

What charges the main battery in auto transfer

Answer 4

AUX GEN >70Np

Question 5

Can APU be started in auto transfer

Answer 5

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

Question 6

TRNSFER FAIL light will indicate

Answer 6

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

Question 7

How is backup battery being charged

Answer 7

EDC 2

Question 8

Backup battery powers standby gyro when

Answer 8

EDC 1 drops below 19v

Question 9

How long can backup battery support standby gyro

Answer 9

30 min

Question 10

What must be on for inverters to work

Answer 10

Radio masters

Question 11

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

Answer 11

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

Question 12

GPU amps and volts required

Answer 12

24 volts, 1600amps min 1800 recommended

Question 13

Can GPU voltage be read in the cockpit

Answer 13

No only amps

Question 14

Can GPU charge the main battery

Answer 14

No

Question 15

What is on the hot battery bus

Answer 15

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

Question 16

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

Answer 16

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

Question 17

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

Answer 17

Emergency mode must be selected prior to turning off both generators

Question 18

Is the battery connected to the hot battery bus

Answer 18

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

Question 19

Is there any protection for overvoltage while on GPU

Answer 19

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

Question 20

When can APU gen provide electrical power to aircraft

Answer 20

95% RPM

Question 21

When does the generator switches from starter to generator

Answer 21

50% Nh

Question 22

How many volts are the inverters

Answer 22

28VDC converted to 115AC and 26AC

Question 23

What generators is EDC busses connected to normally

Answer 23

Right generator

Question 24

If one EDC fail how can you tell which on failed

Answer 24

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

Question 25

When does AUX generator turn on

Answer 25

Np 70%

Question 26

What is the EDC

Answer 26

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

Question 26

What is the EDC

Answer 26

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

Question 27

Functions of GCU

Answer 27

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

Question 28

Functions of AUX GCU

Answer 28

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%

Question 29

Generator Specification

Answer 29

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

Question 30

Battery Specification

Answer 30

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

Question 31

The EMB 120 Electrical system supplies

Answer 31

28VDC and 26/115 AC

Question 32

The EMB 120 has how many generators

Answer 32

5

Question 33

The EMB120 has how many batteries

Answer 33

2

Question 34

When using GPU can APU gen be used

Answer 34

No power source priority

Question 35

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

Answer 35

Central DC bus

Question 36

Can you start the engines in electrical transfer mode

Answer 36

No, no supply to Central DC BUS

Question 37

The main generators are connected to the electrical system by

Answer 37

Main generator contactors

Question 38

The EMB 120 has how many inverters

Answer 38

2

Question 39

The No 1 and 2 inverters is powered through

Answer 39

DC Bus 1 inverter 2 DC Bus 2 inverter 1

Question 40

With total generator failure the main battery will last

Answer 40

Approximately 30 minutes

Question 41

APU generator is identical to

Answer 41

Main generator

Question 42

Are the AUX generator identical to Main GEN

Answer 42

No

Question 43

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

Answer 43

True

Question 44

The primary reason for Auto transfer

Answer 44

Both main generator failure

Question 45

During normal operation AUX GEN power

Answer 45

DC bus 3 and RB DC 3

Question 46

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

Answer 46

EDC 1 drops below 19V

Question 47

The aircraft batteries located

Answer 47

Left nose compartment

Question 48

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

Answer 48

To prevent transients affecting certain instruments

Question 49

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

Answer 49

To power the standby gyro only