Electrical

Question 1

How many generators does the EMB 120 have?

Answer 1

Two Primary
Two Auxiliary
One APU

Question 2

The emergency buses are normally connected to which generator?

Answer 2

the RIGHT main generator

Question 3

AC electrical power is provided by?

Answer 3

Two static inverters.

Question 4

The static inverters convert 28 VDC power into?

Answer 4

115 and 26 VAC.

Question 5

In normal operation Inverter 1 powers __________, and Inverter 2 _______.

Answer 5

Inverter 1 powers the four main buses.

Inverter 2 is standby for the emergency bus.

Question 6

How many batteries are installed on the EMB 120?

Answer 6

1) 24-VDC 36 amp hour NiCad MAIN battery.

2) 24-VDC 5 amp hour sealed lead acid BACKUP battery.

Question 7

The battery has a protective device that?

Answer 7

Opens when the current from the central DC bus exceeds 500 amps.

Question 8

The battery monitoring system incorporates _____ sensors in the compartment that?

Answer 8

2 Sensors. 1 for the gauge and 1 for the warning system.

Question 9

The primary purpose of the backup battery is to?

Answer 9

power the standby artificial horizon.

Question 10

The auxiliary generators are rated at?

Answer 10

28-VDC, 150 amp.

Question 11

The auxiliary generators are driven by _________, and come online at _____.

Answer 11

Their respective propeller reduction gearbox and come online at 70% Np.

Question 12

The main generators are rated at _______.

Answer 12

28-VDC 400 amp.

Question 13

At ______ the GCU (generator control unit) opens the engine start contactor allowing the starter-generator to operate as a generator.

Answer 13

50% Nh (high pressure compressor speed)

Question 14

An overvoltage relay protects the central DC bus if external power VOLTAGE exceeds ______.

Answer 14

32 VDC

Question 15

Auxiliary generators are off below ______.

Answer 15

70% Np.

Question 16

When the battery temp reaches ______ the alarms and warnings are triggered.

Answer 16

70c

Question 17

The backup battery is charged by?

Answer 17

emergency DC bus 2.

Question 18

The standby attitude indicator is powered by?

Answer 18

emergency DC bus 1.

Question 19

Each inverter produces ______ and ______ power.

Answer 19

115 VAC and 26 VAC 400 Hz power.

Question 20

Inverter 1 is powered from _________.

Inverter 2 is powered from _________.

Answer 20

Inverter 1 normal bus (DC Bus 2).

Inverter 2 emergency bus. (Emergency DC Bus 1).

Question 21

If you lose 115 VAC power from Inverter 1 what happens?

Answer 21

Automatically transfers to Inverter 2.

Question 22

If you lose 26 VAC power from Inverter 1 does it automatically transfer to Inverter 2?

Answer 22

NO—-QRH—-flip inverter 1 off—–then it will.

Question 23

Two modes of operation for the aircraft electrical system are?

Answer 23

Normal and Emergency.

Question 24

Under normal conditions, if both main generators fail while operating in normal mode?

Answer 24

The system will automatically switch to Emergency Mode.

Question 25

For the electrical system to switch to emergency mode automatically what conditions must be met?

Answer 25

1) at least one main generator switch ON. 2) PWR SELECT switch in BATT. 3) both main generators lost.

Question 26

What happens in autotransfer/emergency mode?

Answer 26

Normal buses get shut down and emergency buses are powered by the battery.

Question 27

In emergency mode with all generators lost the battery is automatically connected to the emergency DC buses and supplies power for approx?

Answer 27

30 minutes.

Question 28

Hot Battery Bus Items. | acc-dcd-main

Answer 28

autotransfer, clock, courtesy light, DC indication 1 and 2, digital clock, main door, T-handle fire items.

Question 29

To turn the AC system off?

Answer 29

Inverter 2 must be switched off before Inverter 1.

Question 30

The 'Transfer Fail' light will illuminate when?

Answer 30

In emergency mode when auxiliary generators have not transferred to the emergency DC buses and they are being powered by the battery only.

Question 31

The primary electrical power for the EMB 120 is?

Answer 31

28 VDC

Question 32

The backup battery is charged by?

Answer 32

Emergency DC bus 2

Question 33

In normal flight the auxiliary generators power?

Answer 33

DC Bus 3

Question 34

The number 1 inverter is powered by?

Answer 34

DC Bus 2

Question 35

During engine start, the starter/generator is powered from?

Answer 35

Central DC Bus.

Question 36

Inverter number 2 is powered from?

Answer 36

Emergency DC Bus 1.

Question 37

What does the GCU do? | name 3 of the 6

Answer 37

Generator Control Unit- 1) initiates start cycles 2) cancels start cycle at 50% RPM. 3) regulates generator output 4) overvoltage protection 5) overcurrent protection 6) reverse current protection