Electrical

Question 1

What are the electrical sub systems?

Answer 1

(1) Electrical Power Management System (EPMS)
(2) Battery Subsystem
(3) Alternating Current (AC) Electrical Subsystem
(4) Direct Current (DC) Electrical Subsystem
(5) External Ground Power (EXT GND PWR) Subsystem

Question 2

What are the EPMS Components?

Answer 2

(1) Master Ignition (MSTR IGN) switch
(2) Electrical Load Centers (ELC) 1 and 2
(3) Circuit Breaker Panels (CBP) 1 and 2
(4) High Power Switching Modules (HPSM) 1 and 2
(5) Utility Relay Panel

Question 3

What are the battery sub system components?

Answer 3

(1) Battery

(2) Battery Charger

Question 4

What are the AC Electrical Subsystem Components?

Answer 4

(1) Two AC Generators (GEN) 1 and 2

(2) Two Generator Control Units (GCU) 1 and 2

Question 5

What are the DC Electrical Subsystem Components?

Answer 5

Two Transformer Rectifier Units (TRU) 1 and 2

Question 6

What are the External Ground Power Subsystem Components?

Answer 6

(1) External Power Receptacle
(2) External Power Monitor (EPM)
(3) External Power Sense Switch

Question 7

What do the HPSMs do?

Answer 7

(a) Power distribution
(b) Over current sensing
(c) Contactor switching logic for all AC, DC, and battery power requirements

Question 8

What does the CBPs do?

Answer 8

Provide hard wired, unswitched circuit protection to meet system demands, receives power directly from the HPSM buses which are behind the specific CBP.

Question 9

Where is CBP 1 and 2 located?

Answer 9

Behind the Pilot seat

Question 10

What do the ELCs do?

Answer 10

Receive power directly from the terminals on the front of the HPSMs and routes the required power to the using component or system and provides circuit protection.

Question 11

Where are the ELCs located?

Answer 11

ELC1 is located in the forward left EFAB

ELC2 is located in the forward Right EFAB

Question 12

What Is the A/c primary source of electrical power?

Answer 12

Two 45 KiloVolt Ampere (KVA), 3 Phase, 4 wire, 115/200 Vac, 400 Hz, air cooled, brushless AC generators

Question 13

How many volts is the DC Battery?

Answer 13

24 Volts

Question 14

During a total electrical failure, how long with the battery last?

Answer 14

At 80% charge, will supply the normal flight battery loads for a minimum of 12 minutes

Question 15

What do the GCUs do?

Answer 15

Manage the generator output, provides AC power to the HPSMs and disconnects the generator in the event of:
• Over voltage
• Under voltage
• Over current
• Under frequency
• Feeder fault between generator output and system load.

Question 16

Both Generators Fail/Complete Loss of Electrical Power.

Answer 16

GEN1 and GEN2 – reset pilots GEN reset panel
If conditions persist,
Land as soon as possible

Question 17

Single Generator and Single RTRU Failure

Answer 17

Affected GEN 1 or GEN 2 –rest pilots GEN reset Panel
If condition persists,
Land as soon as Practicable

Question 18

What do the TRUs do?

Answer 18

Convert 115 Vac, 3 Phase, 400 Hz power from the HPSM AC bus to regulated 28 ± 0.5 V DC and provide DC power to the Battery Bus.

Question 19

Dual TRU Failure

Answer 19

Land as soon as Possible

Question 20

In the event of a dual TRU failure what can be expected by the pilot?

Answer 20

(a) TADS/PNVS and HDUs will be inoperative.
(b) All navigational functions will be lost.
(c) Some primary flight information will be lost (altitude, heading and airspeed).
(d) FMC functions will be lost.
(e) Stabilator control will be lost.
(f) Primary crewstation lighting will be lost.
(g) Engine Anti-Ice will activate.
(h) The Keyboard Unit will be inoperative.
(i) The crew will be able to transmit and receive on the preset radio frequencies but will not be able to input new frequencies with the keyboard unit.
(j) WPs will be inoperative and the Weapons System will not be functional.
(k) The ECS will be inoperative.
(l) The ice detector will be inoperative.
(m) The left and right pitot heater will be inoperative.

Question 21

What is the note associated with GEN 2 failure?

Answer 21

NOTE
Failure or reset of generator 2 can result in BUCS FAIL caution and FMC DISENGAGE cautions and a loss of one or more FMC channels. After completing the Generator Fail emergency procedure (GEN RESET), reset the BUCS FAIL and the FMC DISENGAGE by re-engaging the affected FMC channels. If the BUCS FAIL is not associated with the GENERATOR FAIL or the reset, the pilot should assume other problems have occurred and complete the BUCS FAIL emergency procedure.