Electrical Systems Flashcards
Transfer relay 2A purpose and power source
Connects Gen 2 to Bus A
No. 2 supervisory panel ACR energized
Transfer relay 2B purpose and power source
Connects alternate generator to bus A
MEDC via Bus A control CB
Transfer relay 3A purpose and power source
Connects Gen 3 to Bus B
No. 3 supervisory panel ACR energized
Transfer relay 3B purpose and power source
Connects alternate generator to bus B
MEDC via Bus B Control CB
Transfer relay 4 purpose and power source
Gives external power priority over gen 4
GOB via external power control CB
Transfer relay 5 purpose and power source
Connects Gen 2 to Bus B
MEDC via GEN 4 TRNS CB
Transfer relay 6 purpose and power source
Connects Gen 3 to Bus A
MEDC via GEN 4 TRANS CB
Transfer relay 7 purpose and power source
Gives Gen 4 priority over the APU
FEDC via Gen 4 Aux control CB
Partial Load Monitoring (below 8,000ft)(single engine-driven Gen or APU gen only) what do you loose?
Sheds…
Feeders: 1,2,3
Eaters: galley power
Heaters: radiant heaters and side windshield defogging system
Activation: activate prop deice and or empanage deice in test or normal op modes What you loose H - HF2 U - UHF 2 A - ADF M - MB A - AP R - Radar I - INS 2
Load monitoring (APU Gen operation only above 8,000ft)
APU monitor control relay energized
- turns off No. 1A hyd pump
- deenergizes empennage deice control relay
- energized load monitor control relay turning off feeders, eaters, and heaters
Activation: automatically at the 8kft px switch
What is on FEDC?
B- command bell U- utility lights G- Gen 4 aux cont cb P- pitch lock reset I- IFF G- GOB G- GPS amp I- inverter power relay C- CDU R- RINU-Gs A- ADDU P- Peanut gyro
RINU-GS #1 MEAC/FEDC #2 BUS A / FEDC
Generator output
120v 400Hz 3 phase
(Three parts): PMG, DC excited generator, main generator
Battery
24v and 31 amps
TRs 1 and 2 max amp rating
TR 3
200 amps
150 amps
BUS A loss indications
Primary: 1 hyd press, No. 1 & 3 fuel boost pumps
Supporting: Elec power, No. 2 Gen off, no AP/RAWS, AP inop, copilot FDI Gyro flag
Bus B loss indications
Primary: no. 1A & 2 hyd press, no. 2 & 4 fuel boost pumps
Supporting: Elec power, no. 3 Gen off, fan out
MEAC BUS loss indications
Primary: R pilot htr out, pilot FDI gyro flag
Supporting: De-icing, AP/RAWS, HSI OFF flags
FEAC loss indications
Primary: L pitot htr out, stby attitude indicator OFF flag
Supporting: De-icing, AP/RAWS
Other: aural RAWS warning
MDC loss indications
Primary: no. 1& 2 hyd press, 1,2,3 & 4 boost pumps,
Supporting: Press system, fan out light, rack ovht ligjt landing gear indicators show barber poles, oil quantity indicators indicate 0, OAT gauge fails
MEDC ESS Feeder 2 loss indications
Lights: All lights inop
Supporting: AOA indicator OFF flag, ICS indicator lights inop, 9% power loss
MEDC ESS feeder 1 loss indications
Lights: none
Supporting: ICS inop, altimeter vibrators inop
3 ways to energize GOB In flight
1) select APU IN FLIGHT ARMING switch to ARM
2) Pull the GOB RELAY CB on FEDC
3) Lower the gear
ways to energize inverter power relay to get start DC and Start AC powered
1) inverter battery test switch to test
2) select engine
3) pull the power sensing cb on MEDC
Operation with One AC Generator
B: boost handle uncover U: utility lights positioned F: flashlight B: brief CP to turn off essential bus mon switch (for peanut gyro) V: VMC
What is on FEAC
R - RADALT E - EFDI P - pitot heat O - outflow valve S- standby gyro E - essential (red) instrument lights
What 3 things does the APU arming switch do
1: nose landing gear up lock switch is bypassed to energize the GOB
2: The APU load control valve is disabled
3: The APU scissor switch Relay is bypassed to allow APU operation during in-flight emergencies
Note: if switch positioned to ARM while on ground: ac and engine starting NA
What does blocking diode number 1 do?
Number 2?
1: allows current to flow from EXT MAIN to MEDC and prevents TR 3 from feeding MAIN DC should a malfunction occur elsewhere in The DC system.
2: connects FEDC and MEDC and the battery can be charger from any TR but prevented from supplying power to MEDC
What are the runaround relays? (5)
Runaround relay number 1 & 2
ESS AC BUS relay number 1 & 2
ESS AC BUS mon relay
They connect its bus or downstream feeder to an alternate power source if voltage drops to +- 85Vs
Manual load monitoring if the emp deice is needed above 8,000’, secure…
Any 3 fuel boost pumps
3 booster packages boost off
2 remaining hyd pumps
Cabin exhaust fan
We do this to prevent the APU from flaming out
If defending back through 8,000’ with the load mon circuits energized, the prop and emp deice must be turned off to denergize those circuits
APU power
GOB
Start motor: EXT MAIN
If used in flight: TR3 cb needs to be pulled prior to ON or START to deenergize MEDC so as to not burn up the diode. It allows only FEDC via the battery to power the motor (FE Job Aid 1-17)
SAM bus cb’s
S: Essential DC Feeder #3 powers SEDC
A: Essential DC Feeder #1: powers “armament” bus
M: Essential DC Feeder #2: powers MEDC lower
What does the ESS MON AC BUS switch do
Disconnects MEAC by removing ESS BUS MON relay and ESS relay number 1 ground
What does the Bus B Mon switch do?
Disconnects power from Gen 3 and the BUS B CONT cb to keep from powering transfer relay 3 (Bus B)
What are the three ESS AC Bus and their purposes?
1: ESS AC BUS mon relay: allows current to be secured to MEAC with ESS BUS MON switch
2: ESS AC BUS relay number 1: gives Bus A priority for powering MEAC
3: ESS AC BUS relay number 2: gives the runaround relays priority over Bus A for powering FEAC
Testing FEDC
Command Bell
Testing GOB
Oil quantity
Testing APU Ess bus
Doors light
Testing SEDC
Voltage guage
Testing SEAC
TIT gushes
