T-38 Systems - Electrical Flashcards
Where does the T-38 get its AC electrical power?
from two 3-phase generators
When do the generators come online in the T-38? What is this range called?
43-48% RPM
Cut-In Range
What is the rated output of each generator (VAC)?
What is the frequency of each generators (Cycles per second)?
115/200 volts AC
320 to 480 CPS
What is the engine RPM range?
7920 at IDLE to 16500 RPM at MIL power
What is the generator gearbox shift range (percent)?
65-75%
If a generator goes “bad” the protection panel allows the other generator to pickup the load by using what?
the Cross-Over Relay
Where are the AC generators located in the aircraft?
On the airframe mounted gearbox
What will happen if the protection panel determines that there is a BUS fault?
It WILL NOT allow a crossover and
The generator of the affected bus is disconnected from its bus
When will the protection panel ALLOW a crossover?
When there is a generator problem and it is disconnected from the bus
The static inverter is powered by the Battery Bus when activated by what 3 possible situations?
Pressing either start button
Advancing either throttle to MAX
Placing the oygen/fuel quantity check switch to CHECK or TEST
In what 3 situations/tasks will the static inverter convert DC to AC power?
Providing ignition for the first engine start on the ground or in-flight
Operating right engine AC instruments (oil pressure and FF on the EED and hydraulic pressure) and both fuel quantity indicators during start of the first engine (**THIS IS THE REASON WE START #2 FIRST)
Power the oxygen quantity indicator (before AC power is available)
FOOLS Fuel Flow Oil Press Oxy Qty L&R Fuel Qty Start CNTRL
What 2 situations will activated the Static Inverter on the ground?
Pushing either start button or
Holding the fuel/oxygen check switch to Gage Test or Quantity Check
What 3 ways will activate the static inverter in-flight?
Pushing either start button
Placing either throttle in MAX
Holding the fuel/oxygen check switch to Gage Test or Quantity Check (operational check of the static inverted is performed by holding the OXY/FUEL check switch in GAGE TEST with oxygen quantity gage pointer moving to “zero”.
What are the 5 AC powered instruments (think liquids)?
Oil pressure (right only) Hydraulic pressure (right only) Fuel flow (right only) Fuel quantity indicators (both) Oxygen quantity indicator (only one)
All are powered by single-phase AC
While in-flight, you notice the MASTER CAUTION and HUD/MFD CAUTION alerts illuminated as well as the LEFT GENERATOR illuminated on the caution panel. What would you suspect? What is the corrective action?
Generator failure - good crossover
Adjust RPM of the engine with the failed generator to the opposite side of the shift range (65-75%)
While flying, you notice a MASTER CAUTION with RIGHT GENERATOR, RIGHT FUEL PRESS and ANTI-ICE lights illuminated. What would you expect? What is the corrective action?
Generator failure - no crossover
Turn generator switch off if reset fails
While advancing the power through 65-75% RPM you notice your MASTER CAUTION, HUD/MFD CAUTION alerts, and “LEFT GENERATOR” light illuminate. What would you suspect is the cause? What is the corrective action?
Gearbox failure to shift
Adjust power to functional range and get in the checklist
If both engines are still operating, simultaneous illumination of the MASTER CAUTION, HUD/MFD CAUTION alerts, generator and hydraulic caution lights is an indication of what? What is the corrective action?
An airframe mounted gearbox failure
Get in the checklist and shutdown the engine if excessive vibration exists
What would you expect is happening if the HUD is operating erratically and the flaps seem to take too long to extend and retract?
Partial electrical failure
Which light will fail with DC power failure?
the FIRE detection system lights become inoperative
What is the purpose of the Transformer Rectifier Units?
The TRUs convert AC power to DC power continuously and is tied to its respective AC bus
Each TRU and pick up the entire load
The TRU produces 28 volt DC power
What are the 3 DC busses?
Left Essential
Right Essential
Non-Essential
If both TRUs fail, which busses will be powered?
ONLY the left and right essential busses until the battery charge drops below 10 volts
What voltage is the battery? What is the minimum volts for the battery relay to close? How long will an 80% charged battery stay online?
24 volt
18 volt minimum to close the relay (relay must be closed for battery to charge) (once relay is close, will remain online until 10 volts)
An 80% charged battery should stay online approximately 15 minutes
What would be the probable cause of the XMFR RECT OUT light illuminating?
Both TRUs have failed
Landing Taxi Light including extension is controlled by which two busses?
Left AC and Right Essential DC
Which busses control FLAP positioning?
Right AC and Left Essential DC
Which bus controls nosewheel steering?
Right Essential DC
Which busses power the Warning, Caution and Indicator lights (WCA)?
Right VAC
Left Essential VDC
